Understanding Junos OS CoS Components for EX Series Switches
This topic describes the Juniper Networks Junos operating system (Junos OS)
class-of-service (CoS) components for Juniper Networks EX Series Ethernet Switches:
•
Code-Point Aliases on page 3148
•
Policers on page 3148
•
Classifiers on page 3148
•
Forwarding Classes on page 3149
•
Tail Drop Profiles on page 3149
•
Schedulers on page 3149
•
Rewrite Rules on page 3149
Code-Point Aliases
A code-point alias assigns a name to a pattern of code-point bits. You can use this name
instead of the bit pattern when you configure other CoS components such as classifiers,
drop-profile maps, and rewrite rules.
Policers
Policers limit traffic of a certain class to a specified bandwidth and
burst size
. Packets
exceeding the policer limits can be discarded. You define policers with filters that can be
associated with input interfaces.
For more information about policers, see “Understanding the Use of Policers in Firewall
Filters” on page 3036.
NOTE:
You can configure policers to discard packets that exceed the rate
limits. If you want to configure CoS parameters such as loss-priority and
forwarding-class
, you must use firewall filters.
Classifiers
Packet classification associates incoming packets with a particular CoS servicing level.
In Juniper Networks Junos operating system (Junos OS),
classifiers
associate packets
with a forwarding class and loss priority and assign packets to output queues based on
the associated forwarding class. Junos OS supports two general types of classifiers:
•
Behavior aggregate or CoS value traffic classifiers—Examines the CoS value in the
packet header. The value in this single field determines the CoS settings applied to the
packet. BA classifiers allow you to set the forwarding class and loss priority of a packet
based on the Differentiated Services code point (DSCP) value, IP precedence value,
and IEEE 802.1p value.
•
Multifield traffic classifiers—Examines multiple fields in the packet such as source and
destination addresses and source and destination port numbers of the packet. With
Copyright © 2010, Juniper Networks, Inc.
3148
Complete Software Guide for Junos
®
OS for EX Series Ethernet Switches, Release 10.3
Summary of Contents for JUNOS OS 10.3 - SOFTWARE
Page 325: ...CHAPTER 17 Operational Mode Commands for System Setup 229 Copyright 2010 Juniper Networks Inc ...
Page 1323: ...CHAPTER 56 Operational Mode Commands for Interfaces 1227 Copyright 2010 Juniper Networks Inc ...
Page 2841: ...CHAPTER 86 Operational Commands for 802 1X 2745 Copyright 2010 Juniper Networks Inc ...
Page 3367: ...CHAPTER 113 Operational Mode Commands for CoS 3271 Copyright 2010 Juniper Networks Inc ...
Page 3435: ...CHAPTER 120 Operational Mode Commands for PoE 3339 Copyright 2010 Juniper Networks Inc ...
Page 3529: ...CHAPTER 126 Operational Mode Commands for MPLS 3433 Copyright 2010 Juniper Networks Inc ...