Wedge between transport and ULP

[Dave Crocker <dhc@dcrocker.net>]

Folks,

Geoff mention an architectural choice that is not currently
represented by any proposals.  It places a multiaddressing wedge layer
between the transport layer and the applications layer.

Some MAST discussions explored this issue a bit, as did early BEEP
discussions.  For what they are worth, here are some observations:

The wedge fits rather nicely into that realm the OSI folks like to
call 'session layer'.  Things put at that layer tend to need to
replicate control (eg, reliability) mechanisms already done in
transport.  This will be particularly true if the layer is expected to
work across multiple transport associations.

Pekka N. noted the compelling requirement for having transport state
NOT cross machine boundaries.

This suggests that the kind of multiaddressing being discussed here
belongs no higher than the bottom of transport.

An application that wants to exists as a single logical entity, but
live across more than one machine, needs something like a
session-level multiaddressing feature.

d/
--
 Dave Crocker <dcrocker-at-brandenburg-dot-com>
 Brandenburg InternetWorking <www.brandenburg.com>
 Sunnyvale, CA  USA <tel:+1.408.246.8253>