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Re: IPv6 fragmentation and IPv6 header parsing

To: Ralf Baechle <ralf@xxxxxxxxxxx>
Subject: Re: IPv6 fragmentation and IPv6 header parsing
From: Matti Aarnio <matti.aarnio@xxxxxxxxxxx>
Date: Thu, 2 Aug 2001 20:34:29 +0300
Cc: Imran Patel <ipatel@xxxxxxxxxxxxxx>, Brad Chapman <kakadu@xxxxxxxxxxxxx>, Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>, netdev@xxxxxxxxxxx
In-reply-to: <20010802133839.C24305@xxxxxxxxxxxxxxxx>; from ralf@xxxxxxxxxxx on Thu, Aug 02, 2001 at 01:38:39PM +0200
References: <200107312208.CAA00330@xxxxxxxxxxxxxx> <003801c11b15$4fb35320$4d61a4ca@zombie> <20010802133839.C24305@xxxxxxxxxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx
On Thu, Aug 02, 2001 at 01:38:39PM +0200, Ralf Baechle wrote:
> On Thu, Aug 02, 2001 at 11:07:58AM +0530, Imran Patel wrote:
> > On the contrary, it might be useful for transition from IPv4 to IPv6 ;-)
> > IPv6 connection tracking is useful for NAT-PT. However, other options on top
> > of IPv6 conntrack like masquerading, v6-v6 NAT, etc look useless and silly.
> 
> You forget real world.  I bet ISPs will continue to only give a single IPv6
> address to their dialup customers, so masquerading will stay ...

   But aren't the addressing specs saying that we must consider
   each and every router port (which I take dialup servers to be)
   as  /64 ?

   Now to think of that... 64k lines of modem pools can thus be
   fitted into a /48,  which is what addressing specs say (as I
   faintly recall without checking it) that ISPs should issue for
   each leased-line customer / corporation.

   Once upon a time I considered allocating something like /120
   for each dialup user, but things aren't completely defined
   in the IETF for dialups of IPv6.

   At least Itojun has written a draft for it:

        draft-itojun-ipv6-dialup-requirement-01.txt

     -----------

3.1.  Address space

It is desired to assign /48 address space, regardless from usage pattern
or size of the downstream site.  If it is apparent that the customers
will have a single subnet behind them, /64 allocation may be desirable.
It is to make future renumbering in downstream site easier on ISP
change.  /128 assignment MUST NOT be made, as it will promote IPv6-to-
IPv6 NAT.

The item is highly related to RIR address allocation recommendations.

     -----------



   The mobile (3GPP) folks will have to consider things more like
   that  /120 instead of  /64, because they have so bloody many
   customers, but if they go to /128, that is pure stupidity.
   (Although, a /40 should be enough for each mobile operator in
    Finland for a long time to come if they issue out static /64
    addresses.  Issuing dynamic addresses saves the day, of course.)

>   Ralf

/Matti Aarnio

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