v6 subnet size for DSL & leased line customers

Joe Greco jgreco at ns.sol.net
Sun Dec 23 23:26:12 UTC 2007

> If operational simplicity of fixed length node addressing is a
> technical reason, then I think it is a compelling one. If you've ever
> done any reasonable amount of work with Novell's IPX (or other fixed
> length node addressing layer 3 protocols (mainly all of them except
> IPv4!)) you'll know what I mean.
> I think Ethernet is also another example of the benefits of
> spending/"wasting" address space on operational convenience - who needs
> 46/47 bits for unicast addressing on a single layer 2 network!? If I
> recall correctly from bits and pieces I've read about early Ethernet,
> the very first versions of Ethernet only had 16 bit node addressing.
> They then decided to spend/"waste" bits on addressing to get
> operational convenience - "plug and play" layer 2 networking.

The difference is that it doesn't "cost" anything.  There are no RIR fees,
there is no justification.  You don't pay for, or have to justify, your 
Ethernet MAC addresses.

With IPv6, there are certain pressures being placed on ISP's not to be
completely wasteful.

This will compel ISP's to at least consider the issues, and it will most
likely force users to buy into technologies that allow them to do what they
want.  And inside a /64, you have sufficient space that there's probably
nothing you can't do.  :-)

... JG
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

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