[AG-TECH] RE: [AG-DEV] Bridge Information
michael.daw at manchester.ac.uk
Wed Mar 8 10:18:10 CST 2006
But we need to retain interoperability between insors and AG toolkit clients, hence hitting this at the level of media rather than venue client.
> -----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: 08 March 2006 15:15
> To: Andrew.Rowley at manchester.ac.uk; 'AG-TECH mailing list'
> Cc: ag-dev at mcs.anl.gov
> Subject: [AG-TECH] RE: [AG-DEV] Bridge Information
> Touching a bunch of packets (filtering for the SDES Name packet and
> modifying it) seems extremely intensive to meet the end goal.
> Are you trying to determine if the local client is bridged or
> if any of the
> remote clients are bridged?
> Seems like it's a bit of information the venueclient already
> has and should
> be able to simply show the user on the local end. It might be
> simple like updating something in the venue to share that so
> you can see the
> state of all non-local clients.
> Does that make sense?
> > -----Original Message-----
> > From: owner-ag-dev at mcs.anl.gov
> [mailto:owner-ag-dev at mcs.anl.gov] On Behalf
> > Of Andrew A Rowley
> > Sent: Wednesday, March 08, 2006 4:49 AM
> > To: AG-TECH mailing list
> > Cc: ag-dev at mcs.anl.gov
> > Subject: [AG-DEV] Bridge Information
> > Hi,
> > I have another idea that someone might like to implement (I
> will try if I
> > have time at some point). Currently, it is difficult to
> work out if a
> > client is bridged or if they are using multicast. The
> bridge forwards the
> > traffic from the client without modification.
> > One idea that would make it easier to determine if someone
> was bridged or
> > not would be to add some information to the RTCP packets
> when they arrive
> > in the bridge program (quickbridge, InSORS bridging
> software or other
> > software), such as adding " (B)" to the end of the NAME
> SDES packet. This
> > would be fairly simple to do I think - when a packet comes
> in with an RTCP
> > header:
> > 1. Search the RTCP packet for the SDES header
> > 2. Search for the SDES NAME packet
> > 3. If the NAME field exists:
> > 3.1 Add 4 to the length of the SDES header (note that
> padding does not
> > need to be altered in this case)
> > 3.2 Add 4 to the length of the NAME field
> > 3.3 Shift the bytes after the name field up by 4
> > 3.4 Add " (B)" to the name field.
> > I guess the main problem here would be if the packets were
> encrypted. In
> > this case, the RTCP packet would not be detected, and
> therefore nothing
> > would happen. Alternatively, the bridge could be given the
> > key.
> > An alternative to modifying the bridge would be to modify
> the actual RTP
> > tools (VIC, RAT, InSORS, etc) to add the " (B)" to the name
> when a unicast
> > connection was being made (or " (U)" if that is more
> generic). This may
> > actually be the easier option.
> > Just an idea...
> > Andrew :)
> > ============================================
> > Access Grid Support Centre,
> > RSS Group,
> > Manchester Computing,
> > Kilburn Building,
> > University of Manchester,
> > Oxford Road,
> > Manchester,
> > M13 9PL,
> > UK
> > Tel: +44(0)161-275 0685
> > Email: Andrew.Rowley at manchester.ac.uk
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