Re: Long AS Path

[Mel Beckman <mel () beckman org>]

You don't have to wonder. You can call and ask them. 

-mel via cell

> On Jun 22, 2017, at 5:47 AM, jim deleskie <deleskie () gmail com> wrote:
>
> I see 5+ prepends as maybe not reason to have your "BGP driving license
> revoked" but if I can continue with the concept that you have your BGP
> learners permit.
> If I think back to when I learned to code or when making ACL's,  we still
> used line number and practice would be to give ourselves lots
> of space 5 or 10 numbers in case we have to insert something in the middle.
> ie I need 2 sets of prepends, I'm still learning this stuff
> so I'll go with 5 and 10. We all started somewhere, we all did dumb stuff,
> hopefully, we all learned.
>
> 12AS hops, I have to go see how they are connected now, maybe someone in
> that chain needs to be invited by an IX to a NANOG or GPF or some such,
> that can't be super efficient.
>
> -jim
>
> On Thu, Jun 22, 2017 at 3:09 AM, Pierfrancesco Caci <pf () tippete net> wrote:
>
> > > > > > > "Mel" == Mel Beckman <mel () beckman org> writes:
> >
> >
> >    Mel> Why not ask the operator why they are pretending this path?
> > Perhaps
> >    Mel> they have a good explanation that you haven't thought of. Blindly
> >    Mel> limiting otherwise legal path lengths is not a defensible
> > practice, in
> >    Mel> my opinion.
> >
> >    Mel>  -mel beckman
> >
> >
> > A prepend like that is usually the result of someone using the IOS
> > syntax on a XR or Junos router.
> >
> > Long ago, someone accidentally prepending 255 times hit a bug (or was it
> > a too strict bgp implementation? I don't remember) resulting in several
> > networks across the globe dropping neighbors. One has to protect against
> > these things somehow.
> >
> > As a data point, here is how many prefixes I see on my network for each
> > as-path length, after removing prepends:
> >
> >
> > aspath length   count
> > -------------------------
> >        0:      340
> >        1:      47522
> >        2:      292879
> >        3:      227822
> >        4:      58390
> >        5:      10217
> >        6:      2123
> >        7:      638
> >        8:      48
> >        9:      58
> >        11:     20
> >        12:     2
> >
> >
> > So, does your customer have a legitimate reason to prepend more than 5
> > times? Maybe. I still think that anyone that does should have their BGP
> > driving licence revoked, though.
> >
> > Pf
> >
> >
> >
> >
> > --
> > Pierfrancesco Caci, ik5pvx