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© 2010 Cisco and/or its aff iliates. Al l rights reserved. Cisco PublicPresentation_ID 2

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Session Goals

To provide you with a thorough

understanding of the Catalyst6500 IP Multicast architectureand packet flow

To provide you with a thoroughunderstanding of the Catalyst4500 & 4900 IP Multicast

architecture and packet flow

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Session Assumptions

Working understanding of

General (platform-independent)IPv4 & IPv6 Multicast

Working understanding of

Catalyst 6500 & 4500/4900(platform-dependent)architecture and operation

General Catalyst 4500/4900 architecture covered in:RST-3445: Cisco Catalyst 4500 Switch Architecture

General Catalyst 6500 architecture covered in:RST-3465: Cisco Catalyst 6500 Switch Architecture

General IP Multicast architecture covered in:IPM-1261: Introduction to IP Multicast

Advanced IP Multicast architecture covered in:IPM-2008: Advanced Topics in IP Multicast Deployment

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IP Multicast - Agenda 1/3

Multicast Overview (15-20m)

• PIM Distribution Modes (~5m)• IGMP/MLD & Snooping (~2m)

• Multicast VPN & Extranet (~2m)

• Multicast High-Availability (~2m)

• Multicast Management (~2m)

• IP Multicast on Catalyst 6500 (~2m)

• IP Multicast on Catalyst 4500/4900 (~2m)

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Catalyst 6500 - Agenda 2/3

Catalyst 6500 (60-70m)

• Multicast Hardware Architecture (~15m)• Multicast Hardware Forwarding (~10m)

• Multicast Hardware Replication (~5m)

• Multicast Packet Flows (~15m)

• IGMP / MLD & PIM Snooping (~5m)

• Multicast Forwarding on VSS (~10m)

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Catalyst 4500/4900 - Agenda 3/3

Catalyst 4500/4900 (30-40m)

• Multicast Hardware Architecture (~10m)• Multicast Hardware Forwarding (~10m)

• Multicast Hardware Replication (~5m)

• Multicast Packet Flows (~15m)

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IP Multicast OverviewPIM Distribution Modes

• Multicast Overview (15-20m)

• PIM Distribution Modes

• IGMP/MLD & Snooping

• Multicast VPN & Extranet

• Multicast High-Availability

• Multicast Management

• IP Multicast on Catalyst 6500

• IP Multicast on Catalyst 4500/4900

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PIM Dense Mode (PIM-DM)

1st Gen. “Flood” & “Prune” (S,G based)

multicast distribution protocol

Designed with the assumption that receiversare “Densely” populated in the network...

Uses only Source-based Trees

• Distribution “trees” are unidirectional (RPF-based)

Does NOT use Rendezvous Points (RP’s), which makes it simpler to implement & deploy

Data-driven Multicast state

• Requires Periodic “Flooding” & “Pruning” on all PIM

routers, and DR Election / Asserts on each subnet

Group membership tracked via IGMP v1 or v2

Catalyst Switches provide support for:

• IPv4 PIM-DM (S,G) forwarding

• IGMPv1 & v2 and Snooping Receivers

Source2

Source TreeRooted at

Source1


Source1

Source1


Source2


Source2

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PIM Sparse Mode (PIM-SM)

2nd Gen. All-Purpose (S,G and / or *,G)


Designed with the assumption that receiversare “Sparsely” populated in the network...

Uses both Shared (RP) & Source based Trees

• Distribution “trees” are unidirectional (RPF-based)

Data-driven Multicast state• Requires Source “Registration”, RP group-mapping, DR

Election & Asserts, and SPT switch-over

Automatic “Source” discovery (via Registers)

Group membership tracked via IGMP v1, v2,or v3 (IPv4) or MLD v1 or v2 (IPv6)


• IPv4 and IPv6 (*,G) forwarding

• IPv4 and IPv6 (S,G) forwarding

• IGMP v1/2/3 & MLDv1/2 and Snooping

RP

Shared TreeRPT: Rooted

at theRendezvous Point

Shared TreeRPT: Rooted

at theRendezvous Point

Source TreeSPT: Rootedat the Source

Source TreeSPT: Rootedat the Source

Source

Receivers

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Source2

PIM Source-Specific Multicast (PIM-SSM)

3rd Gen. “Shortest Path” (S,G based)


Low-Latency variation of PIM-SM, whichassumes the “one-to-many” model

• Internet, Inter-Domain and Voice / Video distribution

Data-driven Multicast state

• Requires only SSM Range, and DR Election / Asserts

Hosts are responsible for “source discovery”

• Typically via some out-of-band mechanism (web page,etc.)

• Eliminates need for RP (Shared trees) & MSDP

Group membership tracked via IGMP v3 (IPv4)or MLD v2 (IPv6)


• IPv4 and IPv6 (S,G) forwarding

• IGMPv3 & MLDv2 and Snooping

• SSM mapping (for IGMPv2 & MLDv1)


Source1


Source1

Source1

S1,G1


Source2


Source2

S2,G1S1,G1 S1,G1

ReceiversS2,G

1

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Bidirectional PIM (PIM-BiDir)

3rd Gen. “Shared Path” (*,G based)


Highly Scalable variation of PIM-SM, whichassumes LOTS of Sources & Receivers

• Intra-Domain multicast & Database distribution

Data-Flow Independent

• Pre-built (RP/DF-based) distribution trees = NO source

registers, DR Asserts, or non-RPF issues

Drastically reduces network mroute state

• Eliminates ALL (S,G) mroute state in the PIM network

• Permits virtually UNLIMITED Sources

• Multicast traffic can flow Up & Down (Bidirectional) on theShared (RP-based) tree

Group membership tracked via IGMP v1 or v2


• IPv4 PIM-Bidir (*,G) forwarding

• IGMP v1/2 & Snooping

RP

Shared TreeBidirectional tree

rooted at theRendezvous Point

Shared TreeBidirectional tree

rooted at theRendezvous Point

Source

Sources/Receivers

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IP Multicast OverviewIGMP/MLD & Snooping









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IGMP / MLD & Snooping

Internet Group Management Protocol (IGMP)

• Host “membership” reporting for IPv4

Multicast Listener Discovery (MLD)• Host “membership” reporting for IPv6

IGMP / MLD operates on L3 PIM Interfaces

• IGMP v1/v2/v3

• MLD v1/v2• SSM mapping

IGMP / MLD “Snooping” constrains multicast

flooding on L2 switchports

• Based on received Join / Leave reports

Snooping process uses both L2 & L3

Hardware & Software information

• Snooping support for IGMPv1/2/3 and MLDv1/v2

• PFC/DFC performs hardware “protocol redirection” of

IGMP & MLD packets to SP CPU for processing

Source

Receivers

Host“Join”Reports

Source

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IP Multicast OverviewMulticast VPN & Extranet









