the edges of the network might be required to alter the CoS settings of the packets that
enter the network to classify the packets into the appropriate service groups.
Figure 80 on page 3147 represents the network scenario of an enterprise. Switch A is
receiving traffic from various network nodes such as desktop computers, servers,
surveillance cameras, and VoIP telephones. As each packet enters, Switch A examines
the packet’s CoS settings and classifies the traffic into one of the groupings defined by
the enterprise. This definition allows Switch A to prioritize resources for servicing the
traffic streams it receives. Switch A might alter the CoS settings of the packets to better
match the enterprise’s traffic groups.
When Switch B receives the packets, it examines the CoS settings, determines the
appropriate traffic groups, and processes the packets according to those settings. It then
transmits the packets to Switch C, which performs the same actions. Switch D also
examines the packets and determines the appropriate groups. Because Switch D sits at
the far end of the network, it can rewrite the CoS bits of the packets before transmitting
them.
Figure 80: Packet Flow Across the Network
Default CoS Behavior on EX Series Switches
If you do not configure any CoS settings on the switch, the software performs some CoS
functions to ensure that user traffic and protocol packets are forwarded with minimum
delay when the network is experiencing congestion. Some CoS settings, such as classifiers,
are automatically applied to each logical interface that you configure. Other settings,
such as rewrite rules, are applied only if you explicitly associate them with an interface.
Related
Documentation
Understanding Junos OS CoS Components for EX Series Switches on page 3148
•
•
Understanding Junos OS EZQoS for CoS Configurations on EX Series Switches on
page 3166
•
Example: Configuring CoS on EX Series Switches on page 3173
•
Example: Combining CoS with MPLS on EX Series Switches on page 3188
3147
Copyright © 2010, Juniper Networks, Inc.
Chapter 107: Class of Service (CoS)—Overview
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 ...