Motorola Network Solutions

M o t o r o l a H e a d e n d N e t w o r k S o l u t i o n s

D i g i t a l N e t w o r k S y s t e m s

Copyright © 2000 by Motorola, Inc.

All rights reserved.

No part of this publication may be reproduced in any form or by any means or used to make any derivative work (such as translation,

transformation or adaptation) without written permission from Motorola, Inc.

Motorola, Inc. reserves the right to revise this publication and to make changes in content from time to time without obligation on the

part of Motorola, Inc. to provide notification of such revision or change.

Motorola, Inc. provides this guide without warranty of any kind, either implied or expressed, including, but not limited, to the implied

warranties of merchantability and fitness for a particular purpose. Motorola, Inc. may make improvements or changes in the

product(s) described in this manual at any time.

MOTOROLA and the stylized M logo are registered trademarks and NETsentry is a trademark of Motorola, Inc.

Cisco is a registered trademark of Cisco Systems, Inc.

ProLiant is a registered trademark of Compaq Computer Corporation.

Netscape and Netscape Communicator are registered trademarks of Netscape Communications Corporation.

Rev Number Description Incorporated By Date

1.0 473294-001-99 First Release - Motorola Headend Network Solutions Seshadri Paravastu 8/10/00

Position Approved Date Document Title

Originator Seshadri Paravastu 8/10/00 Motorola Headend Network Solutions

Digital Network Systems101 Tournament DriveHorsham PA 19044

Document Number:

Revision Number:

473294-001-99

1.0

Motoro la Headend Network So lut ions

Con ten t s

Sect ion 1

I n t r oduc t i on

Scope .......................................................................................................................................1-1

Purpose.....................................................................................................................................1-1

Using This Manual .......................................................................................................................1-1

Related Documentation ................................................................................................................1-2

References ................................................................................................................................1-2

Document Conventions .................................................................................................................1-2

Sect ion 2

Ove r v i ew

Motorola Network Devices ............................................................................................................2-2

Device-to-Device Communication ...................................................................................................... 2-3

DAC2MPS Connection ............................................................................................................... 2-3

MPS* JAVA-enabled console connection ...................................................................................... 2-4

DLS2OM Connection ................................................................................................................. 2-4

DAC2OM Connection................................................................................................................. 2-4

DAC2IRT connection ................................................................................................................. 2-4

IRT2OM connection................................................................................................................... 2-4

RPD2DAC Connection................................................................................................................ 2-5

RPD2NC connection.................................................................................................................. 2-5

NC 1500 JAVA-enabled console connection ................................................................................ 2-5

NC2OM Connection................................................................................................................... 2-5

NC2DAC Connection ................................................................................................................. 2-5

NETsentry Connection.............................................................................................................. 2-6

Recovering the Electronic Program Guide (EPG) Data Feed .................................................................2-6

Using OM 1000 with an RS-530 Interface ......................................................................................... . 2-6

Using the OM 1000’s Ethernet Interface ......................................................................................... ... 2-7

Motorola Headend Broadcast Traffic............................................................................................. 2-10

Remote BOOTP Configuration .......................................................................................................... 2-10

Router Configurations for the Remote BOOTP............................................................................. 2-12

i ii ii ii i C o n t e n t s

Motoro la Headend Network S o lut ions

Sect ion 3

Netwo rk Con f i gu ra t i on E xamp les

Cisco Routers and Switches .......................................................................................................... 3-1

Ethernet Hubs and Switches ......................................................................................................... 3-1

The Network Cloud ...................................................................................................................... 3-2

Example Configuration 1 .............................................................................................................. 3-3

Configuration 1 Headend Parameters .................................................................................................3-5

DAC 6000 ................................................................................................................................3-5

OM 1000..................................................................................................................................3-5

RPD* ........................................................................................................................................3-5

IRT* ........................................................................................................................................3-6

Configuration 1 Traffic Types .............................................................................................................3-6

Central Router (Cisco 3640) ......................................................................................................3-6

Cisco 2600 Series Router Configuration ......................................................................................3-7

Example Configuration 2 .............................................................................................................. 3-8

Configuration 2 Headend Parameters ...............................................................................................3-10

DAC 6000 ..............................................................................................................................3-10

OM 1000................................................................................................................................3-10

RPD* ......................................................................................................................................3-11

IRT* ......................................................................................................................................3-11

Configuration 2 Traffic Types ...........................................................................................................3-11

Special Router Configuration ....................................................................................................3-13

Cisco 2600 Series Router Configuration ....................................................................................3-13

Example Configuration 3 ............................................................................................................ 3-13

Configuration 3 Headend Parameters ...............................................................................................3-15

DAC 6000 ..............................................................................................................................3-15

OM 1000................................................................................................................................3-15

RPD* ......................................................................................................................................3-16

IRT* 3-16

Configuration 3 Traffic Types ...........................................................................................................3-16

Special Router Configuration ....................................................................................................3-18

Cisco 2600 Series Router Configuration ....................................................................................3-18

C o n t e n t s i i ii i ii i ii i i


Appendix A

WAN L ink Capac i t y Cons ide ra t i ons

Recommended Data Rate Settings..................................................................................................A-2

Configuration Specific Link Capacity Budget and Constraints..............................................................A-3

WAN Link Capacity Recommendations for Configuration 1...................................................................A-4

Configuration Recommendations ....................................................................................................... A-4

Constraints ..................................................................................................................................... A-4



Constraints and Recommended Operational Features for Configuration 2 to Operate on a 56 Kbps WAN Link ................................................................................................................................. A-5



Appendix B

Route r Con f i gu ra t i on

Cisco 2600 Series ...................................................................................................................... B-1

Cisco 3600 Series ...................................................................................................................... B-2

Cisco 3640 Central Router Configuration ....................................................................................... B-3

Cisco 2621 Router Configuration Information.................................................................................. B-4

Cisco 2621 FR Router Configuration Information ............................................................................. B-5

Cisco 2900 Switch...................................................................................................................... B-7

NTP Client Configuration for the DAC 6000 ....................................................................................B-10

Appendix C

Netwo rk Cons ide ra t i ons

IP Address Space Considerations .................................................................................................. C-1

Classful IP Addressing ................................................................................................................ C-1

Primary Address Classes .................................................................................................................. C-2

Class A Networks (/8 Prefixes) .................................................................................................. C-2

Class B Networks (/16 Prefixes) ................................................................................................ C-3

Class C Networks (/24 Prefixes) ................................................................................................ C-3

Other Classes........................................................................................................................... C-3

Dotted-Decimal Notation ........................................................................................................... C-3

Subnetting ............................................................................................................................... C-4

Extended-Network-Prefix............................................................................................................ C-5

Subnet Design Considerations ................................................................................................... C-6

Network Link Considerations............................................................................................................. C-7

Frame Relay ............................................................................................................................. C-8

i vi vi vi v C o n t e n t s


High Capacity Terrestrial Digital Service (T1) .....................................................................................C-9

CSU/DSU .................................................................................................................................C-9

Fiber Channel Networks ..................................................................................................................C-10

Ethernet Traffic ........................................................................................................................ C-10

Motorola Headend Ethernet Traffic ...................................................................................................C-11

Switched Ethernet ..........................................................................................................................C-11

Abb re v i a t i ons and Ac ronyms

F i gu res

Figure 2-1 Multi-Headend Control System ....................................................................................... 2-1

Figure 2-2 RS-530 interface PID filtering solution ............................................................................ 2-7

Figure 2-3 Ethernet PID filtering solution ....................................................................................... 2-8

Figure 2-4 Sample Ethernet switch configuration ............................................................................. 2-9

Figure 2-5 Sample remote BOOTP traffic flow ................................................................................ 2-11

Figure 3-1 Example Configuration 1 ............................................................................................... 3-4

Figure 3-2 Example Configuration 2 ............................................................................................... 3-9

Figure 3-3 Example Configuration 3 ............................................................................................. 3-14

Figure C-1 Two-level Internet address structure ............................................................................... C-1

Figure C-2 Principle classful IP address formats .............................................................................. C-2

Figure C-3 Dotted-decimal notation............................................................................................... C-3

Figure C-4 Subnet address hierarchy ............................................................................................. C-4

Figure C-5 Subnetting reduces the routing requirements on the network .............................................. C-5

Figure C-6 Extended-network-prefix ............................................................................................... C-5

Figure C-7 Subnet mask .............................................................................................................. C-6

Figure C-8 Extended-network-prefix length ..................................................................................... C-6

Figure C-9 Multiplexer CSU/DSU .................................................................................................. C-9

C o n t e n t s vvvv


Tab les

Table 2-1 Motorola network device numbers ....................................................................................2-2

Table 2-2 Network device pairs .....................................................................................................2-2

Table 2-3 Single network devices...................................................................................................2-3

Table 3-1 Configuration 1 traffic types ...........................................................................................3-6

Table 3-2 Configuration 2 traffic types ......................................................................................... 3-12

Table 3-3 Configuration 3 traffic types ......................................................................................... 3-17

Table A-1 Minimum Recommended Link Capacity..............................................................................A-1

Table A-2 Device Pair Data Rate Setting Recommendations ................................................................A-2

Table A-3 DLS Data Rates.............................................................................................................A-6

Table A-4 Code upgrade time using an HCT on a 56 Kbps link ..............................................................A-6

Table C-1 Dotted-decimal ranges for each address class................................................................... C-4


Sect ion 1

I n t r oduc t i on

Motorola’s digital cable headend architecture uses standard Transmission ControlProtocol/Internet Protocol (TCP/IP) protocols, User Datagram Protocol/Internet Protocol(UDP/IP), and Ethernet interfaces to interconnect headend devices. This approach provides alarge amount of flexibility to enable system features such as remote-headend andmultiple-headend control.

This document explains the network requirements for interconnecting Motorola headendequipment, and provides information necessary for setting up and maintaining the IP network.Various considerations and networking approaches are discussed, including network setup,configuration, and operation. Finally, three typical system configurations are presented asexamples of how to configure the IP network.

Scope

This document describes general network configurations that are currently operational in thefield. It covers the setup and configuration of remote headends and their correspondingthird party networking equipment, from the Motorola headend to the start of thecommunication line equipment. You must consult your communication line provider for setupand configuration information about their equipment.

Purpose

The purpose of this document is to provide the following information for Motorola headendequipment users:

�� An overview of Motorola network elements within a headend

�� Examples of recommended network configurations for different applications

�� Examples of recommended router/ switch configuration settings

�� A general overview of IP addressing and port assignments

Us ing Th i s Manua l

The following sections provide information on Motorola’s Headend Network:

Section 1 Introduction provides the scope and purpose of this manual, as well as related documentation, references, and document conventions

Section 2 Overview describes the functions of the Motorola Headend Network

Section 3 Network Configurations Examples provides sample Motorola Headend Network configurations

Appendix A WAN Link Capacity Considerations provides WAN link capacity considerations and recommendations

Appendix B Router Configuration provides sample results of running a config command on the routers used in the example configurations

Appendix C Network Considerations provides a general overview of IP addressing

Abbreviations and Acronyms

Abbreviations and Acronyms provides the full spelling of the abbreviations and acronyms used in this manual

1111 ---- 2222 I n t r o d u c t i o n


Re la ted Documenta t i on

The following documents provide additional information on products referenced in this manual:

�� Commander 6 Upconverter Model C6U Installation Manual

�� Commander 8 Upconverter Model C8U Installation Manual

�� DAC 6000 Operation Guide

�� HCT 1000 Headend Configuration Tool User Guide

�� IRT 1000/2000 Integrated Receiver Transcoder Installation and Operation Guide

�� MPS Modular Processing System Mainframe Installation & Operation Manual

�� NC 1500 Network Controller Installation and Operation Guide

�� OM 1000 Out-of-Band Modulator Installation and Operation Guide

�� RPD Return Path Demodulator Installation and Operation Guide

Re fe rences

Semeria, Chuck. 1996. “Understanding IP Addressing: Everything You Ever Wanted to Know.” NSD Marketing, 3Com Corporation.

Gibson, Jerry D. 1996. The Communications Handbook. CRC PRESS.

Stevens, W. Richard, and Wesley, Addison. 1994. “TCP/IP Illustrated”, Volume 1.

Document Conven t i ons

Before you begin, familiarize yourself with the stylistic conventions used in this manual:

Bold type Indicates text that you must type exactly as it appears or indicates a default value

SMALL CAPS Denotes silk screening on the equipment, typically representing front- and rear-panel controls and input/output (I/O) connections, and LEDs

* (asterisk) Indicates that several versions of the same model number exist and the information applies to all models; when the information applies to a specific model, the complete model number is given

Italic type Denotes a displayed variable, a variable that you must type, or is used for emphasis

Courier font Indicates text displayed on a graphical user interface (GUI)


Sect ion 2

Ove r v i ew

A typical Multi-Headend Control System (MHCS) employs a Digital Addressable Controller,DAC 6000 to control a number of devices located in remote headends. This requires Wide AreaNetworks (WAN) connectivity between the DAC 6000 and each remote headend. Thisconnectivity allows two-way communications between devices on different Ethernet networks.These networks may be physically and logically the same (for example, a bridged network), orthey may be separate networks or sub-networks (for example, a routed network). Figure 2-1illustrates a typical MHCS:

F igure 2 -1

Mul t i -Headend Contro l System

DAC 6000

DLS

KLS ethernet

Telco return

Applicationservers

Analogservicesfeed

Eth

erne

t

Ethernet

Ethernet

Ethernet

Headend #0

Headend #1

Headend #N-1

Headend #N

L-bandfeed

L-bandfeed

OM 1000

RPD 1000

NC 1500

C6U

RF combiner

KLS

Network

Modembank

Diplex filter

RF

RF

RF

RF

DCT *

TV

RF networks

IRT 1000

2222 ---- 2222 O v e r v i e w


Communications between devices on these distributed headends involves many differentprotocols. The following list includes many of the protocols used within the Motorola headend:

Physical 802.3 (10 Mbps Ethernet) and 802.3u (100 Mbps Fast Ethernet)

Data Link IEEE 802.3 (MAC) and 802.2 (SNAP)

Network IP, ICMP (IP Error Reporting), and ARP

Transport UDP, TCP

Session RPC

Application SNMP, SNTP, NTP, Telnet, FTP, DNS, BOOTP, TFTP, Application Specific

There are a number of application-specific protocols used by pairs of Motorola Headend devicesto facilitate the communication of special messages between them. For example, the DAC 6000sends messages to the Modular Processing System (MPS*) using a special messaging protocol.These protocols require the correct assignment of UDP/TCP port values based on uniquenumber assignments for each headend device. The correct assignment of these port values isdescribed in the next subsection.

