You configure class of service
(CoS) when you need to override the default packet forwarding behavior
of a J Series or SRX Series device—especially in the three areas
identified in Table 250.
Table 250: Reasons
to Configure Class of Service (Cos)
Default Behavior to Override with
CoS
CoS Configuration Area
Packet classification—By
default, the J Series or SRX Series device does not use behavior aggregate
(BA) classifiers to classify packets. Packet classification applies
to incoming traffic.
Classifiers
Scheduling queues—By default,
the J Series or SRX Series device has only two queues enabled. Scheduling
queues apply to outgoing traffic.
Schedulers
Packet headers—By default, the J Series
or SRX Series device does not rewrite CoS bits in packet headers.
Rewriting packet headers applies to outgoing traffic.
Rewrite rules
You can use either J-Web Quick Configuration or
a configuration editor to configure CoS. This chapter contains the
following topics. For more information about CoS, see the JUNOS Class of Service Configuration Guide.
