Help Center/ Routing Control/ User Guide/ Route Policies/ Modifying a Policy Node in a Route Policy
Updated on 2024-04-29 GMT+08:00

Modifying a Policy Node in a Route Policy

Scenarios

This section describes how to modify a node in a route policy.

Notes and Constraints

  • Route policies change the path through which network traffic passes. If a route policy has already been associated with an enterprise router, evaluate the impact on services before modifying its nodes.
  • Changing a route policy will also change the associated routes. To reduce the impact on network performance, a route policy can only be changed once within 40 seconds.

Procedure

  1. Log in to the management console.
  2. Click in the upper left corner and select the desired region and project.
  3. Click Service List and choose Networking > Enterprise Router.

    The Enterprise Router homepage is displayed.

  4. In the navigation pane on the left, choose Routing Control > Route Policies.

    The Route Policies page is displayed.

  5. Click the name of the target route policy.

    The node list is displayed.

  6. Locate the row that contains the node you want to modify and click Modify in the Operation column.

    The page for modifying a node is displayed.

  7. Configure the parameters based on Table 1.

    Table 1 Parameters for modifying a node

    Parameter

    Description

    Example Value

    Node Number

    Cannot be modified.

    -

    Action

    Cannot be modified.

    -

    Match Condition

    Mandatory

    Select match conditions. You can select a route type, prefix list, or AS_Path list.
    • Route type
      • Static: Manually configured routes

        Custom routes and propagated routes of VPC attachments in enterprise router route tables are static routes.

      • BGP: Routes learned through BGP

        Direct Connect virtual gateways communicate with enterprise routers using BGP so the routes of virtual gateway attachments propagated to enterprise router route tables are BGP routes.

        Also, the routes of peering connection attachments and VPN gateway attachments propagated to enterprise router route tables are BGP routes.

    • An IP prefix list contains prefix rules for route filtering. You can define IP prefixes and netmasks in prefix rules to match the destination addresses or next hops of routes. For more information, see IP Prefix List Overview.
    • An AS_Path list is a collection of filters that are used to filter BGP routes based on AS_Path attributes contained in BGP routes. AS_Path attributes record the number of each AS that BGP routes pass through from the source to the destination in distance-vector order. For more information, see AS_Path List Overview.
    • Route type: BGP
    • IP prefix list: prefixFilter-ab
    • AS_Path list: asPathFilter-ab

    Policy Value

    Optional

    You can configure policy values for a route as required if you set Action to Allow. Each node can have up to two policy values. You can click Add Policy Value to add policy values.
    • PrefVal:

      PrefVal is a Huawei-specific route attribute. A larger PrefVal value indicates a higher route priority.

      You can change the PrefVal value of a route by changing the PrefVal value in the route policy.

      A PrefVal value must be an integer.

      The default PrefVal values of routes for different types of enterprise router attachments are as follows:
      • Virtual gateway attachments: 100
      • Peering connection attachments: 60
      • VPN gateway attachments: 80
      NOTICE:

      Changing the PrefVal value of a route may adversely affect route selection of attachments. Submit a service ticket to evaluate the change.

    • AS_Path attributes record the number of each AS that BGP routes pass through from the source to the destination in distance-vector order.
      You can add, replace, or delete AS_Path policy values.
      • Add a policy value to the left of AS_Path.
      • Replace the original policy value of AS_Path.
      • Delete the specified policy value of AS_Path.
      AS_Path policy values must meet the following requirements:
      • Each value is an integer in the format of x or x.y. (x: 1 to 65535; y: 0 to 65535).
      • A maximum of 10 values can be entered at a time.
      • Each value must be unique.
    • PrefVal: 20
    • AS_Path: 2000 10.2 3.7 500

  8. Click OK.

    The node list is displayed. You can view the modified node.