Multicast Helper-Map Question and Verification

From: Antonio Soares (amsoares@netcabo.pt)
Date: Tue Apr 17 2007 - 20:31:13 ART


Dear GS,

Two questions about Multicast Helper-Map:

Given the topology:

SOURCE==F0/0==router r1===S1/0===S1/0===router r2===F0/0===RECEIVER

SOURCE is sending UDP/2000 broadcast traffic.

Question #1:
-----------
Where should i enable "ip directed-broadcast" ?

Question #2:
-----------
How can we test if we have a working configuration ?

Regarding Question #1, i think we only need to enable it on both
FastEthernet Interfaces:

+++++++++++++++++++++++++++
r1(config)#int f0/0
r1(config-if)#ip multicast helper-map broadcast 224.24.24.24 udp-2000
r1(config-if)#ip pim dense-mode
r1(config-if)#ip directed-broadcast

r1(config)#int s1/0
r1(config-if)#ip pim dense-mode

r1(config)#ip access-list extended udp-2000
r1(config-ext-nacl)#permit udp any any eq 2000

r1(config)#ip forward-protocol udp 2000
+++++++++++++++++++++++++++
r2(config)#int s1/0
r2(config-if)#ip multicast helper-map 224.24.24.24 10.10.10.255 120
r2(config-if)#ip pim dense-mode

r2(config)#int f0/0
r2(config-if)#ip pim dense-mode
r2(config-if)#ip directed-broadcast

r2(config)#ip access-list extended udp-2000
r2(config-ext-nacl)#permit udp any any eq 2000

r2(config)#ip forward-protocol udp 2000
+++++++++++++++++++++++++++

Regarding Question #2, i tried to use IP SLA but i get a weird behaviour.
The udp destination port is always 1967:

!
ip sla monitor 1
 type udpEcho dest-ipaddr 10.10.10.255 dest-port 2000 source-port 9999
 timeout 2
 frequency 1
ip sla monitor schedule 1 life forever start-time now
!

Debug ip packet detail:

*Apr 22 21:21:20.739: IP: tableid=0, s=6.6.6.6 (local), d=10.10.10.255
(FastEthernet0/0), routed via RIB
*Apr 22 21:21:20.739: IP: s=6.6.6.6 (local), d=10.10.10.255
(FastEthernet0/0), len 80, sending
*Apr 22 21:21:20.739: UDP src=9999, dst=1967

Now with destination port=3000 and source port=8888:

ip sla monitor 1
 type udpEcho dest-ipaddr 10.10.10.255 dest-port 3000 source-port 8888
 timeout 2
 frequency 1
ip sla monitor schedule 1 life forever start-time now
!

Debug ip packet detail:

*Apr 22 21:23:47.883: IP: tableid=0, s=6.6.6.6 (local), d=10.10.10.255
(FastEthernet0/0), routed via RIB
*Apr 22 21:23:47.883: IP: s=6.6.6.6 (local), d=10.10.10.255
(FastEthernet0/0), len 80, sending
*Apr 22 21:23:47.883: UDP src=8888, dst=1967

The source port is correctly changed but the destination port is always
1967...

Thanks.
Antonio



This archive was generated by hypermail 2.1.4 : Tue May 01 2007 - 08:28:36 ART