A technical blog about my projects, challenges, and discoveries in the world of data warehousing using SQL Server, Power BI Desktop, DevExpress, and more.

Thursday, July 14, 2011

Ethernet Over Power thermal problems

If my last post was a departure from my normal topics, this one is a detour through back roads. Don't worry, though, I am working on a lengthy post that will get me back on track with SQL topics.

In the meantime, let me explain something that happened to me last week. The very first symptom was that my desktop would not print to my network printer. The printer itself appeared to be working normally, and I could even pull up the printer's web interface from my desktop. But I could not print. As I tried to resolve the communication between my desktop and the printer, I found my overall network connectivity was becoming intermittently interrupted. The problem escalated until at one point I used the ipconfig utility to manually release my IP address and attempted to renew it. No renewal occurred; DHCP was not working for me.

I would have assumed the router itself was down or having trouble, except that the laptops (yes, my wife and I each have two -- each of us has one for work and one personal laptop) were working fine with their wireless connectivity directly to the router. The only device apparently affected was my desktop. Having concluded this, I ordered a replacement network adapter. My desktop has the new PCI Express ports and no standard PCI ports, and I discovered that network adapters that fit PCI Express ports are difficult to impossible to find in a regular store, even an electronics store. So I ordered it on the Internet, and I expect it to arrive on Monday.

In the meantime my IP phone from work started having trouble. And this made me start the whole process over of trying to find the problem. One device that I thought I had tested and eliminated from the equation was the ethernet-over-power (EoP) adapter that I use to bridge my office computer equipment with the router downstairs, which is just barely within the range of the wireless router signal. But when it became apparent that something more was wrong than just the network adapter in my PC, I took another look. I moved the EoP adapter from the wall plug where it normally sits and moved it downstairs. While carrying it, I noticed that the EoP adapter was not just warm; it was downright hot, especially  the metal ports that hold the RJ45 terminator.

It did not occur to me right then, but gradually I began to wonder if the problem was a thermal one. Our air conditioning has been on the fritz for three days, meaning that my office was warmer than usual. Perhaps the PoE adapter was getting too hot to work properly. To test this, I left the adapter unplugged all last night and plugged it in this morning. Voila. Everything is working again on the network, including my desktop and the IP work phone. Unless something more occurs (which I doubt), I am going to chalk this up to thermal issues. I will probably unplug the PoE adapter in the evening before going to bed and plug it back in when I get to my desk the next day.

I post this as a cautionary tale to those out there who use ethernet-over-power adapters. If your network connectivity becomes unstable, don't overlook the possibility that the EoP adapter is overheating. It might save you some time and expense. As for me, I will have to see about the Amazon.com return policy.

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