The mpls ldp frr nexthop command enables LDP FRR on an interface.
The undo mpls ldp frr command disables LDP FRR on an interface.
By default, no interface is enabled with LDP FRR.
mpls ldp frr nexthop nexthop-address [ ip-prefix ip-prefix-name ] [ priority priority ]
undo mpls ldp frr [ nexthop nexthop-address ] [ ip-prefix ip-prefix-name ] [ priority priority ]
| Parameter | Description | Value |
|---|---|---|
| nexthop-address | Specifies the next hop address on a backup LSP. | The value is in dotted decimal notation. |
| ip-prefix ip-prefix-name | Specifies the IP prefix name. Only the FEC that matches the specified IP prefix can trigger the generation of a backup LSP. | The value is an existing IP prefix name. |
| priority priority | Specifies the priority of a backup LSP. The greater the value is, the lower priority the backup LSP has. | The value is an integer ranging from 1 to 65535. By default, the value is 50. |
VLANIF interface view, GE interface view, XGE interface view, MultiGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, Eth-trunk interface view
Usage Scenario
The traditional IP FRR technology cannot effectively protect the traffic on an MPLS network. The device provides the LDP FRR function and the solution to port protection.
In the manual LDP FRR mode, you need to configure a backup LSP by specifying the outbound interfaces or the next hops. This mode applies to simple-structured networks.
When running the mpls ldp frr nexthop command to configure the next hop IP address, note that:
You can configure multiple next hops on one interface. This allows you to configure multiple backup LSPs with different outbound interfaces for the primary LSP.
You can configure different prefix lists for the same next hop on one interface.
If no prefix list is specified, LDP FRR tries to establish backup LSPs along the path specified by nexthop-address for all primary LSPs on the interface.
If only the DENY item is in a specified prefix list, no backup LSP is allowed to set up along the path specified by nexthop-address for the primary LSP mapping to the FEC denied by the interface.
If only PERMIT item is in the specified prefix list, backup LSPs are allowed to set up along the path specified by nexthop-address only for the primary LSPs mapping to the FEC permitted by the interface.
If both PERMIT and DENY items are in the prefix list, only the PERMIT item is effective. That is, backup LSPs are allowed to set up along the path specified by nexthop-address only for the primary LSPs mapping to the FEC permitted by the interface.
A single interface supports LDP FRR with a maximum of 10 priorities. Only a single backup LSP is generated.
Prerequisites
MPLS has been enabled in the interface view using the mpls command.
Precautions
If the undo mpls ldp command is run in the system view or the undo mpls ldp command is run in the interface view to disable LDP functions, the LDP FRR configuration in the interface remains but does not take effect. During the LDP FRR configuration, the LSP that functions as the backup LSP must be in the liberal state. For a backup LSP, the routing status of the backup LSP from the ingress node to the egress node must be Inactive Adv.
LDP FRR cannot be enabled or disabled during LDP GR.
When both LDP FRR and IP FRR are enabled, IP FRR takes effect.
Creating an IP prefix list before it is referenced is recommended. By default, nonexistent IP prefix lists cannot be referenced using the command. If the route-policy nonexistent-config-check disable command is run in the system view and a nonexistent IP prefix list is referenced using the current command, backup LSPs are established for all LDP LSPs on the local interface along the path to the specified next-hop IP address.
<HUAWEI> system-view [HUAWEI] interface vlanif 100 [HUAWEI-Vlanif100] mpls [HUAWEI-Vlanif100] mpls ldp frr nexthop 10.1.1.2
<HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] undo portswitch [HUAWEI-GigabitEthernet0/0/1] mpls [HUAWEI-GigabitEthernet0/0/1] mpls ldp frr nexthop 10.1.1.2