What is Multicast Rendezvous Point (RP) ?

IP Multicast Routing

A Rendezvous Point (RP) is nothing just a router in a multicast network domain that acts like as a shared root for a multicast shared tree. We can assign any number of routers and can be configured to work as Rendezvous Point RPs and they can be configured to cover different group ranges.

 

Reference point for the root of the shared tree

• RP learn about source using PIM register messages (RP pack with register stopped add(s.g).
• RP learns about destination using  PIM join messages and its  Merge two tree together.
• Joining shortest path to source and prune toward RP.

All the routers must agree on the conman RP

Here is the question comes in mind. What if there is no RP?

1. .       Source can not register.
2. .       Join can not be processed.

Rendezvous point (static, auto RP, BSR)

Configuring  Rendezvous point.

• Statically
• Dynamically

1.       Auto-RP

2.       BSR

When you configure Static RP  we have to manually configure RP address on every router

All router must have the same RP address. RP fail-over not possible.

Auto RP

Auto-RP is a Legacy Cisco proprietary method of learning  RP information. all routers automatically learn RP address.

No configuration necessary except on

•  candidate RP (device willing to become RP).
• mapping agent (choose the RP and relay this information to rest of the PIM domain).
• Permit backup RP’s to be configured.

How auto-RP works

1.       Candidate RP generate advertisements using ( s, 224.0.1.39) and groups with group  information

2.       Mapping agent listen for (*. 224.0.1.39) to learn about RP mappings.

3.       Mapping agent generate advertisement using (s.224.0.1.40) to distribute RP mapping information.

• Every router must join 224.0.1.39 and 224.0.1.40 for learning  information from mapping  agent
• By default using spare-mode other routers can not join 224.0.1.40 (mapping agent)

Auto RP with multiple RP

• Providers redundancy and load sharing.
• Access list can be applied to control what ever RP server what ever  group.
• If multiple RP configured mapping agent select the best highest ip
• Cannot use two RP same time for same group.

Drawback of auto RP

Cisco proprietary.

Need to learn about 224.0.1.39/40

Not used in IPv6 multicast.