The rock has turned over for a moment and I have crawled out. It is good to see the sunlight from time to time.
Those who know me know my life has gotten away from networking and that sort of thing, and I am fully immersed in datacenter design and construction for IT type loads (blades, compute, disk, etc.). However, I am presented with the challenge of having to deal with some optical gear (Ciena stuff, mainly). My question: have the optical folks woken up and made things cool front to back, or are they still in to the bottom to top world?
Comments and lambasting: go
Thanks!
Alex Rubenstein <alex@corp.nac.net> writes:
My question: have the
optical folks woken up and made things cool front to back, or are
they still in to the bottom to top world?
Unless something's changed, AT&T NEDS still reads "Systems exhausting
more than 50 W/sq ft must exhaust the air vertically.".
You can always put baffles above and beneath to channel the air
into/from your hot/cold aisles. Makes it nice to be able to have the
connectors on whichever side is convenient.
-r
or you know, rotate the equipment in the rack...
Alex,
Remember the Ascend MAX TNT and the sideways left-right airflow? The
preferred method of deployment was three tall in a two post rack, mid
mount. At the end of about the 10th row you could literally cook a steak
and subsequently burn out the gear beyond that point. We fashioned our own
dividers to keep airflow from forming a jet down the line via ACE hardware
angle brackets that we cored to EIA screw spec and sheets of 1/4"
plexiglass mounted between. Cheap as heck and worked like a champ. Airflow
redirection can work.
Building a plenum for this could be relatively cheap and easy with a small
amount of sheet metal and a pair of tin sheers. Don't forget the warranty;
I'd check for anything explicit around airflow.
Let us know what you do, love the innovation.
Best,
-M<
Once upon a time, Martin Hannigan <hannigan@gmail.com> said:
Remember the Ascend MAX TNT and the sideways left-right airflow? The
preferred method of deployment was three tall in a two post rack, mid
mount.
Shoot, only three tall? With the original dual-slot modem cards and
separate HDLC cards, it took three chassis just to handle one DS3.
Throw another couple in there to start the next DS3 and get cooking! Of
course, they came in the crate with that little piece of sheet metal air
deflector that I don't think I ever saw how to mount.
We had something (Redback SMS-500?) that also cooled side-to-side, but
in the opposite direction; had to make sure it was "upwind" of the TNTs.
...
Indeed I do. I see you've heard the story of PSINet melting components as well.
We used USR(3Com) TotalControl hardware: vertical venting. The chimney effect was impressive. (65F in, 100+ -- sometimes 120 -- out.)
(I've complained for over a decade about $DAYJOB building crap with side-to-side venting.)
--Ricky
We used Livingston Portmaster 3 back in the day. Front to back
ventilation, ran cool as a cucumber, plug it in and it just worked.
Awesome gear until Lucent bought the company to kill the product in
favor of their Ascend TNT space heaters.
I remember that there was an Ascend DSLAM built on the same chassis and it was collocated by someone into Ameritech central offices. Ameritech shut them all down saying that there was no way, no how that the device could be NEBS compliant. I don't know how that fight ever turned out, they were not ours. Side to side airflow is really bad news. Even with vertical you could at least mount some kind of baffles and lose a few Us. With side to side it is really hard to find a way to redirect air with the flanges in the way.
Steven Naslund
Chicago IL
Remember the Ascend MAX TNT and the sideways left-right airflow?
...
Indeed I do. I see you've heard the story of PSINet melting components
as well.
We used USR(3Com) TotalControl hardware: vertical venting. The chimney
effect was impressive. (65F in, 100+ -- sometimes 120 -- out.)
TotalControl stuff was a tank but to get the density you need, you had to give them "TotalControl" of all of your rack space.
We used Livingston Portmaster 3 back in the day. Front to back ventilation, ran cool as a cucumber, plug it in and it just worked.
Awesome gear until Lucent bought the company to kill the product in favor of their Ascend TNT space heaters.
Yep, we called them the "Livingstones" because they were stone age stuff but would never die. We had TONS is issues with the Ascend stuff. On the Ascend Max stuff we had a big problem with their power supplies blowing up. After lots of research we found the same third party supplier and ordered the same voltage with twice the current capacity and had no more problems. They refused to acknowledge that the power supplies were sized too small even after we proved it by replacing them with third party stuff.