Moto ro la Ne two rk Dev i ces

Communications between headend network devices employ one of two transport types —connection oriented Transmission Control Protocol (TCP) or connectionless User DatagramProtocol (UDP) — during a particular phase of operation. Each network device may usesinglecast, multicast, or broadcast (or a combination of the three) to communicate with otherpeers.

Each Motorola network device is assigned a unique number, which is used to compose a uniquedevice-to-device UDP/TCP port number that is used in inter-device communications, asillustrated in Table 2-1:

Tab le 2 -1

Motoro la network dev ice numbers

Network E lement DAC

6000

IRT* NC

1500

OM 1000 RPD* DLS MPS*

Network Number 51 54 56 57/67* 58 59 60 *67 is used for TCP

Table 2-2 describes each network device pair and the type of traffic they generate or receive:

Tab le 2 -2

Network dev ice pa i rs

Network Pair T ransport Default Port

Number

IP Address Mode Comment

DAC2IRT TCP 5154 Singlecast DAC 6000 to IRT* messaging

DAC2MPS UDP 5160 Singlecast DAC 6000 to MPS* messaging

DLS2OM UDP 5957 Broadcast Code download operation

DAC2OM1 UDP 5157 Singlecast Downstream messaging

O v e r v i e w 2222 ---- 3333


Network Pair T ransport Default Port

Number

IP Address Mode Comment

DAC2OM2 TCP 5167 Singlecast During the OM 1000 boot up

RPD2DAC UDP 5851 Singlecast Polling data

IRT2OM UDP 5457 Multicast EPG data stream (IP layer Broadcast, MAC layer Multicast)

NC2OM UDP 5657 Singlecast Interactive operation

RPD2NC UDP 5856 Singlecast Interactive operation

The names in the Network Pair column combine the sender and receiver names of each networkpair. For example, DLS2OM means that the Download Server (DLS) is the sender and theOut-of-Band Modulator, OM 1000 is the receiver. This convention is used throughout thisdocument for UDP ports for the Motorola headend network devices. For the DLS2OM example,the UDP port is 5957 — where 59 is always assigned to the Download Server, DLS 1000, and 57is always assigned to the OM 1000. The OM 1000 also uses port 5167. This is used for the TCPconnections between the DAC 6000 and the OM 1000. This TCP connection is used to passcontrol and status messages.

Other single network devices also support the network devices listed in Table 2-2.Table 2-3 lists each single network device and the type of traffic each generates or receives:

Tab le 2 -3

S ing le network dev ices

Network E lement Transport IP Address Mode Comment

HCT 1000 UDP Broadcast and Singlecast

During network device startup, BOOTP replies are singlecast to the Gateway address and are broadcast on the network if there is no Gateway address field provided in the BOOTP request.

TFTP traffic is singlecast.

MPS* JAVA™-enabled console

UDP Singlecast JAVA applet uploaded from the MPS* HTTP server to a web browser. This is used to configure the MPS*.

NC 1500 JAVA-enabled console

UDP Singlecast JAVA applet uploaded from the NC 1500 HTTP server to a web browser. This is used to configure the NC 1500.

NETsentry™ TCP/UDP Broadcast and Singlecast SNMP Network Manager—receives SNMP traps and can poll SNMP capable devices. Traffic is broadcast during network discovery.

Device-to-Device Communication

The following sections describe the network device pairs listed in Table 2-2, including the typesof connections and the information passed between the devices.

DAC2MPS Connect ion

The Digital Addressable Controller, DAC 6000, sends commands to the Modular ProcessingSystem (MPS*) on UDP port 5160. These commands control MPS decryption, remultiplexing,message insertion, and encryption processing. The DAC 6000 sends commands to a particularMPS’s IP address (singlecast addressing).

2222 ---- 4444 O v e r v i e w


MPS* JAVA-enabled console connect ion

The MPS* is configured using a JAVA-enabled console. The JAVA-enabled console is an appletuploaded to a JAVA-enabled browser from an HTTP server running within the MPS. TheJAVA-enabled console applet uses SNMP over UDP to send set and get messages to the SystemController in order to read or write configuration settings within the MPS’s ManagementInformation Base (MIB).

Netscape Communicator® version 4.5 or later is required to properly run the JAVA-enabledconsole. Remote configuration of the MPS is possible over WAN connections, provided HTTPtraffic passed through the connecting routers. Most routers pass HTTP traffic by default.

DLS2OM Connect ion

The DLS 1000 sends code objects (digital set-top firmware, Electronic Program Guide [EPG]applications, and interactive applications) and download control messages to an OM 1000 onUDP port 5957. This information is typically sent using the network’s broadcast IP address.

DAC2OM Connect ion

The DAC 6000 sends messages to an OM 1000 on UDP port 5157 using UDP. When theOM 1000 initiates its boot process, it exchanges registration process information with theDAC 6000 on TCP port 5167 using TCP.

DAC2IRT connect ion

The DAC 6000 exchanges information with an Integrated Receiver Transcoder, IRT 1000/2000using Remote Procedure Calls (RPC). RPC is a Session Layer protocol that utilizes TCP at theTransport Layer. The IRT* uses the Port Mapper process running on the DAC 6000, whichassigns a dynamic TCP port for temporary use in communicating with the IRT*. The DAC 6000can then use RPC to control the IRT* using the assigned UDP port. The Port Mapper process isreached on TCP Port 111.

IRT2OM connect ion

In a nationally controlled headend, the IRT* acquires the National Control and Service (NC&S)stream (also known as the TCI Access Control [TAC] stream) from a Headend In The Sky(HITS) satellite feed. The IRT* sends the TAC stream information to the OM 1000 over UDPport 5457. This information is sent using an IP broadcast address, and a defined MulticastMedia Access Control (MAC) address. The IP broadcast address is not mapped into a broadcastMAC address. This allows the address to be directed to only the OM 1000s on the plant.

The NC&S information delivered to the OM 1000 makes up the Out-Of-Band (OOB) transportstream. This is an MPEG compliant transport stream. It contains EPG data, Digital ConsumerTerminal (DCT*) authorizations, code objects, and various control channel messages (forexample, virtual channel tables (VCTs), system time, and DCT* configuration and initializationinformation).

On a locally controlled system, where the DAC 6000 is controlling the system, a primary IRT*

receives the same NC&S stream. However, an OM 1000 filters out all but the EPG data fromthis stream. All other OOB information comes from the DAC 6000 and/or the DigitalAddressable Network Interface Server.

O v e r v i e w 2222 ---- 5555


RPD2DAC Connect ion

The Return Path Demodulator, RPD 1000 receives and demodulates up to six separate QPSKupstream signals each carrying Asynchronous Transfer Mode (ATM) cells at 256 Kbps.DigiCipher II (DCII) upstream messages are encapsulated into ATM Adaptation Layer 5Protocol Data Units (PDUs) prior to being broken up into 48 byte ATM cells. The RPD*

aggregates these six channels of information into a single Ethernet frame. These bit streamscontain the poll buffer contents of the DCT*s on the plant. The RPD* sends DCT* poll responsesback to the DAC 6000. The RPD* transmits this data using UDP port 5851 with appropriatedestination IP address. This connection is only used on non-interactive systems, where the DAC6000 is the destination host for the RPD*.

In interactive systems, the RPD* is configured to send received data to the destination IPaddress of the NC 1500, essentially making this a RPD2NC connection. The NC 1500 decideswhether the traffic returned by the RPD* is interactive traffic to be sent to the appropriateapplication server or poll data to be routed back to the DAC 6000. The NC 1500 uses the sameUDP port (5851) to pass poll data back to the DAC 6000.

RPD2NC connect ion

RPD*s receives interactive upstream traffic and polling data from the DCT* population. TheRPD*s encapsulate the upstream data into Ethernet frames using UDP over IP. The RPD* s areconfigured to transmit the data directly to the NC 1500’s IP address. The NC 1500 determines ifthe packets contain polling responses or interactive traffic. It then forwards poll data directly tothe DAC 6000 and sends interactive traffic to the appropriate application server.

Each RPD* in the system is configured to transmit its Ethernet traffic to the NC 1500 usingSinglecast IP. The UDP port used is 5856.

NC 1500 JAVA-enabled console connect ion

The NC 1500 JAVA-enabled console is an applet uploaded from an internal HTTP server to aWeb Browser such as Netscape Communicator� Version 4.5 or later. The console allows users tosetup, configure, and control the NC 1500. The console connection uses the SNMP protocol ontop of the UDP transport layer. Remote configuration of the NC 1500 is possible over WANconnections if HTTP traffic is passed through the connecting routers. Most routers pass HTTPtraffic by default.

NC2OM Connect ion

The NC 15000 uses an OM 1000 path for interactive downstream operation. The NC 1500communicates with the OM 1000 on the UDP port 5657 using singlecast addressing.

NC2DAC Connect ion

The NC 1500 to DAC 6000 connection performs the function of the system return path(RPD2DAC) connection, except that it is only used on interactive systems. The NC 1500 uses thesame UDP port (5851) and addressing mode as a RPD* and passes polling traffic through to theDAC 6000 untouched. The DAC 6000 handles data from the NC 1500 as if it is from anRPD*.

2222 ---- 6666 O v e r v i e w


NETsentry Connect ion

NETsentry is Motorola’s headend management system. It uses SNMP protocol on top ofUDP/TCP transports. The use of UDP or TCP transport depends on the particular networkoperation.

Recove r i ng t he E l ec t r on i c P rog ram Gu ide (EPG) Da ta Feed

The National Control & Signaling (NC&S) stream is delivered to a primary IRT* as part of anisochronous data service. The NC&S stream is “tunneled” into an elementary Packet Identifier(PID) stream that is part of this service. The IRT* recovers the tunneled control stream, which isan entire transport stream destined for the OOB in nationally controlled systems. In locallycontrolled systems, it is often necessary to pass only the EPG data feed from this stream to theOOB. Therefore, the NC&S stream is normally sent to an OM 1000 to filter all but the EPG datafrom the stream. In order to transmit the recovered NC&S stream onto the Local Area Network(LAN), the IRT* encapsulates it into IP datagrams and transmits them over the Ethernet. Thisdata is sent as an IP layer broadcast, but MAC layer multicast addresses are used within theEthernet frames so that one or many OM 1000s on the LAN can receive the information.

One significant advantage of filtering the NC&S stream is that the 1.5 Mbps of capacity thatwould normally be required can be reduced considerably. In most cases, the EPG data feed onlyutilizes around 100 Kbps of network capacity.

There are two ways to pass EPG data (only) received as part of the NC&S stream—using anOM 1000 with an RS-530 interface, or using an OM 1000’s Ethernet interface. In each case, anOM 1000 is used to filter all but the EPG data stream(s). Motorola recommends using anOM 1000 with an RS-530 interface over using an OM 1000’s Ethernet interface. The advantagesand disadvantages of each approach are explained below.

Using OM 1000 with an RS-530 Interface

Motorola recommends using an OM 1000 with an RS-530 serial interface to receive the tunneledcontrol stream and pass only the EPG data. The primary IRT* is configured to detunnel theNC&S stream and route this transport stream out of its RS-530 interface to an OM 1000. AnOM 1000 equipped with the optional RS-530 DTE interface is necessary for thisimplementation. The OM 1000 is configured to pass only the EPG data PID stream(s). TheOM 1000 is also configured to perform an IP broadcast off the EPG data PID stream onto theOperations, Administration, Maintenance, and Provisioning (OAM&P) Ethernet. This allowsmultiple OM 1000s to receive the same EPG data. If the broadcast data is sent to remotelylocated headends, the router must be set-up to forward the broadcasts to each headend.

The advantage of this approach is that only EPG data is transmitted onto the OAM&P LAN.Otherwise, the entire 1.5 Mbps NC&S stream would be transmitted onto the Ethernet, which isobviously an inefficient use of network capacity. Keep in mind that a dedicated OM 1000 isrecommended (although not required) for this approach.

O v e r v i e w 2222 ---- 7777


To set up this configuration, you must complete the following steps:

1 Configure the primary IRT∗ 1000/2000 to extract the NC&S data from the isochronous dataservice.

2 Select RS-530 at the HITS interface menu of the IRT.∗

3 Enable the RS-530 interface on the OM 1000.

4 Route the RS-530 data to the Ethernet output.

5 Configure the Ethernet Output to broadcast this data onto the local LAN.

6 Turn on PID Filtering of all input PID streams.

7 Select the EPG Data PID stream to pass.

Figure 2-2 illustrates the RS-530 interface solution:

F igure 2 -2

RS-530 in ter face P ID f i l te r ing so lut ion

DAC 6000

DLS DANIS

Router

OM 1000 is set up tofilter all PIDs and passonly EPG data PIDs.

Network

RF

QPSK @ IF2 Mbps

10 Base T Ethernet

PID stream containingEPG data is sent out onLAN as an IP broadcast.

RS-530 delivers thede-tunneled NC&Sstream. This is anentire OOB multiplex.

Router configuredto send IP broadcastcontaining EPG datato other remote headends.

IRT 1000 OM 1000

OM 1000

Using the OM 1000’s Ethernet Interface

Although not as desirable as the previous approach, you can also configure the primary IRT* tosend the detunneled NC&S stream to the Ethernet. In this case, the entire NC&S stream will betransmitted onto the Ethernet, so it is recommended that an Ethernet switch be used tosegment this traffic from the OAM&P LAN.

To set-up this configuration you must complete the following steps:

1 Configure the primary IRT * to extract the NC&S data from the isochronous data service.

2 Select Ethernet at the HITS interface menu.

3 Define the Ethernet as a logical input port on the OM 1000.

4 Define the Ethernet as a logical output port on the OM 1000.

2222 ---- 8888 O v e r v i e w


5 Route the Ethernet input data to the Ethernet output port.

6 Configure the Ethernet output to broadcast this data onto the local LAN.

7 Turn on PID filtering of all input PID streams.

8 Select the EPG Data PID stream to pass and configure the switch to block the other traffic.

Figure 2-3 illustrates the Ethernet PID filtering solution:

F igure 2 -3

E thernet P ID f i l te r ing so lut ion

DAC 6000

DLS DANIS

OM 1000

OM 1000

Router

Router

IRT 1000

TVGI feed filtered from the NC&Sstream by the OM 1000, typically asingle PID at 100 Kbps or less; the

TVGI stream passes through theEthernet switch to the main Ethernet.

