Multiple Static RPs and Access-list behaviour

malcolmsalmons · ‎08-15-2012

Hi

Just a quick question, if I configure multiple static RPs and one of the ACLs denies a source will it move on to the next entry that covers it in another acl?

e.g.

access-list 1 deny 239.0.0.0 0.255.255.255

access-list 1 permit 224.0.0.0 15.255.255.255

access-list 2 permit 239.0.0.0 0.255.255.255

access-list 2 deny 224.0.0.0 15.255.255.255

ip pim rp-address 1.1.1.1 1

ip pim rp-address 2.2.2.2 2

i.e. 1.1.1.1 will be used as the RP for 224 to 238 and 2.2.2.2 will be used as the RP for 239.

Will that work correctly, i.e. if a source is trying to register with the router and its for the group 239.1.1.1, will it be denied against the first RP and then permitted against the second RP?

Thanks

Malcolm

Peter Paluch · ‎08-15-2012

Hello Malcolm,

Will that work correctly, i.e. if a source is trying to register with the router and its for the group 239.1.1.1, will it be denied against the first RP and then permitted against the second RP?

Yes, that is the way it should work. Quoting from

http://www.cisco.com/en/US/docs/ios-xml/ios/ipmulti/command/imc_i3.html#GUID-13AFEEB5-ABA4-412E-BBDC-AFF06A9A4F79

 You can configure a single RP for more than  one group using an access list. If no access list is specified, the  static RP will map to all multicast groups, 224/4. 
 You can configure multiple RPs, but only one RP per group range. 
 If multiple              ip                  pim                  rp-address              commands are configured, the following rules apply: 


 Highest RP IP address selected regardless of reachability: If a  multicast group is matched by the access list of more than one  configured                  ip                      pim                      rp-address command, then the RP for the group is determined by the RP with the highest RP address configured.

Best regards,

Peter

malcolmsalmons · ‎08-17-2012

Hi Peter

Thanks for the reponse. That confirms what I thought.

Best regards

Malcolm