User Guide

BSGX4e Business Gateway User Guide 307
Release 01.01 NN47928-102
SIP Configuration
2.When the 200 OK is received (assuming use of the G.729a CODEC), the SC
adjusts the bandwidth to 51 200 bps (100 pps x 64 bytes x 8 bits).
3.When the media is started (assuming the observed packet time is G.729a
20ms), the SC adjusts the bandwidth to 29 600 bps (50 pps x 74 bytes x 8 bits).
To ensure use of all available bandwidth, the Session Controller makes an additional
adjustment when the remaining bandwidth is insufficient for a G.711 10ms call. (The
above CAC algorithm would reject the call in step 1) Instead, the G.711 CODEC, if
present, is removed from the SDP body before the INVITE/SDP messages are relayed.
(This prevents establishment of the call with that CODEC.) Instead, CAC allocates
the maximum bandwidth that could be used by the remaining CODECs.
The limitations of this algorithm are:
 Endpoints must not change the payload type without renegotiating it through
signaling.
 Because every call requires an initial reservation of the maximum possible
bandwidth (107 200 bps), this limits the rate at which calls can be established.
(The CAC must wait for the end of the SDP negotiation before it can adjust the
bandwidth allocation.)