3Com 3C17203 - SuperStack 3 Switch 4400, Руководство по внедрению

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72 C
HAPTER
6: U
SING
T
RAFFIC
P
RIORITIZATION
correctly by other parts of the network, or it can discard the packet. Your
Switch offers 6 predefined standard service levels which are shown in
Table 8 on page 74 .
3 Create a QoS Profile — the next step is to create a QoS profile. A QoS
profile can be made up of several rules. A rule is what defines how a
particular traffic type should be treated by your Switch, and is made up of
a Classifier and service level. Creating a QoS profile therefore is to
associate Classifier(s) with service levels. QoS in your Switch uses the
DSCP values to create classifiers that map to service levels, which then
remark to 802.1p tags. It is the 802.1p tag that determines the queue,
and so the level of service for the identified traffic type. Refer to
Table 9
on page 76 for some examples of rules that can be added to a QoS
profile.
4 Apply a QoS profile — after a QoS profile has been created, it is
assigned to the selected port(s). When the profile is assigned to the
port(s) or to the entire stack, the QoS configuration defined in the profile
will immediately become active.
Methods of
Configuring Traffic
Prioritization
QoS can be configured on your Switch using 3Com Network Supervisor
or via the Command Line Interface (CLI).
■
The 3Com Network Supervisor application supplied on the CD-ROM
accompanying your Switch is the main tool for configuring QoS, and
3Com recommends that you use this application for ease of use.
3Com Network Supervisor automatically configures all QoS-capable
3Com Switches in the network to prioritize the selected applications
and devices, as well as generating a report of all the configurations
made.
■
QoS can also be configured via the Command Line Interface (CLI),
which offers a greater level of configuration. For a detailed description
of the commands required to configure QoS via the CLI, please refer
to the Management Interface Reference Guide supplied in HTML
format on the CD-ROM that accompanies your Switch.
Important QoS
Considerations
Before implementing QoS on your network you need to consider the
following points:
■
Your Switch:
■
Has a predefined Classifier for NBX traffic, which is DSCP service
level 46. If the profile assigned to the port on which the NBX traffic