We used to have customers buying the Linksys BFR-41 routers to use on their DSL 
line and those pieces of crap would do the same god dammed thing.   But of 
course the customers would blame us and claim our DSL service was slow.  It 
took the loss of probably 4-5 customers before I caught on to what was going on 
and often I'd have to spend 4 hours driving out to their house with a spare 
device, proving their POS router was slow, before they would believe they had 
bought a POS.

I'll NEVER buy ANYTHING from Linksys or Belkin as they are known now as a 
result.  I have made absolutely sure to cost them more in lost sales over the 
years than they ever cost us.

How is it that you have so much faith in Ziply as to immediately suspect your 
POS switch instead of blaming them?  THAT is the real mystery! 😉

Ted

-----Original Message-----
From: PLUG <[email protected]> On Behalf Of Keith Lofstrom
Sent: Tuesday, August 6, 2024 7:35 PM
To: [email protected]
Subject: [PLUG] Interesting D-Link Gigabit Ethernet Switch Fail

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]

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