Defining Rewrite Rules

The Configure Rewrite Rule page allows you to define rewrite rules. Use the rewrite rules to alter the CoS values in outgoing packets to meet the requirements of the targeted peer. A rewrite rule examines the forwarding class and loss priority of a packet and sets its bits to a corresponding value specified in the rule.

To define rewrite rules in the J-Web interface:

  1. Select Configure > Class of Service > Rewrite Rules.

    After you make changes to the configuration in this window, you must commit the changes immediately for them to take effect. To commit all changes to the active configuration, select Commit Options > Commit. See Using the Commit Options to Commit Configuration Changes (J-Web Procedure) for details about all commit options.

  2. Click one of the following:
    • Add—To add a rewrite rule. Enter information into the rewrite rule page, as described in Table 33.
    • Edit—To edit a rewrite rule. Enter information into the rewrite rule page, as described in Table 33.
    • Delete—To delete an existing rewrite rule.

Table 33: Rewrite Rules Configuration Page Summary



Your Action

Rewrite rule name

Specifies a rewrite rule name.

To name a rule, type the name; for example, rewrite-dscps.

Rewrite rule type

Specifies the type of rewrite rule: dscp, ieee-802.1, or inet-precedence.


Code point mapping

Rewrites outgoing CoS values of a packet based on the forwarding class and loss priority.

Allows you to remove a code point mapping entry.

To configure the CoS value assignment and add a code point mapping, follow these steps:

  1. Click Add.
  2. Select the code point.
  3. Select a forwarding class from the following list:
    • expedited-forwarding—Provides low loss, low delay, low jitter, assured bandwidth, and end-to-end service. Packets can be forwarded out of sequence or dropped.
    • best-effort—Provides no special CoS handling of packets. Typically, RED drop profile is aggressive and no loss priority is defined.
    • assured-forwarding—Provides high assurance for packets within the specified service profile. Excess packets are dropped.
    • network-control—Packets can be delayed but not dropped.
  4. Select the loss priority:
    • high—Packet has a high loss priority.
    • low—Packet has a low loss priority.
    • medium-low—Packets in this queue are transmitted after low-priority packets.
    • medium-high—Packets in this queue are transmitted after high-priority packets.

To edit an existing code point mapping, select it and click Edit.

To remove a code point mapping entry, select it and click Remove.