Enabling Installation Of Directly Connected Subnets; Configuring Igmp Snooping - Cisco WS-X6066-SLB-APC - Content Switching Module Software Manual

Configuring IGMP Snooping

Non-RPF multicast fast drop (MFD) rate limits packets that fail the RPF check (non-RPF packets) and
drops the majority of the non-RPF packets in hardware. According to the multicast protocol
specification, the router needs to see the non-RPF packets for the PIM assert mechanism to work, so all
non-RPF packets cannot be dropped in hardware. To support the PIM assert mechanism, the PFC leaks
a percentage of the non-RFP flow packets to the MSFC.
Non-RPF MFD is enabled on the switch by default. Non-RPF MFD is supported with Supervisor
Engine 2 only.

Enabling Installation of Directly Connected Subnets

In PIM sparse mode, a first-hop router that is the designated router (DR) for the interface may need to
encapsulate the source traffic in a PIM register message and unicast it to the rendezvous point (RP). To
prevent new sources for the group from being learned in the routing table, the (*,G) flows should remain
completely hardware-switched flows. (subnet/mask, 224/4) entries installed in the hardware FIB allow
both (*,G) flows to remain completely hardware-switched flows, and new, directly connected sources to
be learned correctly. Installation of directly connected subnets is enabled globally by default. One
(subnet/mask, 224/4) is installed per PIM-enabled interface.
Use the show mls ip multicast connected command to view such FIB entries.
To enable installation of directly connected subnets, perform this task:
Task
Enable downloading of directly connected subnets. Router(config) # mls ip multicast connected
This example shows how to install directly connected subnets:
Router(config)# mls ip multicast connected
Router(config)#
Configuring IGMP Snooping
IGMP snooping allows switches to examine IGMP packets and make forwarding decisions based on
their content.
Quality of service (QoS) does not support IGMP traffic when IGMP snooping is enabled.
Note
These sections describe how to configure IGMP snooping:
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Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
40-6
Default IGMP Snooping Configuration, page 40-7
Enabling IGMP Snooping, page 40-7
Specifying IGMP Snooping Mode, page 40-8
Enabling IGMP Fast-Leave Processing, page 40-9
Enabling IGMP Rate Limiting, page 40-8
Displaying Multicast Router Information, page 40-9
Displaying Multicast Group Information, page 40-10
Displaying IGMP Snooping Statistics, page 40-11
Chapter 40 Configuring Multicast Services
Command
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