[112191] in North American Network Operators' Group
Re: Lots of prepends - AS20912 case
daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Fri Feb 20 09:05:59 2009
Date: Fri, 20 Feb 2009 15:05:48 +0100 (CET)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: nanog@nanog.org
In-Reply-To: <7db2dcf90902200551y7d359f45v60d2fd0230813981@mail.gmail.com>
Errors-To: nanog-bounces@nanog.org
On Fri, 20 Feb 2009, Dorn Hetzel wrote:
> Replacing what is conventially thought to be a string with an integer
> multiplier seems a massive violation of the principle of least astonishment.
On a Cisco running 12.0S:
route-map test1
set as-path prepend last-as ?
<1-10> number of last-AS prepends
Cisco seems to be doing more sensible limits, but I do agree that the
feature makes sense.
There are two ways of handling when someone puts in a very high number to
number of prepends:
1. Say "out of limit" and disallow it in the config checker.
2. Actually prepend the number of times specified.
The option done here:
3. Prepend number of times entered modulo 256, is just broken.
--
Mikael Abrahamsson email: swmike@swm.pp.se
