Re: Miscellaneous points

Rik Harris (
Fri, 03 Dec 93 10:05:16 +1100

> The error reports on failures to connect are not very helpful. This is
> partly poor design of the client software and/or lack of diagnostic
> parameters in WINSOCK specifications, and/or the fact that we are in
> early releases, but I think it may also reflect a lack of appropriate
> information at the network level.
> For example, am I getting failures to connect and/or poor transfer rates
> and/or halts because of the link from Salford to the Janet back-bone,
> because of the pipe across the atlantic, or because the server is very
> congested/slow, or because my PC is too slow, or what? I have a
> strongish suspicion it may be the Salford link and/or routers, but there is
> no easy way to find out.
> I have no answer to these sort of problems, but as world-wide access to
> information servers becomes more common, pin-pointing where problems lie
> will become more important. Certainly at present there is no way I would
> want to expose the VC to either MOSAIC or CELLO - too many failures, and
> far, far too slow. Hope it changes soon tho' - the idea is great!

I don't have the experience with SGML or OSI to comment on your other
points, but with this one I would suggest that it is not up to
application software to pinpoint network failures. This should be left
to network management software, as it is a complicated task that
requires detailed knowledge of the network topology, link types,
operating behaviour, protocols, and other factors.

I feel the most you want is distinction between "host does not exist",
"host was not contactable - temporary", "service not available at
host", "network error looking up host name" and possibly "service not
available at host - temporary". Better still: "none of the redundant
hosts were contactable" :-)


Rik Harris -
+61 3 560-3265 (AH & ans.mach)      +61 3 565-3227 (BH)
Department of Robotics and Digital Technology, FCIT, Clayton Campus,
Monash University, Australia