From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Wed Oct 13 2004 - 21:36:23 GMT-3
At 12:44 PM -0500 10/13/04, Gene Thorne wrote:
>What is interesting to me about these myths is how they get started in the
>first place and even more perplexing is how they survive. As Brian pointed
>out, in most cases they can be disproved in 5 minutes on the command line.
>Yet the admin distance 0 myth that I cited can be found in such respected
>sources as Doyle and Caslow/Pavlichenko and the ones Brian lists are equally
>widespread. Weird.
My first IOS was 9.0, but, obviously, I don't have early releases to
try. My source on the AD=0 was Tony Li, who claimed to have written
the code and gave me a fairly lengthy explanation on why his code
needed to deal differently with interface versus next-hop code.
I'm inclined to say that it probably did so in some early releases,
but a major code change supplanted it. While I certainly can't say
when even a significant number of major function rewrites were done,
another would be that OSPF was extremely buggy and was rewritten, I
believe by Derek Yeung, around IOS 9.1(4). It may not have been the
earlier programmer's fault - the RFC for Version 1 of OSPF had some
distinct bugs. Apropos of BGP, RFC 1771 has a number of errors in
its state tables, and its route selection rules differ from the
generally accepted industry algorithm in the current Draft 24
(without looking it up, I think that's the most recent)
>
>-----Original Message-----
>From: James [mailto:james@towardex.com]
>Sent: Wednesday, October 13, 2004 12:32 PM
>To: Brian McGahan
>Cc: Gene Thorne; ccielab@groupstudy.com
>Subject: Re: Something New (the myths we believe)
>
>
>On Wed, Oct 13, 2004 at 01:18:19PM -0400, Brian McGahan wrote:
>> Better yet that you can't remove a line out of a numbered access-list
>> without destroying and recreating the entire list. (you can)
>>
>> "no arp frame-relay" stops inverse-arp replies (it doesn't)
>>
>> ppp authentication is a two way process (it's not)
>>
>> Don't start listing these behaviors as "gotchas" though, they
>> are simply technologies that the fundamental behaviors are
>> misunderstood. Most of these "myths" can be eliminated by simply trying
>> the configuration out and seeing how it works firsthand on the command
>> line.
>
>I fully agree with Brian on these. These questions or "gotchas" likewise
>here
>are probably worth memorizing if this was more or less of a written exam
>pin pointing out how much you know about the specifics. But the lab is
>result
>oriented so whatever you type on the router should give you hints as to what
>is going on :)
>
>-J
>
>--
>James Jun TowardEX Technologies,
>Inc.
>Technical Lead Network Design, Consulting, IT
>Outsourcing
>james@towardex.com Boston-based Colocation & Bandwidth
>Services
>cell: 1(978)-394-2867 web: http://www.towardex.com , noc:
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>
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