Detunneled 1.5 Mbps NC&S streamgenerated at HITS uplink, extracted bythe IRT and multicast to the OM 1000through a dedicated 10 Base T Ethernet.Contains the TVGI feed as well as otherHITS control streams.

Network

RF fromsatellite dish

10 Base T Ethernet

The Ethernet switchblocks the 1.5 Mbpsstream which ismulticast from theIRT to the headend’smain Ethernet.

10 Base T Ethernet

Cable plant

Ethernetswitch

Ethernet switches pass IP broadcasts and multicasts by default. Therefore, you must configurethe Ethernet switch to prevent the primary IRT’s IP multicast data from being passed to theOAM&P. The switch will still pass the OM 1000’s broadcast data (containing the filtered EPGdata feed) by default. Figure 2-4 illustrates a sample Ethernet switch configuration:

O v e r v i e w 2222 ---- 9999


F igure 2 -4

Sample Ethernet sw i tch conf igurat ion

Catalyst 1900 - Port 24 Configuration

Built-in 10Base-T

802.1d STP State: Forwarding Forward Transitions: 1

--------------------Settings------------------

[D] Description/name of port

[S] Status of port Suspended-no-linkbeat

[I] Port priority (spanning tree) 128 (80 hex)

[C] Path cost (spanning tree) 100

Catalyst 1900 - Port 24 Addressing

Address : Unaddressed

--------------------Settings------------------

[T] Address table size Unrestricted

[S] Addressing security Disabled

[U] Flood unknown unicasts Enabled

[M] Flood unregistered multicasts Enabled

Restricted static address definitions:

Enter address (6 hex octets: hh hh hh hh hh hh): 00 00 F8 01 AF 02 [MAC address of the IRT toblock data from *]

Enter the source ports allowed to send to this address.

Enter port numbers: 23

Catalyst 1900 - Port 24 Addressing

Address : Restricted 00-00-F8-01-AF-02

Accepted source ports: 23

2222 ---- 1 01 01 01 0 O v e r v i e w


Moto ro la Headend B roadcas t T ra f f i c

Motorola headend broadcast traffic primarily consists of Entitlement Management Message(EMM) broadcasts, Bootstrap protocol (BOOTP) requests from clients, code download traffic,and network time broadcasts. This broadcast traffic is blocked by routers on the headend bydefault. You need to configure routers to pass broadcast traffic. This can be accomplished onCisco� routers by configuring IP helper addresses. An IP helper address can be configured forthe specific interface to pass the TFTP, BOOTP, Time Service, and DNS datagrams by default.IP helpers are also used to map one network broadcast to another network's broadcast address.IP filters can be configured to block any traffic that should not be passed to other networks.

To pass through specific UDP broadcasts, configure a global IP forward on the router for thespecific UDP port number, as shown in the example below:

Global conf igurat ions Comment

# interface ethernet 0/0 Forwards UDP packets on port 5157 — DAC2OM

# ip forward UDP 5957 Forwards UDP packets on port 5957 - DLS2OM

Internet speci f ic conf igurat ions Comment

# interface ethernet 0/0 Ethernet interface 0 port 0

# ip helper-address 192.2.2.2 Any broadcasts on this interface port will be sent to 192.2.2.2 IP

Refer to Section 3, Network Configuration Examples, for more details on the routerconfigurations for each of the example configurations in this document.

Remote BOOTP Configuration

All of Motorola’s digital headend equipment uses the Internet BOOTP protocol in order toexecute operational code upgrades in the field. The following device's code images can beupgraded in the field using the Headend Configuration Tool’s HCT 1000 BOOTP Server:

�� OM 1000

�� RPD*

�� IRT*

�� NC 1500

�� MPS*

When any of these devices initialize or power cycle, the device's BOOTP Client requests an IPaddress by sending a BOOTP Request (a MAC broadcast) with 'BOOTP server' on port 67 as thedestination. When initializing with the self-boot option, the client device times out waiting for areply. It then initializes itself from the information stored in its NVRAM. The BOOTP server(the HCT 1000) receives the request and generates a 'BOOTP reply' with an IP address andsends it as a broadcast if no gateway address is set in the BOOTP request. If the gatewayaddress is non-zero, the BOOTP server sends the reply singlecast to the gateway address. Therouter sets the gateway address if the BOOTP requests go through routed networks.

If the BOOTP client receives a valid BOOTP response, the BOOTP file-of-files name is extractedfrom the reply. If the name of the BOOTP file is different from the name of the BOOTP file lastloaded, or if no previous BOOTP file was saved in NVRAM, a TFTP request is generated to the

O v e r v i e w 2222 ---- 1 11 11 11 1


BOOTP Server. Then, using "get" and "set" commands, the new code image and fileconfigurations on the BOOTP server is downloaded to the client device, singlecast addressed.

Figure 2-5 illustrates the BOOTP flow for the example network configurations discussed in thisdocument:

F igure 2 -5

Sample remote BOOTP t ra f f ic f low

MAC

MAC+IP

Address

BOOTP Client Routed Network BOOTP Server

Client sendsa broadcastBOOTP request

Router broadcasts the replyto the client network

BOOTP server buildsa reply and sends it tothe Gateway addressas singlecast

1

2

3

4

6

5

7

Singlecast TFTP traffic betweenBOOTP server and BOOTP client

The following steps occur during a remote BOOTP:

1 The client sends a BOOTP request (as a MAC layer broadcast) that includes its MACaddress.

2 The router forwards the BOOTP request to the BOOTP server using the IP helperconfiguration on the remote router. The remote router also includes its IP address in theGateway IP address field of the forwarded request. The router sends this forwarded requestas a singlecast to the BOOTP server.

3 The BOOTP server builds the BOOTP reply and sends it to the Gateway IP address.

4 The router builds an Address Resolution Protocol (ARP) table from the reply information(MAC to IP Mapping).

5 The router forwards the BOOTP reply to the client as a broadcast.

2222 ---- 1 21 21 21 2 O v e r v i e w


6 The client recognizes and receives the BOOTP Reply by observing the MAC address andprotocol.

7 The BOOTP server downloads (singlecast) the software and configuration files to the clientusing TFTP.

Router Conf igurat ions for the Remote BOOTP

You need to configure the IP helper-address on the remote routers closest to the BOOTP clientsin order to pass the broadcast BOOTP traffic. An IP helper address can be configured for therouter interface that receives the client's BOOTP requests as shown below:

Interface speci f ic router conf igurat ion Comment

# interface ethernet 0/0 Select Ethernet interface 0, port 0

# ip helper-address 192.168.1.12 Any broadcasts on this interface port will be sent to IP 192.168.1.12, which is the BOOTP server.

CAUTION!

Configuring the IP helper address also forwards BOOTP, TFTP, DNS, Time Service, andNetBios name server datagrams by default. There may be situations where these datagrams needto be filtered to prevent ingress into other networks. This can be accomplished via setting up IPfilters. IP filters can to be configured to prevent broadcast traffic ingress through the remoterouter into the frame relay and into the OAM&P network. For instance, if a Network TimeProtocol (NTP) server is configured on the remote plant and the remote router is configured withan IP helper address, the NTP broadcasts ingress back into the OAM&P network. To prevent thisfrom happening, you need to configure the remote router (near the local NTP server) with thecommand IP filter UDP 123 which will filter the UDP broadcasts for network time, as shown inthe example below:

Router Conf igurat ion Comment

ip filter UDP 123 Network time UDP datagrams will be filtered.


Sect ion 3

Ne two rk Con f i gu r a t i on E xamp l e s

While there are many possible network configurations, all networks have certain commonattributes. This section contains three examples of typical Motorola headend networkconfigurations. Each configuration attempts to provide an efficient, scalable, and manageabledistributed network system that can be modified to meet specific needs. Some common elementsof all three examples are:

�� Ethernet switches are used to increase efficiency by isolating traffic to nodes that arepassed.

�� Network routers are configured with IP helper addresses so specific broadcast traffic canpass through.

�� IP addressing settings for all Motorola Network Elements are the same for each example.

Cisco 2600 and 3600 series modular access routers are recommended for the three exampleconfigurations discussed here. These routers were used in Motorola Broadband SystemIntegration labs to verify the configurations described in this document. For further details onCisco router options, refer to Appendix B, Router Configuration.

The example networks shown here are class C networks. Please note that the IP addressingschemes and router addresses detailed here are intended to serve only as guidelines. You mayneed to use different IP addresses to suit your configurations.

C isco Rou te r s and Sw i t ches

The sample network headend configurations in this document use Cisco 3600 and 2600 seriesrouters. The Cisco 3640 is an enterprise router used as the central router in the samplesbecause it provides the needed throughput and expandability. It is important to realize that thecentral router has to send traffic to multiple remote networks — this means the trafficgenerated at the output port is generally many times greater than that seen by routers atremote sites. The remote routers in the sample networks are Cisco 2600 series routers. They donot need to be as powerful as the Cisco 3600 series routers because of their location in thenetwork. Appendix B, Router Configuration, provides more information about the Cisco routersused in the sample networks

Motorola has tested these routers in the network headend configurations that follow. This doesnot preclude the use of other vendor’s routers, but the features and command syntax may varyfrom those described in this document.

Cisco 2924 switches were also used in the following network configurations. However, the needto use these devices depends on the location and number of headend devices in the particularconfiguration. The next section explains how switches can help segment the network andimprove traffic flow.

E the rne t Hubs and Sw i t ches

In the sample headend network diagrams that follow, there are blocks labeled “hub/switch.”This indicates that either a hub will suffice, or an Ethernet switch is required. A hub is anetwork device that allows devices to be interconnected to the same network segment (forexample, a physical wire). Hubs regenerate the incoming signals, but they employ no routing

3333 ---- 2222 N e t w o r k C o n f i g u r a t i o n E x a m p l e s


intelligence. A hub simply forwards received Ethernet frames out on all ports, even though thedestination device is only connected to a segment on one port.

Switches, on the other hand, allow a LAN to be separated into different logical/physicalsegments. Switches learn the location of a particular device on a segment and retain thatinformation. When the switch observes Ethernet traffic is on a particular switch port, ittransmits the Ethernet frame to the segment containing the desired destination device.Switches allow connected devices to communicate with each other with greater efficiency than aflat bus configuration. Pairs of devices will often be able to communicate in parallel at the fullcapacity of the media (for example, 10 or 100 Mbps on a 10 or 100BaseT segment, respectively).

The location and numbers of headend components dictate whether a switch or hub is required.For example, a hub will suffice in Example Configuration One. This is because the RPD∗s(located at various remote locations) are all connected to a single physical interface on therouter. Each RPD∗ communicates with a DAC 6000 or NC 1500 located at the central headend.This means there are no device pairs in the remote headend that need to communicate on theLAN. Therefore, the capabilities of a switch are not needed.

Example Configuration 3 would benefit from the use of switches because The NC 1500 sendsinteractive downstream traffic across the LAN to the OM 1000. Furthermore, there can be a fairamount of network traffic between the IRT∗s and the DAC 6000 located in the master headend.A switch would allow independent communication between the DAC 6000 to the IRT∗, andbetween the NC 1500 to the OM 1000, improving network efficiency and diminishing thelikelihood of collisions that would be experienced using a simple 10Base T Hub.

Note that switches will forward all MAC layer broadcasts or multicasts to each connectedsegment (with the exception of the segment where the transmission emanated) by default. Ifswitches are used to limit LAN traffic on a particular segment, they may need to be configuredto prevent some broadcasts/multicasts. Refer to Section 2, Overview, Using the OM 1000’sEthernet Interface for an example of how to configure a switch to block Multicast IP traffic fromthe IRT∗.

The Ne two rk C l oud

The network cloud illustrated in the following examples provides WAN connections over aFrame Relay, SONET RING, T1 or any other typical point-to-point connections. Typically, WANservice requirements for these connections are Customer Service Unit/Data Service Unit(CSU/DSU) and a network router.

Frame Relay service is generally available in bandwidth increments from 56K, 128K, 256K,384K, 512K and up. Point-to-Point services usually provide the following bandwidth options:

�� Fractional T1 (DS-0) 64K

�� 256K

�� 384K

�� 512K

�� Full T1 or DS-1 at 1.54 Mbps

�� T2 or DS-2 at 6.312 Mbps

�� T3 or DS3 at 44.7 Mbps

N e t w o r k C o n f i g u r a t i o n E x a m p l e s 3333 ---- 3333


Contact your local area telephone or Internet service provider for information on the speedoptions in your area. For more information on WAN considerations, refer to Appendix A,WAN Link Capacity Considerations. For more information on network options, refer toAppendix C, Network Considerations.

Examp le Con f i gu ra t i on 1

Example Configuration 1 covers interactive and non-interactive network configurations. Itemploys a combination of Ethernet switching and routing to direct network traffic. EachRPD* communicates back to the central headend through the corresponding plant router to anenterprise router over the WAN. All the network devices are co-located, except for theRPD*s. The RPD*s are located in the remote plant and they provide the return path to theheadend OAM&P. The central router (3600 series) will block any broadcasts on the centralnetwork from being broadcasted to other networks. Central router Cisco model 3640 blocksthese by default. The remote routers will pass the singlecast traffic between the RPD* and theDAC. The remote routers need to be configured for the BOOTP broadcasts from the RPD*s to bepassed through the remote routers and via the network cloud to the OAM&P network. The EPGfeed is located at the central network and hence all the EPG traffic is on the OAM&P network.The RPD* to NC 1500 traffic is passed through the WAN. The NTP server can also be configuredon the OAM&P network.



