nanog mailing list archives
Re: Using /126 for IPv6 router links
From: Mark Smith <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org>
Date: Tue, 26 Jan 2010 14:36:57 +1030
On Mon, 25 Jan 2010 15:15:55 -0500 "TJ" <trejrco () gmail com> wrote:
-----Original Message----- From: Tim Durack [mailto:tdurack () gmail com] Sent: Monday, January 25, 2010 14:03 To: TJ Cc: nanog () nanog org Subject: Re: Using /126 for IPv6 router links<<snip>>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 ISP allocation is /32, which is only 2^16 /48s. Again, not that big. Once you start planning a practical address plan, IPv6 isn't as big as everybody keeps saying...I didn't realize "human friendly" was even a nominal design consideration, especially as different humans have different tolerances for defining "friendly" :)
This from people who can probably do decimal to binary conversion and back again for IPv4 subnetting in their head and are proud of it. Surely IPv6 hex to binary and back again can be the new party trick? :-)
I (continue to) maintain that: *) 2^16 is still a pretty good size number, even allowing for aggregation / summarization. *) If you are large enough that this isn't true - you should (have) request(ed) more, naturally - each bit doubles your space ... /TJ
Current thread:
- Re: Using /126 for IPv6 router links, (continued)
- Re: Using /126 for IPv6 router links Richard A Steenbergen (Jan 25)
- RE: Using /126 for IPv6 router links TJ (Jan 25)
- Re: Using /126 for IPv6 router links Tim Durack (Jan 25)
- Re: Using /126 for IPv6 router links Ryan Harden (Jan 25)
- Re: Using /126 for IPv6 router links Tim Durack (Jan 25)
- Re: Using /126 for IPv6 router links Nathan Ward (Jan 25)
- Re: Using /126 for IPv6 router links Tim Durack (Jan 26)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 25)
- RE: Using /126 for IPv6 router links TJ (Jan 25)
- Re: Using /126 for IPv6 router links Kevin Oberman (Jan 25)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 25)
- Re: Using /126 for IPv6 router links Jim Burwell (Jan 25)
- RE: Using /126 for IPv6 router links TJ (Jan 26)
- Re: Using /126 for IPv6 router links Tim Durack (Jan 26)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 26)
- Re: Using /126 for IPv6 router links Christopher Morrow (Jan 26)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 26)
- Re: Using /126 for IPv6 router links Mark Andrews (Jan 26)
- 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)