Re: [sidr] pCNT & prepending

Sorry for the ambiguity. I mean defending against attacks such as "removing
an AS from the path".
I.e.
suppose the path is <AS1 AS2 AS2 AS3>,
then we need pCNT to avoid AS3 to announce a shorter path <AS1 AS2 AS3>, by
remove one of AS2.

R.
_____________________________________________________
Yang Xiang, PhD student, Tsinghua Univ., about.me/xiangyang

2011/7/28 Montgomery, Douglas <dougm@nist.gov>

> Did your comment mean complete "AS removal" ... or defending against
> adding/removing pre-pends.
>
> dougm
>
> Doug Montgomery - Manager Internet and Scalable Systems Research Group /
> Information Technology Laboratory / NIST
> ________________________________________
> From: sidr-bounces@ietf.org [sidr-bounces@ietf.org] On Behalf Of XIANG
> Yang [xiangy08@csnet1.cs.tsinghua.edu.cn]
> Sent: Thursday, July 28, 2011 11:11 AM
> Cc: sidr wg list
> Subject: Re: [sidr] pCNT & prepending
>
> +1 support.
> It's import to defend "AS removal" attack.
> _____________________________________________________
> Yang Xiang, PhD student, Tsinghua Univ., about.me/xiangyang<
> http://about.me/xiangyang>
>
>
>
> 2011/7/28 Danny McPherson <danny@tcb.net<mailto:danny@tcb.net>>
>
> Doug et al,
> I like the general objective of pCNT and this seems a good idea to me.  My
> only comment at the microphone was that if we add this for compression, then
> validation should require that pCNT MUST be equal to the number of
> _contiguous ASx appearances in the path (i.e., no more, no less, and only
> contiguous).
>
> I do wonder if pCNT=0 for transparent route servers introduces the
> opportunity for some sort of downgrade attack of sorts..
>
> -danny
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