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Re: a radical proposal (Re: protocols that don't meet the need...)
From: Fred Baker <fred () cisco com>
Date: Wed, 15 Feb 2006 15:15:12 -0800


On Feb 15, 2006, at 9:13 AM, Edward B. DREGER wrote:
Of course not. Let SBC and Cox obtain a _joint_ ASN and _joint_ address space. Each provider announces the aggregate co-op space via the joint
ASN as a downstream.

Interesting. This is what has been called metropolitan addressing. I'm certainly not the one who first proposed it, although I have thought about it for a while, dating at least as far back as 2001.

The crux of the concept as several *have* proposed it is that a regional authority - a city, perhaps, or a consortium of ISPs, or in the latest version of the proposal I have seen the country of Korea - gets a prefix, and sets up an arrangement. SOHOs that want to multihome within its territory are able to get small (/48? /56?) prefixes from it, and providers that deliver service in the area may opt in to supporting such SOHO prefixes. If they opt in, they are agreeing to:

 - join a local IXP, which may be a physical switch or
   virtualized by a set of bilateral agreements.
 - outside the region, they advertise the prefix of the
   regional authority
 - within the region, for customers that have gotten such a
   prefix, if they have connectivity to the customer they
   advertise the customer's prefix to the ISPs at the IXP.

Note that the customer is not expected to run BGP or get an AS number, but either the regional authority gets an AS number or each serving ISP is deemed authorized to originate the prefix in its BGP announcements. But if a SOHO has two ISPs, both advertise its prefix within the region, and when a packet is sent to the prefix from wherever, any ISP that is delivering service to the SOHO can legitimately deliver it, and if one gets the packet but is not the servicing ISP, it knows how to hand the packet to the appropriate ISP at the IXP.

This turns the business model of routing on its head. Typically today if Alice is using ISP AliceNet and Bob is using ISP BobNet, Alice hands her packet to AliceNet, AliceNet gets it to BobNet in the cheapest way it can, and BobNet carries it halfway around the world to Bob. Bob's ISP carries the burden of most of the work. But in this model, if AliceNet happens to also provide service in Bob's region, AliceNet might carry the packet to the region and only give it to BobNet for the last 500 feet.

Whenever I have talked about the model with an ISP, I have gotten blasted. Basically, I have been told that

(1) any idea on operations proposed in the IETF is a bad idea because the IETF doesn't listen to operators (2) the ISPs aren't going to be willing to make settlement payments among themselves in accordance with the plan
(3) routing isn't good enough to support it
(4) and in any event, this makes it too easy to change ISPs

In short, "hell no".

So, since nobody in the IETF (according to you) is supporting this model, what I understand from your remark and this thread is that the IETF is not responsive to ideas proposed by operators and doesn't come up with things operators can use, taking as an example that it hasn't told you how to implement metropolitan addressing.

Did I get that right?

I'm not sure how to proceed, given the level of invective I get in any discussion with anyone on the topic.

Note 1: PI addressing for edge networks that can qualify under a sensible set of rules (current ones are inadequate) for an AS number is the preferred way to handle an enterprise of a size r complexity comparable to a small (or large) ISP.

Note 2: Provider-provisioned addresses continue to make sense for folks that don't plan to multihome.


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