3Com 4007, Руководство по внедрению, Страница: 603 / 684

QoS Excess Tagging 603
Important
Considerations
Before you modify or remove classifiers or controls, review these
guidelines:
■
You cannot remove the default classifier or the default control, but
you can modify the default control. You can modify other predefined
classifiers and the predefined controls (for example, if you want to
redefine the handling of Business Critical traffic, which is associated
with predefined control 3).
■
When you apply a control to a classifier, you must remove the control
for a classifier before you can modify or remove the classifier.
■
When you remove a control, the associated classifiers are no longer
controlled and no longer have a rate limit, service level, or 802.1p tag.
■
If you want to modify a classifier that has several address/port
definitions, you must supply them again during the modification
process. If you do not reenter them, the Multilayer Switching Module
deletes these definitions.
■
If you want to modify a control that uses the rate-limit type of
aggregate or receivePort with several rate-limit values, you can change
one rate-limit value without affecting the other defined rate-limit
values.
QoS Excess Tagging
Your Multilayer Switching Module enables you to tag nonconforming
excess packets (that is, packets that exceed the rate-limit criteria) with a
special IEEE 802.1p tag value. This tag refers to any packets marked as
excess that you want to tag. By default, excess tagging is disabled.
You can use your configuration tool (for instance, the Administration
Console) to enable or disable excess tagging and display your excess
tagging information.
If you
enable excess tagging
, you can specify an IEEE 802.1p tag value for
nonconforming excess packets in the range of from 0 through 7 , with 0
as the default. (See “IEEE 802.1p” earlier in this chapter for a list of the
tags and their associated priority levels). Specifying
1 means that
nonconforming excess packets become background traffic.