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Multicast Over MPLS VPN

MVPN

EnterpriseMPLS Core

PE

Receiver

CE

Receiver

Receiver

High-RateSource

CE

Default MDTUsed for

low-bandwidth& control-traffic

only

Data MDTUsed for

high-bandwidthdata stream

Default MDT

Join

Join

Traffic

Shared / Source TreeRooted at CE RP or Source:

controls multicast distributionwithin individual VPN/VRF

MVPN Source TreeRooted at Source PE:

controls multicast distributionwithin MPLS VPN core

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MVPN Extranet

Allows IP Multicast content which originated in one MVPN, tobe distributed to other MVPNs

Two configuration requirements:

On Source PE or Receiver PE (or both) configure all relevant MVRFs

Configure “fallback” static mroute (for Source VRF IP subnets: Source

and / or RP address) to allow RPF check between MVRF’s.

MPLS Core

Receiver

Receiver Source

Join

Traffic

Join

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IP Multicast OverviewMulticast High-Availability









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vlan200

vlan300

vlan100

Multicast Management -

NDE with NetFlow v9 Provides wire-rate statistics

collection for IP Multicastdata flows

Support for Ingress & Egressmulticast statistics

• Ingress NetFlow tracks multicasttraffic received (input) on an

Interface

• Egress NetFlow tracks multicasttraffic replicated (output) on anInterface

Netflow “Sampling” support,to reduce export load

Important for PIM-BiDir networks, where (S,G)entries NOT in mroute table

Ingress

NetFlow v9Export

NetFlow

Collector

Catalyst 6500

g1/1

S1,G1

S2,G1

S1,G2

S3,G1

Egress

Video

Data

Voice

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vlan200

vlan300

vlan100

Multicast Management -

SNMP MIBs & Traps Several Multicast-specific

SNMP MIB’s

PIM, MROUTE, MSDP, MVPN &

IGMP/MLD

Several Multicast-specificSNMP Traps• pimNeighborLoss

• ciscoPimRPMappingChange

• ciscoPimInvalidReFaster

• ciscoPimInvalidJoinPrune

• ciscoPimInterfaceUp

• ciscoPimInterfaceDown

• msdpEstablished1

• msdpBackwardTransition

• ciscoMvpnMvrfChange

Special Trap called MulticastHeartbeat can be used to trackavailability of a Multicast group

ciscoIpMRouteMissingHeartBeats

Ingress

Egress

Video

SNMP Traps

SNMP

Server

Catalyst 6500

g1/1

S1,G1

S2,G1

S1,G2

S3,G1

Data

Voice

SNMP MIBs

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IP Multicast OverviewMulticast on Catalyst 6500









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Catalyst 6500 - Cisco’s Premiere Multicast

Hardware-Switching Platform

Leverages Cisco IOS’s 10+ years of IPv4 & IPv6Multicast expertise & innovation

Delivers Un-Matched Price & Performance• 200+Mpps IPv4 multicast forwarding demonstrated in EANTC tests

• Up to 80G multicast “replication” per-slot with WS-6708-10GE module

• 720Gbps throughput & 1.44Tbps throughput with VSS

Already widely deployed in many of the World’smost business-critical networks

• Global Financials - Exchanges, Brokerages and FSP’s• Video Providers - Domestic / Foreign IPTV and Triple-Play ISP’s

• Retail Enterprise - Inventory & Data-Base Distribution

• Government and Department of Defense

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IP Multicast on Catalyst 6500

Centralized & Distributed IPv4 & IPv6Multicast hardware-switching

• Off-loads the majority of multicast forwarding load(data-plane) from the switch control-plane

IPv4 & IPv6 PIM-SM & PIM-SSM (S,G)mroute forwarding in hardware

IPv4 & IPv6 PIM-SM & PIM-Bidir (*,G)mroute forwarding in hardware

IPv4 MVPN forwarding in hardware

IPv4 IGMP v1/v2/v3 Snooping in hardware

IPv6 MLD v1/v2 Snooping in hardware

IPv4 PIM Snooping in hardware

Switch Fabric provides greater throughputover traditional Bus-based designs

WS-SUP720-3B/XLWS-SUP720-3B/XL

VS-S720-10GE-3C/XL VS-S720-10GE-3C/XL

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Catalyst 4500/4900 IP Multicast

Implements Centralized & Distributed IPv4 and IPv6Multicast hardware-switching

Off-loads the majority of (data-plane) forwarding tasks from the

switch control-plane

Supports IPv4 & IPv6 PIM-SM and PIM-SSM (S,G)mroute forwarding in hardware

Supports IPv4 PIM-SM and PIM-Bidir (*,G) mroute

forwarding in hardware

Supports IPv4 MVPN forwarding in hardware

Supports IGMPv1/v2/v3 snooping in hardware

Supports MLDv1/v2 snooping in hardware

Supports PIM snooping in hardware

Supervisor720 supports Centralized & Distributedmulticast packet-replication

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Multicast Features (Hardware)

Features Classic E-Series

IGMP (Internet Group Management Protocol) v1, v2, v3 Yes Yes

IGMP Snooping (v1, v2, v3) Yes Yes

MLD (Multicast Listener Discovery) v1, v2 No Yes

MLD snooping (v1, v2) No Yes

PIM (Protocol Independent Multicast) SM (Sparse Mode) Yes Yes

PIM DM (Dense Mode) Yes Yes

PIM SSM (Source Specific Mode) Yes Yes

PIM Bi-Dir (Bi-Directional) No Yes

C t l t 6500 (60 70 )

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Catalyst 6500IP Multicast Hardware Architecture

• Catalyst 6500 (60-70m)

• Multicast Hardware Architecture

• Multicast Hardware Forwarding

• Multicast Hardware Replication

• Multicast Packet Flows

• IGMP / MLD & PIM Snooping

• Multicast Forwarding on VSS

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Supervisor Engine “Multicast” Components

PFC Daughter CardSwitch Fabric &

Multicast Replication Engine

Switch Processor (SP)

Route Processor (RP)

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32 Gbps

Bus

Supervisor 720 Baseboard

DBUSRBUS

Supervisor 720 Multicast Architecture

16 GbpsBus

Integrated

720 Gbps

Switch Fabric

…

20 GbpsFabric

Interface &Replication

Engine

CPU Daughter Card

DRAMSP (NMP)CPU

DRAMRP (MSFC3)

