Re: When is the ISIS attached bit set?

That's correct. ATT bit will be set to 1 only if L1/L2 router has and
adjacency in L2 area. The mere declaration that the router is L1/L2
does not make the router set the bit. When you think about it, it
makes perfect sense.

--
Marko Milivojevic - CCIE #18427 (SP R&S)
Senior CCIE Instructor - IPexpert
On Mon, Jul 23, 2012 at 9:06 PM, John Neiberger <jneiberger_at_gmail.com> wrote:
> I'm playing around with ISIS and I'm wondering about something that I
> hadn't really thought about much until now. If you have a mix of L2
> and L1 routers, the L2 routers will set the attached bit to advertise
> their candidacy for a default route. However, this only seems to
> happen if the L1/L2 router is attached to another area or detects an
> L2 router that is attached to another area.
>
> Does this mean that if we run single area ISIS, the L1/L2 routers will
> never set the attached bit and the L1 routers will not have a default
> route out to the rest of the network? If so, in situations like that
> it seems like it would just make more sense to run all one level.
>
> Thoughts?
>
> Thanks,
> John
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
Blogs and organic groups at http://www.ccie.net