Blade ICE G8000 manual Permit/Deny, Filter, COS Queue, Overview, 1 QoS Model

RackSwitch G8000 Application Guide

Overview

QoS helps you allocate guaranteed bandwidth to the critical applications, and limit bandwidth for less critical applications. Applications such as video and voice must have a certain amount of bandwidth to work correctly; using QoS, you can provide that bandwidth when necessary. Also, you can put a high priority on applications that are sensitive to timing out or that cannot tolerate delay, by assigning their traffic to a high-priority queue.

By assigning QoS levels to traffic flows on your network, you can ensure that network resources are allocated where they are needed most. QoS features allow you to prioritize net- work traffic, thereby providing better service for selected applications.

Figure 6-1shows the basic QoS model used by the switch.

Ingress Ports	Classify	Perform
	Packets	Actions
	ACL	Permit/Deny
	Filter

Figure 6-1 QoS Model

The basic QoS model works as follows:

„Classify traffic:

†Read DSCP value.

†Read 802.1p priority value.

†Match ACL filter parameters.

„Perform actions:

†Permit packets.

†Deny packets.

†Map 802.1p Priority to COS queue.

†Map DSCP to COS queue.

†Set the number of COS queues (1-8).

„Queue and schedule traffic:

†Place packets in one of the COS queues.

†Schedule transmission based on the COS queue.

Queue and Egress Schedule

COS

Queue

94 „ Chapter 6: Quality of Service BMD00041, November 2008