Re: Transport level multihoming

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

On Tue, 3 Apr 2001, Joe Abley wrote:

> On Tue, Apr 03, 2001 at 01:03:48PM -0400, Greg Maxwell wrote:
> > > The requirement that no changes should be required in applications
> > > in order to multi-home does not feature in our draft. Do you think
> > > it should be there?
> > > 
> > > If so, why?
[snip]
> > the above, why should backwards application compatibility for multihoming
> > be a factor at all?
> 
> So, is that a "no"? It looks like a "no" but I thought I'd check :)

Too busy with the "why" to answer the question. :)

No, I don't believe it should be.

The reasoning stated more clearly: Application compatibility for
multihoming in IPv6 is not important because IPv6 itself breaks
application compatability to a similar extent as multihoming changes
would. IPv6 supporting application can be deployed with multihoming
support thus making the marginal cost of multihoming support zero.

Additionaly, multihoming changes would likely signifantly lower backwards
compatibility cost then IPv6 itself (for full IPv4 backwards compatiblity
you practically have to run a second overlay network) while special
multihoming support would only have an impact in some additional
application code and the loss of multihoming for legacy applications (good
reason to upgrade!).