My home office network is fairly simple. DSL Modem, to a 5 port 10/100 Hub, Hub to NetGear Router, Router to 5 port 10/100 Switch, Switch to 1 laptop and 1 desktop. Other laptop connects to router via Wifi connection and I have a Vonage phone system connected directly to the router.

The hub is upstream of the router so I can connect a sniffer when needed for diagnosing chatty programs, and other traffic issues both in programs I own as well as those I write. It’s a poor-mans network tap.

Recently I have noticed some strange, albeit rare, behaviour on the switch. (I apologise for the poor quality of the picture, photography is not my strong suit.)

This picture shows the switch in normal operation, you can see that the Link, 100, and Full lights are lit for both workstations as well as the patch cable back to the router.

Every now and then I will come in and find only the Link light active. The 100 and Full Duplex lights will be off for all 3 ports. A simple reset of the switch restores full 100m connectivity. But it baffles me as to why it happens in the first place. My understanding is that the most common cause is that a network card “lost sync” and fell back to 10m half duplex operation. But since it affects all 3 ports I am guessing it is the router that is losing sync.

Anyway, a reset of just the switch suffices. Thought I would share what I have seen in case someone out there knows what the deal is, or if you are experiencing something similar at least you will know you are not alone!

If I ever come across the cause and or solution I will update this post.

Cheers,

Robert Porter