The remote-lfa command enables IPv6 IS-IS remote loop-free alternate (LFA).
The undo remote-lfa command disables IPv6 IS-IS remote LFA.
By default, IPv6 IS-IS remote LFA is disabled.
| Parameter | Description | Value |
|---|---|---|
| level-1 |
Enables IS-IS Level-1 remote LFA. |
- |
| level-2 |
Enables IS-IS Level-2 remote LFA. |
- |
| level-1-2 |
Enables IS-IS Level-1-2 remote LFA. If no level is specified in the command, Level-1-2 remote LFA is used. |
- |
| tunnel |
Enables the device to establish tunnels for remote LFA. |
- |
| ldp |
Enables the device to establish Label Distribution Protocol (LDP) LSPs for remote LFA. |
- |
| over-ipv4 |
Enables the device to use IPv4 LDP LSPs for remote LFA. |
- |
Usage Scenario
LFA FRR cannot calculate backup paths on some large IPv6 networks, especially on ring networks, which fails to meet reliability requirements. IPv6 IS-IS remote LFA FRR can address this problem. To enable IPv6 IS-IS remote LFA, run the remote-lfa command. The remote LFA algorithm calculates the PQ node based on the protection path and establishes a tunnel between the source node and the PQ node for backup next hop protection. If a fault occurs on the protection path, traffic is automatically switched to the backup tunnel, improving network reliability.
Prerequisites
IPv6 FRR has been enabled and the IS-IS IPv6 FRR view has been displayed using the ipv6 frr command.
Precautions
IPv4 IS-IS remote LFA must have been enabled using the remote-lfa command.
If LDP is used to establish tunnels, LDP must be deployed on the entire network. A tunnel can be established and a remote loop-free backup route is generated only if a PQ node exists and the PQ node supports the remote LFA function. IPv6 IS-IS remote LFA FRR protects IPv6 traffic and uses IPv4 LDP LSPs. The IPv6 IS-IS remote LFA must be applied to the same topology as that of IPv4 IS-IS remote LFA. Otherwise, the backup calculation may be incorrect, or a loop may occur.<HUAWEI> system-view [~HUAWEI] isis [*HUAWEI-isis-1] frr [*HUAWEI-isis-1-frr] loop-free-alternate level-2 [*HUAWEI-isis-1-frr] remote-lfa tunnel ldp level-2 [*HUAWEI-isis-1-frr] quit [*HUAWEI-isis-1] ipv6 enable [*HUAWEI-isis-1] ipv6 frr [*HUAWEI-isis-1-ipv6-frr] remote-lfa tunnel ldp over-ipv4 level-2