CPUPort ASIC

1 Gbps

1 Gbps

1GE Uplinks

Central replication-engine

for Bus-based modulesand uplink ports

MET

L3/4

Engine NetFlow

ACLTCAM

QoSTCAM

FIBTCAM

ADJCounter FPGA

L2 EngineProtocolRedirection

Logic

Bidir RP

PFC provides L2 - L3/L4Hardware data-plane, using

TCAM’s & ASICs Bidir RP tablefor DF

Interface check

RP & SP CPU’s control Softwarecontrol-plane and user-interface

L2 CAM

18 x 20Gbps

Fabric Channels

PFC3Daughter

Card

ProtocolRedirection

captures IGMP

/ MLD & PIMpackets

FIB contains(S,G) & (*,G) entries

and RPF VLAN

SP CPU programshardware &

performs IGMP/MLD

& PIM snooping

RP CPUmaintains mroutes

& state, and

downloads tables

ADJ containsrewrite info &

MET index

MET contains OIL’sfor replicationL2 CAM containsmulticast MAC entries

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Supervisor 720-10GE Baseboard

DBUSRBUS

Supervisor 720-10GE Multicast Architecture

32 Gbps

Bus

…

20 Gbps

CPU Daughter Card

DRAMSP (NMP)CPU

DRAMRP (MSFC3C)

CPU

1 Gbps

1 Gbps

MET

L3/4

Engine NetFlow

ACLTCAM

QoSTCAM

FIBTCAM

ADJCounter FPGA

L2 EngineProtocolRedirection

Logic

Bidir RP

PFC3C serves samebasic functions as

PFC3A/B

PortASIC

Fabric


Engine

Port

ASIC

1GE & 10GE Uplinks

L2 CAM

PFC3CDaughter

Card

Central Replication engine

for Bus-based cards anduplink ports

Integrated

720 Gbps

Switch Fabric

20 x 20Gbps

Fabric Channels

RP & SP CPU’sperform all CLI and

control-plane functions

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Supervisor Engine 32 Baseboard

DBUSRBUS

32 Gbps

Bus

10GE Uplinks

MSFC2a Daughter Card

1 Gbps

DRAM

DRAMSP CPU

MET

1 Gbps

Bus Interface &

Replication

Engine

PFC3BDaughter

Card

L3/4Engine NetFlow

ACLTCAM

QoSTCAM

FIBTCAM

ADJ

L2 CAM

Counter FPGA

L2 Engine

RP CPU

WS-SUP32-10GE-3B

Port

ASIC

FPGA

MUX

Port

ASIC

Supervisor 32 Multicast Architecture

Central “replication engine”performs replication for

ENTIRE system

ProtocolRedirection

Logic

Bidir RP

PFC3B is the same asused on Supervisor

720

RP & SP CPU’sperform all CLI and

control-plane functions

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CEF256 Module Architecture + DFC

CEF256

Module

with DFC

Replication

Engine Port

ASIC

Port

ASIC

Port

ASIC

Port

ASIC

MET

4xGE 4xGE 4xGE 4xGE

Example: WS-X6516-GBIC with WS-F6K-DFC

L3/L4

Engine

DFC

Layer 2

Engine

Layer 3Engine for

FIB/ADJ andNetFlowLookups

Layer 2 Engine forMAC learning,

Security / QoS ACL

Lookups, andProtocol Redirection 8 Gbps FabricChannel

Fabric / Bus

Interface

LC-DBUS

LC-RBUS

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CEF720 Module Architecture

CEF720

Module

CFC

Complex BComplex A

Port

ASIC

Fabric


Engine

20 Gbps Fabric

Channel

20 Gbps Fabric

Channel

METMET

Fabric


Engine

Port

ASIC

Port

ASIC

Port

ASIC

12xGE 12xGE 12xGE 12xGE

Example: WS-X6748-SFP

Port ASIC forPhysical

Connectivity,Buffering, and

Queuing

Fabric Interface &Replication Engine -

Connects to Fabric & Bus(CFC), and Replicates

Packets to OILs

METContainsOILs for

Replication

Bus Interface for Control Data Only!!Bus Interface for Control Data Only!!

DBUSRBUS

Bus

Interface

Bus

Interface

Bus

Interface

Bus

Interface

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CEF720 Module Architecture + DFC3

CEF720

Modulew/DFC3

L3/4

Engine

DFC3

Complex BComplex A

Layer 2

Engine

Layer 2

EngineMETMET

Example: WS-X6748-SFP with WS-F6700-DFC3B

20 Gbps Fabric

Channel

20 Gbps Fabric

Channel

12xGE 12xGE 12xGE 12xGE

PortASIC

Fabric

Interface &

Replication

Engine

Fabric

Interface &

Replication

Engine

PortASIC PortASIC PortASIC

Layer 2 Enginefor L2 Lookups

and ProtocolRedirection Layer3/4 Engine for FIB/ADJ,ACL, QoS, and NetFlow Lookups

• Catalyst 6500 (60-70m)

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Catalyst 6500IP Multicast Hardware Forwarding







M lti t C t l Pl

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Multicast Control Plane

RP CPU (L3) IP Multicastcontrol-plane functions:

• Multicast protocols: PIM, IGMP / MLD,

AutoRP / BSR, MSDP, MVPN, etc.• Calculating RPF interfaces

• Managing software IP mroute table

• Downloading IP mroute table entriesto SP (for installation in the PFC / DFC

hardware)

SP CPU (L2) IP Multicast control-plane functions:

• Managing PFC / DFC hardware tables

• IGMP / MLD Snooping packet processing• PIM Snooping / RGMP packet processing

• IGMP / MLD Querier functions

• Statistics Collection & Reporting

1 GbpsRP (MSFC3)

CPU

1 GbpsSP (NMP)

CPU

InbandChannels

GroupMembership

GroupMembership

IP MrouteTable

IP MrouteTable

MSDPMSDP

IGMP / MLDSnooping

IGMP / MLDSnooping

PIMSnooping

PIMSnooping

H d M lti t S it hi

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Hardware Multicast Switching

RP CPU derives 3 important data

structures from the IP Multicast

routing table...

• Multicast FIB: Contains (S,G) & (*,G)entries, RPF VLAN, and BiDir RP index

• Adjacency Table: Contains L2 rewrite

MAC information and MET index

• Multicast Expansion Table (MET):

Contains Output Interface Lists (OILs)

RP CPU downloads tables to SP...

SP CPU installs the tables into the

appropriate hardware...