Figure 3-1 illustrates Example Configuration 1:

F igure 3 -1

Example Conf igurat ion 1

DAC 6000

DLS

192.168.1.10192.168.1.15

192.168.1.13192.168.1.1

192.168.1.27

192.168.1.20

192.168.1.12

OM 1000HCT IRT 1000

NC 1500JAVA console

From satellite(EPG)

Cisco 290010/100 BaseT

Ethernet switch

OAM&Pnetwork

NC 1500

Applicationservers

192.168.10.1

192.168.10.3 192.168.10.4192.168.10.2

192.168.3.1 192.168.4.1192.168.2.1

192.168.3.20 192.168.4.20192.168.2.20

192.168.3.27 192.168.4.27192.168.2.27

Plant #2 Plant #3Plant #1

RPD 1000

CISCO 3600router

Network

Cisco 190010/100 Base TEthernet hub

Cisco 2600router

RPD 1000


Cisco 2600router

RPD 1000


Cisco 2600router

Routers convertbetween full-duplexand half-duplexas needed

This example uses a Class C Network address space with each RPD* cluster located on anindependent network. Users may need to alter the IP addressing scheme shown abovedepending on their specific application needs.

Because Ethernet is half-duplex only and the network cloud (fiber) may be full-duplex, specialattention must be paid when interfacing of these two types of networks. The smart hubs,routers, and/or switches will take care of the conversion between half-duplex to full-duplexautomatically. In most cases, they support auto-detection between the two modes. For moredetails on the specific device, see the equipment manufacturer notes.

Since the DAC 6000 (ProLiant series) is capable to run at 100 Mbps, the central office networkside may run at that speed, provided that a minimum of UTP Category 5 wiring(ISO-11801 EIA/TIA-568) has been used between the DAC 6000 and the enterprise router.



Configuration 1 Headend Parameters

The following sections contain configuration settings that must be set-up for the headendequipment in Configuration 1:

DAC 6000

�� Configure the Network Interface Card (NIC) with an appropriate NIC number, hostname,IP address, netmask, broadcast address, router, and driver information.

�� Build the host file to reflect the correct IP addresses for each piece of headend equipment.

�� Configure the default gateway to be the 3640’s IP address (192.168.1.1). To verify routerconfiguration, type the following command at a 132 prompt on the DAC 6000: > netstat -rn.

�� The DEC HX servers must have cards installed in slots 4, 5, and 6 respective to their type.The IRQs of the cards must be IRQ5 for slot 4, IRQ11 for slot 5, and IRQ15 for slot 6. TheCompaq ProLiant servers should have the cards installed in slots 2, 3, and 4.

�� The proper configuration of a three NIC system is as follows:Lowest NIC Slot # = Headend NetworkMiddle NIC Slot # = Keyserver NetworkHighest NIC Slot # = Any Business Systems

�� All NICs in a server must be the same type. Mixing of cards is not supported.

�� Refer to Appendix B, Router Configuration, for NTP client configuration information.

OM 1000

�� Configure the appropriate IP address and the subnet mask for the OM 1000.

�� Configure the host file with the DAC 6000's IP address (192.168.1.10).

�� Configure the host as DAC 6000 from the front-panel display of the OM 1000. The serviceshould be set to ACC2OM2.

�� Set Port/Protocol to 5167/tcp connection.

RPD*

�� Configure the appropriate IP address and the subnet mask for the RPD*.

�� Configure the host file with the NC 1500's IP address.

�� Configure the gateway (.gtw) file with the local router’s IP address:

Plant Default Gateway

Plant 1 192.168.2.1

Plant 2 192.168.3.1

Plant 3 192.168.4.1

�� Select the NC 1500 as the host from the front-panel display of the RPD*.



IRT*

�� Configure the IP address and subnet mask on the IRT∗.

�� Configure the IP address of the DAC 6000 as the IRT∗'s controller address.

Configuration 1 Traffic Types

Central Router (Cisco 3640)

Since all the headend equipment, except for the RPD∗s, is co-located with the DAC 6000, most ofthe broadcast traffic is on the Ethernet hub. This broadcast traffic needs to be contained on thecentral hub and blocked from the network cloud. The central router needs to be configured toblock the broadcast traffic. This is done by default on most routers.

Because the RPD* is on the remote network, the broadcast BOOTP requests from theRPD* BOOTP Client need to be relayed back to the OAM&P network to get to the BOOTPserver. This is accomplished by configuring the IP-helper address on the Cisco 2600 seriesremote routers and is discussed in the Specific Router Configuration subsection of this section.

Table 3-1 illustrates what types of traffic needs to be passed/blocked by the routers in ExampleConfiguration 1:

Tab le 3 -1

Conf igurat ion 1 t ra f f ic t ypes

Device2Device Transport IP Address

Mode

Router

conf igurat ion

(pass/block)

Comments

DAC2OM1 UDP Singlecast Block OOB Data path—By default, The central router does not pass this traffic on to the remote network by default. No special router configuration is necessary.

DAC2OM1 UDP Broadcast Block The central router does not pass this broadcast traffic on the network cloud by default. No special router configuration is necessary.

DAC2OM2 TCP Singlecast Block The OM 1000s control host interface traffic. The central router does not pass this traffic on the network cloud by default. No special router configuration is necessary.

DLS2OM UDP Broadcast Block Code Download operation—Central routers do not pass this traffic on the network cloud by default.



Device2Device Transport IP Address

Mode

Router

conf igurat ion

(pass/block)

Comments

HCT UDP Singlecast Pass BOOTP replies—Passed by the central router by default because it is singlecast traffic. No special router configuration is required.

IRT2OM UDP Multicast Block EPG data stream—By default, routers do not pass this traffic on the network cloud because of adjacency tests on the local network. This traffic is IP layer broadcast, MAC layer multicast.

NC2DAC UDP Singlecast Block Polling data path when interactive activity is present—By default, routers do not pass this traffic on the network cloud because of adjacency tests on the local network. No special router configuration is necessary.

RPD2NC UDP Singlecast Pass Polling data path—Passed by the router by default since it is singlecast traffic. No special router configuration is required

NC JAVA UDP Singlecast Block NC 1500 Console—By default, routers do not pass this traffic on the network cloud because of adjacency tests. No special router configuration is necessary.

BOOTP Requests MAC Broadcast Pass The BOOTP requests need to be passed through the remote router to the OAM&P network. This means that the IP helper address needs to be configured on the remote router.

Cisco 2600 Ser ies Router Conf igurat ion

The following information needs to be configured on the Cisco 2621 router at the remote plantlocations. The IP helper address on the Cisco router 2621 needs to be set to that of the BOOTPserver's IP address. This way, the RPD* BOOTP client's broadcast BOOTP requests are directedto the BOOTP Server by the 2621 router via the Network Cloud. No helper addresses need to beset on the 3640 Router since all the network devices are configured on the OAM&P network.NTP servers are also located at the OAM&P network. This ensures that all the time broadcastswill be on the OAM&P network.



For detailed information on remote BOOTP, refer to Appendix B, Router Configuration.

Interface speci f ic router conf igurat ion for the Cisco 2621 router Comment

# interface ethernet 0/0

# ip helper-address 192.168.1.12

Sends BOOTP requests to the HCT 1000.


Example Configuration 2 covers non-interactive systems and consists of three separateheadends with a controller located at the central location. Each plant communicates with thecentral controller through the headend router, frame relay, and central office enterprise router.A central office enterprise router handles the aggregate of all network traffic. Each plantreceives EPG data locally; the data is not passed across the WAN connections. NTP servers canbe configured either locally on each plant or on the OAM&P network. Figure 3-2 illustratesExample Configuration 2:



F igure 3 -2


192.168.1.1

192.168.10.1

192.168.10.3192.168.10.2

192.168.3.1192.168.2.1

CISCO 3600router

Network

192.168.10.4

192.168.4.1

From satellite(EPG)

Fromsatellite(EPG)

Plant #2Plant #1 Plant #3

From satellite(EPG)

Possible network media caninclude frame relay fiber, ATM,T1, or fractional T1


Cisco 290010/100 Base TEthernet switch

Cisco 2600router

192.168.2.10

192.168.2.20

192.168.2.27

OM 1000

IRT 1000

RPD 1000


Cisco 2600router

192.168.2.10

192.168.2.20

192.168.2.27

OM 1000

IRT 1000

RPD 1000


Cisco 2600router

192.168.2.10

192.168.2.20

192.168.2.27

OM 1000

IRT 1000

RPD 1000

DAC 6000

DLS

192.168.1.10192.168.1.12

HCT

Cisco 190010/100BaseTEthernet switch

3333 ---- 1 01 01 01 0 N e t w o r k C o n f i g u r a t i o n E x a m p l e s


Example 2 uses a Class C network assignment with each headend located on an independentnetwork. You may need to alter the IP addressing scheme to accommodate your specific needs.The IP addressing scheme shown in this example serves as a guideline.

Since Ethernet is half-duplex only, and the network cloud (fiber) may be full-duplex, specialattention must be paid when interfacing of these two types of networks. The smart hubs,routers, and/or switches will take care of the conversion between half-duplex to full-duplexautomatically. In most cases, they support auto-detection between the two modes. For moredetails on the specific device, see the equipment manufacturer notes.

Since the DAC 6000 (ProLiant series) can run at 100 Mbps, the central office network side canalso run at that speed, provided that a minimum of UTP Category 5 wiring(ISO-11801 EIA/TIA-568) has been used between the DAC 6000 and the enterprise router.


The following sections contain configuration settings for the headend equipment inConfiguration 2:

DAC 6000

�� Configure the NIC with appropriate NIC number, hostname, IP address, netmask,broadcast address, router, and driver information.





�� All NICs in a server must be the same type. Mixing of cards is not supported.


OM 1000


�� Configure the host file with the DAC 6000' s IP address (192.168.1.10).

�� Select the DAC 6000 as the host from the front-panel display of the OM 1000. The serviceshould be set to ACC2OM2.

�� Port/Protocol should be set to 5167/tcp connection.

N e t w o r k C o n f i g u r a t i o n E x a m p l e s 3333 ---- 1 11 11 11 1




Plant 1 192.168.2.1

Plant 2 192.168.3.1

Plant 3 192.168.4.1

RPD*


�� Configure the .hst file with the DAC 6000' s IP address (192.168.1.10)



Plant 1 192.168.2.1

Plant 2 192.168.3.1

Plant 3 192.168.4.1

�� Select the DAC 6000 as the host from the front panel display of the RPD*.

IRT*

�� Configure the IP address and subnet mask on the IRT∗.

�� Add a gateway tag into the Define Network Parameters field. The correct tag is T3 and thegateway is the IP address of the local router:


Plant 1 192.168.2.1

Plant 2 192.168.3.1

Plant 3 192.168.4.1

�� Configure the IP address of the DAC 6000 as the IRT∗'s controller address.


In this configuration, the routers need to be configured to be able to pass through the broadcastUDP traffic from the DAC 6000 to the OM 1000. Similarly, the routers also need to beconfigured to be able to pass through the DLS 1000 to OM 1000 traffic. The return path trafficfrom the RPD* to the DAC 6000 (singlecast) can be passed though the Cisco 2621 router bydefault. The IRT∗ to OM 1000 EPG traffic is IP broadcast data and is local to each remote plant.Because the OM 1000 is on the same network as the IRT∗, the remote router, by default, doesnot forward the broadcast EPG traffic to the other networks. Specific router configurations areoutlined in the next sections.



Table 3-2 illustrates what type of traffic types need to be passed or blocked by the routers inExample Configuration 2:

Tab le 3 -2


Device2Device Transport IP Address Mode Pass/Block Comments

DAC2OM1 UDP Singlecast Pass OOB Data path—Passed by the central router to the remote network by default because the traffic is singlecast. No special router configuration is required.

DAC2OM1 UDP Broadcast Pass Channel Map data— Global IP forwarding is configured in Cisco 3600 series router to enable passing the broadcast traffic.

DAC2OM2 TCP Singlecast Pass The OM 1000s control the host interface traffic — Passed by the router by default because it is singlecast traffic. No special router configuration is required.

DAC2IRT TCP Singlecast Pass IRT* data — Singlecast traffic is passed by the central router to the remote network by default. No special router configuration is required.

DLS2OM UDP Broadcast Pass Code Download — IP forwarding is configured on the central router to enable passing the broadcast traffic to the remote network.

RPD2DAC UDP Singlecast Pass Polling data — Passed by the remote router to the OAM&P network by default. No special router configuration is required.

IRT2OM UDP Broadcast Block Local EPG data stream—Blocked by default by the Cisco 2600 router. This prevents ingress to the OAM&P network. This traffic is IP layer Broadcast, MAC layer Multicast.

HCT UDP Singlecast Pass BOOTP replies—Passed by the central router to the remote network by default because they are singlecast. No special router configuration is required.

BOOTP Requests MAC Broadcast Pass The BOOTP requests need to be passed through the remote router to the OAM&P network. This means that the IP helper address needs to be configured on the remote router.



Special Router Conf igurat ion

The central router needs to be configured with IP helper addresses for the broadcast traffic thatgoes from the DAC 6000 to the different plants. IP helper address can be set to the plants’network addresses. The following interface specific commands need to be configured on theCisco 3640 router.

LAN interface speci f ic commands for the Cisco 3640 router





Global commands

# ip forward-protocol UDP 5157



The following information needs to be configured on the Cisco 2621 series router at the remoteplant location. The IP helper address on the 2621 router needs to be set to the BOOTP server'sIP address. This way, any broadcast BOOTP requests are directed to the BOOTP server by the2621 router through the Network Cloud:

LAN interface speci f ic commands



For a complete list of Cisco router configuration settings, refer to Appendix B,Router Configuration.


Example Configuration 3 covers interactive systems and can consist of two or more separateheadends with a controller located at the central location. Each plant communicates with thecentral controller through the plant router, public network, and central office enterprise router.The headend’s enterprise router handles the aggregate of all network traffic.

EPG data delivery is located at the OAM&P network and is routed through the network cloudfor all the different plants. The De-tunneled 1.5 Mbps NC&S stream generated at the HITSuplink is extracted by the dedicated IRT∗ and is multicast to the dedicated OM 1000 via a10baseT Ethernet that filters the TVGI PID. This dedicated OM 1000 presents the TVGI feed tothe primary OM 1000 for insertion into the OOB steam. For information about the EPG datadelivery methods, refer to Section 2, “Overview.”

