Dag Brattli wrote:
>
> Itai Nahshon <[EMAIL PROTECTED]> writes:
>
> > Transferring files using ftp worked fine (most of the times). Transfer rate
> > was 7.5-8 Kb/sec. That's OK for a 115.2 KB connection (I assume IrLAN
> > has more overhead than PPP)
>
> Well, that depends. PPP uses 8 bytes of header/trailer and IrLAN uses 14
> bytes (Ethernet) which you might notice at low speeds. However if you run
> at 4Mbps then the HDLC, CRC of PPP will give you _much_ worse service than
> IrLAN. I can get over 340Kbytes/s using IrLAN, but PPP over IrCOMM has
> never got itself over 250 Kbytes/s.
I'm trying to compare IrNET to PPP directly over a serial lin (physical
connection) at the same baud rate. I agree it's not a "fair" comparison...
>
> > but I would expect alittle more if compression
> > is used. I had irda_deflate.o loaded from the beginning but I did not see
> > a use count on it. Des compression need a special tweak to be effective?
>
> Compression should work for 2.2 kernels, but not for 2.3 kernels. You need
> to load the compression module on both machines before trying to connect.
>
> Compression is not a part of the IrDA standard and is in fact on its way
> out of the Linux IrLAP layer. I might add it above the TTP layer, but time
> will tell.
>
> > Ping time was very inconsistent. Between 90 and 600 msec. That's not
> > a problem for file transfer but very bad if I want to telnet or to start an
> > X connection. Is there a place for tuning the packet scheduling to
> > minimize the ping time?
>
> Have you enabled "Fast RR's" when you configured your kernel? I get less
> than 50 ms using SIR speeds.
>
> > Trying more than one activity on the connection did not work that well.
> > Ping while transferring a file got errors (lots of messages about wrong
> > data in byte #8). I also tried to run 2 ftp sessions (each computer gets
> > a large file from the other computer). The IrLAN connection went down after
> > some unexpected errors (happened after about 2MB).
>
> Thats strange. I can run IrLAN for weeks without any problems. Could you
> mail me your exact setup? I need to know kernel version, kernel config, did
> you run Linux on both machines etc.
Both machines run Linux-2.3.18ac9irda1. I recompiled the kernel with Fast RR
enabled and things are much better. Strange that it is not symetric (!!).
Kernel IrDA options are the same but other things (I suspect APM) are not.
Ping times now average 160 ms piging from the laptop to the desktop and
100 ms the other way. Now, when I increase the value in
/proc/sys/net/irda/fast_poll_increase (default 50) on the desktop machine, I start
getting ping errors "wrong data byte #8 should be 0xXX but was 0xYY" on the laptop.
I do not get these errors when increasing the value on the laptop and
pinging from the desktop. Maybe all the problems that I have experienced are simple
timeouts that could be adjusted?
Itai
>
> -- Dag
>
> --
> / Dag Brattli | The Linux-IrDA Project /
> // University of Tromsoe, Norway | Infrared communication for Linux //
> /// http://www.cs.uit.no/~dagb | http://www.cs.uit.no/linux-irda/ ///
>
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--
Itai Nahshon [EMAIL PROTECTED]
Also [EMAIL PROTECTED]
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