Nortel Networks NN43001-563 IP Trunk 3.01(and later) DiffSer v support forIP QoS

128 ITG engineering guidelines
and ebb in traffic flows. WAN links appear to be congested at one period
of time time and then are followedby a period of under-utilization. There
are two consequences, as follows:
•WAN link inefficiency
•IP Trunk3.01 (and later) traffic streams are unfairly affected
IP Trunk 3.01(and later) DiffSer v support forIP QoS
If the intranet provides differentiated services based on the DiffServ/TOS
field, then the IP Trunk3.01 (andlater) traffic and other traffic marked with
this DiffServ/TOS value can be delivered with the goal of meeting this class
of traffic’s QoS objectives.
Configure the DiffServ/TOS value for signaling and voice packetsto obtain
better QoS over the IP data network (LAN/WAN).
The Differentiated Service (DiffServ) Code Point (DSCP) determines the
priority of the control and voice packets in the network router queues.
ATTENTION
The values entered in these two fields must be coordinated across the entire IP
data network. Do not change them arbitrarily.
DiffServ values must first be converted to a decimal value of the DiffServ
byte in the IP packet header. Table24 "Recommended DiffSer v classes"
(page 128) shows the recommended DiffServ traffic classes for various
applications.
Table 2 4
Recommended DiffServ classes
Traffic type DiffServ class DSCP (binary) DSCP (decimal)
Voice media Expedited
Forwarding 101110 46
Voice signaling Class Selector 5 101000 40
Data traffic default 000000 0
The DSCP comprises 6 bits within the 8-bit TOS field.
Nortel Communication Server 1000
IP TrunkFundamentals
NN43001-563 02.01 Standard
Release 5.5 21 December 2007
Copyright© 2007, Nor tel Networks
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