Hi all,

I'm enabling isis multi-topology in my network to support ipv6 (ipv4 already in place), but when I enable ipv6 router isis on an interface the adjacency flaps.

In detail, as soon as I configure "ipv6 router isis" on a vlan interface on the other side I get:

%CLNS-5-ADJCHANGE: ISIS: Adjacency to XXXX (VlanXX) Down, adjacency type changed

%CLNS-5-ADJCHANGE: ISIS: Adjacency to XXXX (VlanXX) Up, new adjacency

and the adjaceny type change from ISIS to M-ISIS (as expected).

Tested on 6509 WS-SUP720-3B with 12.2(33)SXH8b and 7606 WS-SUP720-3BXL with 12.2(18)SXF10. ISIS IPv4 is already configured and working as expected.

The global ISIS ipv6 configuration is the following:

router isis

address-family ipv6

multi-topology

exit-address-family

My understanding is that with multi-topology I should not see any flaps.

Am I missing something?

Thanks.

Regards,

Maurizio