1 © 2000, Cisco Systems, Inc. Cisco Confidential QOS For IP Video Conference Albert Garcia [email protected]@cisco.com System Engineer, Cisco

1© 2000, Cisco Systems, Inc. Cisco Confidential

QOS For IP Video Conference

QOS For IP Video Conference

Albert Garcia [email protected]

System Engineer, Cisco Systems

11/14/2001

mailto:[email protected]

2© 2000, Cisco Systems, Inc.

AgendaAgenda

• QOS OverviewQOS Overview

• ClassificationsClassifications

• QOS Design

• H.323 Gatekeeper


Why QoS?Why QoS?

Larger Inputi.e. GE

Smaller Outputi.e. 10/100

Fewer Outputs

More Inputs

No matter how high capacity the backplane is…No matter what the PPS rating is…

No matter if it’s the fastest switch ever…

Congestion is present in ALL NetworksSo QoS will be required..

So lets look at just what QoS is….


Campus QoS Buffer Management and Multiple Queues

Campus QoS Buffer Management and Multiple Queues

• Output buffers can reach 100% in Campus networks

• When an output buffer congests, dropped packets occur at the ingress interfaces

• QoS required when there is a possibility of congestion in buffers

• Multiple Queues are the only way to “Guarantee” Voice Quality

Catalyst Switch

Video

To Core

Data

Data

Data TXTX

RX

RX

RX

RX

Queue assignment

based on Layer2/3

classification

Video put into “delay and

drop” sensitive

queue

Queue scheduling via Round Robin, Weighted RR

or PQ’ing; HW dependent

SiSiTXTX TX TX TX TX


What is QoS?What is QoS?

Policing(Rate Limiting) Rewriting

ClassificationScheduling

Congestion Management


3 Steps for CoS/QoS Implementation3 Steps for CoS/QoS Implementation

Classification – Marking the packet with a specific priority denoting a requirement for special service from the network.

Scheduling – Assigning packets to one of multiple queues (based on Classification) for expedited treatment through the network.

Provisioning – Accurately calculating the required bandwidth for all application and element overhead.


ClassificationClassification


Layer 2 and 3 Traffic Classification

Layer 2 and 3 Traffic Classification

VersionVersionLengthLength LenLen

Standard IPV4: Three MSB Called IP Precedence(DiffServ May Use Six D.S. Bits Plus Two for Flow Control)

Layer 3IPV4

Layer 3IPV4

IDID OffsetOffset TTLTTL ProtoProto FCSFCS IP-SAIP-SA IP-DAIP-DA DataDataToSToS1 Byte1 Byte

07 123456

IP Precedence

DSCP

Unused Bits;Flow Control

for DSCP

Three Bits Used for CoS(802.1D User Priority)

Layer 2802.1Q/pLayer 2

802.1Q/p

FCSFCSDATADATAPTPTTAGTAG

4 Bytes4 BytesSASADADASFDSFDPREAM.PREAM. TypTypee

VLAN IDVLAN IDCFICFIPRIPRI


CoS in 802.1Q (802.1p)CoS in 802.1Q (802.1p)

MAC Length/Type

MAC DATA

PAD

FCS

2

4

2

Used in:• IEEE 802.3ac (VLAN Tag

Task Force)

• IEEE 802.1Q

• IEEE 802.1p

VID (VLAN ID) —12 Bits

3 1

Tag Control Information

UserPriority CFI

Destination Address

Source Address

EtherType = TPID

6

6

2

802.1p


Type of Service (ToS)Type of Service (ToS)

VersionLength

VersionLength

ToS1 Byte

ToS1 Byte LenLen IDID Flags/

offset

Flags/offset

IPV4 HeaderIPV4 Header

Type of Service is a 1 Byte Field in the IPV4 Header

Used to indicate service to be applied to IP Packet

How is Priority assigned to an IP Packet?

TTLTTL ProtoProto FCSFCS IP-SAIP-SA IP-DAIP-DA DataData


IP PrecedenceIP Precedence

1 0 1 0 0 0 0 0 TOS = 10100000 = 160

IP Precedence = 101 = 5Precedence

111 Network Control110 Internetwork Ctl101 Critical100 Flash Override011 Flash010 Immediate001 Priority000 Routine

Delay

0 Normal1 Minimize

Throughput

0 Normal1 Maximize

Monetary Cost0 Normal1 Minimize

Reliability

0 Normal1 Maximize

Reserved

*ALWAYS* set to zero

P P P D T R M R

VersionLength

ToS1 Byte

Len …rest of the header…………….

IPV4 Header IPV4 Header contains ToS Bytecontains ToS Bytewhich equals 8which equals 8bits of which 3bits of which 3are used forare used forprioritypriority


Differentiated Services Code Point (DSCP)

Differentiated Services Code Point (DSCP)

1 0 1 0 1 0 0 0

VersionLength

ToS1 Byte

Len …………………….

