Configuring Path Calculation
Context
To calculate a tunnel path meeting specified constraints, CSPF should be configured on the ingress.
- Link state information sent by IGP-TE and saved in TEDBs
- Network resource attributes, such as the maximum available bandwidth and maximum reservable bandwidth, sent by IGP-TE and saved in TEDBs
- Configured constraints such as explicit paths
An RSVP-TE tunnel can be established on a CSPF-disabled ingress. However, to allow a path to meet tunnel constraints, you are advised to enable CSPF on the ingress before establishing the RSVP-TE tunnel.
Enabling CSPF on all transit nodes is recommended.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
- Run system-view
The system view is displayed.
- Run mpls
The MPLS view is displayed.
- Run mpls te cspf
CSPF is enabled on a node.
CSPF is disabled by default.
- (Optional) Run mpls te cspf preferred-igp { isis [ isis-process-id [ level-1 | level-2 ] ] | ospf [ ospf-process-id [ area { area-id-1 | area-id-2 } ] ] }
A preferred IGP is specified.
By default, OSPF is preferred for CSPF path calculation.
- (Optional) Run mpls te cspf multi-instance shortest-path [ preferred-igp { isis | ospf } [ process-id ] ]
CSPF is configured to calculate shortest paths among all IGP processes and areas.
By default, the multi-instance shortest path policy is disabled.
The mpls te cspf multi-instance shortest-path command is mutually exclusive with the mpls te cspf preferred-igp command. If the mpls te cspf multi-instance shortest-path command is run, this command overrides the mpls te cspf preferred-igp command.
- (Optional) Run mpls te cspf optimize-mode disable
The optimization mode is disabled when CSPF calculates the path.
CSPF provides a method for selecting a path in the MPLS domain. By default, the optimization mode is used for path calculation, and the path calculation is performed from Egress to Ingress. Compared with the common calculation method, the optimization mode has higher efficiency.
The mpls te cspf optimize-mode disable command is used to disable the CSPF optimization mode. After the configuration, the path is calculated from Ingress to Egress.
- Run commit
The configuration is committed.
