Igmp Version 2; Pim Versions - Cisco IE-4000 Software Configuration Manual

Configuring IP Multicast Routing
Information About Cisco's Implementation of IP Multicast Routing

IGMP Version 2

IGMPv2 extends IGMP functionality by providing such features as the IGMP leave process to reduce leave latency,
group-specific queries, and an explicit maximum query response time. IGMPv2 also adds the capability for routers to
elect the IGMP querier without depending on the multicast protocol to perform this task. For more information, see RFC
2236.
Information About PIM
PIM is called protocol-independent: regardless of the unicast routing protocols used to populate the unicast routing
table, PIM uses this information to perform multicast forwarding instead of maintaining a separate multicast routing table.
PIM is defined in RFC 2362, Protocol-Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification. PIM is
defined in these Internet Engineering Task Force (IETF) Internet drafts:

Protocol Independent Multicast (PIM): Motivation and Architecture

Protocol Independent Multicast (PIM), Dense Mode Protocol Specification

Protocol Independent Multicast (PIM), Sparse Mode Protocol Specification

draft-ietf-idmr-igmp-v2-06.txt, Internet Group Management Protocol, Version 2

draft-ietf-pim-v2-dm-03.txt, PIM Version 2 Dense Mode
This section includes the following topics:

PIM Versions, page 677

PIM Modes, page 678

PIM Stub Routing, page 678

IGMP Helper, page 679

Auto-RP, page 679

Bootstrap Router, page 680

Multicast Forwarding and Reverse Path Check, page 680

PIM Versions

PIMv2 includes these improvements over PIMv1:

A single, active rendezvous point (RP) exists per multicast group, with multiple backup RPs. This single RP compares
to multiple active RPs for the same group in PIMv1.

A bootstrap router (BSR) provides a fault-tolerant, automated RP discovery and distribution mechanism that enables
routers and multilayer switches to dynamically learn the group-to-RP mappings.

Sparse mode and dense mode are properties of a group, as opposed to an interface. We strongly recommend
sparse-dense mode, as opposed to either sparse mode or dense mode only.

PIM join and prune messages have more flexible encoding for multiple address families.

A more flexible hello packet format replaces the query packet to encode current and future capability options.

Register messages to an RP specify whether they are sent by a border router or a designated router.
677