Re: Transport level multihoming

[Greg Maxwell <gmaxwell@martin.fl.us>]

On Tue, 7 Aug 2001, Brian E Carpenter wrote:

[snip]
> On the other hand we know that major restructuring of applications isn't going
> to happen - that's the real world. So if we have to do work in the transport
> layer, the transport layer is going to have to hide most of it below some
> sort of socket API. I can't see any reason in principle why that API
> would have to expose a bunch of addresses, even if it turns out that
> multi6 requires more than one. A "primary" address per host would be enough
> to expose to the middleware.

If the primary address is functional at connection setup time, then, yes
it could learn the other transports from the remote end. However, what do
you do if the primary is down? The only solutions I can think of either
require the applications to rotate the address passed to the API, or
require the transport to consult DNS (what an ugly kludge and layering
violation THAT would be!).