[97874] in North American Network Operators' Group
Re: some musings on PI v. PA
daemon@ATHENA.MIT.EDU (Seth Mattinen)
Thu Jul 12 20:29:43 2007
Date: Thu, 12 Jul 2007 16:52:55 -0700
From: Seth Mattinen <sethm@rollernet.us>
To: David Meyer <dmm@1-4-5.net>
CC: nanog@nanog.org
In-Reply-To: <20070712231732.GA17524@1-4-5.net>
Errors-To: owner-nanog@merit.edu
David Meyer wrote:
> OTOH, if I announce PI space, "switching to the new path"
> is controlled by the announcement/withdrawal of the PI
> prefix, and can happen much closer to the source. So in
> this sense aggregation breaks a certain kind of "path
> selection". I think we all realize that there is no free
> lunch, and that this is a property (such as it is) of the
> fact that aggregation throws away information in the
> interest of computability (a standard technique).
>
> So folks are using PI for reasons other than the
> well-known standard laundry list. In particular,
> advertising PI space can cause the "switch" to an
> alternate path during an outage to happen much closer to
> the source and some providers find this to be a desirable
> property.
>
> I am interested in hearing about anyone who is relying on
> this property of PI, or any other comments on what I've
> said above.
>
I always thought that *was* one of the major reasons to use PI space -
no aggregation of your space into another announcement. Not having to
renumber is ancillary to me.
~Seth
