Configuring IPv6 FRR on the Public Network

Usage Scenario

On a traditional IP network, when a lower-layer failure occurs on the forwarding link of a device, the physical interface of the device becomes Down. After the device detects the failure, it instructs the upper-layer routing system to recalculate routes and update routing information. It often takes the routing system several seconds to reselect an available route.

Second-level convergence is intolerable to the services that are quite sensitive to delay and packet loss because it may lead to service interruptions. For example, Voice over Internet Protocol (VoIP) services are only tolerant of millisecond-level interruptions. IPv6 FRR ensures that the forwarding system rapidly responds to link failures and uses backup routes to forward data, minimizing service traffic interruptions.

Only the S5720-EI, S5720-HI, S5720I-SI, S5720S-SI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5730-HI, S5730S-EI, S5730-SI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6720S-SI, S6720-SI, S6730-H, S6730S-H, S6730-S, and S6730S-S support this function.

Pre-configuration Tasks

Before configuring IPv6 FRR on the public network, complete the following tasks:

Configure static routes or an IGP to ensure that there are reachable routes between devices.
Configure different costs for routes to generate two non-equal-cost routes.

Configuration Procedure

Configure a route-policy and then enable IPv6 FRR on the public network for the route-policy.

Procedure

Configure a route-policy.
1. Run system-view
  The system view is displayed.
2. Run route-policy route-policy-name { permit | deny } node node
  A route-policy is created and the route-policy view is displayed.
3. (Optional) Run if-match
  Matching conditions are configured to filter the routes to be backed up.
  
  Select the if-match command according to (Optional) Configuring an if-match Clause.
  
  If no matching condition is configured, backup outbound interfaces and backup next hops will be specified for all routes of the device. This, however, causes backup information to be specified for some routes that do not need to be backed up. To correctly configure backup between routes, you are advised to configure matching conditions.
4. Run apply ipv6 backup-interface interface-type interface-number
  A backup outbound interface is configured.
5. Run apply ipv6 backup-nexthop ipv6-address
  A backup next hop is configured.
  - If a backup next hop is specified, a backup outbound interface also needs to be specified.
  - If a backup outbound interface is configured on a P2P link, no backup next hop needs to be specified.
  - If a backup outbound interface is configured on a non-P2P link, a backup next hop needs to be specified.
6. Run quit
  Return to the system view.
Enable IPv6 FRR on the public network.
1. Run ipv6 frr route-policy route-policy-name
  IPv6 FRR on the public network is enabled.
  
  When using IPv6 FRR, use this command to enable IPv6 FRR so that the route-policy can take effect.
  
  Only one route-policy can be configured every time you use the command. If you run this command multiple times, only the latest configuration takes effect.

Verifying the Configuration

Run the display ipv6 routing-table [ verbose ] command to check information about the IPv6 routing table.