From: Andrew Lissitz \(alissitz\) (alissitz@cisco.com)
Date: Sun Oct 16 2005 - 17:30:28 GMT-3
Hey Group,
Just to comment on production implementations ... this works very good
and should be considered. Anycast can also be used for DNS and critical
servers / services etc...
Here is a good deep link for msdp (more for ISP discussions):
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/
fipr_c/ipcpt3/1cfmsdp.htm
For anycast (read this one to see how clever this protocol / method is):
http://www.cisco.com/univercd/cc/td/doc/cisintwk/intsolns/mcst_sol/anyca
st.htm
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brant I. Stevens
Sent: Sunday, October 16, 2005 1:26 PM
To: 'Stefan Grey'; ccielab@groupstudy.com
Subject: RE: Multicast "HSRP" (by MSDP)
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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