Multicast Source Discovery Protocol (MSDP) is a

Protocol Independent Multicast 400px, Example of a multicast network architecture Protocol-Independent Multicast (PIM) is a family of multicast routing protocols for Internet Protocol (IP) networks that provide one-to-many and many-to-many distribution of data over a LAN, ...

(PIM) family multicast routing protocol defined by Experimental RFC 3618. Despite becoming the IPv4

de facto standard A ''de facto'' standard is a custom or convention that has achieved a dominant position by public acceptance or market forces (for example, by early entrance to the market). is a Latin phrase (literally " in fact"), here meaning "in practice b ...

for inter-domain multicast, development of the protocol stopped in 2006 and it was decided by the authors not to proceed with making it a proposed standard. MSDP interconnects multiple

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...

PIM Sparse-Mode (PIM-SM) domains which enables PIM-SM to have Rendezvous Point (RP) redundancy and

inter-domain Inter-domain routing is data flow control and interaction between Primary Domain Controller (PDC) computers. This type of computer uses various computer protocols and services to operate. It is most commonly used to multicast between internet doma ...

multicasting RFC 4611. MSDP uses TCP as its transport protocol. Each multicast tree needs to have its own RP. All of the RPs are peers (directly or through other MSDP peers). Messages contain the sender (source) address and the multicast group address (S,G). If an RP on its own domain receives a message, it determines if there are listeners for this group. If listeners exist, it triggers a PIM join into the source domain towards the data source. In a peering relationship, one MSDP peer listens for new TCP connections on the well-known port 639. MSDP is deliberately unspecified for IPv6, for a number of reasons, including that protocols such as

Source-Specific Multicast Source-specific multicast (SSM) is a method of delivering multicast packets in which the only packets that are delivered to a receiver are those originating from a specific source address requested by the receiver. By so limiting the source, SSM re ...

(SSM), Bi-directional Multicast and IPv6 Embedded Rendezvous Points would mean there was less requirement for MSDP.

External links

* Multicast BGP

References

{{compu-network-stub Routing protocols Internet protocols