Multicast Routing And Switch Stacks; Configuring Ip Multicast Routing - Cisco Catalyst 3750-X Software Configuration Manual

Multicast Routing and Switch Stacks

CGMP is necessary because the Layer 2 switch cannot distinguish between IP multicast data packets and
IGMP report messages, which are both at the MAC-level and are addressed to the same group address.
CGMP is mutually exclusive with HSRPv1. You cannot enable CGMP leaving processing and HSRPv1
at the same time. However, you can enable CGMP and HSRPv2 at the same time. For more information,
see the
Multicast Routing and Switch Stacks
For all multicast routing protocols, the entire stack appears as a single router to the network and operates
as a single multicast router.
In a switch stack, the routing master (stack master) performs these functions:
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The stack members perform these functions:
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Configuring IP Multicast Routing

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
48-10
"HSRP Versions" section on page
It is responsible for completing the IP multicast routing functions of the stack. It fully initializes and
runs the IP multicast routing protocols.
It builds and maintains the multicast routing table for the entire stack.
It is responsible for distributing the multicast routing table to all stack members.
They act as multicast routing standby devices and are ready to take over if there is a stack master
failure.
If the stack master fails, all stack members delete their multicast routing tables. The newly elected
stack master starts building the routing tables and distributes them to the stack members.
If a stack master running the IP servic e s feature set fails and if the ne wly elected stack master
Note
is running the IP base feature set, the switch stack loses its multicast routing capability.
For information about the stack master election process, see
They do not build multicast routing tables. Instead, they use the multicast routing table that is
distributed by the stack master.
Default Multicast Routing Configuration, page 48-11
Multicast Routing Configuration Guidelines, page 48-11
Configuring Basic Multicast Routing, page 48-12
Configuring Source-Specific Multicast, page 48-14
Configuring Source Specific Multicast Mapping, page 48-17Configuring PIM Stub Routing,
page 48-22 (optional)
Configuring a Rendezvous Point, page 48-24
you want to treat the group as a sparse group)
Using Auto-RP and a BSR, page 48-34
Cisco PIM v1 devices))
Monitoring the RP Mapping Information, page 48-35
Troubleshooting PIMv1 and PIMv2 Interoperability Problems, page 48-35
Chapter 48
44-3.
Chapter 5, "Managing Switch Stacks."
(required)
(required if the interface is in sparse-dense mode, and
(required for non-Cisco PIMv2 devices to interoperate with
(optional)
Configuring IP Multicast Routing
(optional)
OL-21521-01