NEC UNIVERGE SV9100 Manual page 19

Normal throughput
0
High throughput
1
Reliability
Value Description
0 Normal throughput
1 High throughput
3.5 Diffserve (Differentiated Services)
Differentiated Services (Diffserv) is a method of utilising ToS field in an IP header. Diffserv is now
commonly used instead of IP Precedence as it provides greater flexibility. This method uses 6 bits of
the ToS field to determine the priority – which provides up to 64 possible values. The combination of
binary digits is known as the Diffserv Code Point (DSCP).
Differentiated Services Code Point
The example below shows an Ethernet Frame containing one RTP (speech) packet. The IP Packet
has the ToS field set to 101000 (binary) which is the equivalent of Class Selector 5. The router(s) in
this network should be programmed to prioritise based on CS5.
Type of Service Field (Diffserve)
6 bits
Part 1: VoIP Reference Manual 19
2 bits
ECN
(Not QoS related)