nanog mailing list archives
Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses)
From: Owen DeLong <owen () delong com>
Date: Sun, 31 Oct 2010 21:25:33 -0700
On Oct 31, 2010, at 7:43 PM, Mark Andrews wrote:
In message <AANLkTimsB6Uj-jpogLg08Q-RZDUB-+C9c5KMzcKTQKmQ () mail gmail com>, Chri stopher Morrow writes:On Sun, Oct 31, 2010 at 2:01 PM, George Bonser <gbonser () seven com> wrote:ula really never should an option... except for a short lived lab, nothing permanent.I have a few candidate networks for it. =A0Mostly networks used for clustering or database access where they are just a flat LAN with no "gateway". =A0No layer 3 gets routed off that subnet and the only things talking on it are directly attached to it.why not just use link-local then?If you had actually every tried to use link-local then you would know why you don't use link-local.
I use link local often for many things. Try again.
eventually you'll have to connect that network with another one, chances of overlap (if the systems support real revenue) are likely too high to want to pay the renumbering costs, so even link-local isn't a 100% win :( globally-unique is really the best option all around.2^40 is 1099511627776. The chances of collision are so low that one really shouldn't worry about it. You are millions of times more likely of dieing from a asteroid 1-in-500,000[1].
There are almost 7,000,000,000 people on the planet. We have not had anywhere near 14,000 people killed by asteroids, I think their calculation is off.
If you merge thousands of ULA and don't consolidate then you start to have a reasonable chance of collision. Even if you do have colliding ULA prefixes you don't necessarially have colliding subnets when merging companies. Just allocate subnet randomly. It's not like 2^16 internal subnets is going to be a major routing problem.
This is, of course, assuming many things: 1. Everyone follows the same random ULA allocation algorithm. 2. The algorithm is not flawed and yields relatively smooth distribution without significant hot-spots. 3. People are not lazy 4. People read instructions Assumption 1 depends on assumptions 3 and 4. Assumption 2 is still relatively unknown as we don't have enough operational experience with it. Assumption 3 is pretty well provably false. Assumption 4 is virtually guaranteed to fail. Since Assumptions 3 and 4 are non-starters, assumption 1 is seriously flawed at best. Owen
Current thread:
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses), (continued)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Leo Bicknell (Oct 21)
- RE: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) George Bonser (Oct 21)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Adrian Chadd (Oct 21)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Valdis . Kletnieks (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Owen DeLong (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Christopher Morrow (Oct 31)
- RE: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) George Bonser (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) Christopher Morrow (Oct 31)
- RE: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) George Bonser (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) Mark Andrews (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) Owen DeLong (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) David Conrad (Oct 31)
- RE: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) George Bonser (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Christopher Morrow (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Matthew Kaufman (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Matthew Petach (Oct 31)
- RE: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 -Unique local addresses) George Bonser (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Owen DeLong (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) David Conrad (Oct 31)
- Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses) Owen DeLong (Oct 31)
- Re: IPv6 fc00::/7 — Unique local addresses Ray Soucy (Oct 21)