I have 350/350 mbps Ziply ethernet - currently down to 90/90 given a slow Alix firewall interface (faster APU configuration Real Soon Now). Anyway ...
Over the last week. 90/90 dropped to 20/20 mbps, with delayed and lost packets, as measured by Internet Speed Test. More "interesting" ... during the speed test the speed slowly dropped (normally it rises a little). Long story short, the problem traced to an old (March 2007 embossed into the plastic case) D-Link DGS-2208 8 port ethernet switch in the path from the Ziply ONT to the Alix. A different switch brought the speed back, and measured 350/350 to a directly connected Chromebook. Long story long: I opened the D-Link. Inside, a big integrated circuit with an aluminum heat spreader ... but no heat sink (poor design, a naked black plastic package will radiate heat better). I connected two ports with an ethernet cable (intentional loopback No-no!) and launched some ping packets with the Chromebook, watching the blinky lights flash with the tail-chasing packet storm. The heat sink got hot to the touch, and registered 125F with an infrared thermometer; probably hotter given the lousy infrared emissivity of the aluminum spreader. My diagnosis: some packet-munching failing circuitry in the old D-Link, which overheats and fails more packets. A replacement gigabit switch works fine ... so far. I'm back to 90/90 with the Alix, 350/350 with the Chromebook. Silly D-Link thermal design - perhaps the heat spreader was added with the intention of adding a finned heat-sink. With the unit assembled, there is a small roughened black plastic surface on the top lid of the case, facing the chip and the power supply on the PC board, which would help capture some of the infrared heat ... but that would work better if the lid was roughened across the entire top surface. --- Anyway, I share this with PLUG because some of you may encounter similar ethernet slowness in the future. Don't blame your fiber provider or your firewall machine until you check other "simple" devices on the signal path. Correction: Do blame Comcast (I did a few months ago), but not Linux or Ziply, which have been magnificent so far. Keith L. -- Keith Lofstrom [email protected]
