From: Brant I. Stevens (branto@branto.com)
Date: Sun Oct 16 2005 - 14:26:12 GMT-3
The term typically used for this application of MSDP is Anycast RPs.
The logic is that an IGP capable of supporting ECMP (EIGRP, OSPF, IS-IS,
etc...) will carry multiple entries for the RP address (10.10.10.10, in your
example), and that depending on where you are in the network, your
connecting router will choose the best path to the RP as it sees it. Your
configuration should include the advertisement of the RP address into
whatever IGP being used.
To avoid having to statically configure RP information on every router in
the network, you could leverage Auto-RP to propagate the Anycast RP address
for the desired groups.
MSDP peering is configured between the RPs in each "half" of the network to
communicate active source information between peers. Should one RP fail,
the IGP will reconverge, and a new path to the surviving RP will be
recaclulated. At that point, new Multicast flows would be able to be
sent/received on the network once again.
Depending on the speed of convergence of the IGP in use, you can get RP
failover as fast as your IGP can reconverge.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Stefan Grey
Sent: Sunday, October 16, 2005 1:07 PM
To: ccielab@groupstudy.com
Subject: Multicast "HSRP" (by MSDP)
Hello group,
I just read one example of configuring reliable RP point in the PIM sparse
mode using msdp.
Look:
R1 (rouer id is 1.1.1.1)
int lo0
ip add 1.1.1.1
int lo1
ip pim sparse-mode
ip add 10.10.10.10 255.255.255.255
ip msdp peer 1.1.2.2 connect-source lo0
ip msdp originator-id lo0
ip pim rp-address 10.10.10.10
R2 (router-id is 1.1.2.2)
int lo0
ip add 1.1.2.2
int lo1
ip pim sparse-mode
ip add 10.10.10.10 255.255.255.255
ip msdp peer 1.1.1.1 connect-source lo0
ip msdp originator-id lo0
ip pim rp-address 10.10.10.10
something like this and all other routers could use just the 10.10.10.10
address as the RP point. And if one of ther router will fail the other
router could just act as the RP.
I configured this and it seems to work as it should.
When I read about MSDP I read that this is interAS multicast protocol. And
is configured only between different ASs. Well I found just one example when
it could be used in one AS but with different ip addresses of the RPs.
Please. Could some one explain the logic of such behaviour, how is it
possible to use that, and how MSDP acts in this situation. What is really
happening in this config??
Is this correct at all??
Thanks,
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