WorldCast Equinox - Release 3.1 - user manual
– 07/2011
Page 145
Whiterock Business Park - 729 Springfield Road - Belfast BT12 7FP - Northern Ireland
Tel.: +44 28 9067 7200 | Fax: +44 28 9067 7201 | http://www.aptcodecs.com
6.5.21.
Packet Resequencer
There is a packet resequencer included within the WorldCast Equinox. This can be enabled by clicking
on the „Use Resequencer‟ check box located in the IP connect tab as shown below.
Figure: 5-27a Resequencer on/off
The packet resequencer will re-sequence packets that arrive out of order. Packets may arrive out of order
due to diverse routing of packets across a network and the variable length of time each packet takes to
arrive at the destination. The plus point of the resequencer is that it does not add latency therefore the
time period in which it can re-sequence packets is the size (or length of time contained) in the latency
buffer.
Networks with large differential packet delays may require a larger buffer size to allow for the resequenc-
ing to be successful otherwise packet loss will result.
Note:
The packet resequencer should be enabled or disabled BEFORE making a SIP or IP call
– this setting cannot be changed when a call is in progress
Note that the choice of packet size will affect the efficiency of the IP connection. The following table
demonstrates the IP bandwidth required for a range of audio bitrates against a selection of IP packet siz-
es.
IP is inherently a higher latency medium compared to networks such as ISDN and X.21. IP packets must
be created and switched at each router, and there must be a receive buffer to compensate for jitter in the
network.
6.5.22.
FEC (Forward Error Correction)
