H3C S7500E Series Ethernet Switches Operation Manual
Operation Manual – Multicast
H3C S7500E Series Ethernet Switches Chapter 5 PIM Configuration
5-15
As shown in Figure 5-9, Host B and Host C are multicast information receivers. They
send IGMPv3 report messages denoted as (Include S, G) to the respective DRs to
express their interest in the information of the specific multicast source S. If they need
information from other sources than S, they send an (Exclude S, G) report. No matter
what the description is, the position of multicast source S is explicitly specified for
receivers.
The DR that has received the report 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 (Include S, G) or (Exclude 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.
Note:
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.
5.1.7 Protocols and Standards
PIM-related specifications are as follows:
z RFC 2362: Protocol Independent Multicast-sparse Mode (PIM-SM): Protocol
Specification
z RFC 3973: Protocol Independent Multicast-Dense Mode (PIM-DM): Protocol
Specification(Revised)
z draft-ietf-pim-sm-v2-new-06: Protocol Independent Multicast-Sparse Mode
(PIM-SM)
z draft-ietf-pim-dm-new-v2-02: Protocol Independent Multicast-Dense Mode
(PIM-DM)
z draft-ietf-pim-v2-dm-03: Protocol Independent Multicast Version 2 Dense Mode
Specification
z draft-ietf-pim-sm-bsr-03: Bootstrap Router (BSR) Mechanism for PIM Sparse
Mode
z draft-ietf-ssm-arch-02: Source-Specific Multicast for IP
z draft-ietf-ssm-overview-04: An Overview of Source-Specific Multicast (SSM)