I was tempted to argue it as well, but for the reason that the original requirement did not state to ONLY filter routes that passed through AS39, but did not originate from it. My regex will satisfy the requirement, it will however have the additional effect of filtering routes that also originated from AS39.
But that's just semantics and I really have better things to do that argue that :) Jason On Wed, Nov 3, 2010 at 12:01 PM, Marko Milivojevic <[email protected]>wrote: > Well, I would argue that your original solution was still correct, as > technically speaking, that route DID pass through AS39 at some point > of its origination in it ;-) > > Neat solution, though! > > -- > Marko Milivojevic - CCIE #18427 > Senior Technical Instructor - IPexpert > > FREE CCIE training: http://bit.ly/vLecture > > Mailto: [email protected] > Telephone: +1.810.326.1444 > Web: http://www.ipexpert.com/ > > On Wed, Nov 3, 2010 at 15:41, J D'Silva <[email protected]> wrote: > > Yes, I suppose that would match anything originating from AS39 as well. > > Let's try this instead then: > > > > _39_.* > > > > So now there must be at least one other AS before AS39 for the rexex to > > filter. > > > > :) > > > > > > > > On Wed, Nov 3, 2010 at 4:42 AM, Jason Maynard <[email protected]> > > wrote: > >> > >> That is correct > >> > >> > >> > >> > >> > >> The list was added for a couple of reasons > >> > >> · make some over analyze the requirements > >> > >> · perhaps create some confusion > >> > >> · add complex scenarios in the future > >> > >> > >> > >> > >> > >> If the list was not provided would this be correct? > >> > >> > >> > >> Create a regular expression that filters routes that pass through AS39 > >> > >> _39_ > >> > >> > >> > >> Could this also match anything that has originated in AS39? > >> > >> > >> > >> > >> > >> Thanks Jason! > >> > >> > >> > >> From: [email protected] > >> [mailto:[email protected]] On Behalf Of J D'Silva > >> Sent: November-02-10 10:10 PM > >> > >> To: OSL Routing and Switching > >> Subject: Re: [OSL | CCIE_RS] Question 161 > >> > >> > >> > >> Hi Jason et al, > >> > >> First time sending to the list. I just recently entered into the > IPexpert > >> world and joined this list sometime last week. I look forward to > >> participating in the conversations. > >> > >> For the regex question at hand, am mistaken in thinking that the > provided > >> list of AS paths is actually irrelevant to the question? What I'm > filtering > >> for I'm going to filter for regardless of what AS_PATH happens to come > my > >> way? > >> > >> At any rate, here's my regexs: > >> > >> Create a regular expression that filters routes that originate in AS321 > >> > >> _321$ > >> > >> Create a regular expression that filters routes that have instances of > >> AS200 in the path > >> > >> _200_ > >> > >> Create a regular expression that filters routes that are learned from > AS10 > >> > >> ^10_ > >> > >> Create a regular expression that filters routes that are locally > >> originated > >> > >> ^$ > >> > >> Create a regular expression that filters all routes from any AS > >> > >> .* > >> > >> Create a regular expression that filters routes that pass through AS39 > >> > >> _39_ > >> > >> Create a regular expression that filters routes that have a number "20" > >> anywhere within the AS number or path > >> > >> 20 > >> > >> Regards, > >> > >> Jason D'Silva > >> > >> > >> On Tue, Nov 2, 2010 at 6:24 PM, Jason Maynard <[email protected] > > > >> wrote: > >> > >> Wondering if everyone had a chance at the questions below before I post > >> the answers > >> > >> > >> > >> If no one responds I will post them tomorrow. > >> > >> > >> > >> > >> > >> From: [email protected] > >> [mailto:[email protected]] On Behalf Of Jason Maynard > >> Sent: October-30-10 3:10 PM > >> To: 'OSL Routing and Switching' > >> Subject: [OSL | CCIE_RS] Question 161 > >> > >> > >> > >> Alot of people seem to struggle with BGP regular expressions so I put > them > >> together the following questions > >> > >> Here are a list of AS paths (I just threw them together so we can > create > >> regular expressions). The AS that you are in is AS1. > >> > >> 100 110 2009 20093 20100 54 321 > >> 100 110 2009 20111 129 22 10 > >> 10 200 19 24 39 4 32 > >> 16 100 888 1339 2 > >> > >> Create a regular expression that filters routes that originate in AS321 > >> Create a regular expression that filters routes that have instances of > >> AS200 in the path > >> Create a regular expression that filters routes that are learned from > AS10 > >> Create a regular expression that filters routes that are locally > >> originated > >> Create a regular expression that filters all routes from any AS > >> Create a regular expression that filters routes that pass through AS39 > >> Create a regular expression that filters routes that have a number "20" > >> anywhere within the AS number or path > >> > >> Regular Expressions and their usage > >> > >> > >> ^ Start of string > >> $ End of string > >> [] Range of characters > >> - Used to specify range ( i.e. [0-9] ) > >> ( ) Logical grouping > >> . Any single character > >> * Zero or more instances > >> + One or more instance > >> ? Zero or one instance > >> _ Comma, open or close brace, open or close parentheses, start or end of > >> string, or space > >> > >> > >> Have fun > >> > >> _______________________________________________ > >> For more information regarding industry leading CCIE Lab training, > please > >> visit www.ipexpert.com > >> > >> > > > > _______________________________________________ > > For more information regarding industry leading CCIE Lab training, please > > visit www.ipexpert.com > > > > >
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