Does anyone know what local-pref AS701 sets for their customers and their
peers? I called their NOC, and was told that is was set to 100 for both,
though I know most providers set local-pref on peers lower than customers.
I just want to get confirmation on what i was told by their NOC.
TIA.
SHORT NAME COMMUNITY WHAT IT DOES
Local Pref = 80 701:80 set localpref 80
Local Pref = 120 701:120 set localpref 120
AS Path prepend 1 701:1 prepend 1x: 701 [cust-AS]
AS Path prepend 2 701:2 prepend 2x: 701 701 [cust-AS]
AS Path prepend 3 701:3 prepend 3x: 701 701 701 [cust-AS]
Cust but not peers 701:20 propagate to custs, not peers
keep cust routes in North America 701:30 send to custs & peers, but
not 702, 703...
keep AS7046 in AS701 no-export don't propagate beyond AS701
peers 701:666 don't propagate beyond this AS
peers 701:1030 don't propagate beyond this AS
I think you misunderstood the question - what you have detailed here is a
list of customer communities that UUNet accepts, what Sean is trying to
find out is what internal localpref UUNet sets by default - do they
automatically give prefixes from customers a higher localpref than
prefixes heard from peers? I don't know for sure, but I'm thinking that
they do, which makes sense - otherwise it's possible to send traffic to a
peer when there could be a valid path for the traffic via a customer.
-Chris
All the responses I have gotten indicate that UUnet does indeed set
local-pref on both customers and peers to 100 (or leave default in this
case). Thanks for all the responses...
If they set local pref for both peers and customers to 100 how do they
ensure that the customer transit routes are announced to peers?
The reason I ask this is because if a customer announces a customer of
theirs to you that a peer also has as a customer you will have equal
length routes for the same destination AS. While there are many ways to
deterministicly prefer customer routes, local pref is the most common.
Your core routers will only propagate the best route in their routing
tables (normally).
Assuming you have more than one BGP speaking router in your network, if
you don't deterministicly prefer your customer routes (including their
downstreams) then you won't deterministicly announce them for your
customer. Most commonly when somebody pays for transit they want you to
advertise their routes (including any customer routes they announce to
you) to the world.
Mike.
All the responses I have gotten indicate that UUnet does indeed set
local-pref on both customers and peers to 100 (or leave default in this
case). Thanks for all the responses...--
-sean
Spoon!> Date: Fri, 14 Dec 2001 12:01:39 -0500
> From: Christopher A. Woodfield <rekoil@semihuman.com>
> To: German Martinez <gmartine@nic.gip.net>
> Cc: Me <smentzer@mentzer.org>, nanog@merit.edu
> Subject: Re: AS701 peer local-pref?
>
> I think you misunderstood the question - what you have detailed here is a
> list of customer communities that UUNet accepts, what Sean is trying to
> find out is what internal localpref UUNet sets by default - do they
> automatically give prefixes from customers a higher localpref than
> prefixes heard from peers? I don't know for sure, but I'm thinking that
> they do, which makes sense - otherwise it's possible to send traffic to a
> peer when there could be a valid path for the traffic via a customer.
>
> -Chris
>
> >
> > SHORT NAME COMMUNITY WHAT IT DOES
> > Local Pref = 80 701:80 set localpref 80
> > Local Pref = 120 701:120 set localpref 120
> > AS Path prepend 1 701:1 prepend 1x: 701 [cust-AS]
> > AS Path prepend 2 701:2 prepend 2x: 701 701 [cust-AS]
> > AS Path prepend 3 701:3 prepend 3x: 701 701 701 [cust-AS]
> > Cust but not peers 701:20 propagate to custs, not peers
> > keep cust routes in North America 701:30 send to custs & peers, but
> > not 702, 703...
> > keep AS7046 in AS701 no-export don't propagate beyond AS701
> > peers 701:666 don't propagate beyond this AS
> > peers 701:1030 don't propagate beyond this AS
> >
> >
> >
> >
> >
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > * THE DILBERT FUTURE *
> > * Thriving on Stupidity in the 21st Century *
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > "Internet capacity will increase indefinitely
> > to keep up with the egos of the people using it"
> >
> >
> > >
> > >
> > > Does anyone know what local-pref AS701 sets for their customers and their
> > > peers? I called their NOC, and was told that is was set to 100 for both,
> > > though I know most providers set local-pref on peers lower than customers.
> > > I just want to get confirmation on what i was told by their NOC.
> > >
> > > TIA.
> > >
> > > --
> > > -sean
> > > Spoon!
> > >
> > >
> >
>
>
+------------------- H U R R I C A N E - E L E C T R I C -------------------+
they could just be relying on as_path+bgp bestpath
but yeah, i personally prefer a model of
localprefs in this order (highest first obviously)
customer
peer
upstream
this puts traffic across links that you get paid for,
you get for (free?) a lower cost than upstream/transit then
the most expensive link.
- jared
If they set local pref for both peers and customers to 100 how do they
ensure that the customer transit routes are announced to peers?
yup. for a discussion of this with diagrams and all, see a nanog
conversation between vaf, asp, and me circa '97 or so.
randy
> If they set local pref for both peers and customers to 100 how do they
> ensure that the customer transit routes are announced to peers?yup. for a discussion of this with diagrams and all, see a nanog
conversation between vaf, asp, and me circa '97 or so.
I looked over your posts for all of 1997 and those closest I found was
this in March of 1997 (the ensuing thread had lots diagrams etc):
http://www.merit.edu/mail.archives/nanog/1997-03/msg00250.html
You post is example of why you want to prefer customer routes. Since I
can't find a reponse from Andrew Partan I'm not sure if I found the thread
you were referring to. If I missed it please privately send me some
search keywords and I'll dig some more.
While handling equal length routes deterministicly so that you don't drop
your own customer's transit routes (paths longer than just one AS)
somewhat apparent, this is probably unnecessarily confusing for some. So
instead lets take the case where the customer route is longer than the
peer route.
Most often, when you are paid for transit your customer has the
expectation that you will reannounce their routes including their customer
routes.
Assume you have customer A who has customer R who has customer X. You
also peer with B who also has X as a customer.
Customer A expects you announce all the routes they are paying you to
announce, namely A R X. You also hear the shorter route B X. However,
you MUST prefer A R X in order to ensure that it propagates within your
network so that you announce it uniformly.
The two ways to set path selection prior to path length are local pref and
weights.
The prior post asserted that 701 does not use local pref. This would
leave weights or nothing. If they do nothing then this is a big deal for
network A because they can't ensure that R's customer routes will be
announced.
Is there a 701 customer on the list that knows definitely how their
customers customers routes are being handled that can clear this up?
Will the real 701 route selection algorithm stand up? 
Mike.
+------------------- H U R R I C A N E - E L E C T R I C -------------------+