[Xorp-users] Simple multicast configuration

[Pavlin Radoslavov]

> On WinXP #1 I run:
> C:\ssmping\ssmpingd
> 
> On WinXP #2 I run
> C:\ssmping\asmping 224.1.1.1 169.254.2.20
> 
> and it starts to recive back in WinXP#2 only the unicast responses from WinXP#1, but not the multicast responses.
>     Using Ethereal it can be seen that Windows does put the multicast traffic from the sending computer on the ethernet cable, and IGMP requests to join group on the receiving computer's cable.
>     Meanwhile on LiveCD 1.4 we have:
> 
> xorp at LiveCD> show igmp group
> Interface    Group        Source     LastReported Timeout V State
> lnc0         224.0.0.2    0.0.0.0    169.254.1.2      222 2     E
> lnc0         224.0.0.13   0.0.0.0    169.254.1.2      220 2     E
> lnc0         224.0.0.22   0.0.0.0    169.254.1.2      222 2     E
> lnc1         224.0.0.2    0.0.0.0    169.254.2.1      216 2     E
> lnc1         224.0.0.13   0.0.0.0    169.254.2.1      216 2     E
> lnc1         224.0.0.22   0.0.0.0    169.254.2.1      220 2     E
> xorp at LiveCD> show pim join
> Group           Source           RP             Flags
> xorp at LiveCD>

Thank you for the info.
It appears that XORP doesn't see any IGMP reports from the WinXP
hosts, because the "show igmp group" doesn't show anything about
multicast membership from the WinXP hosts.
Also, the multicast traffic from the sender probably didn't
reach XORP, otherwise "show pim join" should show (S,G) entry for
the directly-connected senders.

Which machine did you use to run Ethereal? The Windows machine or
the XORP box?
If you used the Windows machine, please run "tcpdump" on the XORP
box to make sure that the multicast packets (IGMP Joins and
multicast data packets) really reach it.

FYI, in case you are not familiar with tcpdump, you could use the
following command to print everything on interface lnc0:

/usr/sbin/tcpdump -i lnc0 -n -vvv -s 0 -x

See the tcpdump(1) manual page for details in case you need to
filter and print only some of the packets.

Regards,
Pavlin