Alex

I recall seeing a study a few years back that showed direct correlation between packet loss and temperature on DEC Gigaswitches; does anyone else remember this?

I posted a correlation between packet loss at temperature at MAE-East (or Boone more precisely) to NANOG a couple of years ago. Executive summary: * A lot, but not all, of the correlation was put down to the fact that high traffic levels cause both high temperatures and high packet loss. This explained by no means all of the problem, as pointing a fan unit at our router, the concentrator etc. reduced packet loss. * Cisco 7010's and CX-FIP cards degraded under excessive temperature (above about 35 degrees C). * MFS (as then)'s FDDI concentrators, and possibly Gigaswitches degraded under similar conditions * Surprise surprise, this didn't explain all packet loss at the MAE. But yes, it did make a *real* difference. -- Alex Bligh GX Networks (formerly Xara Networks)

On Tue, Oct 06, 1998 at 06:47:05PM -0400, Jared Mauch wrote:

c7200-1>sh env all Temperature readings: chassis inlet measured at 16C/60F chassis outlet 1 measured at 20C/68F chassis outlet 2 measured at 23C/73F chassis outlet 3 measured at 29C/84F

I get to sit close enough to this room that the AC leaks into my office. The AC went out two weeks ago, and the inlet temp went up to 100.

This thread is staring to give the term "Internet Weather Report" a _whole_ new meaning. :-) Cheers, -- jra -- Jay R. Ashworth jra@baylink.com Member of the Technical Staff Buy copies of The New Hackers Dictionary. The Suncoast Freenet Give them to all your friends. Tampa Bay, Florida http://www.ccil.org/jargon/ +1 813 790 7592

Unnamed Administration sources reported that Michael Dillon said:

My experience is that electronic/computer type equipment runs best when it is in a cool environment, i.e. too cold for a human in T-shirt to work in for very long. And when the ambient temperature gets above room temp, then

True. And recall that 15C in will be a lot more coming out. But colder always costs more money.

you get too many wierd and unexplainable problems occurring or just plain equipment failure. Sean Donelan is right to worry about condensation and I

I'm less sure. IMHE, anything running will not promote condensation. It will be warmer than ambient. You DO need to be concerned over too LOW a RH -- for the obvious reason.... static hazard. -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433

This was all good with the exception of temp for condensation. Condensation can occur at just about any temp (within reason) that is what Dew Point is. Humidity is Dew point/(room) Temperature. When they match you have humidity of 100% and start to see condensation/fog. Anyway this is from flight school. I have heard different engineers recommend 40% humidity and maybe 67.5 degrees temp. Something about enough humidity to avoid static dischargies etc...?? PS- Anyone know of any colo space in Jacksonville, Fl?? At 4:07 AM -0000 10/7/98, Michael Dillon wrote:

On Tue, 6 Oct 1998, Jay Adelson wrote:

...

Too cold? Are you serious? Man, I just can't win.

Our readouts were reporting 68-71F... Somebody tell me what this needs to be set to for our exchange facilities. They're all pretty insanely big, so this is something to do ONCE. Nows the time, we're deep into engineering HVAC for the first fifteen. Oh, and I'd love to hear humidity suggestions as well.

My experience is that electronic/computer type equipment runs best when it is in a cool environment, i.e. too cold for a human in T-shirt to work in for very long. And when the ambient temperature gets above room temp, then you get too many wierd and unexplainable problems occurring or just plain equipment failure. Sean Donelan is right to worry about condensation and I believe that you should maintain a fixed humidity level in the air in your facilities. Keep the temperature below 18C but not so low as to cause condensation. Get some Compaq engineers to recommend a humidity level and ask your HVAC peopel to keep it constant. In Palo Alto this will probably mean adding humidity in the summer and removing humidity in the winter. In the Northeast you would need to do the reverse.

-- Michael Dillon - E-mail: michael@memra.com Check the website for my Internet World articles - http://www.memra.com

Thank you, David Diaz Chief Technical Officer Netrail, Inc email: davediaz@netrail.net pager: 888-576-1018 office: 888-NETRAIL Colo facilities: Atlanta-NAP, Miami, Arlington, Chicago, San Francisco 888-NETRAIL for further information