Adjusting the IPv4 IS-IS Route Convergence Speed

Accelerating IS-IS route convergence can improve the fault location efficiency and network reliability.

Usage Scenario

The procedure for implementing IS-IS is as follows:

Establishment of neighbor relationships: establishes neighbor relationships by exchanging Hello packets between two devices.
LSP flooding: implements LSDB synchronization between devices in the same area.
SPF calculation: uses the SPF algorithm to calculate IS-IS routes, and delivers IS-IS routes to the routing table.

To accelerate the IS-IS route convergence, configure the following parameters:

Interval for detecting failures on IS-IS neighboring devices
Flooding parameters of CSNPs and LSPs
Interval for SPF calculation

You can also configure convergence priorities for IPv4 IS-IS routes so that key routes can converge first if the network topology changes, which minimizes adverse impacts on key services.

Pre-configuration Tasks

Before adjusting the IPv4 IS-IS route convergence speed, complete the following tasks:

Configure the link layer protocol on interfaces.
Configure IP addresses for interfaces to ensure that neighboring nodes are reachable at the network layer.
Configure basic IPv4 IS-IS functions.

Configuring the Interval for Detecting IS-IS Neighboring Device Failures: To minimize the impacts of neighboring device failures on IS-IS networks, accelerate the detection IS-IS neighboring device failures.

Setting Flooding Parameters of SNPs and LSPs: To speed up LSDB synchronization between devices, set proper values for flooding parameters of SNPs and LSPs.

Setting the SPF Calculation Interval: To improve the fault location efficiency on an IS-IS network and prevent SPT calculation from consuming excessive system resources, set the SPF calculation interval to a proper value.

Configuring Convergence Priorities for IPv4 IS-IS Routes: IS-IS routes with higher convergence priority converge preferentially when the network topology changes, which minimizes the impacts on critical services. This section describes how to configure convergence priorities for IS-IS routes.

Enabling IS-IS Intelligent Convergence: Enabling IS-IS intelligent convergence can speed up IS-IS route convergence, thereby improving convergence performance.

Verifying the Configuration: After configuring parameters to adjust the IPv4 IS-IS route convergence speed, check the configurations.