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Multi-instance pim, Protocols and standards, Configuring pim-dm – H3C Technologies H3C S7500E Series Switches User Manual

Page 152: Pim-dm configuration task list

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6-15

As shown in

Figure 6-9

, Host B and Host C are multicast information receivers. They send

IGMPv3 report messages to the respective DRs to express their interest in the information of

the specific multicast source S.

Upon receiving a report message, the DR first checks whether the group address in this

message falls in the SSM group range:

z

If so, the DR sends a subscribe message for channel subscription hop by hop toward the

multicast source S. An (S, G) entry is created on all routers on the path from the DR to the

source. Thus, an SPT is built in the network, with the source S as its root and receivers as

its leaves. This SPT is the transmission channel in PIM-SSM.

z

If not, the PIM-SM process is followed: the DR needs to send a (*, G) join message to the

RP, and a multicast source registration process is needed.

In PIM-SSM, the “channel” concept is used to refer to a multicast group, and the “channel

subscription” concept is used to refer to a join message.

Multi-Instance PIM

A multicast router running multiple instances maintains an independent set of PIM neighbor

table, multicast routing table, BSR information and RP-set information for each instance.

Upon receiving a multicast data packet, the multicast router determines the VPN instance the

data packet belongs to, and then forwards the packet as per the multicast routing table of that

VPN instance or creates a multicast routing table entry for that VPN instance.

Protocols and Standards

PIM-related specifications are as follows:

z

RFC 4601: Protocol Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification

(Revised)

z

RFC 3973: Protocol Independent Multicast-Dense Mode (PIM-DM): Protocol

Specification(Revised)

z

RFC 4607: Source-Specific Multicast for IP

z

RFC 5059: Bootstrap Router (BSR) Mechanism for Protocol Independent Multicast (PIM)

z

Draft-ietf-ssm-overview-05: An Overview of Source-Specific Multicast (SSM)

Configuring PIM-DM

PIM-DM Configuration Task List

Complete these tasks to configure PIM-DM: