Associating CR-LSP Establishment with the Overload Setting
Context
When the node is transmitting a large number of services and its system resources are exhausted, the node marks itself overloaded.
When the node is transmitting a large number of services and its CPU is overburdened, an administrator can run the set-overload command to mark the node overloaded.
If there are overloaded nodes on an MPLS TE network, associate CR-LSP establishment with the IS-IS overload setting to ensure that CR-LSPs are established over paths excluding overloaded nodes. This configuration prevents overloaded nodes from being further burdened and improves CR-LSP reliability.
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 path-selection overload
CR-LSP establishment is associated with the IS-IS overload setting. This association allows CSPF to calculate paths excluding overloaded IS-IS nodes.
Before the association is configured, the mpls te record-route command must be run to enable the route and label record.
Traffic travels through an existing CR-LSP before a new CR-LSP is established. After the new CR-LSP is established, traffic switches to the new CR-LSP and the original CR-LSP is deleted. This traffic switchover is performed based on the Make-Before-Break mechanism. Traffic is not dropped during the switchover.
The mpls te path-selection overload command has the following influences on the CR-LSP establishment:CSPF recalculates paths excluding overloaded nodes for established CR-LSPs.
CSPF calculates paths excluding overloaded nodes for new CR-LSPs.
This command does not take effect on bypass tunnels.
If the ingress or egress is marked overloaded, the mpls te path-selection overload command does not take effect. The established CR-LSPs associated with the ingress or egress will not be reestablished and new CR-LSPs associated with the ingress or egress will also not be established.