Configuring a VPN Instance on a PE Device

Procedure

1. Run system-view

   The system view is displayed.

2. Run ip vpn-instance vpn-instance-name

   A VPN instance is created, and its view is displayed.

   

   A VPN instance name is case sensitive. For example, "vpn1" and "VPN1" are different VPN instances.

3. (Optional) Run description description-information

   The description is configured for the VPN instance.

4. (Optional) Run service-id service-id

   A service ID is created for the VPN instance.

   A service ID is unique on a device. It distinguishes a VPN service from other VPN services on the network.

5. Run ipv4-family

   The IPv4 address family is enabled for the VPN instance, and the VPN instance IPv4 address family view is displayed.

   VPN instances support both the IPv4 and IPv6 address families. Configurations in a VPN instance can be performed only after an address family is enabled for the VPN instance based on the advertised route and forwarding data type.

6. Run route-distinguisher route-distinguisher

   An RD is configured for the VPN instance IPv4 address family.

   A VPN instance IPv4 address family takes effect only after being configured with an RD. The RDs of different VPN instances on a PE must be different.

   

   • An RD can be modified or deleted only after the VPN instance is deleted or the VPN instance IPv4 address family is disabled.

   • If you configure an RD for the VPN instance IPv4 address family in the created VPN instance view, the VPN instance IPv4 address family is enabled and the VPN instance IPv4 address family is displayed.

7. Run vpn-target vpn-target &<1-8> [ both | export-extcommunity | import-extcommunity ]

   A VPN target is configured for the VPN instance IPv4 address family.

   A VPN target is a BGP extended community attribute. It is used to control the receiving and advertisement of VPN routing information. A maximum of eight VPN targets can be configured using a vpn-target command.

   Skip this step when the device functions as the MCE only.

8. (Optional) Restrict the number of routes in a VRF.

   The configuration restricts the number of routes or route prefixes imported from the attached CE devices and peer PE devices into a VPN instance on a PE device. It is recommended that you use only one of the following commands.

   By default, the number of routes in a VRF is not limited as long as the total number of routes does not exceed the maximum number of unicast routes supported by the PE device.

   • To set the maximum number of routes in the VPN instance IPv4 address family, run routing-table limit number { alert-percent | simply-alert }.
   • To set the maximum number of route prefixes in the VPN instance IPv4 address family, run prefix limit number { alert-percent [ route-unchanged ] | simply-alert }.

9. (Optional) Run limit-log-interval interval

   The interval for logging the event that the number of routes exceeds the threshold is set for the VPN instance IPv4 address family.

   If the routes or prefixes in the IPv4 address family of a VPN instance reach the maximum, the system will generate logs at intervals (defaulting to 5 seconds). To prevent logs from being displayed frequently, run this step to prolong the interval of log generation.

10. (Optional) Configure a routing policy for the VPN instance.
    In addition to using VPN targets to control VPN route advertisement and reception, you can configure a routing policy for the VPN instance to better control VPN routes.

    • An import routing policy filters routes before they are imported into the VPN instance IPv4 address family.
    • An export routing policy filters routes before they are advertised to other PE devices.
    

    Before applying a routing policy to a VPN instance, create the routing policy. For details about how to configure a routing policy, see Routing Policy Configuration in the S2720, S5700, and S6700 V200R019C10 Configuration Guide - IP Unicast Routing.

    Run the following command as required:

    • To configure an import routing policy for the VPN instance IPv4 address family, run import route-policy policy-name.
    • To configure an export routing policy for the VPN instance IPv4 address family, run export route-policy policy-name.

11. (Optional) Run one of the following commands to configure the label allocation mode in the VPN instance IPv4 address family.

    • Run apply-label per-instance

      MPLS label allocation based on the VPN instance IPv4 address family (known as label per instance) is configured. One label is assigned to all the routes of the VPN instance IPv4 address family.

      When a large number of VPN routes on the PE exhausts MPLS label resources, the label per instance mode saves label resources on the PE and lowers the requirement for the PE capacity.

    • Run apply-label per-route

      MPLS label allocation based on each route (known as label per route) is configured. The VPN instance address family assigns a unique label to each route to be sent to the peer PE.

      When only a small number of VPN routes exist on the PE and MPLS label resources are sufficient, the label per route mode improves system security. In this way, downstream devices can load balance VPN traffic based on the inner labels of packets.

    By default, label per instance is used.