[121727] in North American Network Operators' Group
Re: Using /126 for IPv6 router links
daemon@ATHENA.MIT.EDU (Tim Durack)
Mon Jan 25 21:26:44 2010
In-Reply-To: <DBE3E7B5-5A72-45E5-B879-E90240D0826E@delong.com>
Date: Mon, 25 Jan 2010 21:26:13 -0500
From: Tim Durack <tdurack@gmail.com>
To: Owen DeLong <owen@delong.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mon, Jan 25, 2010 at 8:01 PM, Owen DeLong <owen@delong.com> wrote:
>
> 2^128 is a "very big number." However, from a network engineering
> perspective, IPv6 is really only 64bits of network address space. 2^64
> is still a "very big number."
>
> An end-user assignment /48 is really only 2^16 networks. That's not
> very big once you start planning a human-friendly repeatable number
> plan.
>
> An end-user MINIMUM assignment (assignment for a single "site") is
> a /48. =A0(with the possible exception of /56s for residential customers
> that don't ask for a /48).
> I have worked in lots of different enterprises and have yet to see one th=
at
> had more than 65,536 networks in a single site. =A0I'm not saying they do=
n't
> exist, but, I will say that they are extremely rare. =A0Multiple sites ar=
e a
> different
> issue. =A0There are still enough /48s to issue one per site.
Networks per site isn't the issue. /48s per organization is my
concern. Guidelines on assignment size for end-user sites aren't
clear. It comes down to the discretion of ARIN. That's why I like pp
106. It takes some of the guess-work/fudge-factor out of assignments.
> An ISP allocation is /32, which is only 2^16 /48s. Again, not that big.
>
> That's just the starting minimum. =A0Many ISPs have already gotten much l=
arger
> IPv6 allocations.
Understood. Again, the problem for me is medium/large end-user sites
that have to justify an assignment to a RIR that doesn't have clear
guidelines on multiple /48s.
> Once you start planning a practical address plan, IPv6 isn't as big as
> everybody keeps saying...
>
> It's more than big enough for any deployment I've seen so far with plenty
> of room to spare.
> Owen
>
--=20
Tim:>
Sent from Brooklyn, NY, United States