IPV4 Header IPV4 Header contains ToS Bytecontains ToS Bytewhich equals 8which equals 8bits of which bits of which 6are used forare used forDSCPDSCP

Refer to RFC 2474 (Definition of the DifferentiatedServices Field (DS Field) in the IPv4 and IPv6 Headers).

DSCP can yield up to 64 different levels of Priority I.e. 2 ^^8

The Catalyst 6K assigns an internal DSCP header to a frame as it transitsthe switch (not to be confused with the actual DSCP)

This value is derived from an existing CoS/ToS value and is used to rewritethe CoS/ToS on egress

TOS = 10101000 = 168DSCP = 101010 = 42


DiffServ BehaviorsDiffServ Behaviors

EF

Best Effort

AF11

AF21

AF31

AF41

AF12 AF13

AF22 AF23

AF32 AF33

AF42 AF43

Expedited Forwarding

AssuredForwarding

Per-Hop Behaviours (PHB)DiffServ Code Points

(DSCP)

101110

001010 001100 001110

010010 010100 010110

011010 011100 011110

100010 100100 100110

Class 1

Class 2

Class 3

Class 4

Low Drop Pref

Med Drop Pref

High Drop Pref

000000


Class of Service (CoS)Class of Service (CoS)

IP Header Data

EthernetHeader Data

IP Priority is hidden when encapsulatedBy Ethernet Frame

CoS bits in Ethernet header providepriority

Class of Service bits exist in an ISL Header andAn 802.1Q Header

Class of Service bits exist in an ISL Header andAn 802.1Q Header

ToS bits can bemapped to CoS bits

and vice versa


MappingsMappings

CoS DSCP IP Precedence01234567

01234567

0-78-15

16-2324-3132-3940-4748-5556-63

You can map whatever to whatever


Cisco AVVID ClassificationVoice with CallManagerVoice with CallManager

Cisco AVVID ClassificationVoice with CallManagerVoice with CallManager

• VoiceVoIP Control Channels

H.323 = TCP 1720, 11xxx (RAS = TCP 1719)

Skinny = TCP 2000-2002

ICCP = TCP 8001-8002

MGCP = UDP 2427, TCP 2428

CoS = 3, IP Prec = 3, DSCP = AF31 (26)

VoIP Bearer Channels

UDP 16384-32767

CoS = 5, IP Prec = 5, DSCP = EF (46)


Cisco AVVID Classification, Cont.Video ClassificationVideo Classification

Cisco AVVID Classification, Cont.Video ClassificationVideo Classification

• VideoVideo Control ChannelsH.323 = TCP 1720, 11xxx (RAS = TCP 1719)


Video Bearer ChannelsUDP 16384-32767



Cisco AVVID Classification, Cont.Data Application ClassificationData Application Classification

Cisco AVVID Classification, Cont.Data Application ClassificationData Application Classification

• DataSome data applications may need special handling from the network

This can be for business, technical or Layer 8 reasons

CoS = 0-2, IP Prec = 0-2, DSCP = 0-23

• RecommendationsOnly classify when necessary

Modifying WRED thresholds may be required to insure performance

For a CoS/ToS = 2 applications, configure Queue #1’s 2nd Threshold (CoS/ToS = 2) to drop at 95% instead of 50%


QOS DesignQOS Design


TXTX

Campus QoS Campus QoS

TX

Use LLQ on Campus router WAN. Use mod-CLI for L3 -> L2

scheduling on the Ethernet interface

12.1(5)T Gatekeeper for

Admission Control and dial

plan

TX

Branch Ethernet switches with

multiple queuing based on CoS on

all interfaces

Classify all IP Video traffic

CoS=4All Data traffic

CoS=0

WAN

NJ Edge

All incoming IP Video from NJ Edge should

already be tagged as DSCP=AF41 from NJ Edge

Colleges

All incoming video from WAN

should be classified as DSCP=AF41


Link Capacity = (Min BW for Voice + Min BW for Video + Min BW for Data) / 0.75

Nothing is Free - Especially on low speed links - Engineer the network for Data, Voice, and Video

Sources of Trouble for QOSProvisioningProvisioning

Sources of Trouble for QOSProvisioningProvisioning

0.75 x Link Capacity0.75 x Link Capacity

Video DataVoice Routingetc

Link CapacityLink Capacity

Voice/VideoControl


Layer 3 Policing

Multiple queues on all ports; Priority Queuing for VoIP

WRED within Data queue for Congestion

Management

Layer 3 Policing

Multiple queues on all ports; Priority Queuing for VoIP

WRED within Data queue for Congestion

Management

Speed and Duplex settings

Classification/Trust on Video Endpoint and Access switch

Multiple queues on Access ports

Speed and Duplex settings

Classification/Trust on Video Endpoint and Access switch


Low-Latency Queuing

Link Fragmentation and Interleave

Bandwidth Provisioning

Admission Control

Low-Latency Queuing

Link Fragmentation and Interleave

Bandwidth Provisioning

Admission Control

QoS is Needed to Minimize Packet Loss, Delay and Delay Variation

Where QoS is Needed

QoS is Needed to Minimize Packet Loss, Delay and Delay Variation

Where QoS is NeededCentral Campus

WAN

Remote Branch

QoS - Campus AccessQoS - Campus Access QoS - Campus DistribQoS - Campus Distrib

Classification and Trust Boundaries on IP Video endpoints , Access Layer switch and router


