[AG-TECH] Multicast oddity
eschbach at motorola.com
Fri Sep 13 00:36:37 CDT 2002
> We are investigating a multicast problem on our network but
> I thought I would pose the question here in case one of the
> experts on this list might be able to help out.
> any hints would be appreciated...
I'm no expert, but this may help... I've run into similar trouble
before, and it surrounded our MBGP and MSDP settings. At a high level,
MBGP lets other networks know how to reach your network for multicast
traffic, and MSDP lets other networks know when you are actively
providing a source of multicast traffic.
I just looked on our router and we do not show any Source Active entries
for you (show ip msdp sa-cache 18.104.22.168 22.214.171.124). Assuming
other sites have similar state, it means that others do not receive your
MSDP Source Active messages and therefore do not know that you are a
source of multicast traffic. We also do not show an MBGP entry for your
network (show ip mbgp), so you may also want to look at your BGP/MBGP
settings in addition to your MSDP settings.
Brian Corrie wrote:
> Hello all,
> We are investigating a multicast problem on our network but I thought I would
> pose the question here in case one of the experts on this list might be able
> to help out. Our site (newmic4.bc.net) is running the beacon software. Our
> horizontal column on the web page is showing mostly green and good
> connectivity to most sites. This is reflected when we connect to an AG venue
> as well as we get video and audio from other sites. The vertical column for
> our machine on the beacon web site is completely grey and no one can see or
> hear us when we connect to a venue. I am no multicast expert, but this
> confuses me. Does anyone have any experience with a symptom like this and if
> so point us in the correct direction??? We are obviously receiving multicast
> traffic fine but it appears that nothing is getting out. Our networking
> people are investigating, but any hints would be appreciated...
> Thanks in advance,
Jeff Eschbach eschbach at motorola.com
Networks and Infrastructure Research
Senior Staff Engineer, Motorola Labs Internet2 Initiative
http://internet2.motlabs.com Fax: (847) 576-3240
Desk: (847) 538-5846 Mobile: (847) 980-2240
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