Feb 04

Always measure before running your data cables!!!

I got the request for 5 new data drops for a new system in a warehouse. I was directed to have a vendor come in and run the new data lines from an existing switch. The distance looked fine, but I was skeptical about the distance. I used a measuring wheel to measure the distance. After walking 300ft (100M), I stopped and started measuring to another switch, same problem, it was too far.

Due to the distance, we ordered a switch, cabinet, power outlet and a fiber run. The cost on these data connections went way up due to distance to the closest switch.

If I wouldn’t have measured the distance with a measuring wheel the vendor would have come out and run the data lines (CAT5). The distance would have been around 400ft and they wouldn’t have worked. After finding out that the data lines were too long, I would have had to start the process of ordering a switch, cabinet, power outlet and a fiber run.

By measuring the distance, I was able to install the appropriate equipment in a timely manor. I saved the company time and money.

Always measure your cable runs so you don’t wast time and money having to do them over when they are too long!!!

Tell us a time where you stepped in and saved a project!!!
Share a time where planning wasn’t so good and you had to come up with an alternate solution after you already paid for a solution!!!

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Sep 03

Can you get your fan tray out?

Network hardware vendors are challenged with the need for a fan tray in their chassis. The fan is something that probably won’t go away for a very long time, yet it’s a piece of equipment that can fail. Some chassis have fan trays that are very easy to get out and replace, the Cisco ONS 15454 is one of those chassis. The Cisco ONS 15454 has a fan tray that is removed from the front and it simply pulls out.

Other chassis have the fan tray in a location that cause a problem with being blocked by the data cables. The Cisco 6513 is a great example of a fan tray that can easily be blocked by the data cables. If you are not familiar with the 6513, the line cards are horizontal in the chassis. The air flow needs to go side to side, so the fan is on the left. To avoid the fan tray, all data cables would need to come from the right side of the switch to be connected. This can be a very difficult challenge due to the quantity of cables that the 6513 can support.

On almost all of the network devices that I have seen, the vendor has done their best in the placement of the fans. They usually don’t have a choice on the location of the fan. If it was a different chassis design, then the fan would be in the way somewhere else.

I believe that it is our responsibility to correctly run the cables to avoid the fan tray. I have spent hours labeling and disconnecting cables just to replace a failed fan tray. If the cables were run correctly, the fan should be removed and replaced with out disconnecting any cables. No outage should ever be required to replace the fan tray.

Here are a few chassis that I have seen with very good Fan tray design.

Cisco Nexus 7010
Cisco ONS 15454
Brocade MLX-16

Here are a few chassis that can be challenging to cable and avoid the fan. Maybe the location of the fan tray could be better, maybe not.

Cisco 4500’s
Cisco 6500’s
Cisco 7600’s
Brocade SX800

What chassis have you used that have good or bad fan tray locations?
Have you ever had to take an outage to replace a fan tray?
Please tell us about it!!!

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