All things related to multicast

[Amel Caldwell <>]

Hello all--

I have a customer who I have been working with to get multicast working.  They
are running 2 beacons (phantomworks.org) and can receive fine, the two can
send and recieve to/from each other, but cannot send to anyone else.

This customer is part of our Gigapop AS, but runs their own RP.  We have MSDP
set up and the appropriate boundaries and pim bsr-border interface on their
link.  I have even tried putting in static mroutes and asking them to put in a
static default mroute to no avail.

When I look at the router on my side, I see appropriate RPF info, the MSDP
session is up, but I don't see any entries in my sa-cache or my mcache.  I
have checked Abilene Core routers and University of Washington routers and
they see the IP address space via MBGP as I would expect.


I asked my customer for some info from their router.


sho ip pim rp
Group: 239.255.255.255, RP: 198.107.145.1, v2, v1, next RP-reachable in
00:00:59
Group: 233.2.171.1, RP: 198.107.145.1, v2, v1, next RP-reachable in 00:00:39
Group: 224.2.127.254, RP: 198.107.145.1, v2, v1, next RP-reachable in 00:00:59

THis is as it should be, although I am not sure why v1 also appears.

sho ip pim int

Address          Interface          Version/Mode    Nbr   Query     DR
                                                    Count Intvl
198.107.145.1    FastEthernet1/0    v2/Sparse        0    30     198.107.145.1
198.107.144.2    POS2/0             v2/Sparse        1    30     0.0.0.0


sho ip pim neig
PIM Neighbor Table
Neighbor Address  Interface          Uptime    Expires   Ver  Mode
198.107.144.1     POS2/0             3w3d      00:01:30  v2

Both look okay.

Here is where I think the problem is coming from:


sho ip mcache
IP Multicast Fast-Switching Cache

sho ip msdp sa-cache
MSDP SA caching disabled

sho ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, C - Connected, L - Local, P - Pruned
       R - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPT
       M - MSDP created entry, X - Proxy Join Timer Running
       A - Advertised via MSDP
Outgoing interface flags: H - Hardware switched
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode

[....SNIP....]


(198.49.215.4, 233.2.171.1), 03:42:18/00:02:59, flags: CMT
  Incoming interface: POS2/0, RPF nbr 198.107.144.1, Mroute
  Outgoing interface list:
    FastEthernet1/0, Forward/Sparse, 03:42:18/00:02:37

(198.107.145.4, 233.2.171.1), 00:00:31/00:02:28, flags: PCTA
  Incoming interface: FastEthernet1/0, RPF nbr 0.0.0.0
  Outgoing interface list: Null

(198.107.145.5, 233.2.171.1), 00:01:22/00:01:37, flags: PCTA
  Incoming interface: FastEthernet1/0, RPF nbr 0.0.0.0
  Outgoing interface list: Null

(198.124.224.24, 233.2.171.1), 03:43:00/00:02:59, flags: CMT
  Incoming interface: POS2/0, RPF nbr 198.107.144.1, Mroute
  Outgoing interface list:
    FastEthernet1/0, Forward/Sparse, 03:43:00/00:02:37

[....SNIP....]


The middle two entries are for their clients and the Outgoing interface is
NULL, which makes me think their router does not realize there are other
active sources for this group.

I have asked them to be sure that 'msdp cache-sa-state' is enabled and that
mroute caching is enabled, but have not heard that they have enabled it.

Does anyone else have any ideas on this?

Thanks in advance

Amel Caldwell

UW NDC Network Engineering Services
phone: 206-685-6205  fax: 206-685-4044
email: