Do I need to specify the next hop or egress when configuring a static LSP on the ingress node

3

When configuring a static LSP on the ingress node, ensure that configuration items match routing information, including the destination address, mask, next hop, and outbound interface;otherwise,the LSP cannot become Up.

The system calculates the next hop if you specify the outbound interface. The calculated next hop is the IP address of the local outbound interface. The system calculates the outbound interface if you specify the next hop (the inbound interface of the peer end). The calculated outbound interface is still the local outbound interface.

Therefore, errors may occur during the static LSP configuration on the ingress node. Pay attention to the following points:
If the outbound interface is specified for a static route, you must specify the outbound interface when configuring the static LSP on the ingress node.
In other situations, you need to specify the next hop rather than only the outbound interface.
The fundamental rule is that the static ingress LSP route fully matches routing information.

Other related questions:
Can the next hop address be not specified in a static route
You must specify the next hop address in a static route, but you can choose not to specify the outbound interface. The ip route-static ip-address mask Vlanif vlan-id command specifies the VLANIF interface as the outbound interface in a static route and does not specify the next hop address. This command is not recommended because it does not take effect and lowers device performance.

How to configure the egress node to assign explicit-null labels to the penultimate hop
If the label of the penultimate hop is implicit-null, the value of the label that the egress node assigns to the penultimate hop is 3. If the label of the penultimate hop is non-null, the PHP feature is not used and the egress node properly assigns labels to the penultimate hop. The value of the label is equal to or larger than 16. Typical failure: The label distribution mode is not modified, or the label distribution mode is set to non-null. Solution: In the MPLS view, set the label distribution mode to explicit-null.

How to configure static LSPs on S series switches
For static LSP configuration on S series switches (except the S1700), see "CLI-based Configuration > Configuration Guide - MPLS > Static LSP Configuration > Configuration Examples > Example for Configuring Static LSPs" in S7700&S9700 V200R010C00 Product Documentation. Configurations on different models are the same, and configurations on the S7700 and S9700 are used as examples.

Configure next-hop backup through policy-based routing on an AR router
If multiple carriers are available on a network, configure next-hop backup to keep network connectivity for intranet users and improve network robustness. Run the redirect backup-nexthop ip-address command in the traffic behavior. For details about the configuration of specific policy-based routing, see the URL: Example for Configuring Interface PBR. Configuring Interface PBR.

What need I check when LSP flapping occurs
When LSP flapping occurs, check the following information: Whether the peer end can be pinged. Run the display mpls ldp peer command in the system view to check the peer address (Transport-Address field). Run the ping command to check for traffic loss. Whether route flapping occurs. Run the display ip routing-table command in the system view to check all the current routing information. Set the destination address to check all the current routing information mapping the destination address. Frequently check routing information in a period to check for flapping. Whether LDP session flapping occurs. Run the display mpls ldp session command in the system view to check information about all LDP sessions. Set the peer address to check information about the LDP session with the specified peer. Frequently check LDP session information in a period to check for flapping. Whether lsp-trigger all is configured. Whether exceptions occur by enabling the debugging function.

If you have more questions, you can seek help from following ways:
To iKnow To Live Chat
Scroll to top