Protocol Independent Multicast-Source Specific Multicast Guidelines; Igmpv3 And Pim-Ssm Operation; Rp Set Configuration Considerations; Pim-Ssm Design Considerations - Avaya 8800 Planning And Engineering, Network Design

Protocol Independent Multicast-Source Specific Multicast
guidelines
PIM Source Specific Multicast (SSM) is a subset of the PIM-SM features. In this model, members of
an SSM group can only receive multicast traffic from a single source, which is more efficient and
puts less load on multicast routing devices.
IGMPv3 supports PIM-SSM by enabling a host to selectively request or filter traffic from individual
sources within a multicast group.

IGMPv3 and PIM-SSM operation

Release 3.5 introduces an SSM-only implementation of IGMPv3. This SSM-only implementation is
not a full IGMPv3 implementation, and it processes messages according to the following rules:
• When an IGMPv2 report is received on an IGMPv3 interface, the switch drops the IGMPv2
report. IGMPv3 is not backward compatible with IGMPv2.
• In dynamic mode, when an IGMPv3 report is received with several nonSSM sources, but
matches a configured SSM range, the switch does not process the report.
• When an IGMPv2 router sends queries on an IGMPv3 interface, the switch downgrades this
interface to IGMPv2 (backward compatibility).
This can cause traffic interruption, but the switch recovers quickly.
• When an IGMPv3 report is received for a group with a different source than the one in the SSM
channels table, the switch drops the report.

RP Set configuration considerations

When you configure RP sets (C-RPs or static RPs), Avaya recommends as best practice not to
configure multiple entries that each specify a unique group, but instead specify a range of groups
when possible, thereby decreasing the number of entries required.

PIM-SSM design considerations

Consider the following information when designing an SSM network:
• When SSM is configured, it affect SSM groups only. The switch handles other groups in sparse
mode (SM).
• You need to configure PIM-SSM only on switches at the edge of the network. Core switches
use PIM-SM if they do not have receivers for SSM groups.
• For networks where group addresses are already in use, you can change the SSM range to
match the groups.
June 2016

Protocol Independent Multicast-Source Specific Multicast guidelines

Planning and Engineering — Network Design
Comments on this document? infodev@avaya.com
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