PowerPoint Presentation

IGMPv3 & IGMP Snooping Basics 2IGMPv3RFC 4604Adds Include/Exclude Source ListsEnables hosts to listen only to a specified subsets of the hosts sending to the groupRequires new IPMulticastListen API - New IGMPv3 stack required in the O/SApps must be rewritten to use IGMPv3 include/Exclude featuresIGMPv3New Membership Report address224.0.0.22 (IGMPv3 Routers)All IGMPv3 hosts send reports to this address instead of the target address as in IGMPv1/v2All IGMPv3 Routers listen to this addressHosts do not listen or respond to this addressNo Report SuppressionAll Hosts on wire respond to QueriesResponse Interval may be tuned over broad range - Useful when large numbers of hosts reside on subnetIGMPv3 Example

IGMPv3 Joining a Group

IGMPv3- Joining specific Source(s)

IGMPv3-Excluding specific Source(s)

IGMPv3-Maintaining State

IGMP Snooping & VerificationIGMP Snooping (Join)

IGMP Snooping (Join)

IGMP Snooping (Join)

IGMP Snooping (Join)

IGMP Snooping (default behavior regarding IGMP Leave Processing)

IGMP Snooping(default behavior regarding Leave Processing)

IGMP Snooping(default behavior regarding Leave Processing)

IGMP Snooping(Leave with Fast Leave Processing enable)

IGMP Snooping(Leave with Fast Leave Processing enable)

IGMP Snooping(default behavior regarding IGMP Leaving)

IGMP Snooping ConfigurationIOS-based Switches: IGMP Snooping is on by default To turn if off/on: > IOS: Router(config)# [no] ip igmp snooping

Enabling IGMP Snooping Fast-Leave (off by default) > switch(config-if)# ip igmp snooping fast-leave

Denial of Service

Rate-Limiters to the RescueRouter(config)# mls rate-limit multicast ipv4 igmp 20000 40In the command above:20000 = maximum of 20,000 IGMP Reports allowed per-second to be sent to CPU (configurable)40 = In any given millisecond, maximum of 40-IGMP Reports allowed to sent to CPU (configurable)Packing counting and drops done in hardware .

Verifying IGMP Snooping(IOS)

Verifying IGMP Snooping (Cat6500)

Note: In the cat6500 the SP process did all the multicast related things , i.e igmp snooping Verifying IGMP Snooping (Cat6500)

Verifying IGMP Snooping (other Switches)