nanog mailing list archives
Re: Using /126 for IPv6 router links
From: Owen DeLong <owen () delong com>
Date: Mon, 25 Jan 2010 17:01:29 -0800
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.
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.
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
Current thread:
- Re: Using /126 for IPv6 router links, (continued)
- 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)
- 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)