<[EMAIL PROTECTED]> wrote in message news:42921@palm-dev-forum...
> I was just using beaming as a benchmark. I set Prefs/communication/IR to
PC
> to 115kbs, beamed a file, timed it, and the resulting transfer speed was
> actually 57kbs of data sent.
Makes sense. You're setting the speed used for IR HotSync. This uses the
IrCOMM protocol, but I doubt this setting affects other users of IrCOMM. It
certainly doesn't affect other IrDA protocols, including IrOBEX which is
used for beaming.
I don't think there's any way to control the speed of IrOBEX. There's a way
to control the speed of IrCOMM using the New Serial Manager, but I don't
know what it is. It's probably the same as for "real" serial connections.
The speed of the IrLAP, IrLMP, and TinyTP protocols is negotiated during the
connection. Each side specifies which speeds it supports. You specify the
maximum speed that you support by passing an enum (such as
irOpenOptSpeed115200 defined in IrLib.h) to IrOpen().
> My questions is how much does each layer of IR protocol decrease the
speed?
> What do I gain by using Tiny TP, LMP, or LAP?
These protocols form a "stack", with each one being implemented in terms of
the one below it. So the higher-level protocols introduce more overhead. In
order from top to bottom, we have:
IrCOMM | IrOBEX
TinyTP (IrTTP)
IrLMP
IrLAP
I don't have numbers though. I'm sure it depends on how much data you send
at a time. I've heard that IrCOMM is quite slow. AFAIK, all the others are
reasonably fast. I've heard that switching directions is particularly slow,
so try to send bursts of data in one direction.
--
Danny Epstein
OS Engineer, Palm Inc.
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