Multi-Instance Msdp; Protocols And Standards; Configuring Basic Functions Of Msdp; Prerequisites - HP A6600 Configuration Manual

RPs share the registered multicast information by means of SA messages. In this example, RP 1
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creates an SA message and sends it to RP 2, with the multicast data from Source encapsulated in the
SA message. When the SA message reaches RP 2, RP 2 de-encapsulates the message.
Receivers receive the multicast data along the RPT and directly join the SPT rooted at the multicast
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source. In this example, RP 2 forwards the multicast data down the RPT. When Receiver receives the
multicast data from Source, it directly joins the SPT rooted at Source.
The significance of Anycast RP is as follows:
Optimal RP path—A multicast source registers with the nearest RP so that an SPT with the optimal
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path is built. A receiver joins the nearest RP so that an RPT with the optimal path is built.
• Load balancing between RPs—Each RP needs to maintain just part of the source/group information
within the PIM-SM domain and forward part of the multicast data, thus achieving load balancing
between different RPs.
Redundancy backup between RPs—When an RP fails, the multicast source previously registered on it
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or the receivers that previously joined it will register with or join another nearest RP, achieving
redundancy backup between RPs.
Be sure to configure a 32-bit subnet mask (255.255.255.255) for the Anycast RP address. Namely, be
sure to configure the Anycast RP address into a host address.
An MSDP peer address must be different from the Anycast RP address.

Multi-instance MSDP

MSDP peering relationship can be built between multicast-enabled interfaces that belong to the same
instance. Through exchanges of SA messages between MSDP peers, the MSDP mechanism enables VPN
multicast transmission between different PIM-SM domains.
A multicast router that is running multiple MSDP instances maintains an independent set of MSDP
mechanism for each instance that it supports, including SA cache, peering connection, timers, sending
cache, and cache for exchanging information with PIM, and one instance is isolated from another.
Therefore, interoperability between MSDP and PIM-SM is available only within the same instance.

Protocols and standards

RFC 3618, Multicast Source Discovery Protocol (MSDP)
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RFC 3446, Anycast Rendezvous Point (RP) mechanism using Protocol Independent Multicast (PIM)
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and Multicast Source Discovery Protocol (MSDP)

Configuring basic functions of MSDP

All the configuration tasks should be carried out on RPs in PIM-SM domains, and each of these RPs acts as
an MSDP peer.

Prerequisites

Before you configure the basic functions of MSDP, complete the following tasks:
• Configure any unicast routing protocol so that all devices in the domain are interoperable at the
network layer
Configuring PIM-SM to enable intra-domain multicast forwarding
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