Adjusting the Establishment of an MPLS TE Tunnel
Pre-configuration Tasks
During establishment of an MPLS TE tunnel, specific configurations are required in practice. MPLS TE provides multiple methods to adjust establishment of MPLS TE tunnels.
- Configure a dynamic MPLS TE tunnel. For details, see Configuring a Dynamic MPLS TE Tunnel.
- Configure a dynamic DS-TE tunnel. For details, see Configuring a Dynamic DS-TE Tunnel.
Configuration Procedure
The following configurations are optional and can be performed in any sequence.
- Configuring Loop Detection
- Configuring Route Record and Label Record
- Configuring Re-optimization for CR-LSP
- Configuring Tunnel Reestablishment Parameters
- Configuring the RSVP Signaling Delay-Trigger Function
- Configuring the Tunnel Priority
- Verifying the Configuration of Adjusting the Establishment of an MPLS TE Tunnel
Configuring Loop Detection
Context
In the loop detection mechanism, a maximum number of 32 hops are allowed on an LSP. If information about the local LSR is recorded in the path information table, or the number of hops on the path exceeds 32, this indicates that a loop occurs and the LSP fails to be set up. By configuring the loop detection function, you can prevent loops.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
- Run system-view
The system view is displayed.
- Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
- Run mpls te loop-detection
The loop detection on tunnel creation is enabled.
By default, loop detection is disabled.
- Run mpls te commit
The current tunnel configuration is committed.
Configuring Route Record and Label Record
Context
By configuring route record and label record, you can determine whether to record routes and labels during the establishment of an RSVP-TE tunnel.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
- Run system-view
The system view is displayed.
- Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
- Run mpls te record-route [ label ]
The route and label are recorded when establishing the tunnel.
By default, routes and labels are not recorded.
- Run mpls te commit
The current tunnel configuration is committed.
Configuring Re-optimization for CR-LSP
Context
By configuring the tunnel re-optimization function, you can periodically recompute routes for a CR-LSP. If the recomputed routes are better than the routes in use, a new CR-LSP is then established according to the recomputed routes. In addition, services are switched to the new CR-LSP, and the previous CR-LSP is deleted.
If an upstream node on an MPLS network is busy but its downstream node is idle or an upstream node is idle but its downstream node is busy, a CR-LSP may be torn down before the new CR-LSP is established, causing a temporary traffic interruption. In this case, you can configure the switching and deletion delays.
If the re-optimization is enabled, the route pinning cannot be used at the same time.
The CR-LSP re-optimization cannot be configured when the resource reservation style is FF.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
- Run system-view
The system view is displayed.
- Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
- Run mpls te reoptimization [ frequency interval ]
Periodic re-optimization is enabled.
By default, re-optimization is disabled. The default periodic re-optimization interval is 3600 seconds.
- Run mpls te commit
The current tunnel configuration is committed.
- Run quit
The system view is displayed.
- (Optional) Set the switching and deletion delays.
Run mpls
The MPLS view is displayed.
Run mpls te switch-delay switch-time delete-delay delete-time
The switching and deletion delays are set.
By default, the switching delay is 5000 ms and the deletion delay is 7000 ms.
- Run return
Back to the user view.
- (Optional) Run mpls te reoptimization [ tunnel interface-number ]
Manual re-optimization is enabled.
After you configure the automatic re-optimization in the tunnel interface view, you can return to the user view and run the mpls te reoptimization command to immediately re-optimize all tunnels or the specified tunnel on which the automatic re-optimization is enabled. After you perform the manual re-optimization, the timer of the automatic re-optimization is reset and counts again.
Configuring Tunnel Reestablishment Parameters
Context
By configuring the tunnel reestablishment function, you can periodically recompute the route for a CR-LSP. If the route in recomputation is better than the route in use, a new CR-LSP is then established according to the recomputed route. In addition, services are switched to the new CR-LSP, and the previous CR-LSP is deleted.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
- Run system-view
The system view is displayed.
- Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
- Run mpls te timer retry interval
The interval for re-establishing a tunnel is specified.
By default, the interval for re-establishing a tunnel is 30 seconds.
- Run mpls te commit
The current tunnel configuration is committed.
If the establishment of a tunnel fails, the system attempts to reestablish the tunnel within the set interval and the maximum number of attempts is the set reestablishment times.
Configuring the RSVP Signaling Delay-Trigger Function
Context
In the case that a fault occurs on an MPLS network, a great number of RSVP CR-LSPs need to be reestablished. This causes consumption of a large number of system resources. By configuring the delay for triggering the RSVP signaling, you can reduce the consumption of system resources when establishing an RSVP CR-LSP.
Perform the following configurations on each node on which multiple CR-LSPs need to be reestablished.
Configuring the Tunnel Priority
Context
In the process of establishing a CR-LSP, if no path with the required bandwidth exists, you can perform bandwidth preemption according to setup priorities and holding priorities.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
- Run system-view
The system view is displayed.
- Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
- Run mpls te priority setup-priority [ hold-priority ]
The priority for the tunnel is configured.
Both the setup priority and the holding priority range from 0 to 7. The smaller the value is, the higher the priority is.
By default, both the setup priority and the holding priority are 7. If only the setup priority value is set, the holding priority value is the same as the setup priority value.
The setup priority should not be higher than the holding priority. So the value of the setup priority must not be less than that of the holding priority.
- Run mpls te commit
The current tunnel configuration is committed.
- Configuring Loop Detection
- Configuring Route Record and Label Record
- Configuring Re-optimization for CR-LSP
- Configuring Tunnel Reestablishment Parameters
- Configuring the RSVP Signaling Delay-Trigger Function
- Configuring the Tunnel Priority
- Verifying the Configuration of Adjusting the Establishment of an MPLS TE Tunnel