[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Wedge between transport and ULP
On 3-mrt-04, at 7:12, Dave Crocker wrote:
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.
We've discussed this a while ago (where you on the list yet back
then?). I'm not sure if everyone agreed in the end, but my position was
and is that this can't work in a sane way.
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.
The problem is that you can't know how much data made it to the other
end at any particular moment in time so retiring one TCP session and
continuing over another means you have to resync. For some protocols
(most HTTP, FTP) this can be done with relative ease, but solving the
general case means effectively tunneling TCP over TCP, which makes no