v11i020: Idle demon

[Roy M. Silvernail]

p554mve at mpirbn.mpifr-bonn.mpg.de (Michael van Elst) writes:

> In article <2868 at wyse.wyse.com> bob at wyse.UUCP (Bob McGowen x4312 dept208) wri
> >If my understanding of "sliding window" protocols is correct, it IS possible
> >for a download to never (or seldom) have a response.  The basic idea is that
> >if an error has not occured, why spend the overhead to ack the packet.
> 
> No, even with a "sliding window" protocol, acknoledgements are sent.
> The main difference is that you don't wait for an ack to continue
> transmission but wait if a specified number (window size) of acks
> is missing.

I think Bob is thinking of a streaming protocol, such as Zmodem. Zmodem
will leave the return channel completely empty, unless an error is
discovered by the receiving end. Streaming protocols are, of course,
distinct from sliding-window protocols.

Now, the question in my mind (and this really has nothing to do with the
original thread :-) is... which type is SEAlink? I have used it on
several systems, and had varying results. In some cases, it has behaved
as a streamer (with no activity seen on the alternate-channel modem
light), and sometimes it's acted like a sliding-window, if not downright
packetized.
--
    Roy M. Silvernail   | #include <stdio.h>                 | Does virtual
    now available at:   | main(){                            | reality need
 cybrspc!roy at cs.umn.edu |  float x=1;                        | swap space?
(cyberspace... be here!)|  printf("Just my $%.2f.\n",x/50);} | -- me