Re: [Idr] WGLC on draft-ietf-idr-as-private-reservation-00 concluded, extended to consider ASN range

[Jared Mauch <[e-mail]>]

On Thu, Dec 20, 2012 at 12:50:46PM -0500, Jeff Wheeler wrote:
> On Thu, Dec 20, 2012 at 12:04 PM, Jared Mauch <[e-mail]> wrote:
> >         I think this poses the need to have vendors replace regex
> > with something where you can specify a list or range of the integers
> > you wish to match.
> 
> This already exists in major implementations.  Most of us are so used to
> how regexps work in other environments, we don't realize there is more than
> one way.  For example, on a Juniper box, do this:
> root@Juniper> show route aspath-regex ".* [3000-3999] .*" terse
>  ... matches plenty of routes like you'd hope ...
> 
> Similar thing works on Cisco.  Unfortunately the regexp engines used for
> offline processing (Perl, grep, whatever) are usually not customized for
> dealing with AS_PATH expressions.
> $ perl -wne 'print if / [6000-6999] /;' routes-from-tinet.txt |head -3
> inet.0: 423540 destinations, 1806800 routes (423540 active, 0 holddown, 0
> hidden)
>   5.144.136.0/21          A.B.C.D         0                  3257 22652
> 22652 8304 I
>   18.0.0.0/8              A.B.C.D         90                 3257 174 3 I
> 
> Obviously, the above won't "do what you mean" in Perl.  But with the
> proposed extended Private ASN range 4.2B+, you will be able to match that
> using any common regexp engine.

	Not likely:

RP/0/RSP0/CPU0:r07.dllstx09.us.bb#sh bgp regexp [65000-1024000]
BGP router identifier x.x.x.x, local AS number 65000
BGP generic scan interval 60 secs
BGP table state: Active
Table ID: 0xe0000000   RD version: 70417360
BGP main routing table version 70417360
BGP scan interval 60 secs

Status codes: s suppressed, d damped, h history, * valid, > best
              i - internal, r RIB-failure, S stale
Origin codes: i - IGP, e - EGP, ? - incomplete
   Network            Next Hop            Metric LocPrf Weight Path
*> 1.0.0.0/24         x.x.x.x             0             0 3356 15169 i
* i                   x.x.x.x         4294967294    100      0 1299 15169 i
* i                   x.x.x.x         4294967294    100      0 1299 15169 i
* i                   x.x.x.x         4294967294    100      0 3356 15169 i
* i                   x.x.x.x         4294967294    100      0 3356 15169 i
* i                   x.x.x.x         4294967294    100      0 1299 15169 i
...

This is on modern code built and released in the past 6 months.

	- Jared


-- 
Jared Mauch  | pgp key available via finger from [e-mail]
clue++;      | http://puck.nether.net/~jared/  My statements are only mine.