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Rewriting, Queueing, User-priority mapping – Brocade Network OS NETCONF Operations Guide v4.1.1 User Manual

Page 454: Configuring the qos trust mode

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Network OS NETCONF Operations Guide

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Rewriting

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Rewriting

Rewriting a frame header field is typically performed by an edge device. Rewriting occurs on frames
as they enter or exit a network because the neighboring device is untrusted, unable to mark the
frame, or is using a different QoS mapping.

The frame rewriting rules set the Ethernet CoS and VLAN ID fields. Egress Ethernet CoS rewriting is
based on the user-priority mapping derived for each frame as described later in the queueing
section.

Queueing

Queue selection begins by mapping an incoming frame to a configured user priority, and then each
user-priority mapping is assigned to one of the switch’s eight unicast traffic class queues or one of
the eight multicast traffic class queues.

User-priority mapping

For a description of user priority mapping default values, refer to the Network OS Administrator’s
Guide
.

Configuring the QoS trust mode

The QoS trust mode controls user priority mapping of incoming traffic. The Class of Service (CoS)
mode sets the user priority based on the incoming CoS value. If the incoming packet is not priority
tagged, then fallback is to the Interface Default CoS value.

NOTE

When a CEE map is applied on an interface, QoS trust mode is not allowed. The CEE map always
puts the interface in the CoS trust mode.

To configure the QoS trust mode, perform the following steps.

1. Issue the RPC to configure the node in the

urn:brocade.com:mgmt:brocade-interface namespace.

2. Under the node, include the , ,

, , or node element.

3. Under the , , ,

, or node, include the element and set its
value to the name of the interface for which you want to configure QoS trust mode.

4. Under the , , ,

, or node, include the element located in the
urn:brocade.com:mgmt:brocade-qos namespace.

5. Under the node, include the / element hierarchy to set the interface

mode to CoS “trust”.

6. Issue the RPC to save the running-config file to the startup-config file.

The following example sets the trust mode on interface 22/0/2.