From: John Gibson (johngibson1541@yahoo.com)
Date: Tue Jul 10 2007 - 17:39:23 ART
Yeah, it clearly indicates confed AS numbers are
excluded.
John
--- "Mike Kraus (mikraus)" <mikraus@cisco.com> wrote:
> John,
>
> This is a good doc for BGP path selection:
>
> http://www.cisco.com/warp/public/459/25.shtml
>
> The important excerpt is: "The AS_CONFED_SEQUENCE
> and AS_CONFED_SET
> are not included in the AS_PATH length."
>
> -----Original Message-----
> From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> John Gibson
> Sent: Tuesday, July 10, 2007 1:41 PM
> To: Jason Guy (jguy)
> Cc: ccielab@groupstudy.com
> Subject: RE: BGP path selection process,
> confederation peer's AS numbers
> doesn't count toward AS path lengh right?
>
> We are not talking about the same thing.
>
> Yes, (65502) is stripped when going out of the big
> AS (the typically
> registered).
>
> But within the big AS, when a different confed
> receives "(65502)" , this
> "(65502)" does not count toward "AS path length". My
> key emphasis is
> "length" here.
>
> My experiment has Path of "(65502) 200 i" and "100
> i" of 2 routes
> arriving at the router.
> And I use always compare med.
>
> When I change med (set metric) from outside the big
> AS, it effects path
> selection. MED is lower ranked than AS path length.
> This means "(65502)
> 200 i" and "100 i" are considered of the same "As
> path length".
>
> Mike Kraus says I am correct.
>
>
> John
>
>
> --- "Jason Guy (jguy)" <jguy@cisco.com> wrote:
>
> > John,
> >
> > The AS-Path counts within the confederation. As
> soon as the prefix is
>
> > advertised outside (to the real world) the
> confederation AS-path is
> > stripped, and the global AS is prepended. Within
> the confederation,
> > most of the same eBGP rules apply.
> >
> > The MED value can be set regardless of where the
> prefix is advertised
> > (confed peer or other peer).
> >
> > Jason
> >
> >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com
> > [mailto:nobody@groupstudy.com] On Behalf Of
> > > johngibson1541@yahoo.com
> > > Sent: Tuesday, July 10, 2007 2:18 PM
> > > To: ccielab@groupstudy.com
> > > Subject: BGP path selection process,
> confederation
> > peer's AS numbers
> > > doesn't count toward AS path lengh right?
> > >
> > > I have tried to use MED to influence 2 routes
> > >
> > > one with "(65502)" confederation peer AS
> > >
> > > another without the confederation peer AS
> > >
> > > MED takes effect.
> > >
> > >
> > > John
> > >
> > >
> >
>
This archive was generated by hypermail 2.1.4 : Sat Aug 18 2007 - 08:17:40 ART