[Xorp-users] New to this multcast - Can this work with xorp?

[Pavlin Radoslavov]

> I think that my setup it okay now and that the problem lies out of my linux
> box. But this part is not under my control.
> 
> The setup is for ip phones. The phones are on the same network as the eth0
> network card, and my tunnel is linked to a distant 2811 cisco router.
> 
> The RP is a single machine (10.254.0.1).
> 
> My local eth0 ip is 10.132.3.20
> The ip of the tunnel is : 10.254.0.14
> and the ip of the remote machine on the other end of the tunnel is :
> 10.254.0.13
> 
> The thing now is that my linux box do not join any multicast group...

Just to clarify: the receivers are on the eth0 subnet, but are NOT
running on the Linux box.

If you run tcpdump on the eth0 interface do you see any IGMP
membership messages from the receivers (in respond to the Query
messages from the XORP box)?

tcpdump -i eth0 -n -vvv -s 0 -x proto \\igmp

[Note: depends on your login shell you might or might not need the
double-backslash].

If you can see the membership messages from the receivers, a common
problem is having firewall rules installed in the kernel which
filter-out the IGMP messages. As a starter, for testing purpose it
is best to remove all firewall rules.

> Here is the output of show igmp group
> 
> Interface    Group           Source          LastReported Timeout V State
> eth0         224.0.0.2       0.0.0.0         10.132.3.20      206 2     E
> eth0         224.0.0.13      0.0.0.0         10.132.3.20      205 2     E
> eth0         224.0.0.22      0.0.0.0         10.132.3.20      199 2     E
> tun0         224.0.0.2       0.0.0.0         10.254.0.14      201 2     E
> tun0         224.0.0.13      0.0.0.0         10.254.0.14      203 2     E
> tun0         224.0.0.22      0.0.0.0         10.254.0.14      205 2     E
> 
> 
> In fact I see that the only machines that answers the IGMP are my local
> mathines IF
> I have igmp enabled on both interface (tunnel and eth0)
> 
> A show pim join dont output anyting I have to send a show pim join all and
> now I get.
> 
> Group           Source          RP              Flags
> 224.0.0.0       10.254.0.1      10.254.0.1      RP
>     Upstream interface (RP):   tun0
>     Upstream MRIB next hop (RP): UNKNOWN
>     Upstream state:            NotJoined
>     Join timer:                -1
>     Joins RP:                  ...
>     Join state:                ...
>     Prune state:               ...
>     Prune pending state:       ...
>     Could assert WC:           ...
>     I am DR:                   OOO
>     Immediate olist RP:        ...
>     Inherited olist SG:        ...
>     Inherited olist SG_RPT:    ...

Yes, if there are no receivers, then in your setup "show pim join"
won't show any routing entries.
However, from the above entry I see another problem: the "Upstream
MRIB next hop (RP)" is unknown. The interface is known, so most
likely you don't see any PIM Hello messages from the other side the
tunnel. If PIM-SM is running on the other side of the tunnel, what
is the output of "show pim neighbors".

> From this I know that I am not in the multicast group...
> 
> Just for my information, do I have to enable PIM on both interface? Or only
> on my tunnel interface?

Yes, you need to enable PIM on both interfaces.

> And I read that PIM-SM works with IGMP so am I right when I say that it
> can't work with anyting else like RIP and OSPF?

IGMP has different purpose: it is to discover directly connected
receivers and to tell PIM-SM about them.
The purpose of RIP and OSPF is to tell PIM-SM about the Reverse Path
Forwarding information. E.g., where to send the PIM Join messages
towards, say, the RP or the Sender itself. 

> The thing is also that I dont see the IGMP join request from the phones on
> my eth0 interface, I should see them right?

Yes you should so this is one of the problems (see above).

> Ive set ip_forward to 1
> rp_filter are all set to 0

OK, that's good.

> Do you want me to paste my xorp conf file? I know that some hates the config
> file pasting ;)

You could send it to me in a personal email to double-check there
are no other issues there, but from what I've seen above so far the
problem doesn't seem to be in your config.

Regards,
Pavlin

> Thanks for your time :)
> 
> -- 
> Ubuntu est un ancien mot africain qui veut dire "Je ne peux pas configurer
> Debian"
> --
> Daniel Paquet
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