[Udpcast] "--full-duplex" option in cast-o-matic initrd images

Tom Carpenter tomc at bio.umass.edu
Tue Jan 19 21:53:05 CET 2010


Yes, I did try to use "--full-duplex" as an option for a
'receiver' image. Based my reading of the information on
this page


Networking options

The following networking options should be supplied both
on the sender and the receivers:





I thought it would at least be possible to use "--full-duplex"
as an option (whether it was a good idea or not). But, more of
the story follows.

I booted twenty PCs using a cast-o-matic 'receiver' image, built
without specifying "--full-duplex" (which, I assume uses
"--half-duplex" by default - given information on the same web
page as mentioned above). I used the "--full-duplex" switch to
start the 'sender', but the transfer stopped after roughly 160MB
had been sent. I started a new transfer session; 'receiver' systems
were booted with the same cast-o-matic image, the udpcast sender
was started using the "--half-duplex" switch, and all went
relatively well, aside from a lot of 'not ready' messages from
the receivers on the 'sender' console.

Not to distract from the main question of whether one can specify
half- or full-duplex in cast-o-matic images, I'll also mention that
the 'receiver' PCs don't seem to be auto negotiating half/full
duplex connections with the switch to which they're connected.

Jens Breuer wrote:
> Hello Tom,
> could it be that you specified --full-duplex as a command for the receiver?
> I think it doesn't make sense for the receiver as the part that spits
> the traffic and therefore has to take care of the amount of traffic is
> solely the sender.
> However, at my end the sender happily eats the option whereas the
> receiver errors out.
> Kind regards
> Jens
> On Tue, Jan 19, 2010 at 7:45 PM, Tom Carpenter <tomc at bio.umass.edu> wrote:
>> Is "--half-duplex" the default setting used by cast-o-matic
>> images? I tried adding "--full-duplex" to the "Additional
>> Udpcast command-line parameters" field of the current "Cast-o-matic
>> Stage 2" configuration page, but I get the error "unrecognized
>> option '--full-duplex'". (Note: '--full-duplex' was entered as
>> the first of two command-line parameters.)
>> --
>> Tom Carpenter
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Tom Carpenter
Computer Systems Specialist
Biology 347 Morrill
611 North Pleasant Street
Amherst, MA 01003-9297
phone: 413-577-2311
fax: 413-545-3243
email: tomc at bio.umass.edu

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