• MET installed in replication engines

• Multicast FIB and Adjacency tables

installed in PFC/DFC hardware

SP CPU also maintains L2 tables

for IGMP/MLD & PIM snooping

MDSSMDSS

PIM, IGMP,

MLD &

IP Mrouting

PIM, IGMP,

MLD &

IP Mrouting

MMLS-SPMMLS-SP

MMLS-LCMMLS-LC

MMLS-RPMMLS-RP

RP (MSFC)

SP (Supervisor )MET Manager,

IGMP & PIM

Snooping

MET Manager,IGMP & PIM

Snooping

LC (Linecard)

SCP / ICC

SCP

MMLS-LCMMLS-LC

LC (Linecard)

METMET METMETFIB/ADJFIB/ADJ

M lti t FIB TCAM L k

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1

2

3

4

5

6

7

8

RPF VLANAdj Index

Result

Replication Engine(s)

Compare

FIB TCAMMasks Patterns

FFFFFFFF FFFFFFFF

10.1.1.10, 239.1.1.1

10.1.1.10, 239.1.1.1

10.1.1.10, 239.1.1.1

10.1.1.10, 239.1.1.1

10.1.1.10, 239.1.1.1

10.1.1.10, 239.1.1.1

10.1.1.10, 239.1.1.1

10.1.1.10, 239.1.1.1

Multicast FIB TCAM Lookup

Lookup Key

GenerateLookup

Key

GenerateLookup

Key

(S,G)

10.1.1.10, 239.1.1.1

MulticastPacket

MAC, MET Index

MAC, MET Index

MAC, MET Index

MAC, MET Index

Adjacency Table

1

2

3

4

S,G compares

all bits in

Source IP and

Group IP

MET

OIL #1

OIL #2

OIL #3

OIL #4

5

10.1.1.10, 239.1.1.1

HIT!HIT!

6

BiDir FIB TCAM Lookup

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1

2

3

4

5

6

7

8

Replication Engine(s)

Compare

FIB TCAMMasks Patterns

00000000 FFFFFFFF

xxxxxxxx, 239.1.1.99


xxxxxxxx, 239.14.14.1

xxxxxxxx, 239.44.12.1

xxxxxxxx, 239.1.1.1



xxxxxxxx, 239.2.1.1

BiDir FIB TCAM Lookup

Lookup Key

GenerateLookup

Key

GenerateLookup

Key

S,G

10.1.1.10, 239.1.1.1

MulticastPacket

MAC, MET Index

MAC, MET Index

MAC, MET Index

MAC, MET Index

Adjacency Table

1

2

3

*,G compares

all bits in

Group IP

MET

OIL #1

OIL #2

OIL #3

OIL #4

67

DF Set

DF Set

DF Set

DF Set

RP #1

RP #2

RP #3

RP #4

Bidir RP Table5

XXXXXX, 239.1.1.110.1.1.10, 239.1.1.1

Bidir RP IndexAdj Index

Result

4HIT!HIT!

BiDir RP to DF Mapping Table

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10.1.1.1

10.2.2.2

10.3.3.3

10.4.4.4

0

1

2

3

Mapping Table(Software Data Structure)

RPIndex

RP IPAddress

VLAN 1 2 3

VLAN 3 4 5 6

VLAN 3 4093

VLAN 200 201

DFInterfaces

0 1 2 31 2 3 4 5 6 … 4093 4094

RP

Index DF Interface Set

1 1 2 3 4 5 6 … 4093 4094

2 1 2 33 4 5 6 … 40934093 4094

3 1 2 3 4 5 6 … 4093 4094

4K VLAN IDs

BiDir RP-to-DF Mapping Table

DF Set

DF Set

DF Set

DF Set

RP #1

RP #2

RP #3

RP #4

Bidir RP Table

(PFC/DFC)

Multicast Expansion Table (MET)

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100 Gi4/12,Gi4/19

OIF VLAN Port List

101 Gi9/1

102 Gi9/25,Gi9/29

100 Gi4/12,Gi4/22,Gi4/30

1019 Te1/1

4030 Te8/1

4031 Te8/3

4032 Te2/1,Te2/2,Te2/9

700 Gi4/1,Gi4/2,Gi4/3

Index A from ADJ

MET Block

Index B from ADJ

Index C from ADJ

Index

A

B

C

Multicast Expansion Table (MET)

Replication

EngineMET

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Multicast Replication

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Multicast Replication

Process of creating “copies” of multicastpackets on each Layer 3 OIF

• Example: A PIM-SM (S,G) with 3 OIFs - multicast replicationcreates three copies of every packet received from source (S)& destined to group (G)

• Catalyst 6500 supports 3 types of “replication”

Layer 3 multicast replication• For Layer 3 Forwarding between (1 or many) interfaces

• “Replication Engine” does the replication

Layer 2 multicast replication• For Layer 2 Forwarding between ports in same LC

• “Port ASIC” does the replication

Fabric multicast replication• For Egress Forwarding between ports on different Modules

• “Fabric ASIC” does the replication

Multicast Replication Modes

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Multicast Replication Modes

Replication Mode refers to exactlywhere in the system that multicast

replication occurs Replication occurs in one or more

“replication engine” ASIC’s

In a Classic (bus) system, replicationoccurs centrally on the Supervisorreplication engine

In a Fabric-enabled system, thereare two possible replication modes:

• Ingress replication

•Egress replication

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Egress Replication-Mode

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AA

DD

CC

Egress Replication Mode

Supported on Supervisor 720’swith certain modules

• e.g. CEF720, 6516A, 6548A-GETX, SIP’s

Requires ALL “egress-capable” modules Input packets get one lookup on ingress

PFC/DFC, replicated packets get lookup

on egress PFC/DFC

For OIFs on ingress module, the localRE performs the replication

For OIFs on other (egress) modules,

the ingress RE only sends a single copy

of packet over Switch Fabric

The replication-engine on the egressmodule then replicate for local OIF’s

MET on different egress-capable

modules can be different / asymmetric

BB

Switch

Fabric

One Packet CrossesSwitch Fabric

One Packet CrossesSwitch Fabric

= Replication Engine

RE

RE

RE

RE

RE = Replication Engine

Egress Replication - Same Module

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Egress Replication Same Module


Switch

Fabric

RE

RE

MET Contents

2/1

2/2

RE 2/3

2/4

Receiver Green

Source

With Egress Replication OIF entries are symmetricalamong replication-engines on the same module...

