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Networking/Ethernet Training
Guy WalkerTraining and A&E Manager
2 /Comnet / 2008
“Review”
IP addressing scheme (class A, B, etc) MAC address vs. IP address TCP vs UDP OSI layers Topologies Why is it hot?
What solutions do you use? What issues are you seeing?
3 /Comnet / 2008
Basic Network Components
Switches, hubs Cabling Edge devices Protocols
Language of packets Relates to network Relates to devices on network
00101101011100101001010101010100101101110000101
0010
1101
0111
0010
1001
0101
0101
0100
1011
0111
0000
101
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Corporate Office Building
Gigabit Network
WAN
100Mbps Network
Core Switch
Gateway
Edge Switch
Bridge
Remote Office Building
Wireless Bridge
Edge Device
Edge Device
DVR
Parking Lot
Remote Client
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MATRIX SWITCH
VOIPVIDEO
IPCODEC
VOIP
CARD ACCESS
INTERCOM DVR
DATA OVER IP
Security Architecture Example
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Types of Networks
LAN – Local Area Network• A network covering a small physical area, like a home, office, or small group of buildings, such as a
school, or an airport.
MAN – Metro Area Network• A MAN is a network larger than a LAN, ranging from several blocks of buildings to entire cities. A MAN
might be owned and operated by a single organization, but it usually will be used by many individuals and organizations. MANs might also be owned and operated as public utilities.
WAN – Wide Area Network• A network that covers a broad area (i.e., any network whose communications links cross metropolitan,
regional, or national boundaries). Less formally, a WAN is a network that uses routers and public communications links.
Source: IEEE Standards
7 /Comnet / 2008
Types of Messages
Unicast• A one-to-one communication link. Packets are sent from one IP address to another IP address.
Broadcast• A one-to-everyone communication link. Packets are sent from one IP address to all ports and IP
addresses on the network.
Multicast• A dynamic, one-to-many communication link. Packets are sent from one IP address to any other IP
addresses that request the packets. Since this a dynamic relationship, devices can “subscribe” and “un-subscribe” at will.
• IGMP – Internet Group Multicasting Protocol
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Multicasting Example
0010110101110010100101010101010010110111
0010
1101
0111
0010
1001
0101
0101
0100
1011
011
0010
11
0010110101110010100101010101010010110110010101000110101
0010
11
Command Center Remote Client
0010
11
0010
11
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The Open Systems Interconnection model defines seven functional layers of the overall system. A layer is a group of conceptually similar functions that provide services to the layer above it and receives service from the layer below it.
Application
Session
Transport
Network
Data link
Physical
Presentation
7
6
5
4
3
2
1
Mostlyhardware
Mostlysoftware
Layer 1 (Hub and cables)
Layer 3 (Router)
Layer 2 (Switch)
OSI Model
Source: Wikimedia Commons
10 /Comnet / 2008
Application
Session
Transport
Network
Data link
Physical
Presentation
7
6
5
4
3
2
1
Mostlyhardware
Mostlysoftware
RS-232, POTS, 802.11 (wireless), 10Base-T
IP, IGMP
802.3 (Ethernet), VLAN, PPP
OSI Model - Examples
TCP, UDP
Half/Full Duplex
MPEG, SSL
HTTP, Telnet
Source: Wikimedia Commons
11 /Comnet / 2008
Ethernet
Ethernet is a family of frame-based computer networking technologies for local area networks (LANs). Packets
It defines a number of wiring and signaling standards for the Physical Layer of the OSI networking model, through means of network access at the MAC/Data Link Layer, and a common addressing format. Layer 1 and 2
Ethernet is standardized as IEEE 802.3. This includes versions for twisted pair cabling, fiber optics and wireless. 10Base-T 100Base-T (Fast Ethernet) 1000Base-T (Gigabit) 100Base-FX, etc. (fiber-based)
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Ethernet Packet
Source: Wikimedia Commons
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Connectors and Cabling
RJ45 – more correctly called the 8 Position 8 Contact (8P8C) connector.
