nanog mailing list archives
Re: IPv6 fc00::/7 — Unique local addresses
From: Matthew Kaufman <matthew () matthew at>
Date: Wed, 20 Oct 2010 19:47:23 -0700
On 10/20/2010 7:22 PM, Mark Andrews wrote:
Too bad that support didn't come first, or all the issues with address allocation and routing table size being discussed elsewhere wouldn't be a problem for operators.In message<4CBF9B7A.1000500 () matthew at>, Matthew Kaufman writes:On 10/20/2010 6:20 PM, Mark Smith wrote:To make it clear, as it seems to be quite misunderstood, you'd have both ULA and global addressing in your network.Right. Just like to multihome with IPv6 you would have both PA addresses from provider #1 and PA addresses from provider #2 in your network. Only nobody wants to do that either.Only because there isn't good support for it yet.
ULA + PA can have the same problems, especially if your ULA is inter-organization ULA, which was one of the cases under discussion.ULA + PA actually works today. The IP stack can do the address selection without worrying about reachability. The chances of the ULA being unreachable and the PA being reachable between two nodes in the same ULA prefix are negligable. If I'm talking to a ULA address I'll use my ULA address. If I'm talking to a non-ULA address I'll use my PA addresses. PA + PA is a problem because you need to worry about source address selection and that is driven by reachability. You also need to worry about egress points due to source address filtering. etc.
Matthew Kaufman
Current thread:
- Re: IPv6 fc00::/7 — Unique local addresses, (continued)
- Re: IPv6 fc00::/7 — Unique local addresses Mark Smith (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses James Hess (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Mark Smith (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Matthew Kaufman (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Mark Smith (Oct 20)
- RE: IPv6 fc00::/7 — Unique local addresses George Bonser (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Mark Smith (Oct 20)
- RE: IPv6 fc00::/7 — Unique local addresses George Bonser (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Matthew Kaufman (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Mark Andrews (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Matthew Kaufman (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Mark Andrews (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Mark Smith (Oct 20)
- Re: IPv6 fc00::/7 — Unique local addresses Owen DeLong (Oct 21)
- Re: IPv6 fc00::/7 — Unique local addresses Matthew Kaufman (Oct 21)
- Re: IPv6 fc00::/7 ??? Unique local addresses Steve Meuse (Oct 21)
- Why ULA: low collision chance (Was: IPv6 fc00::/7 — Unique local addresses) Jeroen Massar (Oct 21)