Flexible Algorithm enables the creation of multiple logical topologies within the same SRv6 underlay, allowing traffic to be steered according to specific performance requirements rather than relying solely on the default shortest-path calculation. This test validated the operation of Flexible Algorithm  in an SRv6-enabled network, demonstrating the ability of the routing system to compute and enforce distinct forwarding paths based on different optimization objectives.

The test focused on two Flex-Algo instances defined with different optimization criteria. One Flex-Algo (FA 128) instance was configured to chose paths based on delay optimization, while another Flex-Algo (FA 129)instance relied on a Traffic Engineering (TE) metric to influence path selection.
To support delay-aware routing, Two-Way Active Measurement Protocol (TWAMP) was used on selected links to provide dynamic delay measurements, while other links used statically configured delay values. .

The routing entries associated with the test prefixes explicitly indicated the Flexible Algorithm locators, confirming that the routes were computed using the intended Flex-Algo instance rather than the default IGP topology.
The forwarding behavior confirmed that SRv6 traffic followed the paths calculated by the selected Flexible Algorithm instances.

In one case, an issue was observed with a vendor implementation. Specifically, the node did not advertise the local and remote link identifiers in its IS Extended IS Reachability TLV. As a result of the missing link identifiers, the affected links could not be incorporated into the topology used for Flexible Algorithm computation.