SC – fiber optic cable connector
LC – fiber optic cable connector
RJ-45 SC LC
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Connectors and CablingCategory 5 UTP Four twisted pairs in a single cable jacket. Up to 100Mbps Typically has three twists per inch of each twisted pair of 24 gauge copper. NO Power Over Ethernet (POE).
Category 5e UTP Four twisted pairs in a single cable jacket, but more twists per inch to
avoid crosstalk. Up to 1000Mbps.
Category 6 UTP or STP Four twisted pairs. Up to 1000Mbps
Category 7 STP Four individually shielded pairs inside an overall shield. Up to 10Gig
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The Media Access Control layer of the OSI stack. This is the lowest layer (Layer 1) and makes for an easier and
more simplified packet transfer.
A MAC address is a 48-bit address defined by the manufacturer and the hardware. It is a hard-coded, unique
address that is burned onto the device during manufacturing.
The first three bytes will define the manufacturer and the last three bytes define the device.
00-2A-9Z-3C-78-05
Manufacturer Hardware
MAC Address
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MAC Addresses essentially provide an unchanging, unique network identifier for a device.
This also adds another layer of security that may be utilized within the network.
Switches convert IP addresses to MAC addresses to deliver packets.
MAC Address
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The Internet Protocol Suite (commonly TCP/IP) is the set of communications protocols used for the Internet and other similar networks. It is named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard.
TCP/IP
Internet Protocol
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Internet Protocol
TCP - is responsible for verifying the correct delivery of data from client to client, and to trigger retransmission until the data is correctly and completely received.
IP - is responsible for moving packets of data from node to node. IP forwards each packet based on the IP address. The IP scheme operates through “gateway” machines that allows data to move from department to organization to region and then around the world.
Socket - is an end-point of a bidirectional process-to-process communication flow across an IP based network. A socket is an interface between an application process and the TCP/IP protocol stack provided by the operating system.
Source: Wikimedia Commons
19 /Comnet / 2008
IP Version 4 (current)
32 bit binary code 4 sections of 8 bits each Network ID, Host ID
IP Addressing rules: The Network ID cannot start with a ZERO
The Host ID cannot end with a ZERO
No two systems, on the same network, can have the same Host ID
No two systems on one network can have the same IP Address.
An octet’s value will never exceed 255
IP Addressing 126.15.101.10
IP Version 6 (future)
128 bit binary code
3ffe:1900:4545:3:200:f8ff:fe21:67cf
Backwards compatible
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Class A
n = network h = host
nnnnnnnn.hhhhhhhh.hhhhhhhh.hhhhhhhh
NOTES: The 127.1.1.1 address is reserved for MS Loopback. Over 16 million possible HOSTS
Network ID Host ID
First Octet range (1-127)
IP Addressing
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Class B
n = network h = host
nnnnnnnn.nnnnnnnn.hhhhhhhh.hhhhhhhh
NOTES: Over 65,000 possible HOSTS
Network ID Host ID
First Octet range (128-191)
IP Addressing
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Class C
n = network h = host
nnnnnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh
NOTES: Only 254 possible HOSTS
Network ID Host ID
First Octet range (192-223)
IP Addressing
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Class D
Multicast
224.0.0.0 to 239.255.255.255
Class E
Experimental
240.0.0.0 to 254.255.255.255
IP Addressing
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IP AddressingPrivate Addresses Three ranges assigned by Internet Assigned Numbers Authority (IANA):
Computers not connected to the Internet do not need to have globally unique IP addresses. These addresses are not routed on the Internet, and thus do not need to be coordinated with an IP address registry.
