[THIN] Re: Limits of Latency
- From: "Brian Madden" <brian@xxxxxxxxxxxxxxx>
- To: <thin@xxxxxxxxxxxxx>
- Date: Thu, 25 Sep 2003 19:28:22 -0400
Hi guys..
Just thought I'd "geek up" this conversation a bit.. Regarding the claim
that satellite will never be any better than 600ms due to the distance
involved and the speed of light... I don't think that this is true.
Geostationary satellites (most "one-way" communications satellites, like
stock, news, tv, weather, etc) are 22,223 miles up, which of course makes a
round-trip impossible in anything under 250ms or so. However, the newer
"two-way" communications satellites are in low Earth orbit, only about 200
miles up. In this case you could bounce a signal off a satellite and back
for about the same time that you could make a land-line call. (This is what
Gates' company Teledesic plans to use when it launches its satellite-based
broadband service.)
Brian
Brian Madden
+1 202.302.3657
brian@xxxxxxxxxxxxxxxx
--------
Visit www.brianmadden.com for thin client white papers, books, product
reviews, courseware, and training videos.
-----Original Message-----
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf
Of Jan Broucinek
Sent: Thursday, September 25, 2003 5:01 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: Limits of Latency
It depends on the app. In our experience, If the user is typing, the max
would be about 150-200ms. If it is a click and select check-boxes type app,
then perhaps as high as 400-600ms would be acceptable. Satellite will NEVER
be any better than 600ms due to the distance involved and the speed of
light.
Disconnects are generally caused by lost packets, you need to see how many
retries and packets you lose on the average connection.
----- Original Message -----
From: Christopher_Wilson@xxxxxxxxxxxxxx
To: thin@xxxxxxxxxxxxx
Sent: Thursday, September 25, 2003 4:39 PM
Subject: [THIN] Limits of Latency
Hi, list.
Is there any documentation from Citrix or another source that sets a
bound on how much latency an ICA session will tolerate?
I have a few new locations that have recently been set up our
WAN/Satellite guy to use a DirectWay satellite connection to the internet
then on into Nfuse and my MF 1.8 farm. The problem is that these locations
experience frequent disconnects from ICA sessions to the point of rendering
Citrix unusable. (No problems surfing mind you.) A ping from them to us
returns with a latency of 850-1000ms. The best I remember hearing from
this list and elsewhere, latency beyond 300-400ms degrades performance and
can cause disconnects. Is this accurate? What is the max latency tolerance
by your experience?
Also, I have already tweaked the recommended ICA time-out and TCP
retransmission settings with no results for this problem. Is there any
other tweaking that might help?
Thanks in advance,
Christopher Wilson
Citrix Administrator
BJ Services Network Support
713.895.5681
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