To allow IS-IS to collect and flood information about the intra-area IPv4 link delay, you can enable the advertisement of IPv4 delay information for an IS-IS process.
Traditional path computation algorithms compute the optimal path to a destination address based on costs. However, such a computed path may not have the minimum delay. For services that have stringent requirements on delay, path computation can be performed based on the delay rather than on the cost to ensure that service traffic is transmitted along the path with the minimum delay. To meet these requirements, enable the advertisement of IPv4 delay information for an IS-IS process. After this function is enabled, IS-IS collects and floods information about the intra-area IPv4 link delay, and BGP-LS reports the information to the controller. This allows the controller to use the delay information to compute the optimal path on the P2P network.
The system view is displayed.
An IS-IS process is created, and its view is displayed.
process-id specifies an IS-IS process ID. The default IS-IS process ID is 1. To bind an IS-IS process to a VPN instance, run the isis process-id vpn-instance vpn-instance-name command.
A cost style is set for IS-IS.
The link delay normalization function is configured for the IS-IS process.
For the delay-based Flex-Algo algorithm, the difference in delay between links is generally different and may be very small. However, according to the existing SPF algorithm, only one optimal path can be generated even if the difference is very small, and load balancing cannot be implemented within a certain delay tolerance range. Consequently, link resources on a network cannot be fully utilized. To solve this problem to the greatest extent, normalization can be performed on the link delays with a very small difference or with a difference within an acceptable range, so that load balancing can be implemented and link resources on the network can be fully utilized.
You can also run the isis [ process-id process-id-value ] metric-delay normalize interval interval-value [ offset offset-value ] command in the IS-IS interface view to configure the link delay normalization function on an interface. If the function is configured both for an IS-IS process and an IS-IS interface, the interface's configuration takes precedence over the process's configuration.
TE is enabled on a specified level for the IS-IS process.
The advertisement of delay information is enabled.
Parameters used to suppress the advertisement of delay information are configured.
The configuration is committed.
After configuring the function, verify the configuration.
Run the display isis interface verbose traffic-eng command to check information about IS-IS-enabled interfaces.