[AG-TECH] Multicast

[Williams S.R.]

Hi Chris

> Someone tell me I'm just having a bad week!

You're having a bad day.

> from a different manufacturer, the chances are that multicast
> doesn't work until someone complains that it isn't working.

I think this is an interesting line and shadows our experience. With the
increase in real-time traffic the tendency of many sites' admins to just do
a 'quick fix' which may reload a router/switch/firewall(!) or drop a link
for a few seconds is having a greater impact - as voice/video calls are
being dropped. Of course the old web/mail traffic doesn't care. Same applies
with longer fixes/kit changes -  but no thorough check of whether the
network is completely back up.

There may be a need for education here in that site admins need to be more
aware that they no longer can do the little 're-jigs' with the network - or
at least they need to check what is going on first.

Maybe there should be a longer checklist for after re-jigs. Changing from:

Ping  OK / Not OK
Web page OK / Not OK

Which seems to be common, to: 

IPv4 Ping OK / Not OK
IPv6 Ping OK / Not OK
Multicast beacon OK / Not OK
etc


It would be interesting for people who have kit combinations running to
share them. E.g. we run PIM through Cisco<->Riverstone<->Riverstone<->Cisco
but MSDP only Cisco to Cisco - hops over the Riverstones. That works OK for
us at the moment, but I am getting high CPU on Cisco 7206 = +20% per 8Mbps
multicast stream.

Cheers

Steve
-------------------------------------------------------------
Steve Williams
Video Network Manager
University of Wales Swansea
Singleton Park
Swansea
SA2 8PP

+44 (0)1792 295167
s.r.williams at swansea.ac.uk
www.wvn.ac.uk



> -----Original Message-----
> From: Osland, CD (Chris) [mailto:C.D.Osland at rl.ac.uk]
> Sent: 25 June 2004 09:57
> To: ag-tech at mcs.anl.gov
> Subject: [AG-TECH] Multicast
> 
> Is it just me, or is the worldwide 'uptime' of multicast
> actually going down at present?  Or is this a UK-only
> observation?  Or am I paranoid and there are just more people
> using AG, and therefore chatting on ag-tech, than before?
> 
> The problems I sense are that more suppliers are now in the
> market and the interoperability between manufacturers is
> decreasing, so when a site changes a router, especially to one
> from a different manufacturer, the chances are that multicast
> doesn't work until someone complains that it isn't working.
> As a result there are an increasing number of local problems
> (compounded by the usual one of finding anyone who knows
> anything concrete about multicast at a given site) rather than
> a global cause, but the result is an increasing global problem.
> 
> Someone tell me I'm just having a bad week!> 
> Cheers
> 
> Chris
> 
> ____________________________________________________________________
> Chris Osland                                               Office tel: +44
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> Digital Media and Access Grid                          Medialab tel: +44
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> 
> 
> > -----Original Message-----
> > From: owner-ag-tech at mcs.anl.gov [mailto:owner-ag-tech at mcs.anl.gov]On
> > Behalf Of Ivan R. Judson
> > Sent: 24 June 2004 16:31
> > To: ag-tech at mcs.anl.gov
> > Subject: [AG-TECH] TVS being rebooted
> >
> >
> >
> >
> > We're rebooting the TVS, as soon as it's back we'll restart
> > the Venue Server
> > so meetings can continue.
> >
> > We're sorry for the interruption.
> >
> > --Ivan
> >