Hence replication bandwidth usage is not optimized

MET entry for Non-Local port

OIF Dest IndexEntry

MET Contents

2/32 2/3

OIF Dest IndexEntry

2/2 2/22

2/1 2/11

2/11 2/1

DROP

Index

Module A

Module B


Egress Local ReplicationMET C t t

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g ess oca ep cat o


Switch

Fabric

RE

RE

2/1

2/2

RE2/3

2/4

Receiver Green

Source

Egress “local replication” optimizes the replicationbandwidth within the same module, by includingonly the local ports of each replication engine

Cat6500(config)# mls ip multicast egress local

MET Contents

OIF Dest IndexEntry

2/2 2/22

2/1 2/11

OIF Dest IndexEntry

MET Contents

2/31 2/3

Index

Module A

Module B


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Ingress Replication (1)

NOTE: Packet-Flow Steps

are kept in the Slide Notes



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Source

Receiver

Blue VLAN

Orange VLANGreen VLAN

Red VLAN

Purple VLAN

Entire Packet

Packet Header

R

S

Supervisor

Engine 720L3/4 EngineL3/4 Engine

DBUSRBUS

CEF256

Module A8 Gbps

LC-DBUS

LC-RBUS

Replication

Engine Port ASIC

A

Port ASIC

B

LC-RBUSLC-DBUS

CEF256

Module B

Fabric

Interface

8 Gbps

R

R R

Port ASIC

A

Fabric

Interface

720 Gbps

Switch

Fabric

SBlue Blue

Orange

R R

Port ASIC

B

RedGreen Purple

MET

PFC3

L2 EngineL2 Engine

4

1

Replication

EngineMET

2

3

are kept in the Slide Notesp

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Egress Replication (1)





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DFC3

L3/4 EngineL3/4 Engine

CEF720

Module B

w/DFC3Supervisor Engine 720

PFC3PFC3

R

CEF720

Module A

w/DFC3


DFC3

L2 EngineL2 Engine

L2 EngineL2 Engine

S

R R

Orange

R R

RedGreen Purple

Port ASIC Port ASIC

Blue Blue

Fabric Interface &

Replication Engine

Port ASIC Port ASIC

20 Gbps

720 Gbps

Switch

Fabric

2 0 G b

p s

Fabric Interface &

Replication Engine

MET

MET

1

2

3

4

Source

Receiver

Blue VLAN

Orange VLAN

Green VLANRed VLAN

Purple VLAN

Internal VLAN

Entire Packet

Packet Header

R

S

p

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Egress Replication (3)





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DFC3


CEF720

Module B

w/DFC3Supervisor Engine 720

PFC3PFC3

R

CEF720

Module A

w/DFC3


DFC3

L2 EngineL2 Engine

L2 EngineL2 Engine

S

R R

Orange

R R

RedGreen Purple

Port ASIC Port ASIC

Blue Blue

Fabric Interface &

Replication Engine

Port ASIC Port ASIC

20 Gbps

720 Gbps

Switch

Fabric

2 0 G b

p s

Fabric Interface &

Replication Engine

MET

MET

10

11

12 12

Source

Receiver

Blue VLAN

Orange VLAN

Green VLANRed VLAN

Purple VLAN

Internal VLAN

Entire Packet

Packet Header

R

S

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IGMP / MLD

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Purpose: Signal & Refresh group

“membership” on receiver subnets

IGMP (IPv4) & MLD (IPv6) supported

IGMP v1, v2 & v3 protocol support for

PIM-SM & PIM-BiDir

IGMP v3 protocol support for PIM-SSM

• Option for “SSM Mapping” to translate IGMPv2 (*,G) joinsinto PIM-SSM (S,G) joins

MLD v1 & v2 protocol support for PIM-SM

MLD v2 protocol support for PIM-SSM• Option for “SSM Mapping” to translate MLDv1 (*,G) joins

into PIM-SSM (S,G) join

Operates on Layer 3 PIM interfaces

IGMP / MLD Snooping

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Purpose: Constrain unnecessary multicast“flooding” on Layer 2 host ports

IGMP/MLD Snooping code leverages both

Hardware and Software:• Switch “snoops” Layer 3 contents of IGMP / MLD packets

• PFC/DFC ASIC’s recognize IGMP / MLD packets and

“redirects” them to SP CPU (protocol redirection logic)

• Switch installs static Layer 2 forwarding entries for eachmulticast group MAC address

• Multicast data traffic forwarded to appropriate Interfaces

according to MAC address table entries (per VLAN)

Snooping does NOT affect the performanceof multicast data traffic

Redirection logic ONLY redirects IGMP/MLDpackets, not UDP (multicast data) packets

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L2 Snooping Packet Flow





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Supervisor Engine 720 Baseboard

Integrated

720 GbpsSwitch Fabric

Fabric Interface

& ReplicationEngine

RP (MSFC3)

CPU

SP (NMP)

CPU

CPU Daughter Card

MET

Port ASIC

CEF720

Modulew/DFC3


DFC3L2 EngineL2 Engine

Port ASICPort ASIC

Fabric Interface &

Replication Engine

ProtocolRedirection

Logic

ProtocolRedirection

Logic

1

2

3

4

5SNOOPING

PROCESS

• Catalyst 6500 (60-70m)



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Catalyst 6500IP Multicast Forwarding on VSS





Virtual Switching System - Overview

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Multicast with VSS - Load-Sharing

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VSL

Stand-Alone

Non-DR

STP/HSRP

DR

Receivers Receivers

VSS

DR

RP RP

L3 MECL3 MEC

L2 MECL2 MEC

ECMPECMP

L2 STPL2 STP

VSS provides Multicast Load-sharing across multiple links with MEC

Receivers Receivers

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Multicast with VSS - Simplified Topology

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VSS Simplifies Multicast Topologies

VSS Logical ViewStand-Alone

DR Non-DR

Non-RPF flows

In Stand-Alone (multi-home) topologies, inter-switch link bandwidthis wasted due to non-RPF traffic between DR & non-DR

DR

VSS is a single DR, so there is no non-RPF traffic

Multicast Re-convergence Scenarios

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4

3

1

2

RP

Receivers Receivers

4. Downlinks Failure

1. Uplinks Failure 3. Switch Interlink Failure

2. Supervisor Failure

L3 L3

L2/L3L2/L3

DR

Multicast State: 500 PIM groups @ 10sources per-group = 5000 mroute entries

With MMLS Egress Replication-Mode =10,000 shortcuts in hardware

Time is in Seconds

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VSS Multicast: FIB Programming

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• The VS Standby SP is

treated as a DFC modulefrom a FIB / ADJforwarding perspective.

• The VS Active SP installsforwarding shortcuts ontothe Active PFC, StandbyPFC and all other DFC’s

in the VS System.

