Re: RIP Justification

[Mark Smith <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org>]

On Thu, 30 Sep 2010 14:13:11 +1000
Julien Goodwin <nanog () studio442 com au> wrote:

> On 30/09/10 13:42, Mark Smith wrote:
> > One of the large delays you see in OSPF is election of the designated
> > router on multi-access links such as ethernets. As ethernet is being
> > very commonly used for point-to-point non-edge links, you can eliminate
> > that delay and also the corresponding network LSA by making OSPF treat
> > the link as a point-to-point link e.g.
> >
> > int ethernet0
> >   ip ospf network point-to-point
> >
> >
> > If your implementation doesn't support point-to-point mode for an
> > interface, point-to-multipoint mode on an ethernet would achieve
> > something somewhat equivalent.
>
> Do any implementations go point-to-point automatically if an ethernet
> has a /30 or /31 mask?

Don't know.

If you want to see what interface model OSPF is using, on a Cisco you
use

show ip ospf interface <blah>


The interface type for loopback interfaces can be a bit surprising and
the consequences a bit unexpected if you're intentionally or
otherwise not using a /32 prefix length on one.


Regards,
Mark.