User Manual

Configuring Quality of Service
378
M6100 Web Management User Guide
Table 155. CoS Interface Queue Drop Precedence Status
Field Description
Interface Displays the CoS configurable interface.
Queue ID Displays the Queue ID.
Drop Precedence Level Displays the drop precedence level.
WRED Minimum Threshold Displays the weighted RED minimum queue threshold value.
WRED Maximum Threshold Displays the weighted RED maximum queue threshold value.
WRED Drop Probability Scale Displays the packet drop probability value.
Differentiated Services
The QoS feature contains Differentiated Services (DiffServ) support that allows traffic to be
classified into streams and given certain QoS treatment in accordance with defined per-hop
behaviors.
Standard IP-based networks are designed to provide “best effort” data delivery service. “Best
ef
fort” service implies that the network delivers the data in a timely fashion, although there is
no guarantee that it will. During times of congestion, packets may be delayed, sent
sporadically, or dropped. For typical Internet applications, such as e-mail and file transfer, a
slight degradation in service is acceptable and in many cases unnoticeable. Conversely, any
degradation of service has undesirable effects on applications with strict timing requirements,
such as voice or multimedia.
Defining DiffServ
To use DiffServ for QoS, the Web pages accessible from the Differentiated Services menu
page must first be used to define the following categories and their criteria:
1. Class - Create classes and define class criteria.
2. Policy - Create policies, associate classes with policies, and define policy statements.
3. Service -
Add a policy to an inbound interface
Packets are classified and processed based on defined criteria. The classification criteria is
defined by a class.
The processing is defined by a policy's attributes. Policy attributes may be
defined on a per-class instance basis, and it is these attributes that are applied when a match
occurs. A policy can contain multiples classes. When the policy is active, the actions taken
depend on which class matches the packet.
Packet processing begins by testing the class match criteria for a packet. A policy is applied
to a packet when a class match within that policy is found.
The Differentiated Services menu page contains links to the various Diffserv configuration
and display features.
From the DiffServ link under the QoS tab, you can access the following pages: