Multicast not working with CEF/Fast Sw?

From: aniz.kv@gmail.com
Date: Thu Sep 13 2007 - 13:55:40 ART


I was configuring multicast on the IE WB v4.1 Lab4. Could not get it working.

The requirement says that they should be able to ping 2 multicast listener IGMP groups on 2 interfaces of R3, from VLAN 48. The groups are 225.25.25.25 & 239.39.39.39. I'm able to ping 225.25.25.25 consistently without any problems. However, ping to 239.39.39.39 works only after i issued either "no ip mroute-cache" on the f0/0, or "no ip cef" on R2.

In the topology, R2 is the RP for 225.25.25.25 & R5 is the RP for 239.39.39.39. R8 is the mapping agent. I'm pinging from BB3.

-It starts working when i move the RP to R2 (for grp 239...)
-auto rp listener is added on all
-it also starts working with "no ip mroute-cache" on the f0/0, or "no ip cef" on R2.
- i'm using 12.3(21) on c7200 (Dynamips)

R3(s2/0.1)---FR---(s2/0)R2(f0/0)----Tun0--(f1/0)R5(F0/0,s0/0,s0/1)---R4(f1/0)--BB3

----| FR |---| |---| |---| |
 R3 |----| R2|---|R5 |---| R4|--|BB3
----| |---| | |---| |---| |
               |
             |---|
             | R8|
             |---|

Here's some interesting output from R2 (i enabled PD on the interfaces to troubleshoot).

Rack1R2#sh ip nbar protocol-discovery stats packet-count protocol icmp

 Tunnel0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 86 0
   unknown 3 0
   Total 89 0

 Serial2/0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 0 0
   unknown 0 0
   Total 0 0
Rack1R2#sh ip nbar protocol-discovery stats packet-count protocol icmp

 Tunnel0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 100 0
   unknown 4 0
   Total 104 0

 Serial2/0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 0 0
   unknown 0 0
   Total 0 0
Rack1R2#
Rack1R2#
Rack1R2#
Rack1R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Rack1R2(config)#int f0/0
Rack1R2(config-if)#no ip mroute-cache
Rack1R2(config-if)#^Z
Rack1R2#
*Sep 13 19:22:30.455: %SYS-5-CONFIG_I: Configured from console by console
Rack1R2#
Rack1R2#
Rack1R2#sh ip nbar protocol-discovery stats packet-count protocol icmp

 Tunnel0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 104 4
   unknown 5 0
   Total 109 4

 Serial2/0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 4 0
   unknown 0 0
   Total 4 0
Rack1R2#sh ip nbar protocol-discovery stats packet-count protocol icmp

 Tunnel0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 116 16
   unknown 6 0
   Total 122 16

 Serial2/0
                            Input Output
   Protocol Packet Count Packet Count
   ------------------------ ------------------------ ------------------------
   icmp 16 0
   unknown 0 0
   Total 16 0
Rack1R2#



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