flex-algo identifier

Usage Scenario

Originally, IGPs can use only the SPF algorithm to calculate the shortest paths to destination addresses based on link costs. As the SPF algorithm is fixed and cannot be adjusted by users, it cannot calculate the optimal paths based on diverse user requirements. For example, it cannot support traffic forwarding along the lowest-delay path or without passing through certain links.

On a network, constraints used for path calculation may be different. For example, an IGP needs to use delay as the constraint to calculate paths for autonomous driving, which requires an ultra-low delay network, or needs to exclude some links that have high costs. These constraints may also be combined.

To make path calculation more flexible, users may want to customize IGP algorithms for different requirements. They can define an algorithm value to identify a fixed algorithm. When all devices on a network use the same algorithm, their calculation results are also the same, preventing loops. Since users, not standards organizations, are the ones to define these algorithms, they are called Flex-Algos.

With Flex-Algo, an IGP can automatically calculate eligible paths based on the link cost, delay, or TE constraint to flexibly meet TE requirements.

To configure a Flex-Algo with a specified ID, run the flex-algo identifier command.