1 Dec 2004 03:58
Re: Connection Admission Control in SIP
<Wayne.Davies <at> didata.com.au>
2004-12-01 02:58:44 GMT
2004-12-01 02:58:44 GMT
Joanna,
SIP preconditions if you have seen discussion about them on
implementors or read the draft would seem the best fit here. Otherwise it
may be possible to reduce the offered codec list based on some external
logic (IPCIF, IP Calculated Impairment Factor | MOS etc). If the UA is
offered only high bandwidth codecs, G.711, then you can use a 415 with
Accept-Encoding offering a lower speed codec. When network congestion is
determined to have passed the UA could go back to offering a full suite of
codecs including G.711.
QoS is a complex area - where using above measurement based CAC is
limited in that you will selectively deny, or accept and a certain rate, a
codec for a call. This determination is based on how the newtork is
behaving now, or in the last 5min interval used for determination of a
score. But network congestion is by nature dynamic and with nothing
reserving the RTP flow on a hop-by-hop basis when signalling is complete
may result in the call degrading or terminating after successful setup.
But I digress you said lightweight and perhaps the first para is a start
point.
Regards,
Wayne.
>Hi all,
>I'm developing a SIPServer and I would like to embed
>a light connection admission control (CAC) implementation.
>Does anyone have any idea of what could a SIPServer do
>in the means of CAC (for example, due to low bandwith, can
>a SIPServer reject a call or interfere to the SDP body of an INVITE
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