From: Chris Lewis (chrlewiscsco@yahoo.com)
Date: Sat Dec 03 2005 - 11:38:26 GMT-3
Look at the multicast configuration guide in the documentation CD at
It references these two sections specifically
"PIM Version 1, together with the Auto-RP feature, can perform the same tasks as the PIM Version 2 BSR. However, Auto-RP is a standalone protocol, separate from PIM Version 1, and is Cisco proprietary. PIM Version 2 is a standards track protocol in the IETF. We recommend that you use PIM Version 2. Either the BSR or Auto-RP should be chosen for a given range of multicast groups. If there are PIM Version 1 routers in the network, do not use the BSR. "
and later on.......
When Cisco and non-Cisco routers are being operated in a single PIM domain with PIM Version 2 BSR, care must be taken when configuring candidate RPs because the Cisco IOS implementation of the BSR RP selection is not fully compatible with RFC 2362.
RFC 2362 specifies that the BSR RP be selected as follows (RFC 2362, 3.7):
---------------------------------
Step 1 Select the candidate RP with the highest priority (lowest configured priority value).
Step 2 If there is a tie in the priority level, select the candidate RP with the highest hash function value.
Step 3 If there is a tie in the hash function value, select the candidate RP with the highest IP address.
---------------------------------
Cisco routers always select the candidate RP based on the longest match on the announced group address prefix before selecting an RP based on priority, hash function, or IP address.
Inconsistent candidate RP selection between Cisco and non-Cisco RFC 2362-compliant routers in the same domain if multiple candidate RPs with partially overlapping group address ranges are configured can occur. Inconsistent candidate RP selection can lead to disconnectivity between sources and receivers in the PIM domain. A source may register with one candidate RP and a receiver may connect to a different candidate RP even though it is in the same group.
The following example shows a configuration that can cause inconsistent RP selection between a Cisco and a non-Cisco router in a single PIM domain with PIM Version 2 BSR:
access-list 10 permit 224.0.0.0 7.255.255.255
ip pim rp-candidate ethernet1 group-list 10 priority 20
access-list 20 permit 224.0.0.0 15.255.255.255
ip pim rp-candidate ethernet2 group-list 20 priority 10
ip pim rp-candidate ethernet2 group-list 20 priority 10
Anderson Nery Vilas Boas <andervb@yahoo.dk> wrote:
that is it :
" it the case of wanting one RP to be primary for half the groups and secondary RP for the other half and be able to become the RP for all groups if the other RP fails ".
Can I use ip pim rp-candidate for both groups but with differente priorities ? So I will have two RPs , one for half of the groups? If one fail - by priorities the other can assume the entire function?
Can I user just AUTO-RP for this?
ps: the questions asks to use PIM V2.
Thanks Chris.
Chris Lewis skrev:
Hi,
Could you be a little more specific in the question please?
Are you looking for a multicast source and receiver to be able to find each other even if the RP for the group being used is down? If so I believe dense mode fallback is on by default and should work. Or is it the case of wanting one RP to be primary for half the groups and secondary RP for the other half and be able to become the RP for all groups if the other RP fails?
Chris
andervb@yahoo.dk wrote:
Hi , let see , If I configure 2 routers for sparse-dense mode.
r1 is rp for half of the administrately scope ,
r2 is the rp for the second half.
r3 send the discovery.
everybody uses auto-rp.
But if one RP fails routers must try to learn the multicast groups dynamically .
How could I resolve this?
Ander
This archive was generated by hypermail 2.1.4 : Mon Jan 09 2006 - 07:07:50 GMT-3