nanog mailing list archives

Re: DSL Network Design Question


From: Mark Foster <blakjak () blakjak net>
Date: Mon, 15 Aug 2005 23:36:55 +1200 (NZST)




On Mon, 15 Aug 2005 abuse () cabal org uk wrote:


Roy Badami <roy () gnomon org uk> wrote:
[...]
Interesting, thanks. TBH, I really don't understand why Cisco have
kept the classful support for this long...

When a friend was doing a CCNA back in 2003-ish, Cisco were still
teaching classful addressing. There was plenty of other misinformation
there. Apparently my home network is impossible to build with such few
IP addresses. (I use proxy ARP to avoid creating unnecessary subnets
of the already too small block I have.)

Meanwhile, RIPE's training sessions rap you on the knuckles for using
terms like "Class C" even though in a world of broken stacks from
Cisco and Microsoft, you pretty much need to know about it anyway.

I recently did the CCNA training courses (Its now broken into two - "INTRO-E" (As the instructor put it.. Intro 'essentials' means fit a 4 day course into 3 days by stripping or abbreviating that which isn't quite as 'essential) and ICND) and IP Classes are still covered.

It was basically a history lesson but it helps newcomers to understand the decision making process behind a lot of the historical network configs and legacy options within IOS. (And how you can theoretically set up an interface without a netmask).

I dont see the harm in retaining the terms and the training for historical perspective. As long as its clearly explained. Most especially for those who dont understand that class c != /24 .

Mark.


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