RE: Consensus on identifier/locator split?

["Christian Huitema" <huitema@windows.microsoft.com>]

> However, if you want to keep the existing TCP (and I would think that's a
> good idea, if you want to try and keep within the bounds of what's vaguely
> feasible), then I suppose you have a point.

I am not sure that I want to keep the existing TCP, and in fact I wrote a draft back in 1995 explaining how TCP could be rather simply upgraded to make sure that connections can survive address changes. The trick is simple: create an identifier inside TCP, and then associate several addresses/locators to the connection. I actually like the fact that TCP can see and manage "locators", because the transport is one of the best places to maintain short term knowledge about the relative performance of a specific path, and thus arbitrage between the various paths.

The idea of an optional upgrade to TCP is interesting because it allows hosts to "opt in" the new facility. I would expect that many hosts would actually opt out, either because they only use short lived sessions and thus don't care for an exceptional failure, or because their applications know how to manage sessions and patch together multiple connections. Indeed, this is a generic requirement for any identifier scheme: hosts that don't see the point should be able to opt-out and not bear the burden associated with the "layer of indirection."

-- Christian Huitema