WB1 8.13 Auto-RP - Filtering Candidate RPs

8.13 Auto-RP - Filtering Candidate RPs

• Configure R5 to filter announcements for the group 224.110.110.110 received from SW4.

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The Auto-RP mapping agent allows for the filtering of incoming RP
announcements sent by RP candidates. This type of filtering applies only to Auto-
RP announcements received by listening to the 224.0.1.39 multicast IP address
and thus is only effective on Mapping Agents. You configure a filtering statement
using the following syntax:

ip pim rp-announce-filter {group-list <access-list> | rp-list <access-list> [group-list <accesslist>]}.

All access-lists are either numbered or named standard ACLs. RP
announcements are inspected and if a match is found for the group and the RP
IP address, the action is taken based on the “permit” or “deny” statement.
If you omit the rp-list keyword, then any announcements containing groups
matching the group-list are matched. If you omit the group-list
parameter, then all updates from the RPs in rp-list are matched.

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R5:
ip access-list standard RP_LIST
permit 150.1.10.10
!
ip access-list standard GROUP_LIST
deny 224.110.110.110
permit any
!
ip pim rp-announce-filter rp-list RP_LIST group-list GROUP_LIST

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Use the command debug ip pim auto-rp on the MA to monitor the updates
that are filtered.

Rack1R5#
*Mar  1 20:44:44.782: Auto-RP(0): Received RP-announce packet of length 60, from 150.1.10.10, RP_cnt 1, ht 181
*Mar  1 20:44:44.786: Auto-RP(0): Filtered -224.110.110.110/32 for RP 150.1.10.10
*Mar  1 20:44:44.790: Auto-RP(0): Update (232.0.0.0/5, RP:150.1.10.10), PIMv2 v1
*Mar  1 20:44:44.794: Auto-RP(0): Update (224.0.0.0/4, RP:150.1.10.10), PIMv2 v1
*Mar  1 20:44:44.798: Auto-RP(0): Received RP-announce packet of length 60, from 150.1.10.10, RP_cnt 1, ht 181
*Mar  1 20:44:44.802: Auto-RP(0): Filtered -224.110.110.110/32 for RP 150.1.10.10
*Mar  1 20:44:44.802: Auto-RP(0): Update (232.0.0.0/5, RP:150.1.10.10), PIMv2 v1
*Mar  1 20:44:44.802: Auto-RP(0): Update
Rack1R5# (224.0.0.0/4, RP:150.1.10.10), PIMv2 v1
Rack1R5#

Rack1R5#
*Mar  1 20:45:00.962: Auto-RP(0): Received RP-announce packet of length 60, from 150.1.8.8, RP_cnt 1, ht 181
*Mar  1 20:45:00.970: Auto-RP(0): Update (-224.110.110.110/32, RP:150.1.8.8), PIMv2 v1
*Mar  1 20:45:00.974: Auto-RP(0): Update (224.0.0.0/5, RP:150.1.8.8), PIMv2 v1
*Mar  1 20:45:00.974: Auto-RP(0): Update (224.0.0.0/4, RP:150.1.8.8), PIMv2 v1
*Mar  1 20:45:00.974: Auto-RP(0): Received RP-announce packet of length 60, from 150.1.8.8, RP_cnt 1, ht 181
*Mar  1 20:45:00.974: Auto-RP(0): Update (-224.110.110.110/32, RP:150.1.8.8), PIMv2 v1
*Mar  1 20:45:00.974: Auto-RP(0): Update (224.0.0.0/5, RP:150.1.8.8), PIMv2 v1
*Mar  1 20:45:00.974: Auto-RP(0): Update (224.0.0.0/4, RP:150.1.8.8), PIMv2 v1

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Rack1R5#show ip pim rp mapping
PIM Group-to-RP Mappings
This system is an RP-mapping agent (Loopback0)
Group(s) 224.0.0.0/5
  RP 150.1.8.8 (?), v2v1
    Info source: 150.1.8.8 (?), elected via Auto-RP
         Uptime: 00:32:30, expires: 00:02:41
Group(s) 224.0.0.0/4
  RP 150.1.10.10 (?), v2v1
    Info source: 150.1.10.10 (?), elected via Auto-RP
         Uptime: 00:33:17, expires: 00:02:23
  RP 150.1.8.8 (?), v2v1
    Info source: 150.1.8.8 (?), via Auto-RP
         Uptime: 00:32:30, expires: 00:02:41
Group(s) (-)224.110.110.110/32
  RP 150.1.8.8 (?), v2v1
    Info source: 150.1.8.8 (?), elected via Auto-RP
         Uptime: 00:32:30, expires: 00:02:43
Group(s) 232.0.0.0/5
  RP 150.1.10.10 (?), v2v1
    Info source: 150.1.10.10 (?), elected via Auto-RP
         Uptime: 00:29:45, expires: 00:02:24
Rack1R5#