Each plant has an NC 1500 on its network. The NC 1500 handles interactive activity andprovides a firewall between the Motorola headend network and third party application servers.The OAM&P network in Example Configuration 3 comprises of the DAC 6000, NC 1500 Javaconsole, HCT 1000 (BOOTP Server), and the EPG data feed.



Figure 3-3 illustrates Example Configuration 3:

F igure 3 -3



192.168.1.1

192.168.10.1Possible network media caninclude frame relay fiber, ATM,T1, or fractional T1


CISCO 3600router

Network

192.168.10.3192.168.10.2

192.168.3.1192.168.2.1




Cisco 2600router

Cisco 2600router

Cisco 2600router

192.168.10.4

192.168.4.1

Plant #2Plant #1 Plant #3

192.168.2.10

192.168.2.20

192.168.2.27

OM 1000

IRT 1000

RPD 1000

NC 1500

Applicationservers

192.168.3.10

192.168.3.20

192.168.3.27

OM 1000

IRT 1000

RPD 1000

NC 1500

Applicationservers

192.168.4.10

192.168.4.20

192.168.4.27

OM 1000

IRT 1000

RPD 1000

NC 1500

Applicationservers

DAC 6000

DLS

192.168.1.10192.168.1.12

HCT

192.168.1.13

NC 1500JAVA console

EPG data feed

RS-530

From L-bandsatellite NC&S

OM 1000 IRT 1000



Configuration 3 uses a Class C network assignment, with each headend located on anindependent sub-net. You may need to alter the IP addressing scheme to accommodate yourspecific needs. The IP addressing scheme shown in this example serves as a guideline.

Since Ethernet is half-duplex only and the network cloud (fiber) may be full-duplex, specialattention must be paid when interfacing of these two types of networks. The smart hubs,routers, and/or switches will take care of the conversion between half-duplex to full-duplexautomatically. In most cases, they support auto-detection between the two modes. For moredetails on the specific device, see the equipment manufacturer notes.

Since the DAC 6000 (ProLiant series) can run at 100 Mbps, the central office network side canalso run at that speed, provided that a minimum of UTP Category 5 wiring(ISO-11801 EIA/TIA-568) has been used between the DAC 6000 and the enterprise router.


The following sections contain configuration settings for the headend equipment inConfiguration 3:

DAC 6000

�� Configure the Network Interface Card with appropriate NIC number, hostname, IP address,netmask, broadcast address, router, and driver information.





�� All NICs in a server must be the same type; mixing of cards is not supported.


OM 1000


�� Configure the host file with the DAC 6000' s IP address (192.168.1.10).

�� Port/Protocol should be set to 5167/tcp connection.



�� Configure the gateway (.gtw) file with the local routers IP address:


Plant 1 192.168.2.1

Plant 2 192.168.3.1

Plant 3 192.168.4.1

�� Select the DAC 6000 as the host from the front-panel display of the OM 1000. The serviceshould be set to ACC2OM2.

RPD*


�� Configure the .hst file with the DAC 6000' s IP address (192.168.1.10)

�� Configure the gateway (.gtw) file with the local routers IP address:


Plant 1 192.168.2.1

Plant 2 192.168.3.1

Plant 3 192.168.4.1

�� Select the DAC 6000 as the host from the front panel display of the RPD*

IRT*

�� Configure the IP address and subnet mask on the IRT*.

�� Add a gateway tag into the Define Network Parameters field via the user interface. Thecorrect tag is T3 and the gateway is the IP address of the local router:


Plant 1 192.168.2.1

Plant 2 192.168.3.1

Plant 3 192.168.4.1

�� Configure the IP address of the DAC 6000 as the IRT*’s controller address.


In this configuration, the routers need to be configured to pass through TCP/UDP traffic fromthe DAC 6000 to the OM 1000. Similarly, the routers need to be configured to pass through theDAC 6000 to the IRT*, the DLS 1000 to the OM 1000, and the EPG traffic. The return pathtraffic from the NC 1500 to the DAC 6000 needs to be passed though the Cisco 2621 router. TheIRT* to OM 1000 traffic is multicast EPG data to the OM 1000. Because the OM 1000 is on thesame network, the router does not forward the EPG traffic on to the remote headend or othernetworks. Specific router configurations are outlined in the next sections.



Table 3-3 illustrates what type of traffic types need to be passed or blocked by the routers inExample Configuration 3:

Tab le 3 -3



DAC2OM1 UDP Singlecast Pass OOB data — Passed by the central router by default. No special router configuration is required.

DAC2OM1 UDP Broadcast Pass Channel Map information — IP forwarding configured on the Cisco 3600 router enables this to be passed to the remote network.

DAC2OM2 TCP Singlecast Pass The OM 1000s control the host interface traffic — Passed by the router by default. No special router configuration is required.

DAC2IRT TCP Singlecast Pass Flush/Fill operation — Passed by the central router by default. No special router configuration is required.

DLS2OM UDP Broadcast Pass Code download traffic — IP forwarding configuration on the Cisco 3640 router enables this to be passed to the remote headend.

IRT2OM UDP Broadcast Block EPG data stream — This traffic is IP layer Broadcast, MAC layer Multicast.

NC2OM UDP Singlecast Block This is singlecast traffic on the local network. The remote router blocks this form the WAN by default. No special router configuration is required.

RPD2NC UDP Singlecast Block This is singlecast traffic on the local network. The remote router blocks this form the WAN by default. No special router configuration is required.

NC2DAC UDP Singlecast Pass Polling data — Passed by the router by default. No special router configuration is required.

HCT 1000 UDP Singlecast Pass BOOTP Operation—Passed by the router by default. No special router configuration is required.




BOOTP Requests MAC Broadcast Pass The BOOTP requests need to be passed to the OAM&P network through the remote router. This means that the IP helper address needs to be configured on the remote router.

NC JAVA UDP Singlecast Pass NC 1500 JAVA-enabled Console — Singlecast traffic is passed by the router by default. No special router configuration is required.

Special Router Conf igurat ion

The central router needs to be configured with IP helper addresses for the broadcast traffic thatgoes from the DAC 6000 to the different plants. IP helper address can be set to the plants’network addresses. The following interface specific commands need to be configured on theCisco 3640 router:

Interface speci f ic commands on the Cisco 3640 router





Global commands





The following information needs to be configured on the Cisco 2621 router at the remote plantlocation. The IP helper address on the router 2621 needs to be set to that of the BOOTP server'sIP address. This way, any broadcast BOOTP requests are directed to the BOOTP server by the2621 router through the Network Cloud:

LAN interface speci f ic commands



For a complete list of Cisco router configuration settings, refer to Appendix B,Router Configuration.


Appendix A

WAN L i nk Capac i t y Cons i de r a t i on s

This appendix provides WAN link capacity recommendations and considerations for theheadend network configuration examples given in this document. For more information aboutthe example configurations, refer to Section 3, Network Configuration Examples.

While in steady state operation, the DAC 6000 sends messages to IRT∗s, OM 1000s and MPS∗

devices over the WAN. These messages include IRT∗ and MPS∗ control commands, settop boxauthorizations and configuration commands, code objects, and network information. The WANalso carries polling traffic from the set-tops (RF Global/ Upstream Plant/ Single Terminal) thatis received by the RPD∗ and routed to the DAC 6000 for processing. Finally, there may also beother traffic on the same network from EPG servers, third party Interactive/ApplicationServers, and Network Time Servers.

Table A-1shows the minimum recommended WAN link capacities for each of the exampleconfigurations discussed in this document:

Tab le A -1

Min imum Recommended L ink Capac i t y

Example Conf igurat ion Minimum Recommended L ink Capacity

Configuration 1 56 Kbps



The link capacity numbers described in Table A-1 are based on a working test configuration in the MotorolaBCS SI lab with the following headend elements software releases. These bandwidth numbers typically don’tvary with the software release versions.

DAC 6000 v 2.45-4-5OM 1000 v 3.2.0RPD 1000 v 3.2.0DCT 1000 v 6.43DCT 2000 v 6.50IRT 1000 v 1.5.1

The link capacities indicated in Table A-1 can be changed with certain headend performancetradeoffs. For instance, Example Configuration 2 can operate using a 56 Kbps link rather thanthe recommended 256 Kbps link. To do so however, you must change certain DAC 6000parameters to less than optimal values. These changes will result in sub-optimal systemperformance, such as a code download rate much slower than recommended to support ExampleConfiguration 2.

AAAA ---- 2222 B a n d w i d t h C o n s i d e r a t i o n s


Recommended Da ta Ra te Se t t i ngs

Table A-2 contains the recommended data rate settings based on the WAN link capacitiesspecified for each example configuration. The table lists the device pair traffic types and therecommended data rate settings for the device pair. The table is divided into variable (tunablevia a DAC 6000), fixed, and miscellaneous data rates. The rates listed below provide enoughmargins to accommodate expected bursts of traffic, increased reliability, and reduction of datalatency.

Tab le A -2 Dev i ce Pa i r Da ta Ra te Se t t i ng Recommenda t i ons

Dev ice Pair T raf f ic

Type

Recommended Data Rate Sett ings

based on WAN L ink Capacity for

Example Conf igurat ions

Comments

56 Kbps Example 1

256 Kbps Example 2

512 Kbps Example 3

DLS2OM Broadcast N/A 60 Kbps 180 Kbps This traffic is broadcast to all the OM 1000s on the headend; therefore, additional OM 1000s do not add significant traffic. Example configuration 1 is on a 56 Kbps WAN link. This link is used only to pass the upstream traffic from RPD2DAC. All other traffic is on the 10BaseT OAM&P network. This facilitates operation of DLS2OM at 180 Kbps in example 1. DLS2OM traffic in examples 2 and 3 is on the WAN link and the recommended settings are as shown.

EMM/NETPIDs2OM

Broadcast N/A 80 Kbps 80 Kbps This traffic is broadcast to all the OM 1000s on the headend; therefore, additional OM 1000s do not add significant traffic. Example configuration 1 is on a 56 Kbps WAN link. This link is only used to pass the upstream traffic from RPD2DAC. All other traffic is on the 10BaseT OAM&P network. This facilitates operation of EMM/NETPID2OM traffic at 80 Kbps in example 1. The traffic in examples 2 and 3 is on the WAN link and the recommended settings are as shown.

Varia

ble

Data

Rat

es

DAC2IRT RPC Singlecast

N/A 20 Kbps 20 Kbps This traffic is generated periodically for programming information (Load IRT∗) and during operator initiated flush and fill operations. This is singlecast to each IRT∗. Each IRT∗ added to the network contributes some periodic traffic between the DAC 6000 and the IRT∗. Load IRT ∗commands are queued and hence are sent to one IRT∗ at a time.

B a n d w i d t h C o n s i d e r a t i o n s AAAA ---- 3333


56 Kbps Example 1

256 Kbps Example 2

512 Kbps Example 3

IRT2OM Singlecast to the downstream plant’s OM 1000

N/A N/A 150 Kbps This EPG traffic is carried over the WAN link to each downstream plant.

RPD2DAC Singlecast 20 Kbps 20 Kbps 20 Kbps Depending on the number of parallel polls, the RPD∗ traffic on the example headend was approximately 20 Kbps with 30000 settops that have a 20% buy rate.

Fixe

d Da

ta R

ates

56 Kbps Example 1

256 Kbps Example 2

512 Kbps Example 3

Mis

cella

neou

s

SNMP, BOOTP, ARP, etc

10 Kbps 10 Kbps 10 Kbps This includes the miscellaneous data transfers such as the SNMP traffic, the BOOTP traffic, ARP requests, and so on.

Con f i gu ra t i on Spec i f i c L i nk Capac i t y Budge t and Cons t ra in t s

There are two ways to configure the examples in this document to handle the return pathtraffic:

1 Interactive settops can be configured on an upstream frequency, which sends the interactiveATM cells back to the NC 1500.

2 Non-interactive settops can be configured on a different upstream frequency to the RPD∗.

In Configuration 1, all the headend elements, with the exception of the RPD∗, are co-locatedwith the DAC 6000. The only Ethernet traffic that comes back to the central headend networkfrom the remote site is the RPD∗ return path purchase/poll data from the settops. TheRPD2DAC traffic primarily consists of the RF poll traffic and the diagnostic polls. Therecommended minimum link capacity required for this traffic is 56 Kbps.

Configuration 2 moves the OM 1000’s to remote plants. This results in the WAN carrying IPtraffic:

�� From the DAC 6000 to the OM 1000’s on the remote plant

�� To the IRT’∗s on the remote plant and the return path traffic as well

�� From the remote RPD∗’s to the DAC 6000

Minimum WAN link capacity recommended for this configuration is 256 Kbps.

Configuration 3 is similar to but more complex than Configuration 2. There is an additional 150Kbps of EPG data traffic routed through the WAN. The IRT∗, OM 1000’s, NC 1500’s, and RPD∗‘sare all on the remote plant. This means the WAN carries the DAC 6000 traffic to the OM 1000’sand the IRT∗’s on the remote plant. The WAN also carries the return path traffic from theremote RPD∗’s to the DAC 6000. There may also be interactive set-tops sending traffic to thirdparty application servers using the NC 1500.



WAN L ink Capac i t y Recommenda t i ons f o r Con f i gu ra t i on 1

Example Configuration 1 covers interactive and non-interactive network configurations. All thenetwork devices are co-located at a central site, except for the RPD∗s. Each RPD∗ communicatesback to the central head-end through the corresponding plant router to an enterprise routerover the WAN.

The RPD∗s are located in the remote plant and they provide the non-interactive return path fordiagnostic polls and purchase poll traffic to the headend OAM&P. Motorola recommendsconfiguring the interactive traffic on a different demodulation frequency from thenon-interactive traffic. If there is any interactive traffic, the link capacity budget of the WANlink needs to be increased accordingly to handle the corresponding interactive traffic.

The different devices on the central network communicate on a 10/100BaseT network.Non-interactive traffic on the WAN consists of the RF return path traffic from the set-tops,which is the RPD2DAC traffic. The return path traffic consists of the diagnostic polls and thepurchase polls. Motorola recommends that the WAN support at least 56 Kbps. The RPD∗ iscapable of operating at an upstream RF data rate of 256 Kbps.

Configuration Recommendations

The following DAC 6000 configurations are suggested for this configuration. The trafficgenerated by the DAC 6000 settings below is present only on the OAM&P network and not onthe WAN link.

