Re: Multihoming by IP Layer Address Rewriting (MILAR)

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

On Tue, 4 Sep 2001, Ramakrishna Gummadi wrote:

[snip]
> My second complaint, and this applies to SCTP as well, is that we are
> implicitly assuming here that one end can do DNS lookups to learn the
> addresses of the other end---this may be impossible with busy servers.

This is not an issue for SCTP. SCTP learns assoiations from it's peer
directly. The only time DNS plays into it is connection built-up, where
DNS is required in the non-multihomed case as well.

> Also, I don't think it is a good idea to mandate every application to be
> aware of all multi-address details, which SCTP requires. We must remember
> that SCTP was invented primarily for carrying signaling messages (the
> abstract says as much), and one of its co-authors I talked to says he
> thinks that general applications should *not* have to deal with all these
> details.

You can wrap a TCP like api so the application is unaware of any
multihoming issues.

Have you read the SCTP RFC? It's a very clear superset of TCP and every
feature it has is an important feature that current apps are emulating at
higher layers over TCP or UDP (like the use of concurant connections with
HTTP to simulate multiple streams, or the abundance of UDP apps which
impliment their own reliable deliverly (and usually misimpliment
congestion control)).