RE: Reg Experts!

Thanks!

You're right, 1\ is wrong. It should be this listing. ^([0-9]+)(_\1)*$ The \1 means to repeat the first group.

As for the question mark one

My understanding is ^([0-9]+)?$

[0-9]+ means it can repeat one or more characters. = Any AS
Grouping it with ( )? Means it can repeat zero or one times.

This one I tested in lab and works, just was confused with all that back slash.

Thanks again,
JB

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Jack Router
Sent: Wednesday, June 09, 2010 1:44 PM
To: 'Jack Router'; ccielab_at_groupstudy.com
Subject: RE: Reg Experts!

Expression "(_1\)" is wrong because \ tells to match following character
which is ")". The second bracket is not a closing bracket but a character to
match, leaving expression incomplete, without closing bracket.

Disclaimer:
I reserve the right to be wrong.

-----Original Message-----
From: Jack Router [mailto:pan.router_at_gmail.com]
Sent: 9-Jun-10 14:28
To: ccielab_at_groupstudy.com
Subject: RE: Reg Experts!

1.
^200_300$ - as path is "200 300"
_200_300$ - as path must end with "200 300", for example "111 222 333 200
300"

2.
^([0-9]+)?$ - Does it make sense ? Just the part ([0-9]+) tells me that AS
must be 10 digit long. There is no such AS.
^([0-9]+)(_1\)*$ - Same as above and the expression looks invalid if tested
on a public router:

route-views.optus.net.au>sh ip bgp regexp ^([0-9]+)(_1\)*$

% unmatched ()
% Invalid regular expression

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
Poplawski, James
Sent: 9-Jun-10 13:19
To: 'ccielab_at_groupstudy.com'
Subject: Reg Experts!

Just going through Narbik's Regular Expression listings and using INE
"Understanding BGP Regular Expressions" for reference.

I have some questions if anyone can explain in people terms. Here goes.

What's the difference between?
       deny ^200_300$
       deny _200_300$

       ^([0-9]+)?$
       ^([0-9]+)(_1\)*$

       _100+
       ^([0-9]+)(_\1)*$

In regards to ^([0-9]+)(_\1)*$ why is the number 1 chosen? Why have it at
all? Why not have a 0 or a 2 in there? I'm still looking through
documentation on \.

Any help is appreciated, thanks!
JB

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Received on Wed Jun 09 2010 - 14:06:18 ART