1 © 2000, Cisco Systems, Inc. Cisco Confidential QOS For IP Video Conference Albert Garcia System Engineer, Cisco Systems 11/14/2001

2 © 2000, Cisco Systems, Inc. Agenda QOS OverviewQOS Overview ClassificationsClassifications QOS Design H.323 Gatekeeper

3 © 2000, Cisco Systems, Inc. Why QoS? Larger Input i.e. GE Smaller Output i.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 Networks So QoS will be required.. So lets look at just what QoS is….

4 © 2000, Cisco Systems, Inc. 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 TX 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 TX

5 © 2000, Cisco Systems, Inc. What is QoS? Policing (Rate Limiting) Rewriting Classification Scheduling Congestion Management

6 © 2000, Cisco Systems, Inc. 3 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.

7 © 2000, Cisco Systems, Inc. Cisco Confidential Classification

8 © 2000, Cisco Systems, Inc. Layer 2 and 3 Traffic Classification VersionLengthLen Standard IPV4: Three MSB Called IP Precedence (DiffServ May Use Six D.S. Bits Plus Two for Flow Control) Layer 3 IPV4 IDOffsetTTLProtoFCSIP-SAIP-DAData ToS 1 Byte IP Precedence DSCP Unused Bits; Flow Control for DSCP Three Bits Used for CoS (802.1D User Priority) Layer Q/p FCSDATAPT TAG 4 Bytes SADASFDPREAM. Typ e VLAN ID CFI PRI

9 © 2000, Cisco Systems, Inc. CoS in 802.1Q (802.1p) MAC Length/Type MAC DATA PAD FCS Used in: IEEE 802.3ac (VLAN Tag Task Force) IEEE 802.1Q IEEE 802.1p VID (VLAN ID) —12 Bits 31 Tag Control Information User Priority CFI Destination Address Source Address EtherType = TPID p

10 © 2000, Cisco Systems, Inc. Type of Service (ToS) Version Length Version Length ToS 1 Byte ToS 1 Byte Len ID Flags/ offset Flags/ offset IPV4 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? TTL Proto FCS IP-SA IP-DA Data

11 © 2000, Cisco Systems, Inc. IP Precedence TOS = = 160 IP Precedence = 101 = 5 Precedence 111 Network Control 110 Internetwork Ctl 101 Critical 100 Flash Override 011 Flash 010 Immediate 001 Priority 000 Routine Delay 0 Normal 1 Minimize Throughput 0 Normal 1 Maximize Monetary Cost 0 Normal 1 Minimize Reliability 0 Normal 1 Maximize Reserved *ALWAYS* set to zero PPPDTRMR Version Length ToS 1 Byte Len…rest of the header……………. IPV4 Header contains ToS Byte which equals 8 bits of which 3 are used for priority

12 © 2000, Cisco Systems, Inc. Differentiated Services Code Point (DSCP) Version Length ToS 1 Byte Len……………………. IPV4 Header contains ToS Byte which equals 8 bits of which bits of which 6 are used for DSCP Refer to RFC 2474 (Definition of the Differentiated Services 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 transits the switch (not to be confused with the actual DSCP) This value is derived from an existing CoS/ToS value and is used to rewrite the CoS/ToS on egress TOS = = 168 DSCP = = 42

13 © 2000, Cisco Systems, Inc. DiffServ Behaviors EF Best Effort AF11 AF21 AF31 AF41 AF12AF13 AF22AF23AF32AF33AF42AF43 Expedited Forwarding Assured Forwarding Per-Hop Behaviours (PHB) DiffServ Code Points (DSCP) Class 1 Class 2 Class 3 Class 4 Low Drop Pref Med Drop Pref High Drop Pref

14 © 2000, Cisco Systems, Inc. Class of Service (CoS) IP HeaderData Ethernet Header Data IP Priority is hidden when encapsulated By Ethernet Frame CoS bits in Ethernet header provide priority Class of Service bits exist in an ISL Header and An 802.1Q Header Class of Service bits exist in an ISL Header and An 802.1Q Header ToS bits can be mapped to CoS bits and vice versa

15 © 2000, Cisco Systems, Inc. Mappings CoSDSCPIP Precedence You can map whatever to whatever

16 © 2000, Cisco Systems, Inc. Voice with CallManager Cisco AVVID Classification Voice with CallManager Voice VoIP Control Channels H.323 = TCP 1720, 11xxx (RAS = TCP 1719) Skinny = TCP ICCP = TCP MGCP = UDP 2427, TCP 2428 CoS = 3, IP Prec = 3, DSCP = AF31 (26) VoIP Bearer Channels UDP CoS = 5, IP Prec = 5, DSCP = EF (46)

