H3C Technologies H3C S10500 Series Switches - Manual (Page 219)

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MSDP configuration
NOTE:
•
The term router in this document refers to both routers and Layer 3 switches.
• For more information about the concepts of designated router (DR), bootstrap router (BSR),
candidate-BSR (C-BSR), rendezvous point (RP), candidate RP (C-RP), shortest path tree (SPT) and
rendezvous point tree (RPT) mentioned in this document, see the chapter “PIM configuration.”
• The term interface in the MSDP features refers to Layer 3 interfaces, including VLAN interfaces and
route-mode (or Layer 3) Ethernet ports. You can set an Ethernet port to operate in route mode by using
the port link-mode route command (see
Layer 2—LAN Switching Configuration Guide).
MSDP overview
Multicast source discovery protocol (MSDP) is an inter-domain multicast solution that addresses the
interconnection of protocol independent multicast sparse mode (PIM-SM) domains.You can use it to
discover multicast source information in other PIM-SM domains.
In the basic PIM-SM mode, a multicast source registers only with the RP in the local PIM-SM domain, and
the multicast source information about a domain is isolated from that of another domain. As a result, the
RP obtains the source information only within the local domain, and a multicast distribution tree is built
only within the local domain to deliver multicast data from a local multicast source to local receivers.
MSDP enables the RPs of different PIM-SM domains to share their multicast source information, so that the
local RP can join multicast sources in other domains, and multicast data can be transmitted among
different domains.
With MSDP peer relationships established between appropriate routers in the network, the RPs of
different PIM-SM domains are interconnected with one another. These MSDP peers exchange source
active (SA) messages, so that the multicast source information is shared among these different domains.
NOTE:
•
MSDP is applicable only if the intra-domain multicast protocol is PIM-SM.
• MSDP is meaningful only for the any-source multicast (ASM) model.
How MSDP works
MSDP peers
Configuring one or more pairs of MSDP peers in the network forms an MSDP interconnection map,
where the RPs of different PIM-SM domains are interconnected in series. An SA message that an RP
sends and that these MSDP peers relay can be delivered to all other RPs.