10.0.0.0 10.255.255.255
172.16.0.0 172.31.255.255
192.168.0.0 192.168.255.255
To
To
To
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IP AddressingMulticasting IGMP – Internet Group Management Protocol Reserved IP Addresses:
Any Ethernet packet with an IP destination within this range will be treated as a Multicast stream by network switches/routers that support IGMP.
A multicast address is associated with a group of interested receivers. The sender sends a packet to the multicast address, and the intermediary routers take care of making copies and sending them to all receivers that have registered their interest in data from that sender
This range was formerly called "Class D."
224.0.0.0 239.255.255.255To
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Multicasting Example
0010110101110010100101010101010010110111
0010
1101
0111
0010
1001
0101
0101
0100
1011
011
0010
11
0010110101110010100101010101010010110110010101000110101
0010
11
Command Center Remote Client
0010
11
0010
11
27 /Comnet / 2008
IP Scheme
WAN switches
Workgroup switches
Workstations, cameras, access
Source: Microsoft TechNet
28 /Comnet / 2008
Subnet MaskingA way of further segregating HOSTS in a network.
Subnetting allows the network to be logically divided regardless of the physical layout of a network, since it is possible to divide a physical network into several subnets by configuring different host computers to use different routers
Class A – 255.0.0.0
Class B – 255.255.0.0
Class C – 255.255.255.0
IP Addressing
Class C – 192.168.151.1
Class C – 255.255.255.0
masking
29 /Comnet / 2008
Virtual Local Area Network
802.1Q
A configuration scenario where hosts are separated into groups to segment traffic on the network.
VLANs are created to provide the segmentation services traditionally provided by routers in LAN configurations. VLANs address issues such as scalability, security, and network management.
Switches may not bridge IP traffic between VLANs as it would violate the integrity of the VLAN broadcast domain.
Virtual LANs are essentially Layer 2 constructs, compared with IP subnets which are Layer 3 constructs.
VLAN
Source: Wikimedia Commons
30 /Comnet / 2008
Video(VLAN 2)
Operations Center
(Operation Center belongs to all 3 VLANs)
Card Access
(VLAN 3)
Emergency Phone (VLAN 1)
VLAN
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Video
Port 1 VLAN 1
Port 2 VLAN 2
Port 5 VLAN 3
Emergency Phone Card Access
IP Codecs
VLAN
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Network protocols are a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints.
Most protocols specify one or more of the following behaviors: Detection of the underlying physical connection (wired or
wireless), or the existence of the other endpoint or node Handshaking Negotiation of various connection characteristics How to start and end a message How to format a message What to do with corrupted or improperly formatted messages Termination of the session or connection
Protocols
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SNMPSimple Network Management ProtocolSNMP is used to monitor network-attached devices for conditions that warrant administrative attention. It consists of a set of standards for network management, including an Application Layer protocol, a database schema, and a set of data objects.
MIB – Mgmt Information Base – a type of database that describes the condition of a network device.
MIB Library Agent TRAP
RMONRemote MONitoring
A MIB that uses SNMP to communicate “Flow based” monitoring versus SNMP’s “device based” monitoring A little easier to implement
Protocols
RFC 3411 — An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks
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Routing
A Layer 3 protocol
Routing is utilized to effectively manage data packets on the network. The Router does this by the use of a preconfigured “Routing Table”.
This can be accomplished a few different ways based on the level of routing allowed by the Router.
The three common routing tools are as follows:
IP Address
MAC Address
System Name
Protocols
35 /Comnet / 2008
RIP – Routing Information Protocol - an older interior gateway protocol (IGP) using the distance-vector routing algorithm. Considered outdated.
IS-IS – Intermediate System to Intermediate System: is a link-based routing protocol, meaning that it operates by flooding network topology information throughout the routers. Each router will then independently build a picture of the network's topology. Likewise, packets are forwarded based on the best path through the network to the destination address.
Protocols
36 /Comnet / 2008
OSPF – Open Shortest Path First - is another dynamic routing protocol for use in IP networks. Specifically, it is a link-state routing protocol and falls into the group of interior gateway protocols, operating within an autonomous system.
