nanog mailing list archives
Re: Using /126 for IPv6 router links
From: Tim Durack <tdurack () gmail com>
Date: Mon, 25 Jan 2010 21:26:13 -0500
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. (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 that had more than 65,536 networks in a single site. I'm not saying they don't exist, but, I will say that they are extremely rare. Multiple sites are a different issue. There 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. Many ISPs have already gotten much larger 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
-- Tim:> Sent from Brooklyn, NY, United States
Current thread:
- Re: Using /126 for IPv6 router links, (continued)
- Re: Using /126 for IPv6 router links Randy Bush (Jan 27)
- Re: Using /126 for IPv6 router links Owen DeLong (Jan 27)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 27)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 27)
- Message not available
- Re: Using /126 for IPv6 router links Randy Bush (Jan 27)
- Re: Using /126 for IPv6 router links Mark Andrews (Jan 27)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 27)
- Re: Using /126 for IPv6 router links Nathan Ward (Jan 27)
- Re: Using /126 for IPv6 router links Larry Sheldon (Jan 27)
- Re: Using /126 for IPv6 router links Owen DeLong (Jan 25)
- Re: Using /126 for IPv6 router links Tim Durack (Jan 25)
- Re: Using /126 for IPv6 router links Christopher Morrow (Jan 25)
- Re: Using /126 for IPv6 router links Tim Durack (Jan 26)
- Re: Using /126 for IPv6 router links Seth Mattinen (Jan 26)
- Re: Using /126 for IPv6 router links Christopher Morrow (Jan 26)
- Re: Using /126 for IPv6 router links Owen DeLong (Jan 26)
- Re: Using /126 for IPv6 router links Christopher Morrow (Jan 25)
- RE: Using /126 for IPv6 router links TJ (Jan 26)
- Re: Using /126 for IPv6 router links Nick Hilliard (Jan 26)
- Re: Using /126 for IPv6 router links Owen DeLong (Jan 25)
- Re: Using /126 for IPv6 router links Larry Sheldon (Jan 25)