Classifying Frame Relay Traffic

For J Series and SRX210, SRX240, and SRX650 device interfaces with Frame Relay encapsulation, you can set the loss priority of Frame Relay traffic, based on the discard eligibility (DE) bit. For each incoming frame with the DE bit containing the CoS value 0 or 1, you can configure a Frame Relay loss priority value of low, medium-low, medium-high, or high.

You can apply a classifier to the same interface on which you configure a Frame Relay loss priority value. The Frame Relay loss priority map is applied first, followed by the classifier. The classifier can change the loss priority to a higher value only (for example, from low to high). If the classifier specifies a loss priority with a lower value than the current loss priority of a particular packet, the classifier does not change the loss priority of that packet.

This section is organized as follows:

Assigning the Default Frame Relay Loss Priority Map to an Interface

The default Frame Relay loss priority map contains the following settings:

loss-priority low code-point 0;loss-priority high code-point 1;

This default map sets the loss priority to low for each incoming frame with the DE bit containing the 0 CoS value. The map sets the loss priority to high for each incoming frame with the DE bit containing the 1 CoS value.

To assign the default map to an interface, include the frame-relay-de default statement at the [edit class-of-service interfaces interface-name unit logical-unit-number loss-priority-maps] hierarchy level:

[edit class-of-service interfaces interface-name unit logical-unit-number loss-priority-maps]frame-relay-de default;

Defining a Custom Frame Relay Loss Priority Map

To define a custom Frame Relay loss priority map, include the following statements at the [edit class-of-service] hierarchy level:

[edit class-of-service]loss-priority-maps { frame-relay-de map-name {loss-priority (low | medium-low | medium-high | high) code-point (0 | 1);}}

A custom loss priority map sets the loss priority to low, medium-low, medium-high, or high for each incoming frame with the DE bit containing the specified 0 or 1 CoS value.

Applying the Map to a Logical Interface

The map does not take effect until you apply it to a logical interface. To apply a map to a logical interface, include the frame-relay-de map-name statement at the [edit class-of-service interfaces interface-name unit logical-unit-number loss-priority-maps] hierarchy level:

[edit class-of-service interfaces interface-name unit logical-unit-number loss-priority-maps]frame-relay-de map-name;

Verifying Your Configuration

To verify your configuration, you can issue the following operational mode commands:

show class-of-service forwarding-table loss-priority-map
show class-of-service forwarding-table loss-priority-map mapping
show chassis forwarding
show pfe fwdd

Note: On J Series devices, show commands might still display a loss-priority-map as applied to an interface even if the commit configuring it fails.