Msdp support for vpns, Protocols and standards – H3C Technologies H3C S12500 Series Switches User Manual
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Figure 58 Intra-domain Anycast RP through MSDP
The work process of Anycast RP is as follows:
1.
The multicast source registers with the nearest RP. In this example, Source registers with RP 1, with
its multicast data encapsulated in the register message. When the register message arrives at RP
1, RP 1 de-encapsulates the message.
2.
Receivers send join messages to the nearest RP to join in the RPT rooted as this RP. In this example,
Receiver joins the RPT rooted at RP 2.
3.
RPs share the registered multicast information by means of SA messages. In this example, RP 1
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.
4.
Receivers receive the multicast data along the RPT and directly join the SPT rooted at the multicast
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.
IMPORTANT:
•
Be sure to configure a 32-bit subnet mask 255.255.255.255 for the Anycast RP address.
•
An MSDP peer address must be different from the Anycast RP address
MSDP support for VPNs
The interfaces on the multicast routers in a VPN can set up MSDP peering relationship between each
other. By exchanging SA messages between MSDP peers, multicast transmission in a VPN between
different PIM-SM domains can be implemented.
To support MSDP for VPNs, a multicast router that runs MSDP maintains an independent set of MSDP
mechanism for each VPN that it supports, including SA cache, peering connection, timers, sending
cache, and cache for exchanging PIM messages. The information in one VPN is isolated from another,
and MSDP and PIM-SM messages can be exchanged only within the same VPN.
Protocols and standards
•
RFC 3618, Multicast Source Discovery Protocol (MSDP)
•
RFC 3446, Anycast Rendezvous Point (RP) mechanism using Protocol Independent Multicast (PIM)
and Multicast Source Discovery Protocol (MSDP)