Re: BGP Route Issues

[Fakrul Alam Pappu <fakrulalam () gmail com>]

Won't it be backslash rather than forward slash?

_([0-9]+) _\1_\1_\1_


On Mon, Aug 19, 2013 at 9:51 AM, Randy <randy_94108 () yahoo com> wrote:

> 11 prepends is beyond-excessive besides being annoying.
> filter please _([0-9]+) _/1_/1_/1_
>
>
>
>
> > ________________________________
> > From: Blake Dunlap <ikiris () gmail com>
> > To: Christopher Karel <chris.karel () gmail com>
> > Cc: "nanog () nanog org" <nanog () nanog org>
> > Sent: Sunday, August 18, 2013 7:42 PM
> > Subject: Re: BGP Route Issues
> >
> >
> > Local Pref (which is common by the way to be set so customers > peers >
> > transit). AS Path doesn't beat it.
> > You can only request people follow the routes you want ingress, there's
> > nothing you can do to force them to take a path to you short of
> > deaggregation, and that only works until they notice it, and it irratates
> > the rest of the world as well by using additional route slots.
> >
> > Poor routing is purely a viewpoint problem, not necessarily in agreement
> > between all parties.
> >
> > -Blake
> >
> >
> > On Sun, Aug 18, 2013 at 8:33 PM, Christopher Karel <chris.karel () gmail com
> > wrote:
> >
> > >   Good evening,
> > >
> > >     I'm hoping you guys might be able to offer some advice or insight
> into
> > > a BGP problem I've got.  I've noticed some strange routes between our
> > > network, AS27270, and AS22943.  It looks like both our networks are dual
> > > homed.  One ISP as the primary, and the other used as a backup, with
> path
> > > prepending to prevent it from actually being used except in an outage.
> > >  However, our route to 22943 appears to be using their backup link.
> (27270
> > > 4323 7018 22943 22943 22943 22943 22943 22943 22943 22943 22943 22943
> > > 22943)  Which is strange, because we can reach their primary ISP without
> > > any such rigmarole.
> > >
> > >     Playing around with Looking Glass servers indicates that Cogent
> > > (AS174) has a similar backup route to our network.  (174 22402 27270
> 27270
> > > 27270 27270 27270 27270)  Everywhere else I check seems perfectly sane.
> > >  But since Cogent is essentially in-between the two networks I'm
> > > troubleshooting, I would assume that the other network has a similar
> route.
> > >  But Cogent won't talk with me about this, since I'm not a customer.
> > >
> > >     So as far as advice goes, is there a common issue that might result
> in
> > > such poor routes in both directions?  Any further troubleshooting that I
> > > should be doing?  Or any ideas on how to help remedy things that appear
> to
> > > be outside our network/ISP?  Or are we doing something so wrong that
> this
> > > is all my fault?
> > >
> > > I'd really appreciate any input on this.