DFC

Standby

SP

C2+

VS STANDBY

FIB/ADJ

FIB/ADJ

VSL

MET

MET

MET

MET

MET

MET

Active

SP

67XX

C2+

HA FIB-CAPABLE

ICC MCAST GROUP

DFC

VS ACTIVE

FIB/ADJ

FIB/ADJ

MET

VSS Multicast: MET programming

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VSL

StandbySP

C2+

STANDBY SCP METMCAST GROUP

DFC

ActiveSP

DFC

C2+

C2+

ACTIVE SCP METMCAST GROUP

• The VS Standby SP istreated as a Supervisor

module from a METprogramming perspective

• The SP on each Chassis

manages & programs it’sown MET, and the MET’sof all local C2+ modules

• DFC modules manage and

program their own MET’s

MET

MET

MET

MET

MET

MET

MET

VS STANDBYVS ACTIVE

Multicast Ingress Forwarding Model

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E

M1

M0

R

R

E

M1

M0

R

R

RR M1M1

EE

M0M0RR

EE

M1M1

M0M0

RR

RR

VSLLC1 (Ingress)

LC2

LC3

Ingress Core Egress Core

LC 1

LC2

Switch 1 Switch 2

LC 3

LC 4

1

MEC

4

6 7

Access Switch

5

E

MET2

MET3

8

R3

R4

R5

S

R1

R2

All forwarding-lookups & replication occur on the Ingress modules

Subsequent modules only perform L2 egress lookup. Multiplereplications cross the Ingress Core’s Switch Fabric and / or VSL

I-E-E-E (Ingress-VSL- VSL-Egress)•Multicast packets may cross up to 4 DFC’s

•Ingress DFC performs L2-L4 forwarding lookup

•Up to 3 DFC’s (VSL) perform L2 egress lookup





3

2

9

Multicast Egress Forwarding Model

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RR M1M1

EE

M0M0RR

EE

M1M1

M0M0

RR

RR

E

M1

M0

R

R

E

M1

M0

R

R

VSLLC1 (Ingress)

LC2 (Egress)

LC3 (Egress)

MET3LC 1

LC2

Switch 1 Switch 2

LC 3

LC 4

1

MEC

S

R1

R2

4

6 7 8E

10

5

MET2

MET3

Access Switch

Ingress Core Egress Core

93

R3

R4

R5

2

Ingress modules replicate locally & one copy to Egress modules

Egress modules (on Ingress Core) then replicate locally, and also for allreceivers on the Egress Core. Multiple replications cross the VSL

MET2





I-E-E-E (Ingress-VSL- VSL-Egress)•Multicast packets may cross up to 4 DFC’s

•Ingress DFC performs L2-L4 forwarding lookup

•Up to 3 DFC’s (VSL) perform L2 egress lookup

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Cat4K Architecture

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Packet Processor: receive, extract, reconstruct, and send.

Forwarding Engine: lookup, rewire, replication, and Qos

Packet MemoryPacket Memory

Forwarding EngineForwarding Engine

Packet LookupDescriptor (PLD)

Packet TransmitDescriptor(PTD)

Layer2module

FWDmodule

OutputServices

InputServices

ReplicationModuleReplicationModule

ReplicationQueue

ReplicationQueue

CPUCPU

Packet Processor Packet Processor

Cat4K Multicast Architecture

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Single copy of multicast packet in Packet Memory => Excellent buffercapability

Same path as unicast => deterministic and low latency/jitter



Packet LookupDescriptor (PLD)

Packet TransmitDescriptor(PTD)

ReplicationTable

Layer2module

FWDmodule

OutputServices

InputServices

ReplicationModule

ReplicationQueue

CPUCPU


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Multicast Forwarding Overview

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S,GRPF

interfaceRP ID RET index

S1, G1 Vlan3 0 1219

S2, G2 Vlan7 0 1279

…

*, G4 2 1356

…

index Set of {vlan switchport}

0

..

1279 {vlan3, Fa3/1} {vlan5, Fa3/2}

…

1356 {vlan101, te1/1} {vlan1007, te1/8}

Forwarding TCAM RET table

Hardware FIB Table

Install mroute table except OIL

(Outgoing Interface List)

Hardware RET Table

Install OIL information of mroute

These two tables constitute the MFIB entry

Multicast PIM BiDir Forwarding Overview

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S,GRPF

interfaceRP ID RET index

S1, G1 Vlan3 0 1219

S2, G2 Vlan7 0 1279

…

*, G4 2 1356

…

index Set of {vlan switchport}

0

..

1279 {vlan3, Fa3/1} {vlan5, Fa3/2}

…

1356 {vlan101, te1/1} {vlan1007, te1/8}

Forwarding TCAM RET table

VLAN 1 2 … 7

1 0 0 0

… 0 0 0

101 0 1 0

…

4094 0 0 0

VLAN DF Table

• Catalyst 4500/4900 (30-40m)




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Catalyst 4500/4900IP Multicast Hardware Replication


Replication Module

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PLD

PTD

ReplicationTable

ReplicationTable

Layer2module

FWD

module

OutputServices

InputServices

ReplicationQueue

ReplicationQueue

ReplicationModule

CPUCPU


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Replication Table

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Stores replication vlan/portsets informationfor L2 multicast/broadcast/flooding and IP

multicast forwarding

With Classic Supervisors, this module is calledMulticast Expansion Table (MET). The MET

size is 64K [it is 32K for SupII+, SupII+TSand SupII+10GE]

With E-Series Supervisors, this module is

called Replication Expansion Table (RET). TheRET size is 102K

ReplicationTable

Replication Queues

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PLD

PTD

ReplicationTable

ReplicationTable

Layer2module

FWD

moduleOutput

Services

InputServices

ReplicationModule

ReplicationModule

ReplicationQueue

CPUCPU


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• Catalyst 4500/4900 (30-40m)





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Catalyst 4500/4900IP Multicast Packet Flows

IP Multicast Forwarding

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PLD

PTD

Host A—VLAN 1

Multicast Source

Host B—VLAN 2Multicast Receiver

Host C—VLAN 3

Multicast Receiver

Packet

Processor

Packet

Processor

ModulesModules

ReplicationTable

Layer2module

FWDmodule

OutputServices

InputServices

ReplicationModule

Replication

Queue

CPUCPU

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Session Take-Away’s

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Catalyst Switches leverage proven IP Multicast IOS code

Hardware Switching provides Higher Throughput• Software-based Multicast forwarding is limited by CPU & Memory (vs. bandwidth)

• MLS & CEF offloads a significant portion of Multicast routing (packet rewrite) to hardware

• WS-SUP720-3B & VS-S720-10G provide 720Gbps Fabric-based throughput (VSS @ 1.44Tbps)

• WS-SUP32-3B provides 32Gbps Bus-based throughput

• DFC’s + Egress Replication capable of 30/48Mpps of throughput

• Supervisor 6E & Catalyst 4900M capable of 250Mpps of replication.