17 © 2000, Cisco Systems, Inc. Video Classification Cisco AVVID Classification, Cont. Video Classification Video Video Control Channels H.323 = TCP 1720, 11xxx (RAS = TCP 1719) CoS = 3, IP Prec = 3, DSCP = AF31 (26) Video Bearer Channels UDP CoS = 4, IP Prec = 4, DSCP = AF41 (42)

18 © 2000, Cisco Systems, Inc. Data Application Classification Cisco AVVID Classification, Cont. Data Application Classification Data Some 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 Recommendations Only 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%

19 © 2000, Cisco Systems, Inc. Cisco Confidential QOS Design

20 © 2000, Cisco Systems, Inc. TX 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=4 All 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

21 © 2000, Cisco Systems, Inc. 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 Provisioning Sources of Trouble for QOS Provisioning 0.75 x Link Capacity Video Data Voice Routing etc Link Capacity Voice/Video Control

22 © 2000, Cisco Systems, Inc. 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 Multiple queues on Access ports 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 Central Campus WAN Remote Branch QoS - Campus Access QoS - Campus Distrib Classification and Trust Boundaries on IP Video endpoints, Access Layer switch and router Multiple queues on Access ports Classification and Trust Boundaries on IP Video endpoints, Access Layer switch and router Multiple queues on Access ports QoS - WAN QoS - Branch

23 © 2000, Cisco Systems, Inc. Cisco Confidential H.323 Gatekeeper

24 © 2000, Cisco Systems, Inc. Multimedia Conference Manager Jack Yvette Multimedia Conference Manager Ms. Gomez Kim Mike IP ISDN Cisco IOS software feature that functions as a high-performance H.323 gatekeeper and proxy MCM Cisco 2500, 3810, 2600, 3600, 7200

25 © 2000, Cisco Systems, Inc. Multi Zone WAN Model MCU GK QoS Enabled IP WAN GW ISDN H.320 Video Unit MCU Gatekeeper Gateway H.323 Terminals GK MCU Zone 1 Zone 2 Zone 3

26 © 2000, Cisco Systems, Inc. NJ Edge Gatekeeper Design Campus A Campus B Gatekeeper/proxy Directory Gatekeeper ATM NJ Edge POP 3540 MCU

27 © 2000, Cisco Systems, Inc. Features and Benefits of Cisco Gatekeeper Multimedia Conference Manager Features Allows the implementation of QoS policies to guarantee bandwidth availability and manage bandwidth usageAllows the implementation of QoS policies to guarantee bandwidth 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 Benefits Provides gatekeeper, proxy, and routing functions on a single hardware/software platformProvides gatekeeper, proxy, and routing functions on a single hardware/software platform Accommodates small to large H.323 network deployments according to router platformsAccommodates small to large H.323 network deployments according to router platforms Is interoperable with H.323v1 and v2-compliant endpointsIs interoperable with H.323v1 and v2-compliant endpoints Uses address instead of IP addressesUses address instead of IP addresses

28 © 2000, Cisco Systems, Inc. Call Admission Control (CAC) Bandwidth Management 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 1 3 2

29 © 2000, Cisco Systems, Inc. Cisco 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 routing Proxy Gatekeeper MCM Performs Two Functions MCM

30 © 2000, Cisco Systems, Inc. Cisco MCM Proxy Security MCM H.323 Gatekeeper/Proxy H.323 Clients H.323 Room System Network H.323 Clients H.323 Room System

31 © 2000, Cisco Systems, Inc. Key Differentiators of MCM Multimedia Conference Manager Differentiators from other Vendors Unique in offering proxy services as well as gatekeeper servicesUnique in offering proxy services as well as gatekeeper services Combines gatekeeper/proxy services with routing capabilities on a single hardware platformCombines gatekeeper/proxy services with routing capabilities on a single hardware platform Supports a multiservice IP networking environment for data, voice, and H.323 videoconferencing on a common software baseSupports a multiservice IP networking environment for data, voice, and H.323 videoconferencing on a common software base Offers scalability through a wide range of Cisco router platformsOffers scalability through a wide range of Cisco router platforms Offers excellent price/performance ratio for small and large H.323 network deploymentsOffers excellent price/performance ratio for small and large H.323 network deployments

32 © 2000, Cisco Systems, Inc.