But anyway, I was thinking of polling intervals of around 30 seconds. =
At that
rate, maintaining a connection for the lifetime of the job is probably =
cheaper
than tearing down and re-establishing a connection for each poll. HTTP=
servers
are free to close connections any time, so if the server is running low=
on
memory it can close idle connections at will. If the server has the re=
sources
to keep the connection open, then the client shouldn't close it unless =
the
client will not be using the server again for at least a minute, since =
closing
and then reopening adds computational overhead to the server, adds roun=
d trip
delays, results in more network traffic from overhead (SYN, ACK, FIN) t=
han
payload data, and consumes server resources with closed connections in
TIME_WAIT.
References:
HTTP Connection Management:
ftp://ietf.org/internet-drafts/draft-ietf-http-connection-00.txt
The Case for Persistent-Connection HTTP:
http://www.research.digital.com/wrl/techreports/abstracts/95.4.html
-Carl
ipp-owner@pwg.org on 02/05/98 01:10:31 PM
Please respond to ipp-owner@pwg.org @ internet
To: ipp@pwg.org @ internet
cc:
Subject: Re: IPP> Notifications
> Anyway, polling might not be elegant, but I think it can do the job. =
With
> HTTP/1.1, the client will be polling over a persistant connection,
>
> <RKD> So you assume that we would keep a connection open until
> <RKD> a print job is completed and a notification provided? I
> <RKD> don't know if I'd agree that this is a good idea.
I agree with Roger. Maintaining a connection for the lifetime
of the job will not scale very well in large environments.
Maintaining a constant connection might be ok for the "Internet fax
printer" scenario, but it just won't fly in the enterprise.
...jay
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