• Supervisor 6L-E capable of 225Mpps of replication.

Hardware Switching provides Less Latency / Jitter • Software-based forwarding incurs high latency / jitter during routing & replication

• Hardware-based forwarding is only limited by ASIC replication times

High-Availability (SSO/NSF) Minimizes Traffic Loss• Loss of an adjacency will cause RPF re-calculation, DR/DF election, before convergence

• Forwarding entries are synchronized & adjacencies will not drop, resulting in near-zero loss

Recommended Reading

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Continue your Networkers @Cisco Live learning experiencewith further reading from Cisco

Press

Check the RecommendedReading flyer for suggestedbooks

Available Onsite @ the

Cisco Company Store

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APPENDIX:IP Multicast Troubleshooting

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Catalyst 6500IP Multicast Troubleshooting

Multicast Troubleshooting Overview

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Configuration

Software and hardware multicast forwarding state

Software and hardware scalability limits

Most of the troubleshooting is applicable toCatalyst 4500/4900 as well.

There is note on the slide if that is specific toCatalyst 6500.

Key Problem Areas

Verify the Multicast Configuration

Verify that ip m lticast ro ting is enabled!

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Verify that ip multicast-routing is enabled!

If MVPN, verify ip multicast-routing is enabled “per-VRF”

PIM enabled on all of the Interfaces (including Loopbacks)

If PIM-SM and / or PIM-BiDir, verify the RP configuration(AutoRP, BSR, Anycast, Phantom RP, Static)

Hardware MMLS/CEF and IGMP Snooping enabled

(enabled by Default, but can be disabled) Watch out for TTL thresholds, multicast boundary, security

ACLs, VACLs, policers, etc.

Watch for proper SSM or BiDir address-range configuration(SSM & Bidir require coordination between Network andApplication groups)

Unicast Routing is enabled & RPF information is correct ☺

Troubleshooting Forwarding State

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Verify RP and DR/DF state

Verify software IP mroute state

Verify hardware multicast forwarding tables

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Verifying Group-to-RP Mappings

Catalyst-6506E#show ip pim rp mapping

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Catalyst 6506E#show ip pim rp mapping

PIM Group-to-RP Mappings

Group(s): 224.0.0.0/4, Static

RP: 10.255.255.3 (tstevens-6509.cisco.com)

Catalyst-6506E#show ip pim rp

Group: 239.1.1.10, RP: 10.255.255.3, v2, uptime 00:01:10, expires never





Catalyst-6506E#

Verifying IP RPF Information

Catalyst-6506E#show ip rpf 10.255.255.3

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y p p

RPF information for tstevens-6509.cisco.com (10.255.255.3)

RPF Interface: GigabitEthernet1/5

RPF neighbor: tstevens-6513 (10.20.1.2)

RPF route/mask: 10.255.255.3/32

RPF type: unicast (ospf 10)

RPF recursion count: 0

Doing distance-preferred lookups across tables

Catalyst-6506E#

Identifying the DR for a Segment

h i i I t f id tifi DR f h I t f

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show ip pim Interface identifies DR for each Interface

Catalyst-6506E#show ip pim Interface

Address Interface Ver/ Nbr Query DR DR

Mode Count Intvl Prior

10.255.255.2 Loopback0 v2/S 0 30 1 10.255.255.2

10.255.254.1 Loopback1 v2/S 0 30 1 10.255.254.1

10.10.1.2 GigabitEthernet4/3 v2/S 1 30 1 10.10.1.2

10.30.1.1 GigabitEthernet4/16 v2/S 1 30 1 10.30.1.2

10.100.1.1 Vlan100 v2/S 1 30 1 10.100.1.2

10.101.1.1 Vlan101 v2/S 1 30 1 10.101.1.2

10.200.1.1 Vlan200 v2/S 1 30 1 10.200.1.2

10.201.1.1 Vlan201 v2/S 1 30 1 10.201.1.2

Catalyst-6506E# This router’s Interfaceaddresses

Compare with DRaddress

Identifying Bidir DF Interfaces

Catalyst-6506E#show ip pim Interface df

Interface RP DF Winner Metric Uptime

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Interface RP DF Winner Metric Uptime

Loopback0 10.255.255.3 10.255.255.1 2 02:21:07

GigabitEthernet1/5 10.255.255.3 10.20.1.2 0 02:21:08





Vlan100 10.255.255.3 10.100.1.2 2 00:03:39

Vlan101 10.255.255.3 10.101.1.2 2 00:01:13

Vlan200 10.255.255.3 10.200.1.2 2 00:01:10

Vlan201 10.255.255.3 10.201.1.2 2 00:01:07

Catalyst-6506E#

PIM enabledInterfaces

IP address of currentDF winner

Winner’s routingmetric to RP

Bidir RPaddress

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Verifying Software IP Mroute State

Ensure IP mroute exists in software

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Ensure IP mroute exists in software...show ip mroute

Does (*,G) and/or (S,G) exist in software mroute table?

Does Hardware state information in show ip mroute output

appear correct?

Ensure RPF Interface is known and correct

Make sure show ip mroute and show ip rpf show correct

RPF Interface for (*,G) or (S,G)

PIM reliance on unicast routing means multicast issues oftencaused by unicast routing issues

Verifying Software IP Mroute State (2)

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Ensure PIM neighbors active and stable

(show ip pim neighbor) IGMP dictates connected receiver membership—

ensure joins/leaves sent by receivers and receivedby RP CPU

Might need to verify PIM and IGMP packet exchangeusing SPAN/sniffer and/or debugs

OIFs are Known and Correct

OIF Inclusion driven by PIM or IGMP

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Bidir-PIM (*,G/m) Entries

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Source-only traffic must reach RP (could be receiverson other branches)

For efficiency, system installs (*,G/m) hardwareforwarding entry/entries to transport this traffic

Entries based on Bidir-PIM RP ACL configuration

At RP, assuming no receivers on other branches,packets dropped in hardware

NOTE: (*,G/m) entries not shown in software mroutetable today

Viewing Bidir (*,G/m) Forwarding Entries

* Catalyst 6500 Only

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Catalyst-6506E#show mls ip multicast rp-mapping gm-cache