�� Configure the DLS data rate for 4MPEG/UDP and 30UDP/sec rate. This will operate at anestimated bandwidth of 180 Kbps. This traffic is not on the WAN.

�� Set the EMM data rate be at the default rate of 80 Kbps. Only authorized field personnelshould modify this value.

�� Set the NET PID data rate at the default rate of 80 Kbps. Only authorized field personnelshould modify this value.

�� Set the ALL PID data rate at the default rate of 80 Kbps. Only authorized field personnelshould modify this value.

�� Configure the reportback_timeout tunable to the default value of 1000 milli sec. Onlyauthorized field personnel should modify this value.

Constraints

The 56 Kbps link capacity for the WAN is based on simulations of two RPD∗s with fullypopulated chassis.




Example Configuration 2 covers non-interactive systems and consists of three separateheadends with a controller located at the central location. Each plant communicates with thecentral controller through the WAN, the headend router, and the central office enterpriserouter. A central office enterprise router handles the aggregate of all network traffic. Each plantgets its EPG data locally, so the data is not passed across the WAN connections. For thisconfiguration, Motorola recommends that the WAN support at least 256 Kbps. The sameconfiguration can be run on a 56 Kbps link after some data rate throttling. This procedure isdescribed in the Constraints and Recommended Operational Features for Configuration 2 tooperate on a 56 Kbps WAN link section that follows.


In order to support the device-to-device message rates specified in Table A-2, the followingDAC 6000 configurations are required:

�� Configure the DLS 1000 data rate for 4 MPEG/UDP and 10 UDP/sec rate. This will operateat an estimated bandwidth of 60 Kbps.

�� Set the EMM data rate be at the default rate of 80 Kbps. Only authorized field personnelshould modify this value.

�� Set the NET PID data rate at the default rate of 80 Kbps. Only authorized field personnelshould modify this value.

�� Set the ALL PID data rate at the default rate of 80 Kbps. Only authorized field personnelshould modify this value.

�� The DAC 6000 is capable of parallel polling. This translates to the number of DCT∗’s thatsend the upstream poll data simultaneously in case of a global poll. Motorola recommendssetting this value to the default DAC 6000 value of 12. Only authorized field personnelshould modify this value.

�� Configure the reportback_timeout tunable to the default value of 1000 ms. Only authorizedfield personnel should modify this value.

Constraints and Recommended Operational Features for Configuration 2 to

Operate on a 56 Kbps WAN Link

Configuration 2 can also operate on a 56 Kbps WAN link, with some trade-offs in headendperformance. Changing some default values on the DAC 6000, such as the EMM and NET PID,enables you to operate Configuration 2 on a 56 Kbps WAN link, as shown below.


�� Configure the DLS data rate for 4 MPEG/UDP and 1 UDP/sec rate. This will operate at anestimated bandwidth of 6.4 Kbps. This means that the code download will take 20 times aslong as the code download streams operating at the recommended 4 MPEG/UDP and30 UDP/sec (180 Kbps) for the 256 Kbps link.

�� The following table serves as a guideline for DLS data rate tunables. It is recommended topackage more MPEGs/UDP and keep the UDP rate low due to the lower UDP overhead.



Tab le A -3

DLS Data Rates

Data Rate

(Kbps)

MPEG/

UDP

UDP/

Sec

MPEG/

Sec

MPEG Bytes/

Sec

Bytes/Sec

including overhead

6.4 4 1 4 752 798

30.4 4 5 20 3760 3806

60.5 4 10 40 7520 7566

180.8 4 30 120 22560 22606

�� Flush and Fill conditions on the IRT∗ typically generate approximately 300 kilobits of data,depending on the number of services on the IRT∗. This takes approximately five times aslong to complete as it would take on a 256 Kbps link for Configuration 2. Since this is not afrequently conducted operation, this does not have much affect on the performance of thesystem.

�� Set the EMM data rate at 24 Kbps. Only authorized field personnel should modify thisvalue.

�� Set the NET PID data rate at 24 Kbps. Only authorized field personnel should modify thisvalue.

�� Set the ALL PID data rate at 24 Kbps. Only authorized field personnel should modify thisvalue.

�� Space terminal refreshes apart by at least 10 seconds using the DAC 6000 GUI screen.


�� The following table contains estimated times for code upgrades to various headend devicesfrom the HCT 1000 (located at the central headend):

Tab le A -4

Code upgrade t ime us ing an HCT on a 56 Kbps l ink

Source Dest inat ion F i le s ize Ki lo

Bytes

Est imated t ime for

upgrade in minutes Descr ipt ion

HCT 1000 OM 1000 1,560 KB 4 min Fof, img, ini, hst, gtw.svc, msg, tsk, adb, htm files

HCT 1000 IRT ∗ 983 KB 2 min cod files and off file

HCT 1000 RPD ∗ 1.181MB 3 min All config files + v3.1 code




This example consists of two or more separate headends with a controller located at the centrallocation. Each plant communicates with the central controller through the plant router, publicnetwork, and central office enterprise router. The headend’s enterprise router handles theaggregate of all network traffic. EPG data delivery is located at the OAM&P network and isrouted through the network cloud for all the different plants. The de-tunneled 1.5 Mbps NC&Sstream generated at the HITS uplink is extracted by the dedicated IRT ∗. It is then multicast tothe dedicated OM 1000 using a 10BaseT Ethernet, which filters the TVGI PID. This dedicatedOM 1000 presents the TVGI feed to the primary OM 1000 for insertion into the OOB stream.This adds an additional 150 Kbps traffic on the WAN.



�� Configure the DLS data rate for 4 MPEG/UDP and 30 UDP/sec rate. This will operate at anestimated bandwidth of 180 Kbps.

If need be, the DLS rate can be scaled down to 4 MEPG/UDP and 10 UDP/sec rate tooperate at an estimated bandwidth of 60 Kbps. This would mean that it would takeapproximately three times as long for the code download to the set-tops compared to thesetting above.

�� Set the EMM data rate to the default 80 Kbps. Only authorized field personnel shouldmodify this value.

�� Set the NET PID data rate to the default 80 Kbps setting. Only authorized field personnelshould modify this value.

�� Set the ALL PID data rate to the default 80 Kbps. Only authorized field personnel shouldmodify this value.



Appendix B

Rou te r Con f i gu r a t i on

This section provides the following information:

�� An overview of what options are available with the Cisco 2600 and 3600 series routers.

The Motorola Broadband Communications Sector (BSC) SI lab used Cisco modular routers2621 and 3640 for the remote configurations examples tested in this manual.

�� The configuration file results from the Cisco routers and switch tested in the Motorola BCSSI lab

For more information on the Cisco routers discussed in this manual, refer to the appropriateCisco documentation.

C isco 2600 Se r i e s

Cisco 2600 series routers share modular interfaces with the Cisco 1600, 1700 and 3600 seriesrouters. They support:

�� Secure Internet/intranet access with firewall protection

�� Multiservice voice/data integration

�� Analog and digital dial access services

�� Virtual Private Network (VPN) access

�� Inter-VLAN routing, routing with Bandwidth Management

The Cisco 2600 series is available in the following six base configurations:

�� Cisco 2610: One Ethernet port

�� Cisco 2611: Two Ethernet ports

�� Cisco 2612: One Ethernet port and One Token Ring port

�� Cisco 2613: One Token Ring port

�� Cisco 2620: One 10/100 Mbps auto-sensing Ethernet Port

�� Cisco 2621: Two 10/100 Mbps auto-sensing Ethernet Ports

Each model has two WAN interface card slots, one network module slot, and one AIM slot. AllCisco 2600s include the Cisco IOS IP feature set.

BBBB ---- 2222 R o u t e r C o n f i g u r a t i o n


C isco 3600 Se r i e s

The Cisco 3660, Cisco 3640, and Cisco 3620 routers are, respectively, 6-, 4- and 2-slotmulti-service access routers. Their LAN and WAN connections are configured byinterchangeable network modules and WAN interface cards. The Cisco 3660 also incorporates 1or optionally 2 integrated 10/100 (Ethernet/Fast Ethernet) ports. The following networkmodules are available for the Cisco 3660, Cisco 3640, and Cisco 3620 routers:

�� Analog and Digital (T1) Voice Network Modules

�� Single-Port High-Speed Serial Interface (HSSI)

�� ATM 25 Mbps Network Module (Q1 CY 2000 for the Cisco 3660)

�� ATM OC3 155 Mbps Network Module

�� 6-, 12-, 18-, 24- and 30-digital modem network modules (Q1 CY 2000 for the Cisco 3660)

�� LAN with modular WAN (WAN Interface Cards)

�� 8 and 16 analog modem network modules (Q1 CY2000 for the Cisco 3660)

�� Channelized T1, ISDN PRI and E1 ISDN PRI network modules (Q1 CY 2000 for the Cisco3660)

�� Combined Fast Ethernet and PRI network modules (Q1 CY 2000 for the Cisco 3660)

�� 4- and 8-port ISDN BRI network modules (Q1 CY 2000 for the Cisco 3660)

�� 16- and 32-port asynchronous network modules

�� 4- and 8-port synchronous/asynchronous network modules

�� 1-and 4-port Ethernet network modules

�� 1-port Fast Ethernet (10/100) network modules (100BaseT - "TX" and Fiber - "FX")

�� 8- and 16-port analog modem modules (Q1 CY 2000 for the Cisco 3660)

�� 4-port serial network module

�� Compression network module (Cisco 3620 and Cisco 3640, AIM for the Cisco 3660)

R o u t e r C o n f i g u r a t i o n BBBB ---- 3333


C isco 3640 Cen t ra l Rou te r Con f i gu ra t i on

The following table contains the results of running config for the Cisco 3640 router used in theexample headend networks in this document:

Router Conf igurat ion Comments

version 12.0

!

interface Ethernet0/0 Ethernet interface 0/0

ip address 192.168.10.1 255.255.255.0

ip helper-address 192.168.3.20 Direct broadcasts from the 129 network to the OM's (not needed for example configuration 1)

ip helper-address 192.168.2.20 Direct broadcasts from the 129 network to OM's (not needed for example configuration 1)

ip helper-address 192.168.4.20 Direct broadcasts from the 129 network to OM's (not needed for example configuration 1)

ip directed-broadcast

!

interface Serial0/0 Serial interface 0/0

No ip address

Ip directed-broadcast

Encapsulation frame-relay Encapsulation frame relay

No ip mroute-cache

No fair-queue

Frame-relay lmi-type ansi

!

Interface Serial0/0.1 point-to-point Serial sub interface 1

Ip address 192.168.10.102 255.255.255.0


Frame-relay interface-dlci 102 Additional tag needed for the frame relay

!


Ip address 192.168.11.103 255.255.255.0


Frame-relay interface-dlci 103

!


Ip address 192.168.12.104 255.255.255.0




Frame-relay interface-dlci 104

!

!

ip classless

ip forward-protocol udp 5957 Enable 5957 broadcasts

ip forward-protocol udp 5157

ip route 192.168.20.0 255.255.255.0 192.168.10.201 Send all the traffic from 129 network destined to 20 network will go through the 10.201 network



no ip http server

!

line con 0 Allows us to configure from con 0

exec-timeout 5 0

line aux 0 Aux port 0

line vty 0 Virt term 0

End

c3640#

C isco 2621 Rou te r Con f i gu ra t i on I n fo rmat i on

The following table contains the results of running config for the Cisco 2621 router used in theexample headend networks in this document:

Conf ig on the Router Comments

sh run

interface Loopback0 Loopback interface config

no ip address No IP address for the interface

no ip directed-broadcast No IP broadcast forwards

!

interface FastEthernet0/0 Fast Ethernet interface

ip address 192.168.20.1 255.255.255.0 IP address for the interface

ip helper-address 192.168.1.12 IP helper address set to the BOOTP server


!

interface Serial0/0 Serial Interface 0/0

no ip address




encapsulation frame-relay

no ip mroute-cache

frame-relay lmi-type ansi

!

interface Serial0/0.1 point-to-point Serial interface 0/0.1 config

ip address 192.168.10.201 255.255.255.0 IP address and subnet mask


frame-relay interface-dlci 201 Interface to the frame relay dlci port 201

!

ip classless

ip route 192.168.129.0 255.255.255.0 192.168.10.102 static routing table

no ip http server

End

C isco 2621 FR Rou te r Con f i gu ra t i on I n fo rmat i on

The following table contains the results of running config for the Cisco 2621 FR router used inthe example headend networks in this document:


c2621_frsw#show run

hostname c2621_frsw Router’s name

!

no ip subnet-zero Default setting

!

frame-relay switching Enable router for frame-relay communications

interface FastEthernet0/0 Fast Ethernet interface settings

no ip address

no ip directed-broadcast

Shutdown Fast Ethernet interface disabled

!

interface Serial0/0 Settings for Serial 0/0 interface

no ip address No IP address

ip directed-broadcast Default setting' to allow broadcasts go through

encapsulation frame-relay Set encapsulation to Frame-Relay

no ip mroute-cache Default setting



clockrate 800000 Sets clock rate to 800 Kbps

frame-relay lmi-type ansi Lmi-type ansi. Must be the same for all routers to communicate

frame-relay intf-type dce Server

frame-relay route 102 interface Serial0/1 201 Route dlci 102 to interface dlci 201



!


no ip address No IP address assigned



clockrate 56000 Clock rate set at 56000 bps (clock rate of the cloud)


frame-relay intf-type dce

frame-relay route 201 interface Serial0/0 102

!


no ip address No IP address assigned



clockrate 56000 Clock rate set at 56000 bps




!


no ip address No ip address assigned



clockrate 56000 Clock rate set at 56000 bps




End

c2621_frsw#



C isco 2900 Sw i t ch

The following table contains the results of running config for the Cisco 2900 switch used in theexample headend networks in this document:


c2924sw#sh run

hostname c2924sw Host name

interface VLAN1

ip address 192.168.20.250 255.255.255.0

no ip route-cache

!

interface FastEthernet0/1

spanning-tree portfast

!



!



!



!



!



!



!



!




switchport access vlan 2


!




!




!


Switchport access vlan 2

Spanning-tree portfast

!

Interface FastEthernet0/13



!

Interface FastEthernet0/14



!




!




!




!






!




!




!




!




!




!


switchport access vlan 3 This port belongs to vlan 3

spanning-tree portfast For the spanning tree

!

