[Xorp-users] PIM-SM Problems

[Moshe Ortov]

Hi,

I'm having problems with PIM-SM.  A few threads in the archive show others
have had difficulties too, but none of those seemed directly relevant,
although it did give me a few things to try but without success.

I have a network with a number of locations and I need to configure my
network with PIM-SM to allow some of the advanced features of my VOIP phone
system.  Basically, when, for example, I want to conference a call, the VOIP
system sends a PIM-SM join and each of the extensions send a join too.
Thereafter the conference is done using multicast.  ('Normal' calls use
unicast and they're fine.)

My network has 4 main locations.  The 'top' router has around 14 network
interfaces to a variety of network segments (i.e. local, LANs) and to the
other 3 locations (a sub-office, a nearby office and a remote office).

The secondary location has a link to the top router, 2 local networks, and a
remote office.

This means the top router, the nearby office and the remote office is in a
triangular configuration to give redundant routes.  Both the links to the
remote office are over a tunnel (openVPN).

The sub-office is connected directly to the top router and has links to a
couple of branch offices.

The multicast traffic should be routeable to all locations and all the local
networks but, for now, I'd be happy to just get it working between the top
router and the local nearby office.

What I'm getting, after much configuration testing and reconfiguration, is a
uni-directional communication which is basically close, but no cigar.

The output from an in-progress [attempted] conference is like this :

[tlr is the top-level-router; nslr is the local sub-office router]

root at tlr> show pim interface
Interface    State    Mode   V PIMstate Priority DRaddr          Neighbors
eth0         DISABLED Sparse 2 DR              1 192.168.255.254         0
eth1         UP       Sparse 2 DR              1 192.168.254.254         1
eth10        DISABLED Sparse 2 DR              1 192.168.252.129         0
eth2         UP       Sparse 2 NotDR           1 192.168.252.242         1
eth3         UP       Sparse 2 DR              1 172.18.63.254           0
eth4         UP       Sparse 2 DR              1 172.19.255.254          0
eth5         UP       Sparse 2 DR              1 172.20.255.254          0
eth6         UP       Sparse 2 DR              1 172.18.31.254           0
eth7         DISABLED Sparse 2 DR              1 192.168.32.254          0
eth8         DISABLED Sparse 2 DR              1 172.21.255.254          0
eth9         DISABLED Sparse 2 DR              1 172.22.255.254          0
tun0         UP       Sparse 2 DR              1 192.168.250.254         0
register_vif UP       Sparse 2 DR              1 192.168.254.254         0
root at tlr> show pim mfc
Group           Source          RP
224.0.1.2       172.20.32.1      192.168.252.242
    Incoming interface :      eth5
    Outgoing interfaces:      ............O
224.0.1.2       172.20.32.3     192.168.252.242
    Incoming interface :      eth5
    Outgoing interfaces:      ............O
239.255.255.250 172.20.32.5     192.168.252.242
    Incoming interface :      eth5
    Outgoing interfaces:      ............O
root at tlr>


And for NSLR :

root at nslr> show pim interface
Interface    State    Mode   V PIMstate Priority DRaddr          Neighbors
eth0         UP       Sparse 2 DR              1 172.16.31.254           0
eth2         DISABLED Sparse 2 DR              1 192.168.252.46          0
eth3         DISABLED Sparse 2 DR              1 192.168.240.254         0
eth4         UP       Sparse 2 DR              1 192.168.252.242         1
eth5         UP       Sparse 2 DR              1 172.16.63.254           0
tun0         UP       Sparse 2 DR              1 192.168.251.254         0
register_vif UP       Sparse 2 DR              1 172.16.31.254           0
root at nslr> show pim mfc
Group           Source          RP
224.0.1.2       172.16.2.245    192.168.252.242
    Incoming interface :      eth0
    Outgoing interfaces:      .......
224.0.1.2       172.20.32.1     192.168.252.242
    Incoming interface :      register_vif
    Outgoing interfaces:      O......
224.0.1.2       172.20.32.3     192.168.252.242
    Incoming interface :      register_vif
    Outgoing interfaces:      O......
224.0.1.59      172.16.6.1      192.168.252.242
    Incoming interface :      eth0
    Outgoing interfaces:      ....O..
239.255.255.250 172.16.32.62    192.168.252.242
    Incoming interface :      eth0
    Outgoing interfaces:      ....O..
239.255.255.250 172.20.32.5     192.168.252.242
    Incoming interface :      register_vif
    Outgoing interfaces:      ....O..
root at nslr>


This is showing an in-progress conference call which has 2 x internal users
on the 172.20/16 network and 2 x external users via the 172.16/19 network (
i.e. on the voip phone server).

The external users can hear all parties and can hear each other ( i.e. 2
external callers and hear and speak to each other).

The internal users can hear each other but not the external parties.

The multicast for the conference is 224.0.1.2 which as you will see on nslr
does not have any outgoing interface marked but on tlr, this does have an
external interface marked.

I think this is part of the problem - it's the fix that's the real pest
right now.  The absence of a route out for the multicast on nslr would also
explain why the internal users do not hear the external users and the
external users do hear the internal ones.

Have I missed something entirely ?  Perhaps someone can suggest where I
should look next ?

(Configs not attached due to the mailing list posting size limit).

Moshe
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