
270 ◾ IP Communications and Services for NGN
bandwidth, or they may be working behind firewalls. ese users need extra pro-
cessing and this is done through the use of mixers and translators [3].
When participants use links and networks of lower bandwidth, it might be
necessary to degrade the bandwidth offering of better networks so that all of them
use a lower bandwidth. is, however, leads to reduced quality due to transcoding
or bit rate reduction or modification. e RTP provides a more optimal solution by
using an RTP-level relay called a mixer (Figure 14.5). A mixer may be located near
the low-bandwidth source or receiver. e mixer resynchroni ...