!

End

c2924sw#

BBBB ---- 1 01 01 01 0 R o u t e r C o n f i g u r a t i o n


NTP C l i en t Con f i gu ra t i on f o r t he DAC 6000

Check the following files when troubleshooting the NTP client configuration (the ntp_gi scriptconfigures these files automatically):

/etc/rc2.d/S85tcp

::::::::::::::::::::

... about line 178 >> make sure "timed" is commented out <<

# Uncomment these lines if you want to run timed. Add -M

# to the timed command if you want this machine to be a

# potential master server.

## if [ -x /etc/timed -a ! -f /etc/ntp.conf ]; then

# timed ; echo "timed \c"

# fi

>> make sure the "ntpdate -b ... " line appears similar <<

#

# Xntpd - Don't run this at the same time as timed.

if [ -x /etc/xntpd -b -f /etc/ntp.conf ]; then

ntpdate -b ntp_server1 ; xntpd -b >/dev/null; echo "xntpd \c"

fi

::::::::::::::::::::

/etc/ntp.conf

::::::::::::::::::::

# >> verify the entries in the ntp.conf file <<

# expected to run at stratum level 3

broadcastclient yes

R o u t e r C o n f i g u r a t i o n BBBB ---- 1 11 11 11 1


driftfile /etc/ntp.drift

resolver /etc/xntpres

keys /etc/ntp.keys >> keys are only needed if using system <<

requestkey 65529 >> names, not system IP addresses <<

server ntp_server1 version 1 >> verify NTP server name/IP address <<

server ntp_server2

::::::::::::::::::::

/etc/ntp.keys

::::::::::::::::::::

65529 A key_password >> only needed if using keys <<

Although unsupported at this time, the following NTP configuration file may be used as a guidelinefor setting up a UNIX system as an NTP server system that broadcasts NTP synchronization data.

::::::::::::::::::::

/etc/ntp.conf

::::::::::::::::::::

# /etc/ntp.conf file for a SCO UNIX NTP server

# Declare this system as a server with stratum 10/11

server 127.127.1.10 # Local System Clock

fudge 127.127.1.10

# our local sub-nets (sub-nets to broadcast over)

broadcast 168.84.250.255

# enable monitoring feature

monitor yes

driftfile /etc/ntp.drift

resolver /etc/xntpres


Appendix C

Ne two rk Cons i de r a t i on s

The following considerations need to be addressed before network setup can begin. All of theissues described in this section may affect the performance, cost, and manageability of thenetwork equipment at the cable headend.

I P Add ress Space Cons ide ra t i ons

Network scaling is a major concern when the IP Address space is subdivided and allocatedbetween network devices. How much IP host space will be needed two or three months, or evenyears, down the road? Should the network be one contiguous IP space or split into sub-nets?

C lass fu l I P Add ress ing

When IP was first standardized in September 1981, the specification required that each systemattached to an IP-based Internet be assigned a unique, 32-bit Internet address value. Somesystems, such as routers, which have interfaces to more than one network, must be assigned aunique IP address for each network interface.

The first part of an Internet address identifies the network, on which the host resides, while thesecond part identifies the particular host on the given network. This created the two-leveladdressing hierarchy, as illustrated in Figure C-1:

F igure C -1

Two- leve l In ternet address s t ructure

Network-number

Network-prefix

Host-number

Host-number

or

In recent years, the network-number field has been referred to as the "network-prefix" becausethe leading portion of each IP address identifies the network number. All hosts on a givennetwork share the same network-prefix but must have a unique host-number. Conversely, anytwo hosts on different networks must have different network prefixes but may have the samehost-number.

CCCC ---- 2222 N e t w o r k C o n s i d e r a t i o n s


Primary Address Classes

In order to provide the flexibility required to support different size networks, the designersdecided that the IP address space should be divided into three different address classes - ClassA, Class B, and Class C. This is often referred to as "classful" addressing because the addressspace is split into three predefined classes, groupings, or categories. Each class fixes theboundary between the network-prefix and the host-number at a different point within the 32-bitaddress. The formats of the fundamental address classes are illustrated in Figure C-2:�

F igure C -2

P r inc ip le c lassfu l IP address fo rmats �

0

10

110

0

0

0

bit #

bit #

bit #

Class A

Class B

Class C

1

2

3

7

15

23

8

16

24

31

31

31

Network-number

Network-number

Network-number

Host-number

Host-number

Host-number

One of the fundamental features of classful IP addressing is that each address contains aself-encoding key that identifies the dividing point between the network-prefix and thehost-number. For example, if the first two bits of an IP address are 1-0, the dividing point fallsbetween the 15th and 16th bits. This simplified the routing system during the early daysbecause the original routing protocols did not supply a "deciphering key" or "mask" with eachroute to identify the length of the network-prefix.

Class A Networks (/8 Pref ixes)

Each Class A network address has an 8-bit network-prefix with the highest order bit set to 0and a seven-bit network number, followed by a 24-bit host-number. Today, it is no longerconsidered ‘modern’ to refer to a Class A network. Class A networks are now referred to as "/8s"(pronounced "slash eight" or just "eights") since they have an 8-bitnetwork-prefix.

A maximum of 126 (27 -2) /8 networks can be defined. The calculation requires that the 2 issubtracted because the /8 network 0.0.0.0 is reserved for use as the default route and the /8network 127.0.0.0 (also written 127/8 or 127.0.0.0/8) has been reserved for the "loopback"function. Each /8 supports a maximum of 16,777,214 (224 -2) hosts per network. The hostcalculation requires that 2 is subtracted because the all-0s ("this network") and all-1s("broadcast") host-numbers may not be assigned to individual hosts.

N e t w o r k C o n s i d e r a t i o n s CCCC ---- 3333


Since the /8 address block contains 231 (2,147,483,648) individual addresses and the InternetProtocol version four (IPv4) address space contains a maximum of 232 (4,294,967,296) addresses,the /8 address space is 50% of the total unicast address space.

Class B Networks (/16 Pref ixes)

Each Class B network address has a 16-bit network-prefix with the two highest order bits set to1-0 and a 14-bit network number followed by a 16-bit host-number. Class B networks are nowreferred to as"/16s" since they have a 16-bit network-prefix.

A maximum of 16,384 (214) /16 networks can be defined with up to 65,534 (216 -2) hosts pernetwork. Since the entire /16 address block contains 230 (1,073,741,824) addresses, it represents25% of the total unicast address space.

Class C Networks (/24 Pref ixes)

Each Class C network address has a 24-bit network-prefix with the three highest order bits setto 1-1-0 and a 21-bit network number, followed by an 8-bit host-number. Class C networks arenow referred to as "/24s" since they have a 24-bit network-prefix.

A maximum of 2,097,152 (221) /24 networks can be defined with up to 254 (28 -2) hosts pernetwork. Since the entire /24 address block contains 229 (536,870,912) addresses, it represents12.5% (or 1/8th) of the total unicast address space.

Other Classes

In addition to the three most popular classes, there are two additional classes, class D and classE. Class D addresses have their leading four-bits set to 1-1-1-0 and are used to support IPMulticasting. Class E addresses have their leading four-bit set to 1-1-1-1 and are reserved forexperimental use.

Dotted-Decimal Notat ion

To make Internet addresses easier for human users to read and write, IP addresses are oftenexpressed as four decimal numbers, each separated by a dot. This format is called"dotted-decimal notation." Figure C-3 shows how a typical /16 (Class B) Internet address can beexpressed in dotted-decimal notation:

F igure C -3

Dot ted -dec imal notat ion

10010001 00001010 00100010 00000011

0bit # 31

145

145.10.34.3

10 34 3

Dotted-decimal notation divides the 32-bit Internet address into four 8-bit (byte) fields andspecifies the value of each field independently as a decimal number with the fields separated bydots.



Table C-1 displays the range of dotted-decimal values that can be assigned to each of the threeprinciple address classes. The xxx represents the host-number field of the address, which isassigned by the local network administrator.

Tab le C -1

Dot ted -dec imal ranges fo r each address c lass

Address c lass Dotted-decimal notat ion ranges

A (/8 prefixes) 1.XXX.XXX.XXX through 126. XXX.XXX.XXX

B (/16 prefixes) 128.0.XXX.XXX through 191.255.XXX.XXX

C (/24 prefixes) 192.0.XXX.XXX through 223.255.255.XXX

Subnett ing

In 1985, Request For Comments (RFC) document 950 defined a standard procedure to supportthe subnetting, or division, of a single Class A, B, or C network number into smaller pieces.Subnetting was introduced to overcome some of the problems that parts of the Internet werebeginning to experience with the classful two-level addressing hierarchy:

�� Internet routing tables were beginning to grow.

�� Local administrators had to request another network number from the Internet before anew network could be installed at their site.

Both of these problems were addressed by adding another level of hierarchy to the IP addressingstructure. Instead of the classful two-level hierarchy, subnetting supports a three-levelhierarchy. The basic idea of subnetting is to divide the standard classful host-number field intotwo parts — the subnet-number and the host-number on that subnet, as illustrated inFigure C-4:

F igure C -4

Subnet address h ie rarchy

Network-prefix

Network-prefix Host-number

Subset-number Host-number

Two-level classful hierarch y

Three-level subnet hierarchy

Subnetting solved the expanding routing table problem by ensuring that the subnet structure ofa network is never visible outside of the organization's private network. The route from theInternet to any subnet of a given IP address is the same, no matter which subnet thedestination host is on. This is because all subnets of a given network are numbered using thesame network-prefix but different subnet numbers. The routers within the private organizationneed to differentiate between the individual subnets, but as far as the Internet routers areconcerned, all of the subnets in the organization are collected into a single routing table entry.This allows the local administrator to introduce arbitrary complexity into the private networkwithout affecting the size of the Internet's routing tables.

Subnetting overcame the registered number issue by assigning each organization one (or atmost a few) network number(s) from the IPv4 address space. The organization was then free to



assign a distinct sub-network number for each of its internal networks. This allows theorganization to deploy additional subnets without needing to obtain a new network numberfrom the Enterprise Network.

A site with several logical networks uses subnet addressing to cover them with a single /16(Class B) network address. The router accepts all traffic from the Internet addressed to network130.5.0.0, and forwards traffic to the interior sub-networks based on the third octet of theclassful address, as illustrated in Figure C-5:

F igure C -5

Subnet t ing reduces the rout ing requ i rements on the network

Internet Router

130.5.32.0

130.5.64.0

130.5.96.0

130.5.128.0

130.5.160.0

130.5.192.0

130.5.224.0

130.5.0.0

Private network

The deployment of subnetting within the private network provides several benefits:

�� The size of the global Internet routing table does not grow because the site administratordoes not need to obtain additional address space and the routing advertisements for all ofthe subnets are combined into a single routing table entry.

�� The local administrator has the flexibility to deploy additional subnets without obtaining anew network number from the Enterprise Network.

�� Route flapping (such as the rapid changing of routes) within the private network does notaffect the network routing table since Internet routers do not know about the reachability ofthe individual subnets — they just know about the reachability of the parent networknumber.

Extended-Network-Pref ix

Internet routers use only the network-prefix of the destination address to route traffic to asubnetted environment. Routers within the subnetted environment use the extended-network-prefix to route traffic between the individual subnets. The extended-network-prefix is composedof the classful network-prefix and the subnet-number, as illustrated in Figure C-6:

F igure C -6

Ex tended-network -pre f i x

Network-prefix Host-numberSubset-number

Extended-network-prefix



The subnet mask has traditionally identified the extended-network-prefix. For example, if youhave the /16 address of 130.5.0.0 and you want to use the entire third octet to represent thesubnet-number, you need to specify a subnet mask of 255.255.255.0. The bits in the subnetmask and the Internet address have a one-to-one correspondence. The bits of the subnet maskare set to 1 if the system examining the address should treat the corresponding bit in the IPaddress as part of the extended-network- prefix. The bits in the mask are set to 0 if the systemshould treat the bit as part of the host-number, as illustrated in Figure C-7:

F igure C -7

Subnet mask

Network -Pre f i x

Subnet

Number

Host

Number

IP Address: 130.5.5.25 10000010.00000101.00000101.00011001

Subnet Mask: 255.255.255.0 11111111.11111111.11111111.00000000

Extended Network-Prefix

The standards describing modern routing protocols often refer to the extended-network-prefix-length rather than the subnet mask. The prefix length is equal to the number of contiguousone-bits in the traditional subnet mask. This means that specifying the network address130.5.5.25 with a subnet mask of 255.255.255.0 can also be expressed as 130.5.5.25/24. The/<prefix length> notation is more compact and easier to understand than writing out the maskin its traditional dotted-decimal format, as illustrated in Figure C-8:

F igure C -8

Ex tended-network -pre f i x l ength

130.5.5.25 10000010.00000101.00000101.00011001

255.255.255.0 11111111.11111111.11111111.00000000

or

130.5.5.25/24 10000010.00000101.00000101.00011001

24 Bit Extended Network-Prefix

However, it is important to note that modern routing protocols still carry the subnet mask.There are no Internet standard routing protocols that have a one-byte field in their header thatcontains the number of bits in the extended-network prefix. Rather, each routing protocol is stillrequired to carry the complete four-octet subnet mask.

Subnet Design Considerat ions

The deployment of an addressing plan requires careful thought on the part of the networkadministrator. The following four key questions must be answered before any design should beundertaken:

1 How many total subnets does the organization need today?

2 How many total subnets will the organization need in the future?

3 How many hosts are there on the organization's largest subnet today?

4 How many hosts will there be on the organization's largest subnet in the future?



The first step in the planning process is to take the maximum number of subnets required andround up to the nearest power of two. For example, if an organization needs 9 subnets, 23 (or 8)will not provide enough subnet addressing space, so the network administrator will need toround up to 24 (or 16). When performing this assessment, it is critical that the networkadministrator always allows adequate room for future growth. For example, if 14 subnets arerequired today, then 16 subnets might not be enough in two years when the 17th subnet needsto be deployed. In this case, it might be wise to allow for more growth and select 25 (or 32) as themaximum number of subnets.