TCP versus UDP
TCP has error correction
UDP is “fire and forget”
Implications for video streaming
Protocols
37 /Comnet / 2008
IEEE 802.1d
Defined as where two bridges are used to interconnect the same two computer network segments, spanning tree is a protocol that allows the bridges to exchange information so that only one of them will handle a given message/packet that is being sent between two computers within the network.
The spanning tree protocol prevents the condition known as a bridge loop.
Also provides redundancy capability when switches are connected in a ring topology.
30 to 50 second response.
Spanning Tree Protocol
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IEEE 802.1w
Same purpose as STP, but with faster results – and it’s backwards compatible to STP.
Less than 1 second response.
Rapid Spanning Tree Protocol
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Rapid Spanning Tree Protocol
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RSTP and IGMP
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RSTP and IGMP
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QoS
Quality of Service is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow.
CoS
Class of Service is a field within a layer two Ethernet frame header. It specifies a priority value of between 0 (signifying best-effort) and 7 (signifying priority real-time data) that can be used by Quality of Service disciplines to differentiate traffic.
DHCP (Server)
Dynamic Host Configuration Protocol is used by networked devices (hosts) to obtain the parameters necessary for operation in an IP network.
NTP
Network Time Protocol is a protocol for distributing the Coordinated Universal Time (UTC) to computer systems across a network.
Protocols
43 /Comnet / 2008
Dropped Packets
Routers or switches might fail to deliver (drop) some packets. This is normal for most networks and is not a concern unless it happens in large amounts.
Lost Packets
This is not good. This means packets were dropped but can’t be retransmitted.
Delay
It might take a long time for a packet to reach its destination because it gets held up in long queues, or takes a less direct route to avoid congestion. In some cases, excessive delay can render an application, such as video, unusable.
Jitter
Packets from the source will reach the destination with different delays. This can seriously affect the quality of streaming audio and/or video. (UDP can solve this)
Real Problems
44 /Comnet / 2008
Bad IP Scheme
Can cause lots of problems – like edge devices dropping off the network.
Edge Devices
These need to be configured properly, especially video. Are reduced frame rates being used? Is it your recorder? etc
Multicast Support
All network devices need to support IGMP on large or busy systems.
Bandwidth
Are you exceeding limits? What is an appropriate limit?
Standard vs. Custom Protocols
Many big switch manufacturers customize standard protocols.
Problems, Really?
45 /Comnet / 2008
Wireless
IEEE 802.11 is a set of standards for wireless local area networks (WLAN), in the 5 GHz and 2.4 GHz public spectrum bands (unlicensed).
802.11b and 802.11g – use 2.4GHz ISM band and gets up to 54Mbps over up to 38 meters.
802.11n – not a standard yet, but up to 600Mbps by utilizing MIMO.
Point-to-Point Point-to-Multipoint Mesh
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Wireless Topologies
Point-to-Point
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Wireless Topologies
Point-to-Multipoint
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Wireless Topologies
Mesh
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Wireless
Pros Less expensive than running cable Indoor and outdoor Flexible
Cons Unreliable Interference Limitations
50 /Comnet / 2008
Power Over Ethernet
PoE IEEE 802.3af DC power over Ethernet cable - CAT 5e or higher Supplies 48V at 350 mA max 13 Watts max
PSE – Power Source Equip.PD – Powered DeviceMidspan HubEndspan Hub
Can you put a non-PoEDevice into a PoE switch?
25k Ohm resistor
802.3at standard coming – supplies more power
51 /Comnet / 2008
Ethernet Advantages- Flexible Open Architecture IEEE 802.x
- Not Vendor Specific
- Extremely Scalable
- Lost Cost Solution
- Designed for Reliability
- Bandwidth is only used when needed
- Variety of Topologies Available
- Widely Available Management Tools
Summery / Review
