[RTPproxy Devel] RTPProxy-Client API for Java

[Maxim Sobolev]

Marcos Hack wrote:
> Hello Maxim,
> 
> Suppose I have an RTPProxy session that already received RTP packets
> from both legs. If I issue a new 'Update' command without the IP
> address and Port, for example "cookie U callid 0 0 from_tag to_tag".

No, you should always send IP/port in the U, even if they have not changed.

> Is RTPProxy going to "reset" the Callee address association and start
> to forward the packets to a new IP and port that will start to send
> the RTP packets?

There is a bit of heuristics in there. If the address historically 
cannot be trusted (i.e. LAN IP in the SDP) the RTPproxy will note the 
update, however the destination for RTP packets will not change 
immediately pending receiving some actual RTP packets from the new 
source. This is done to prevent NAT'ed address generated by the 
re-INVITE from distracting the session. If the address is "trustworthy", 
the change would happen immediately.

> It's for a call transfer scenario when I want to change the Caller or
> Callee media address to the transfer destination.

Two approaches are possible here:

1. You can simply update RTPproxy with the new addresses.

2. You can create a whole new session in the proxy for the transferred 
call leg and use that session instead when doing transfer.

Hopefully it helps. Don't hesitate to contact me if you have any other 
questions.

Regards,
-- 
Maksym Sobolyev
Sippy Software, Inc.
Internet Telephony (VoIP) Experts
T/F: +1-646-651-1110
Web: http://www.sippysoft.com
MSN: sales at sippysoft.com
Skype: SippySoft