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Re: Multi-6 [WAS: OT - Vint Cerf joins Google]

  • From: Patrick W. Gilmore
  • Date: Sat Sep 10 14:44:41 2005 
On Sep 10, 2005, at 10:17 AM, Joe Abley wrote:


[Perhaps this thread should migrate to Multi6?]
multi6 hasn't existed for some time. The "level-3 shim" approach to multi-homing that was the primary output of multi6 is being discussed in shim6.
Guess I'm behind.  I'll have to subscribe to shim6.
Suppose they not only have no plan but couldn't really put together a plan to support 200 customers? Does this mean Google, or any other content provider, is "unworthy" of globally routeable space?
Yes, according to the current RIR policies. [So the determination of "unworthy" above has been made, in effect, by RIR members.]
And this is why v6 has failed and will continue to fail.

The Internet is no longer an academic experiment. It is not run by the 'best technology'. It is run by the best business results.

Content providers and other large business, without who's funds the Internet would fail, have a right not to be tied to a single provider. And while I admit I am not up-to-date on v6 multi-homing strategies, the ones I have seen are either evil, unworkable or ridiculous, and simply will not fly.


's not as though this line of thinking hasn't been followed many, many times before. The counter-argument goes like this:

1. There is more v6 space than there is v4 space, by virtue of the fact that the address is 96 bits wider.

2. Because there is vastly more v6 space than v4 space, if entitlement to PI space in v6 was opened up the chances are many more people would have v6 PI space than currently have v4 PI space.
This assumption has more holes in it than swiss cheese.
3. Every PI assignment/allocation takes up a routing slot in every router in the DFZ.

4. Given 2 and 3, there is potential for the amount of state in the DFZ to exceed the capabilities of the network to hold and process it (e.g. enormous RIBs, soaring processor requirements for dealing with updates, etc).
Ignoring the problems with #2, what is made of the idea that each AS might only have a single block, since blocks are so much larger? (And lots of other questions I'm sure you guys have already covered which are probably not on-topic for NANOG.)


It's possible that the number of PI assignments might not be that high, and the scaling properties in practice might not be so bad. However, you only get to find this out after you've opened the floodgates, and if it turns out that it doesn't scale, it's hard to push the water back into the reservoir.

The goal in shim6 is to find a mechanism which provides all the functional benefits of multi-homing without holding all the state in DFZ routers.
Perhaps the goal ... was chosen poorly?
There seems to be some ongoing perception that various protocol/ research organisations have no idea about the value of multi-homing for enterprises in the real network, and hence ignore it. While that might have once been the case (I certainly remember thinking so around 1997 whilst shouting on the ipng list), I don't believe it's the case today.
That is _absolutely_ the impression I get from speaking to v6 supporters today. The profess otherwise, but the solutions and technologies they suggest disprove their protestations.

Guess I better get over to shim6 and see what I'm missing out on.

--
TTFN,
patrick