Configuring CoS Rewrite Rules (NSM Procedure)

You configure rewrite rules to alter CoS values in outgoing packets on the outbound interfaces of a device to match the policies of a targeted peer. Policy matching allows the downstream router in a neighboring network to classify each packet into the appropriate service group.

In addition, you often need to rewrite a given marker such as IP precedence, DSCP, or IEEE 802.1p at the switch's inbound interfaces to accommodate behavior aggregate (BA) classification by core devices.

You do not need to explicitly apply rewrite rules to interfaces. By default, rewrite rules are applied to routed packets.

To configure CoS rewrite rules:

  1. In the navigation tree, select Device Manager > Devices
  2. Click the Device Tree tab, and then double-click the device for which you want to configure CoS rewrite rules.
  3. Click the Configuration tab. In the configuration tree, expand Class of Service
  4. Select Rewrite Rules.
  5. Add or modify settings as specified in Table 206.
  6. Click one:
    • OK—Saves the changes.
    • Cancel—Cancels the modifications.

Note: After you make changes to a device configuration, you must push that updated device configuration to the physical security device for those changes to take effect. You can update multiple devices at one time. See the Network and Security Manager Administration Guide for more information.

Table 206: Configuring and Applying Rewrite Rules

Task

Action

Configure rewrite rules for DiffServ CoS.

  1. Click Configure next to Rewrite Rules.
  2. Click Add new entry next to Dscp.
  3. In the Name box, type the name of the rewrite rules—for example, rewrite-dscps.

Configure best-effort forwarding class rewrite rules.

  1. Click Add new entry next to Forwarding class.
  2. In the Queue num box, type 1.
  3. In the Class name box, type the name of the previously configured best-effort forwarding class—for example, be-class.
  4. Click Add new entry next to Loss priority.
  5. From the Loss val list, select low.
  6. In the Code point box, type the value of the low-priority code point for best-effort traffic—for example, 000000.
  7. Click OK.
  8. Click Add new entry next to Loss priority.
  9. From the Loss val list, select high.
  10. In the Code point box, type the value of the high-priority code point for best-effort traffic—for example, 000001.
  11. Click OK twice.

Configure expedited forwarding class rewrite rules.

  1. Click Add new entry next to Forwarding class.
  2. In the Class name box, type the name of the previously configured expedited forwarding class—for example, ef-class.
  3. Click Add new entry next to Loss priority.
  4. From the Loss val list, select low.
  5. In the Code point box, type the value of the low-priority code point for expedited forwarding traffic—for example, 101110.
  6. Click OK.
  7. Click Add new entry next to Loss priority.
  8. From the Loss val list, select high.
  9. In the Code point box, type the value of the high-priority code point for expedited forwarding traffic—for example, 101111.
  10. Click OK twice.

Configure assured forwarding class rewrite rules.

  1. Click Add new entry next to Forwarding class.
  2. In the Class name box, type the name of the previously configured expedited forwarding class—for example, af-class.
  3. Click Add new entry next to Loss priority.
  4. From the Loss val list, select low.
  5. In the Code point box, type the value of the low-priority code point for assured forwarding traffic—for example, 001010.
  6. Click OK.
  7. Click Add new entry next to Loss priority.
  8. From the Loss val list, select high.
  9. In the Code point box, type the value of the high-priority code point for assured forwarding traffic—for example, 001100.
  10. Click OK twice.

Apply rewrite rules to an interface.

  1. Click Add new entry next to Interfaces.
  2. In the Interface name box, type the name of the interface—for example, ge-0/0/0.
  3. Click Add new entry next to Unit.
  4. In the Unit number box, type the logical interface unit number—for example, 0.
  5. Click Configure next to Rewrite rules.
  6. In the Rewrite rules name box, under Dscp, type the name of the previously configured rewrite rules—for example, rewrite-dscps.
  7. Click OK.

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