We preferred the TotalControl stuff but in the days of the modem standards wars, certain modems worked better with Ascend and some with USR so we maintained some of both. We were in firmware fix hell on both the USRs and the Ascends for a period of years.
Steven Naslund
Chicago IL
Ascend kit was a horror to deal with. I ran isdn dialin on some of their
lower end kit at one stage. It only worked because I put it on a power
timer which power-cycled it twice a day.
+1 on portmasters, though.
Nick
energis pop the cab doors would not open due to heat warping after loaded with two tnt max
colin
We used Livingston Portmaster 3 back in the day. Front to back
ventilation, ran cool as a cucumber, plug it in and it just worked.
Awesome gear until Lucent bought the company to kill the product in
favor of their Ascend TNT space heaters.
Ascend kit was a horror to deal with. I ran isdn dialin on some of their
lower end kit at one stage. It only worked because I put it on a power
timer which power-cycled it twice a day.
+1 on portmasters, though.
My ISP grew up on Livingston Postmaster 2e & 3s. I even had a Postmaster 4 for a bit. Lucent swapped that out for an APX 8000. I still have an Ascend TNT running the remainder of my modem pool. 8 Active users on it at the moment.
Recently won a state contract for IP services. The very first order was for a chunk of dialup accounts so the Department of Conservation and Recreation could call in from their firepowers.
It just keeps chugging away in a forgotten corner of my datacenter.
It is interesting where this conversation turned. But for history's sake...
NAC started on PM2e with Microcom's, and then USR Sportster. I remember USR sending us PROM chips to change from 28.8 to 33.6. After that, PM3's. We were early PM3 users, working with Megazone on an almost continuous basis to work on bugs. We tried the PM4, that went nowhere. Then we tried Assured Access - it had promise but ultimately was no good. Ultimately, went to used AS5800's with ChDS3 cards, which ran from a long time ago until just a couple months ago when we finally (and literally) pulled the plug on dialup (I think we had about 30 active accounts from a peak of over 35,000).
There was a time where NAC was by far the largest customer of the LEC portion of Sprint in NJ, with two DS3's of PRI's out of NWTNJ alone (look that up, it's in the woods in 07860). Sprint had to actually buy software upgrades for the DMS we were out of to accommodate a hunt-group that large (or, so we were told). This was after we had about 700 POTS lines to a house and they begged us to move to the CO.
Ahh, the good old days. And it is amazing how well it all worked, in retrospect, and how much fun the business was. Then you see things like "Net Neutrality", and it makes me want to hide in the woods and shed a tear.
Dell - Internal Use - Confidential
Still alive and well out here in 07860. 
My memory is somewhat rusty as it's been a while, but at Tellurian I'm pretty positive we ran a DS3+ worth of lines from Sprint from 07860 so I'm not sure if "by far" is totally accurate. 
We terminated on a PM4 here, mostly with bleeding edge fixed code that I don't think was even officially released by Lucent. It helps if you know the developers. We had access to the source code as well at one time for the Portmaster line. I remember an emergency one time where we basically provisioned an on demand T1 to connect POPs together through the Portmasters via ISDN. They were cool machines. I also used to run a Portmaster ORU at my house which was also rock solid. Great for gaming back then...
I know once we ported numbers away from Sprint to Focal/Broadwing/Level 3, at our peak we had two DS3's of PRI's on an AS5800 as well. Those boxes bothered me as the modems frequently rotted over time and required regular maintenance to refresh them and make them happy again... otherwise your call completion rates started dipping.
I'm surprised you had so few dialup accounts. When we shutdown all of our dialup (we sent most of them to NAC), we had far more than 30 active accounts based on all RADIUS logs. I don't know how in this day and age, but they were there and dialing in still up to the day I pulled the power on the AS5800, despite customers being warned.
Ah, memories... now I'm thinking back when I ran a BBS on Fidonet... FOSSIL drivers, Frontdoor, echomail. Now those were the days!
-Vinny
Dell - Internal Use - Confidential
Was forced to get an Ascend Superpipe to work with a PM4 for one of our customers ages ago. Two ISDN lines... as soon as the 4th channel was thrown into multilink, it would drop the 3rd channel. >:O
Finally got it working after a lot of trial and error with stupid settings on the Ascend garbage. It was clearly a bug but I forge the specific setting that caused that to happen.
-Vinny