[c-nsp] Rationale for ISIS default origination behavior

[Andrew Miehs]

On Tue, Jan 22, 2013 at 8:20 PM, Saku Ytti <saku at ytti.fi> wrote:

> On (2013-01-20 09:41 -0700), John Neiberger wrote:
>
> > This is sort of a follow-up to a question I had a few weeks ago about how
> > to configure conditional default origination in IOS XR. It seems that
> ISIS
> > default origination in both IOS and IOS XR behaves in a pretty suboptimal
> > way. I don't have a lot of history with IS-IS, so I'm curious about this.
>
> You could pick some fairly important/stable Internet address, say 8.8.8.8
> then you could add loop42 with 10.42.42.42/32 in RD and RA. Then all
> routers could have
>

Why would you do this?

If you have a full routing table, you don't need a default route.
If you don't have full routing tables, or want/ need a default route -
point it to your two major "up-streams".

On routers with only a single connection, just use a static default route
on that box, and don't bother learning it from your neighbours.

Or have I misunderstood something?