nanog mailing list archives

Re: ISP customer assignments


From: TJ <trejrco () gmail com>
Date: Tue, 6 Oct 2009 09:45:45 -0400

Actually, I would argue IPv6 is a bit of both classfull and classless.
(Moreso the latter ...)

The protocol itself, /64 "mandate" aside, certainly allows you to place
arbitrary-bit-long prefix lengths - and to aggregate/summarize at any
point.  And /64s do not so much apply in some cases, whether 'permitted' by
spec (/128) or not(/126).  Thus classless.

OTOH, we have policies that define how we will allocate this address space
that do look eerily similar to the Classfull methods we started off with in
IPv4.

I too am always ... hmm, surprised isn't the right word ... when this
angers|scares|confuses people.


Anyway, I enjoy the conversation and hope this helps ...
/TJ


On Tue, Oct 6, 2009 at 9:36 AM, Dan White <dwhite () olp net> wrote:

On 05/10/09 22:28 -0400, Ricky Beam wrote:

On Mon, 05 Oct 2009 17:13:37 -0400, Dan White <dwhite () olp net> wrote:

I don't understand. You're saying you have overlapping class boundaries
in your network?


No.  What I'm saying is IPv6 is supposed to be the new, ground-breaking,
 unimaginably huge *classless* network.  Yet, 2 hours into day one, a
 classful boundary has already been woven into it's DNA.  Saying it's


I would disagree. IPv6 is designed around class boundaries which, in my
understanding, are:

A layer two network gets assigned a /64
A customer gets assigned a /48
An ISP gets assigned a /32 (unless they need more)

 classless because routing logic doesn't care is pure bull.  In order for
 the most basic, fundamental, part (the magic -- holy grail -- address
 autoconfig) to function, the network has to be a minimum of /64.  Even
 when the reason for that limit -- using one's MAC to form a (supposedly)
 unique address without having to consult with anything or fire off a
 single packet -- has long bit the dust; privacy extensions generate
 addresses at random and have to take steps to avoid address collisions, so
continuing to cling to "it has to be 64bits" is infuriating.


IPv6 provides you the opportunity to design your network around your layer
two needs, not limited by restrictive layer 3 subnetting needs.

If your complaint is that all devices in a /64 are going to see IPv6
broadcast/multicast packets from the rest of the devices in that subnet,
then don't assign 2^64 devices to that subnet.

I still don't understand why its infuriating to you, but I can certainly
tell that it is.

--
Dan White
BTC Broadband




-- 
/TJ


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