"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