Classification and Trust Boundaries on IP Video endpoints , Access Layer switch and router


QoS - WANQoS - WAN QoS - BranchQoS - Branch

SiSi

SiSi


H.323 GatekeeperH.323 Gatekeeper


Multimedia Conference ManagerMultimedia Conference Manager

Jack

Yvette

Multimedia Conference Manager

Ms. Gomez

Kim

Mike

IP

ISDN

Cisco IOS software feature that functions as a Cisco IOS software feature that functions as a high-performance H.323 gatekeeper and proxyhigh-performance H.323 gatekeeper and proxy

MCM

Cisco 2500, 3810, 2600, 3600, 7200


Multi Zone WAN ModelMulti Zone WAN Model

MCU

GK

QoS Enabled IP WAN

GW

ISDNH.320Video Unit

MCU

Gatekeeper

Gateway

H.323 TerminalsH.323 Terminals

H.323 Terminals

GK

GK

MCU

MCU

Zone 1 Zone 2

Zone 3


NJ Edge Gatekeeper DesignNJ Edge Gatekeeper Design

Campus A Campus B

Gatekeeper/proxy Gatekeeper/proxy

DirectoryGatekeeper

ATM

NJ Edge POP

3540 MCU 3540 MCU


Features and Benefits ofCisco Gatekeeper

Features and Benefits ofCisco Gatekeeper

Multimedia Conference Manager FeaturesMultimedia Conference Manager Features• Allows the implementation of QoS policies to guarantee Allows the implementation of QoS policies to guarantee

bandwidth availability and manage bandwidth usagebandwidth availability and manage bandwidth usage• SecuritySecurity• Address resolution and call routingAddress resolution and call routing• User authentication and call accountingUser authentication and call accounting

Multimedia Conference Manager BenefitsMultimedia Conference Manager Benefits• Provides gatekeeper, proxy, and routing functions on a single Provides gatekeeper, proxy, and routing functions on a single

hardware/software platformhardware/software platform• Accommodates small to large H.323 network deployments Accommodates small to large H.323 network deployments

according to router platformsaccording to router platforms• Is interoperable with H.323v1 and v2-compliant endpointsIs interoperable with H.323v1 and v2-compliant endpoints• Uses e-mail address instead of IP addressesUses e-mail address instead of IP addresses


Call Admission Control (CAC)Bandwidth Management

Call Admission Control (CAC)Bandwidth Management

GK GK

Interzone—Bandwidth from a local or default zone to all other local zones or remote zones(1 and 3

Remote—Bandwidth to and from all local zones to all remote zones – BETWEEN PHYSICAL GATEKEEPERS (3 only)

Total—Total bandwidth in a zone (1+2+3)

Session—Bandwidth per session in a zone

Zone A

Zone B

Zone C

IOS Bandwidth Commands

13

2


Cisco Router IOS MCMCisco Router IOS MCM

• MCM gatekeeperMCM gatekeeper

Address resolution

User authorization

Zone bandwidth management

• MCM proxyMCM proxy

Security (address translation)

QoS for non QoS capable hosts and gateways,

Application specific routingProxyProxy

GatekeeperGatekeeper

MCM PerformsTwo Functions

MCM


Cisco MCMProxy Security

Cisco MCMProxy Security

MCM H.323 Gatekeeper/Proxy

H.323 Clients

H.323 Room

System

NetworkNetwork

H.323 Clients

H.323 Room

System

218.6.5.1 192.7.6.1

10.1.1.1010.3.1.12

11

22

33


Key Differentiators of MCMKey Differentiators of MCM

Multimedia Conference Manager Differentiators Multimedia Conference Manager Differentiators from other Vendorsfrom other Vendors

• Unique in offering proxy services as well as Unique in offering proxy services as well as gatekeeper servicesgatekeeper services

• Combines gatekeeper/proxy services with routing Combines gatekeeper/proxy services with routing capabilities on a single hardware platformcapabilities on a single hardware platform

• Supports a multiservice IP networking environment Supports a multiservice IP networking environment for data, voice, and H.323 videoconferencing on for data, voice, and H.323 videoconferencing on a common software basea common software base

• Offers scalability through a wide range of Cisco Offers scalability through a wide range of Cisco router platformsrouter platforms

• Offers excellent price/performance ratio for small Offers excellent price/performance ratio for small and large H.323 network deploymentsand large H.323 network deployments


Documents

1 © 2000, Cisco Systems, Inc. Cisco Confidential QOS For IP Video Conference Albert Garcia [email protected]@cisco.com System Engineer, Cisco