On Tue, 27 May 2008 09:12:43 +0200 "Ole Troan" <[EMAIL PROTECTED]> wrote:
> > FYI, > > > > This issue, from cisco-nsp list, might be of interest here. When an > > interface is looped, it will fail DAD, and if the condition lasts long > > enough, you might not recover from it automatically. > > this is a flaw in the way DAD was designed. one solution could be to > add a nonce option to ND. another would be to turn DAD off. > I'd have expected that administratively disabling and then re-enabling the interface (after having fixed the looped interface issue) would restart the DAD process. Regards, Mark. > /ot > > > On Tue, 27 May 2008, Gert Doering wrote: > >> On Tue, May 27, 2008 at 03:00:26AM +0300, Hank Nussbacher wrote: > >>> When we did some line testing and did some loop testing on the link we > >>> got: > >>> %IPV6-4-DUPLICATE: Duplicate address FE80::215:2CFF:FE87:B240 on POS11/0/0 > >>> > >>> petach-tikva-gp# sho ipv6 int pos11/0/0 > >>> POS11/0/0 is up, line protocol is up > >>> IPv6 is stalled, link-local address is FE80::215:2CFF:FE87:B240 [DUP] > >> [..] > >> > >>> I know I can use "ipv6 nd dad attempts 5" but wanted to know whether I > >>> should open a TAC case for this. > >> > >> I have seen this as well, and it's especially annoying if it happens > >> as consequence of a link outage from the carrier (link going down, going > >> into "loop" state, then coming back to "up") - if you're unlucky, a short > >> glitch can kill your IPv6 on the line hard until you manually reset the > >> interface. > >> > >> The current behaviour is pretty much a direct consequence from the RFC > >> (DAD is mandatory), but I think that IOS could be a bit more smart about > >> it, like "restart DAD every 5 minutes" or "recognize a looped->up > >> transition on the interface, and then restart DAD". > >> > >> So - by all means, please open a TAC case. > >> > >> As a workaround, we have used "ipv6 nd dad attempts 5" on the specific > >> line that gave us headaches - so we've never pressed the issue with Cisco. > >> > >> gert > >> > >> > >> > > > > -- > > Pekka Savola "You each name yourselves king, yet the > > Netcore Oy kingdom bleeds." > > Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings > > -------------------------------------------------------------------- > > IETF IPv6 working group mailing list > > [email protected] > > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > > -------------------------------------------------------------------- > > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > [email protected] > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
