Table 6-4 Diffserv Parameters - NEC Sl2100 Networking Manual

SL2100
Throughput
Reliability
Delay
Cost
6.5 Diffserv (Differentiated Service)
Differentiated Services (Diffserv) uses the ToS field in an IP header. Diffserv is now commonly used
instead of IP Precedence (refer to
method uses six 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 Codepoint (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 prioritize based on CS5.
Ethernet Frame Example - Containing One RTP (Speech) Packet
Source Destination Protocol
172.16.0.21 172.16.0.101 RTP
Info
Payload type=ITU-T G.729, SSRC=732771006, Seq=30885, Time=20560
Frame 159 (65 bytes on wire, 65 bytes captured)
Arrival Time: Jan 18, 2005 13:55:44.834497000
Time delta from previous packet: 0.000445000 seconds
Time since reference or first frame: 2.901831000 seconds
Frame Number: 159
Packet Length: 65 bytes
Capture Length: 65 bytes
Ethernet II, Src: 00:60:b9:c1:ab:a3, Dst: 00:60:b9:c6:6e:45
Destination: 00:60:b9:c6:6e:45 (Nitsuko_c6:6e:45)
Source: 00:60:b9:c1:ab:a3 (Nitsuko_c1:ab:a3)
6-16
Value
0
1
Value
0
1
Value
0
1
Value
0
1
IP Precedence on page

Table 6-4 Diffserv Parameters

6 bits
Description
Normal Throughput
High Throughput
Description
Normal Reliability
High Reliability
Description
Normal Delay
Low Delay
Description
Normal Cost
Low Cost
6-15) as it provides greater flexibility. This
ECN (Not QoS related)
Network Design Considerations
ISSUE 1.0
2 bits