The second step is to answer the question of whether IP addresses should be private or public.Private addresses are Class A 10.0.0.0-10.255.255.255, Class B 172.16.0.0-172.31.255.255, ClassC 192.168.0.0-192.168.255.255 and are for internal use only (not connected to the Internet orany other network, maintained by an organization). Public addresses are all other valid IPaddresses, assigned in accordance with IANA (Internet Assigned Network Authority)regulations and are globally unique. When designing a network, one must consider which ofthese two addresses schemes will be used. Private network IP addresses can be assigned whenthere will be no external network connections. If in the future external connections are requireda protocol such as Network Address Translator (NAT) can be used to translate between theseprivate and public addresses (this requires a pool of public addresses be available for this use aswell as routing hardware to support the protocol). Public addresses will assure that the devicescan be externally connected, but will require the proper procedures to acquire blocks of IPaddresses from the Internet authorities. A detailed determination of the IP addressingrequirements for the present and future must be assessed and enough time allowed for theappropriate IP address request paper work.

The third step is to make sure that there are enough host addresses for the organization'slargest subnet. If the largest subnet needs to support 50 host addresses today, 25 (or 32) will notprovide enough host address space so the network administrator will need to round up to 26

(or 64 –2).

The final step is to make sure that the organizations address allocation provides enough bits todeploy the required subnet addressing plan. For example, if the organization has a single /16, itcould easily deploy 4-bits for the subnet-number and 6-bits for the host number. However, if theorganization has several /24s and it needs to deploy 9 subnets, it may be required to subnet eachof its /24s into four subnets (using 2 bits) and then build the Internet by combining the subnetsof 3 different /24 network numbers. An alternative solution would be to deploy network numbersfrom the private address space (RFC 1918) for internal connectivity and use a Network AddressTranslator (NAT) to provide external Internet access.

Network Link Considerations

The following network link considerations are discussed below:

�� Frame Relay

�� Committed information rate

�� Local loop speed

�� Port speed

�� Committed burst size

Other network link options, such as ATM, are also available.



Frame Relay

Frame Relay provides a packet-switching data communications capability that is used acrossthe interface between user devices (for example, routers, bridges, host machines) and networkequipment (for example, switching nodes). User devices are often referred to as data terminalequipment (DTE), while network equipment that interfaces to DTE is often referred to as datacircuit-terminating equipment (DCE). The network providing the Frame Relay interface can beeither a carrier-provided public network or a network of privately owned equipment serving asingle enterprise.

As an interface between user and network equipment, Frame Relay provides a means forstatistically multiplexing many logical data conversations (referred to as virtual circuits) over asingle physical transmission link. This contrasts with systems that use onlytime-division-multiplexing (TDM) techniques for supporting multiple data streams. FrameRelay's statistical multiplexing provides more flexible and efficient use of available bandwidth.It can be used without TDM techniques or on top of channels provided by TDM systems.

Another important characteristic of Frame Relay is that it exploits the recent advances inwide-area network (WAN) transmission technology. Earlier WAN protocols such as X.25 weredeveloped when analog transmission systems and copper media were predominant. These linksare much less reliable than the fiber media/digital transmission links available today. Overlinks such as these, link-layer protocols can forego time-consuming error correction algorithms,leaving these to be performed at higher protocol layers. Greater performance and efficiency istherefore possible without sacrificing data integrity. Frame Relay is designed with thisapproach in mind. It includes a cyclic redundancy check (CRC) algorithm for detecting corruptedbits (so the data can be discarded), but it does not include any protocol mechanisms forcorrecting bad data (for example, by re-transmitting it at this level of protocol). Frame Relay,therefore, does not include explicit flow control procedures that duplicate those in higher layers.Instead, very simple congestion notification mechanisms are provided to allow a network toinform a user device that the network resources are close to a congested state. This notificationcan alert higher-layer protocols that flow control may be needed.

To provision the communication line from the Frame Relay circuit to the target site, the phonecompany will need to know the following parameters:

�� Committed Information Rate (CIR)

�� Local loop speed

�� Port speed

�� Committed burst size

Committed Information Rate (CIR)

The CIR represents the maximum sustained rate of data traffic that your carrier is committingto carry for you. You may burst above this rate, but your traffic above the CIR will be marked"discard eligible," and may get thrown away in the event of congestion in the network. So CIR isreally the only true data rate number of these three (local loop, port speed, CIR) that you cancount on. You could have, for example, a T1 local loop, a 384k port speed, but only 128k CIR.And you could only count on 128k throughput, though you might be able to burst for a shorttime up to 384k.



Local Loop Speed

The local loop speed is typically either T1 or 56k. These are the only two options available fromthe phone companies for frame relay. They are options not on the router, but when you buy theframe relay circuit from the Phone Company. They will ask you this question to provision theline. If you buy a T1 local loop, you can buy a port speed and CIR up to 1.5 Mbps. If you buy a56k circuit, the highest port speed and CIR you can buy is 56k and you could only count on 128kthroughput, though you might be able to burst for a short time up to 384k.

Port Speed

Port speed is a measure of the speed of access you buy from the frame relay network provider.This can vary from 15k to 1.5 Mbps. This parameter literally measures the speed at which youaccess into the frame relay providers network. This speed also represents the maximum speedup to which you can burst.

Committed Burst Size

Committed burst size is the maximum amount of data (in bits) that the network agrees totransfer, under normal conditions, during some defined time interval.

High Capacity Terrestrial Digital Service (T1)

T1 digital transport services are available through telephone companies and even manyInternet Service Providers (ISPs). T1 refers to a physical layer protocol that supportstransmission of digital serial data over TDM channels at rates up to 1.544 Mbps. A CSU/DSU isrequired on both ends of a T1 link to translate data from the Routers, over various physicalinterfaces (e.g. RS-232, RS-449, V.35, etc.), into the proper physical format and TDM channels(i.e. time slots). T1 service providers usually offer fractional T1 capabilities, wherein multiplesof 64 Kbps TDM channels can be purchased rather than an entire T1. An entire T1 wouldconstitute 24 of these 64 Kbps time slots.

CSU/DSU

A Channel Service Unit (CSU) is Customer Premises Equipment (CPE) that terminates a digitalcarrier circuit and provides line conditioning, diagnostics, and testing functions. A Data ServiceUnit (DSU) is CPE that provides an interface to a digital carrier such as a T1.

At the user end of every T1 and DDS (Digital Data Service) line is a CSU. The CSU can be aseparate device or be combined with a DSU as a dual function device. The carrier requires aCSU/DSU unit in any situation where a user has purchased a high-speed service such as a T1,Fractional T1, or a DDS 56k/64k line, as illustrated in figure C-9:

F igure C -9

Mul t ip lexer CSU/DSU

DSU CSURouter Telco

User interface(V.35 or RS-449)

Receive pair

Transmit pair

If the T1 CSU/DSU has more than one user port, it can function as a multiplexer allocating theDS-0 time slots between the ports in multiples of 64 Kbps or 56 Kbps.

CCCC ---- 1 01 01 01 0 N e t w o r k C o n s i d e r a t i o n s


The Router interface to CSU/DSU is an RS-449 type interface. The serial connector on therouter end of the cable is the same regardless of the type of serial interface (V.35, RS-232,RS-449, EIA-530, or X.21) on the modem or CSU/DSU.

The DSUs provide:

�� Timing to each user port

�� Input signal format manipulation -i.e., takes the incoming user data signals (e.g., RS-449,RS-232 or V.35) and converts them into the form needed for transmission over the Telcoprovided line. This conversion manipulates the input signal into the specified line code andframing format.

The three Primary Functions of the CSU are:

�� Protection for the T1 line and the user equipment from lightening strikes and other types ofelectrical interference and a keep-alive signal

�� Storage for keeping track of statistics

�� Capabilities for Telco initiated loopback

Fiber Channel Networks

The major application area of fiber channel, which became an American National StandardsInstitute (ANSI) standard in 1994, is to provide high-bandwidth (up to 100 Mbps) connectivityfor peripheral devices. Fiber channel defines a point-to-point or switched point-to-point link,which includes definitions of the physical layer, transmission code, and higher level functionssuch as flow control and multiplexing.

Access networks provide interconnections between the customer equipment and central officeslocations. The average distance of these types of networks is usually less than 3 miles. Thecomponents of access networks are extremely cost sensitive. The design of the access network isthus to minimize the use of active devices such as laser diodes or confine the use of such deviceswithin central offices. The current fiber deployment strategies are divided into the following twocategories: hybrid fiber coaxial (HFC) and fiber to home (or fiber in the loop).

E the rne t T ra f f i c

The Ethernet evolved from a random access protocol that was developed at the University ofHawaii in the 1970s. Ethernet protocol is located at the Data Link Layer, which sits on top ofthe Physical Layer in the Open Systems Interconnection (OSI) network model for computercommunications. The Data Link Layer is formed from the Logic Link Control (LLC-802.2)sub-layer on top of the Media Access Control (MAC-802.3), or simply Ethernet protocol. All802.3 MAC (Ethernet) standards share certain common features. Chief amongst them is acommon MAC framing format for the exchange of information. This format includes thefollowing:

�� A fixed preamble for synchronization, destination and source address for managing frameexchanges

�� A start of frame delimiter and length of frame field to track the boundaries of the frames

�� A frame check sequence to detect errors

�� A data field and a pad field for collision detection

N e t w o r k C o n s i d e r a t i o n s CCCC ---- 1 11 11 11 1


Prior to transmitting frames, the MAC layer senses the physical channel. If transmittingactivity is detected, the node continues to monitor until a break is detected, at which time thenode transmits its frame. Only one device (node) can send its frame to an intended destinationat a time. This mode of operation is called half-duplex. In spite of the prior channel sensingperformed, it is possible that the frame will collide with one or more other frames. Suchcollisions may occur either because two or more nodes concurrently initiate transmissionsfollowing the end of the previous transmission, or because propagation delays prevent a nodefrom sensing the transmission initiated by another node at the earlier instant.

In order to resolve collisions, the Ethernet nodes retransmit after a randomly chosen delay. Theprobability distribution of the retransmission delay of a given packet is updated each time thepacket experiences collision. The choice of the initial probability distribution of theretransmission delay, and the dynamics of its updates, determines whether the population ofnew and retransmitted users can transmit successfully. Thus, the retransmission algorithm liesat the heart of the Ethernet protocol.

Because of the collision resolution process, the order in which the Ethernet serves packetsdepends on the traffic intensity. During the periods of light traffic, service is first come, firstserve. During the periods of heavy contention, some colliding users will defer theirretransmission into the future.

Motorola Headend Ethernet Traffic

Motorola headend devices such as the DAC 6000, OM 1000, IRT∗, RPD*, and NC 1500 areinterconnected with network links from an Ethernet system with a mix of communicationspeeds. A network can have multiple Ethernet systems that are interconnected with routers,switches, or combinations thereof. Peak data rates are buffered depending on the device andtraffic load. The average data rate (during peak message loading) drives the size of thecommunication link.

The network link bandwidth availability depends on the network’s configuration, setup, andactivity. Variations in code download bandwidth, between 10 to 100 Kbps, will affect thenetwork bandwidth in some cases. These variations includes the following:

�� The number of MPEG packets per UDP frame

�� The number of packets per second

�� The number of objects per stream

�� The number of streams per multiplex

The amount of bandwidth available is also affected during interactive activity such as clientrequests, and the collisions that occur during client requests or server responses.

Switched Ethernet

To resolve the Ethernet’ s half-duplex deficiency, switched Ethernet techniques have been used.Switching directs network traffic in a very efficient manner; it sends information directly fromthe port of origin to its destination ports. Switching establishes a direct line of communicationbetween two ports and maintains multiple simultaneous links between various ports. Itmanages network traffic by reducing media sharing — traffic is contained to the segment forwhich it is destined.

CCCC ---- 1 21 21 21 2 N e t w o r k C o n s i d e r a t i o n s


Ethernet switches segment a LAN into many parallel-dedicated lines that can enable apowerful, scalable architecture. A switch port may be configured as a segment with manystations attached to it, or with a single station connected to it. The rule is that only oneconversation may originate from any individual port at a time, regardless of whether there areone or many stations connected off that port. That is, all ports still listen before they speak.

When a single LAN station is connected to a switched port, it may operate in full-duplex mode.Full duplex does not require collision detection; there is a suspension of MAC protocols. A singledevice resides on that port; therefore, there will be no collisions. An estimate for the aggregatebandwidth of an Ethernet switch may be calculated by multiplying the number of switchedports “n” by the media bit rate (mbr) and dividing this number by two since a conversationinvolves two parties (communication involves sender and receiver):

(n•mbr)/2 = ~aggregate bandwidth of an Ethernet switch

For full-duplex operation, the equation is the same except the division is unnecessary since asingle port both sends and receives information. Full-duplex switching enables traffic to be sentand received simultaneously. Aggregate throughputs for 10 Mbps Ethernet networks jump to 20Mbps, and from 100 Mbps to 200 Mbps. Hubs between a workgroup and a switch will not runfull duplex, because the hub is governed by collision detection requirements. (The workgroupconnected to the hub is unswitched Ethernet). Ethernet switches are used when there is a needto minimize collision domain. Not only it will provide hub operation, it also uses full-duplexmode whenever possible.


Abb re v i a t i on s and Ac r on yms

ARP Address Resolution Protocol

ATM Asynchronous Transfer Mode

BOOTP Boot Protocol

DAC 6000 Digital Addressable Control Computer

DCT* Digital Consumer Terminal

DLM Data Link Manager

DLS Download Server

DNS Domain Name System

EMM Entitlement Management Message

EPG Electronic Program Guide

GUI Graphical User Interface

HCT 1000 Headend Configuration Tool

HITS Headend In The Sky

IP Internet Protocol

IRT* Integrated Receive Transcoder 1000/2000

KLS Key List Server

LAN Local Area Network

MAC Media Access Conrtol

MPS* Modular Processing System

MSO Multiple System Operator

NAS National Authorization System

NC 1500 Network Controller

NC&S National Control and Service

OAM&P Operations, Administration, Maintenance, and Provisioning

OM 1000 Out-of-Band Modulator

OOB Out-of-Band

PID Packet identifier

RPC Remote Procedure Call

SNMP Simple Network Management Protocol

TCP/IP Transmission Control Protocol/Internet Protocol

TFTP Trivial File Transfer Protocol

TVGI TV Guide Interactive

UDP User Datagram Protocol

WAN Wide Area Network

473294-001-99

8/00

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