When I run TAHI Self-Test Tool 5.0.0 to test Ubuntu 15.04 kernel 3.19.0, I get several failures, including nd.2 Test 138 Default Router Switch. Is this a known issue with the current IPv6 implementation in the Linux kernel?

Test 138 advertises two default routers to the node under test (nut). It then sends ICMPv6 Echo requests every three seconds. At some point, router 1 becomes unreachable and the nut is supposed to detect this. Then, when the nut receives another ICMPv6 Echo request, it is supposed to select router 2 and send out Neighbor Solicitation messages to resolve router 2's L3 address to its L2 address. This never happens. Neighbor Solicitations are sent to router 1's solicited node multicast address. This is after the nut has sent Neighbor Solicitation messages to router 1's unicast address and determined that router 1 is unreachable.

Does anybody have more information on this? Is there a configuration setting that will make Linux pass this test and all IPv6Ready Logo Phase-2 Core Protocols tests?