Multicast - AutoRP RP filtering

Overview

AutoRP announcements are sent to the group 224.0.1.39 and listened to by sparse mode hosts configured as mapping agents. Mapping agents then send PIM messages about the RPs and their associated groups to the group 224.0.1.40. The RP announcements can be filtered by mapping agents using the command ip pim rp-announce-filter rp-list RP_ACL group-list GROUP_ACL.


Concepts tested

• Configuring PIM sparse dense mode
• Configuring RP announce filtering
• Configuring sparse mode group filtering

Topology

Lab Tasks

• Configure PIM sparse dense mode on all paths between R1 and R5
• Configure R2 and R3 as RP's using Cisco's proprietary Autorp.
• Configure R4 as the mapping agent.
• Filter R4 so that the group 224.10.10.10 is switched using dense mode only
• Prevent 

GNS3 configuration file, requires IOS v15 for the 7200 router: Link


Solution


R1(config)#ip multicast-routing

R1(config)#int g0/0

R1(config-if)#ip pim sparse-dense-mode

R2(config)#ip multicast-routing

R2(config)#int loopback 0

R2(config-if)#ip pim sparse-dense-mode

R2(config)#int g0/0

R2(config-if)#ip pim sparse-dense-mode

R2(config)#int g1/0

R2(config-if)#ip pim sparse-dense-mode
R3(config)#ip pim send-rp-announce loopback 0 scope 15 group-list M_GROUPS
R3(config)#ip access-list standard M_GROUPS
R3(config-std-nacl)#deny 224.10.10.10
R3(config-std-nacl)#permit any

R3(config)#ip multicast-routing

R3(config)#int loopback 0

R3(config-if)#ip pim sparse-dense-mode

R3(config-if)#exit

R3(config)#int g0/0

R3(config-if)#ip pim sparse-dense-mode

R3(config-if)#int g1/0

R3(config-if)#ip pim sparse-dense-mode
R2(config)#ip pim send-rp-announce loopback 0 scope 15 group-list M_GROUPS
R2(config)#ip access-list standard M_GROUPS
R2(config-std-nacl)#deny 224.10.10.10
R2(config-std-nacl)#permit any

R4(config)#ip multicast-routing
R4(config)#int g0/0
R4(config-if)#ip pim sparse-dense-mode
R4(config-if)#int g1/0
R4(config-if)#ip pim sparse-dense-mode
R4(config-if)#int loopback 0
R4(config-if)#ip pim sparse-dense-mode
R4(config-if)#exit
R4(config)#int g2/0
R4(config-if)#ip pim sparse-dense-mode
R4(config-if)#exit
R4(config)#ip access-list standard M_GROUPS

R4(config-std-nacl)#deny 224.10.10.10
R4(config-std-nacl)#permit any
R4(config-std-nacl)#
R4(config-std-nacl)#ip access-list standard ALLOWED_RP
R4(config-std-nacl)#permit 4.4.4.4
R4(config)#ip pim rp-announce-filter rp-list ALLOWED_RP group-list M_GROUPS
R4(config)#ip pim send-rp-discovery loopback 0 scope 15

R5(config)#ip multicast-routing
R5(config)#int g0/0
R5(config-if)#ip pim sparse-dense-mode

Verification

R4#sh ip pim rp mapping
PIM Group-to-RP Mappings
This system is an RP-mapping agent (Loopback0)

Group(s) 224.0.0.0/4
  RP 3.3.3.3 (?), v2v1
    Info source: 3.3.3.3 (?), elected via Auto-RP
         Uptime: 01:42:29, expires: 00:02:51
  RP 2.2.2.2 (?), v2v1
    Info source: 2.2.2.2 (?), via Auto-RP
         Uptime: 01:42:31, expires: 00:02:17
Group(s) (-)224.10.10.10/32
  RP 2.2.2.2 (?), v2v1
    Info source: 2.2.2.2 (?), elected via Auto-RP
         Uptime: 00:37:40, expires: 00:02:15

R5#ping 224.10.10.10 rep 100

Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 224.10.10.10, timeout is 2 seconds:

Reply to request 0 from 120.0.0.1, 208 ms
Reply to request 1 from 120.0.0.1, 96 ms.
Reply to request 3 from 120.0.0.1, 104 ms

R1#sh ip mroute 224.10.10.10

<snip>

(*, 224.10.10.10), 00:21:32/stopped, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    GigabitEthernet0/0, Forward/Sparse-Dense, 00:21:32/00:00:00

(120.0.45.5, 224.10.10.10), 00:01:08/00:01:51, flags: PLT

  Incoming interface: GigabitEthernet0/0, RPF nbr 120.0.0.3

  Outgoing interface list: Null

R2#sh ip mroute 224.10.10.10

<snip>

(*, 224.10.10.10), 00:21:26/stopped, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    GigabitEthernet1/0, Forward/Sparse-Dense, 00:21:26/00:00:00

    GigabitEthernet0/0, Forward/Sparse-Dense, 00:21:26/00:00:00

(120.0.45.5, 224.10.10.10), 00:01:01/00:01:58, flags: PT

  Incoming interface: GigabitEthernet1/0, RPF nbr 120.0.24.4

  Outgoing interface list:

    GigabitEthernet0/0, Prune/Sparse-Dense, 00:01:01/00:01:58

R3#

*Nov 27 09:06:28.159: %PIM-1-INVALID_RP_REG: Received Register from router 120.0.45.5 for group 224.10.10.10, 3.3.3.3 not willing to be RP

R4#

*Nov 27 09:05:48.975: Auto-RP(0): Received RP-announce packet of length 54, from 3.3.3.3, RP_cnt 1, ht 181
*Nov 27 09:05:48.975: Auto-RP(0): Filtered -224.10.10.10/32 for RP 3.3.3.3