Are you having much luck with QCharts, Chris, with the server problems? I switched to eSignal, which runs smoothly, without slowdowns or interruptions, every day. The quote sheets and charts are very similar to those in QCharts.
One has (or had) to find all sorts of workarounds with QCharts' server problems. It was interesting to read on the QCharts list that one oft-proposed solution -- pinging -- wasn't all that effective.
Message: 1
Date: Thu, 25 Jan 2001 10:29:18 -0000
From: "Eric Scott Hunsader" <eric@hunsader.com>
Subject: Re: ESH.... cc.ini updating
Dear Larry,
QCharts doesn't manage any of the connectivity (other than telling
the DLL to connect). QCharts is really no different from other 3rd
party applications (at least while I was there).
Periodically, the dll will "ping" the other servers and sort the list
in the cc.ini based on which server is "closer". Servers can (and do)
impose "ping penalties" to discourage traffic if they are busy.
You can override this behavior by setting the AutoUpdateServerList to
false, but I don't recommend it unless you are experienced in the
nuances of TCP connections on the internet. I'll expand on that.. if
you are noticing the behavior of surges of data and periods of
inactivity, you are likely experiencing IP router congestion in your
path to Continuum. Ping Plotter can *sometimes* point out congestion,
but you need to be aware that it's not nearly as accurate at locating
congestion as most people believe. Pings are sent out as ICMP
messages which are marked differently from TCP messages -- so they
are treated much differently by IP routers along the path (and as the
internet matures, this is happening more and more often).
The other problem with ping programs is that they only tell you the
state of the path at a particular moment in time. You really need to
monitor for long periods of time to ascertain whether or not your
path gets congested. Ping might show things are clear, when in
reality, TCP packets are being discarded by a saturated router in the
path. The congested IP router may be happily responding to Ping
Plotter's ICMP messages because it can process those types of
messages much quicker, while at the same time, silently discarding
the TCP packets from Continuum (to route a TCP message, the router
has to do a little work and figure out where to send it, to route an
ICMP message, the router merely reflects it back to the sender).
You can detect saturation behavior with QCharts by looking for surges
of data updates. What is happening is a TCP packet got dropped by a
router and is being retranmitted. When things get retransmitted, the
link catches up and you see a "blast" of data appear. There is very
little that applications can do about this other than switch servers
and hopefully find one on a better path. If the congested router is
located at your ISP -- then there is nothing anyone (other than the
ISP) can do to fix the problem.
Hope that helps.
Regards,
Eric |
