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 encryption 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: [email protected] 

Reply via email to