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forwarding-class (Fibre Channel Interfaces)

Syntax

Hierarchy Level

Description

Configure a Layer 3 fixed classifier on a Fibre Channel (FC) interface. The fixed classifier places all traffic received from the FC network into the specified forwarding class. The forwarding class must be lossless. (That is, the forwarding class must be either the default fcoe or no-loss forwarding class, or the forwarding class must be configured with the no-loss drop attribute.) If you attempt to specify a lossy forwarding class, the system returns a commit error.

FCoE networks typically use priority 3 (IEEE code point 011) for FCoE traffic. The QFX Series default configuration uses IEEE 802.1p priority 3 for FCoE traffic. If the IEEE 802.1p code point value that the Ethernet network uses for FCoE traffic is different than code point 3, you can rewrite the code point to the value used in your Ethernet (FCoE) network. The lossless forwarding class specified in the fixed classifier uses the rewrite-value statement as the IEEE 802.1p code point (priority) for FCoE traffic on the FCoE network.

To rewrite the code point value, include the rewrite-value input ieee code-point code-point-bits statement at the [edit class-of-service interfaces fc-interface-name] hierarchy level.

Note:

If you are not using the default configuration (priority 3 for FCoE traffic), the lossless forwarding class specified in the FC interface fixed classifier must be mapped to the IEEE 802.1p code point specified in the rewrite value statement.

In order to avoid fate sharing (separate flows that affect each other’s throughput), the code point (priority) used for the lossless forwarding class (the code point specified in the rewrite value statement) should be the only code point classified to that forwarding class (at the [edit class-of-service classifiers] hierarchy level). For example, if the rewrite value uses code point 101 for lossless FCoE forwarding class fcoe_fc1, then in the classifier configuration attached to ingress Ethernet interfaces, code point 101 is the only code point that should be classified to the fcoe_fc1 forwarding class. Now if you also attach a classifier to an interface that maps code point 110 to forwarding class fcoe_fc1, then congestion on priority 110 unfairly (and unintentionally) affects the FCoE traffic that uses priority 101. Both priorities 101 and 110 are classified into forwarding class fcoe_fc1, so the traffic from both priorities shares the same fate.

Options

lossless-forwarding-class-name—Name of the lossless forwarding class.

Required Privilege Level

interfaces—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 12.3.