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 <deles...@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 <p...@tippete.net> wrote: > >>>>>>> "Mel" == Mel Beckman <m...@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 >>