Technical data

VoIP Service 253
SBX IP 320 Features & Operation Guide
Normal/Fast mode for H.323
H.323 endpoints may establish media channels in a call by using either the procedures defined
in Recommendation H.245 or the "Fast Connect" procedure described below. The Fast Connect
procedure allows the endpoints to establish a basic point-to-point call with as few as one
round-trip message exchange, enabling immediate media stream delivery upon call connection.
The calling endpoint initiates the Fast Connect procedure by sending a SETUP message
containing the fastStart element to the called endpoint. The fastStart element consists of a
sequence of OpenLogicalChannel structures describing media channels which the calling
endpoint proposes to send and receive, including all of the parameters necessary to immediately
open and begin transferring media on the channels.
Admin Programming
• Normal/Fast Mode (PGM 340 - F 18)
TOS for H.323
In the IP Datagram, 8 bits are reserved to the Service type. These bits can be further broken into
5 subfields given below.
The 3 precedence bits specify the datagram precedence varying from 0 to 7. This allows the
senders to indicate the importance of each datagram. The TOS provides a mechanism that can
allow control information precedence over data. The other 3 bits represent the following:
D - requests low delay
T - requests high throughput
R - requests high reliability
The precedence bits (bits - 0,1,2) are significant in having an effect on load. So, we vary these
bits and try to monitor the changes in the RTT (Round Trip Time) for varying loads.
01234567
PRECEDENCE D T R UNUSED