Addressing plan exercise for our IPv6 course

Thu Jul 22 02:10:36 UTC 2010

On Wed, 2010-07-21 at 18:57 +0200, Alex Band wrote:
> We've been working on an exercise for the IPv6 training course
> [...]
> how to subdivide prefixes over their network and how to write an
> addressing plan.
> Here's a PDF with the exercise (two pages A3): http://bit.ly/c7jZRJ
> I'm curious to hear if you think it's clear and useful.

I think it is very clear, and very useful. Areas that might be improved:

1: It does not mention technical or management policy considerations.
Those need to be clear before you can start divvying up your allocation.
A technical policy point, for example, might be whether you are going to
stick to /64 subnets throughout, or accept /126 on point to point links.
A management policy might be to always provide for some level of
expansion. I think the exercise would be better if it were prefaced by a
phase where students (or the class as a group) work out the policies
that will apply.

2: It is a very detailed, specific example using real numbers. The
exercise demands a lot of technical precision that doesn't relate to the
intellectual problem at hand. Technical precision is good, but it might
be better sought in a separate exercise. You might get more out of
students by getting them to think about what they would do in more
general terms - i.e., the sizes and groupings of subnets rather than
what specific subnets they would use. This would also help emphasis the
point that it's not addresses that matter in IPv6 - it's subnets.

3: "There is no significant growth". Part of any network design should
be to mitigate the unexpected. So IMHO students should be encouraged to,
for example, duplicate addressing structures across POPs as much as is
feasible, build in reserves for expansion and contraction, and use ULA
addressing for internal networking components to reduce the pain if
networks are split or merged.

Regards, K.

-- 
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Karl Auer (kauer at biplane.com.au)                   +61-2-64957160 (h)
http://www.biplane.com.au/~kauer/                  +61-428-957160 (mob)

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