State: H - Hardware Switched, I - Install Pending, D - Delete Pending,

Z - Zombie

RP Address State Group Mask State Packet/Byte-count

10.255.255.3 H 224.0.0.0 240.0.0.0 H 1183799/1754389822

Catalyst-6506E#Statistics

Group IP andMask (224/4)

Bidir RP IPAddress

Troubleshooting Group Membership

Verify IGMP / MLD & IGMP / MLD Snooping

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y gconfiguration status

Make sure IGMP snooping requirements are met Make sure the Layer 3 and Layer 2 entries exist and

Interface/port membership is correct

Verifying IGMP / MLD & SnoopingConfiguration Status

Catalyst-6506E#show ip igmp Interface vlan 100

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y p g p

Vlan100 is up, line protocol is up

Internet address is 10.100.1.2/24

IGMP is enabled on Interface

Current IGMP host version is 2

Current IGMP router version is 2

IGMP query interval is 60 secondsIGMP querier timeout is 120 seconds

IGMP max query response time is 10 seconds

Last member query count is 2

Last member query response interval is 1000 ms

Inbound IGMP access group is not set

IGMP activity: 3 joins, 2 leaves

IGMPConfigurationState

IGMP PacketStatistics

Verifying IGMP / MLD & SnoopingConfiguration Status (2)

Multicast routing is enabled on Interface

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Multicast TTL threshold is 0

Multicast designated router (DR) is 10.100.1.3

IGMP querying router is 10.100.1.2 (this system)

No multicast groups joined by this system

IGMP snooping is globally enabled

IGMP snooping is enabled on this Interface

IGMP snooping Gist-leave is disabled and querier is disabled

IGMP snooping explicit-tracking is enabled

IGMP snooping last member query response interval is 1000 ms

IGMP snooping report-suppression is disabled

Catalyst-6506E#

IGMP Snooping Configuration State

DR & Querier

Information

Verifying IGMP Snooping Requirements

IGMP querier must be present in the VLAN

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q p

Could be multicast router or switch configured as querier

Make sure all multicast router ports knownSwitch tracks location of all multicast routers on per-VLANbasis

Detection based on IGMP queries and PIM hellos

Snooping switch uses list of mrouter ports to flood certaintraffic—e.g., proxied joins/leaves

Loss of multicast router port will impact traffic flow

Viewing Multicast Routers

Catalyst-6506E#show ip igmp snooping mrouter

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y p g p p g

vlan ports

-----+----------------------------------------

100 Gi3/7,Gi3/16

101 Gi3/7,Gi3/16

200 Gi3/7,Gi3/16

201 Gi3/7,Gi3/16

Catalyst-6506E#VLAN for Which

Specified Ports AreMulticast Router Ports

List of Multicast RouterPorts for VLAN

Verifying IGMP Membership

IGMP enabled when PIM configured on an Interface

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For receiver segments, IGMP drives OIF presencein mroute table

Use show ip igmp groups to see IGMP join status on mrouter

Use debug ip igmp <group> to monitor IGMP packet reception at router

Be aware of effect of IGMP snooping on Layer 3 IGMP behavior(e.g. not all joins/leaves seen by router)

Verify IGMP querier consistency and group membership for routerson shared segments

Watch for IGMP access groups, multicast boundary

Verify IGMP snooping entries

Make sure entry exists and port membership correct

Verifying IGMP Entries

Catalyst-6506E#show ip igmp groups

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Catalyst 6506E#show ip igmp groups

IGMP Connected Group Membership

Group Address Interface Uptime Expires Last Reporter

239.1.2.0 Vlan200 00:00:12 00:00:00 10.200.1.101

239.1.2.1 Vlan200 00:00:12 00:00:00 10.200.1.101

239.1.2.2 Vlan200 00:00:12 00:00:00 10.200.1.101

239.1.2.3 Vlan200 00:00:12 00:00:00 10.200.1.101

239.1.1.10 Vlan201 00:00:13 00:00:00 10.201.1.101

224.0.1.40 Loopback0 1w4d 00:02:18 10.255.255.1

Catalyst-6506E#

Multicast Group Joined

Interface withConnected Receiver

IP Address of LastReceiver to Report for

the Group on theInterface

Verifying IGMP Snooping Entries

Catalyst-6506E#show mac-address-table multicast igmp

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vlan mac address type learn qos ports

-----+---------------+--------+-----+---+--------------------------------200 0100.5e01.0101 static Yes - Gi3/1,Gi3/7,Gi3/16

100 0100.5e01.0101 static Yes - Gi3/5,Gi3/7,Gi3/16

101 0100.5e01.0101 static Yes - Gi3/6,Gi3/7,Gi3/16

Catalyst-6506E#

VLAN Where GroupMAC Is Learned

Group Destination MAC

List of Receiver Ports(Also Includes Any

Multicast Router Portsin VLAN)

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show mls ip multicast summary

show mls ip multicast summary

* Catalyst 6500 Only

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Catalyst-6506E#show mls ip multicast summary

21210 MMLS entries using 3394656 bytes of memory

Number of partial hardware-switched flows: 0

Number of complete hardware-switched flows: 21210

Directly connected subnet entry install is enabled

Hardware shortcuts for mvpn mroutes supported

Current mode of replication is Ingress

Auto-detection of replication mode is enabled

Consistency checker is enabled

Bidir gm-scan-interval: 10

Catalyst-6506E#

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Layer 2 Entry Capacity

Limit is 15,488 Layer 2 multicast groups

Li it i fi bl i

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Limit is configurable using ip igmp snooping

l2-entry-limit command Syslog posted when limit exceeded or hash collision

occurred%MCAST-SP-6-GC_LIMIT_EXCEEDED: IGMP snooping was trying to allocate

more Layer 2 entries than what allowed (15488)

%MCAST-SP-6-L2_HASH_BUCKET_COLLISION: Failure installing (G,C)->index: (0100.5e01.1465,1017)->0x82C

When limit exceeded, flooding occurs for additional

group MACs

Monitoring Layer 2 Entry Capacity

show mac-address-table multicast igmp count

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Catalyst-6506E#show mac-address-table multicast igmp count

Multicast MAC Entries for all vlans: 455

Catalyst-6506E#

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Catalyst 4500/4900IP Multicast Troubleshooting

Multicast Related Entries

IGMP snoopingPIM/IGMPEIGRP/OSPFProtocols

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Unicast Routing

Table

Multicast Routing

Table

MFIBCEF

Layer 2 Forwarding

Table

Hardware

Tables

CEF – MFIB Subsystem

Software

Tables

H/W FIB

Table

H/W adjacency

Table

S/W adjacency

Table

S/W FIB

Table

Replication

Table

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Documents

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