nanog mailing list archives
Re: Policy Statement on Address Space Allocations
From: Curtis Villamizar <curtis () ans net>
Date: Wed, 31 Jan 1996 13:38:43 -0500
In message <9601301900.AA16710 () maze MIT EDU>, marthag () MIT EDU writes:
Here's my suggestion. If you put that multi-homed customer in a larger aggregate (have them pick one of the providers and allocate from their address space) all of the providers must then announce the more specific. Some providers will block the longer prefix. The longer prefix will be preferred and traffic will avoid going through those providers that block it. This might cause longer or suboptimal routing for the longer prefix. Providers everywhere will have either the shorter prefix or both, so full connectivity would exist. If the multi-homing is sufficiently localized within the topology (for example, multiple providers in the same region or country) there might be a chance to draw an aggregation boundary around the whole thing and block the longer prefix outside of that locality and avoid the possibility of suboptimal routing due to long prefix filtering. CurtisExcept that if the shorter prefixed route goes down, half the world will not be able to see any route to site, which sort of defeats the purpose of being multi-homed. Martha Greenberg marthag () mit edu
True. What this protects against is losing the tail circuit to either provider. If the primary provider is single homed to the rest of the world or is otherwise unreliable and their entire aggregate disappears from global routing, then you lose connectivity to providers blocking long prefixes. I think that is the best you can do as long as some providers plan to block your long prefix. Pick a very stable aggregate to cover your long prefix. Curtis
Current thread:
- Re: Policy Statement on Address Space Allocations, (continued)
- Re: Policy Statement on Address Space Allocations Andrew Partan (Jan 30)
- Re: Policy Statement on Address Space Allocations Michael Dillon (Jan 30)
- Re: Policy Statement on Address Space Allocations Alan Barrett (Jan 31)
- Re: Policy Statement on Address Space Allocations Yakov Rekhter (Jan 30)
- Re: Policy Statement on Address Space Allocations Geoff Huston (Jan 30)
- Re: Policy Statement on Address Space Allocations Robert A. Rosenberg (Jan 29)
- Re: Policy Statement on Address Space Allocations Alex.Bligh (Jan 30)
- Re: Policy Statement on Address Space Allocations Iljitsch van Beijnum (Jan 30)
- Re: Policy Statement on Address Space Allocations Dave Siegel (Jan 30)
- Re: Policy Statement on Address Space Allocations marthag (Jan 30)
- Re: Policy Statement on Address Space Allocations Curtis Villamizar (Jan 31)
- Re: Policy Statement on Address Space Allocations Scott Huddle (Jan 30)
- Re: Policy Statement on Address Space Allocations Geoff Huston (Jan 30)
- Re: Policy Statement on Address Space Allocations Iljitsch van Beijnum (Jan 30)
- Re: Policy Statement on Address Space Allocations Brett D. Watson (Jan 30)
- Re: Policy Statement on Address Space Allocations Vadim Antonov (Jan 30)
- Re: Policy Statement on Address Space Allocations Robert A. Rosenberg (Jan 31)
- Re: Policy Statement on Address Space Allocations Robert A. Rosenberg (Jan 31)
- Re: Policy Statement on Address Space Allocations Christian Huitema (Jan 31)
- Re: Policy Statement on Address Space Allocations Yakov Rekhter (Jan 31)
- Re: Policy Statement on Address Space Allocations George Herbert (Jan 31)
- Re: Policy Statement on Address Space Allocations Yakov Rekhter (Jan 31)