About address allocating (IPv6, variable length SLA/prefixes?)

[Wilfried Woeber, UniVie/ACOnet]

  Hi Francis et.al.,
  
  as I said a couple of days ago in Budapest, I would like to see an
  explanation and/or review from the routing point of view.

  Judging from my (limited) knowledge about IPv6, going for a variable
  length SLA field would either leave us with "wasted" address space (as
  the network next door would be a different site and thus should have a
  different NLA field anyway), or we would end up with a variable length
  network prefix length (much like in the v4 environment), effectively
  extending the NLA field into the SLA field.
 
  Doing so would probably require a cross-check against existing
  IPv6-aware IGPs. That is where I would like to see input from the
  routing camp(s).
  
  Regards,
  Wilfried.
______________________________________________________________________
From: Francis Dupont <Francis.Dupont@enst-bretagne.fr>
To: itojun@iijlab.net
CC: Haisang Wu <hswu@ns.6test.edu.cn>, 6bone@ISI.EDU
Subject: Re: About address allocating
Date: Sat, 20 May 2000 15:17:57 +0200

 In your previous mail you wrote:

   
   >   hi, I have the following questions about address allocating:
   >     I know SLA is /48, and interface ID should be 64 bits, 
   >   does it mean that the smallest unit when allocating address is /48?
   >   In other words, if I allocate a /48 to a large university, could I 
   >   allocate a /48 to four middle schools, thus each middle school gets
   >   an block less than /48, which is /50. Is this plan reasonable?
   >
   >=> we'd like to get a /48, ISPs would like to give a /64 to us:
   > - /48 seems a bit too large for a default allocation size
   > - /64 is unusable when you need subneting
   >then the current idea, as presented yesterday here in Budapest
   >at the RIPE meeting, is to introduce "small site" which get
   >/56 (on byte boundary, large enough for up to 256 subnetworks or
   >a few levels of hierarchy).
   >Then /56 will become the default allocation size in RIR
   >allocation & assignment document.
   
   	I'm not sure if introducing "small sites" is a good thing...
   	when we switch ISP and they force me to switch from /48 to /56,
   	renumber becomes very hard.
   
=> the idea is that it is easier for someone which needs a /48
to deal with its ISP than for a common customer to fight in order to
get a /48 because /64 is not enough: this is a compromise for common
customers (ie you at home, IIJlab is strong enough to get a /x with x <= 48).
I believe it is a good compromise...

Regards

Francis.Dupont@enst-bretagne.fr
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  Wilfried Woeber                 : e-mail: Woeber@CC.UniVie.ac.at
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