Information About Pim; Pim Versions; Pimv1 And Pimv2 Interoperability - Cisco Catalyst 2960-XR Configuration Manuals

Configuring PIM

Information About PIM

PIM is 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

PIM Versions

PIMv2 includes these improvements over PIMv1:
• A single, active rendezvous point (RP) exists per multicast group, with multiple backup RPs. This single
• A bootstrap router (BSR) provides a fault-tolerant, automated RP discovery and distribution function
• Sparse mode and dense mode are properties of a group, as opposed to an interface.
• 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
• Register messages sent to an RP specify whether they are sent by a border router or a designated router.
• PIM packets are no longer inside IGMP packets; they are standalone packets.

PIMv1 and PIMv2 Interoperability

To avoid misconfiguring multicast routing on your switch, review the information in this section.
The Cisco PIMv2 implementation provides interoperability and transition between Version 1 and Version 2,
although there might be some minor problems.
You can upgrade to PIMv2 incrementally. PIM Versions 1 and 2 can be configured on different routers and
multilayer switches within one network. Internally, all routers and multilayer switches on a shared media
OL-29426-01
RP compares to multiple active RPs for the same group in PIMv1.
that enables routers and multilayer switches to dynamically learn the group-to-RP mappings.
Note We strongly recommend using sparse-dense mode as opposed to either sparse mode or
dense mode only.
options.
Catalyst 2960-XR Switch IP Multicast Routing Configuration Guide, Cisco IOS Release 15.0(2)EX1
Information About PIM
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