Netgear GS108

The Netgear GS108 is an 8-port gigabit ethernet switch. In 2007, Netgear released version 2 which added support for jumbo frames. I bought several of these.

The death of an ethernet switch

One died on me in 2009. It didn't happen overnight. The computers started to lose their network connections every now and then. At first, I suspected the ethernet adapters since ifconfig eth0 down; ifconfig eth0 up always seemed to clear up the problem. It became frequent enough that after a while, each computer had a crontab entry running that command once an hour.

Eventually, the switch all but stopped passing ethernet frames and I had to replace it. Funny, the intermittent connection problem did not return...

There is a lifetime warranty on GS108 bought after 2007-05-01. Fortunately, mine was bought that month. Filled an RMA with Netgear. Had a short phone conversation with a lady with an Oriental accent and an Irish surname. Sent the dead switch to an address in France. A new switch arrived in the mail a week or two later.

It's not contagious, is it ?

In 2010, another GS108 bought in 2007-05 kicked the bucket. Different symptoms and a swifter demise.

On Wednesday, noticed that some remote X apps were even more sluggish than usual. Running netperf -H server from the X terminal showed nothing alarming but netperf -H xterminal from the server reported 70 Mbps (that was supposed to be a gigabit link).

On Thursday, the LTSP client would not boot. The LTSP server saw the DHCP requests and sent offers back but the client did not see them. The few times it did, it didn't go much further.

The two GS108 in the path seemed to work fine. They passed TCP (modulo the intermittently rotten transfer rates mentioned above). Changed the horribly frayed ethernet cable between the last GS108 and the LTSP client, to no avail.

Plugged a laptop at the end of the cable and it got its DHCP with no apparent difficulty. If it's not the server and it's not the network, it must be the client, right ? Wrong. Changing the ethernet adapter on the LTSP client made no difference.

So did what I should have done in the first place and replaced the GS108. The one in the server room was good. The other one was the culprit.

Another RMA to file.

Why did DHCP work for the laptop ? Perhaps because it had a 100 Mbps adapter (versus 1 Gbps for the LTSP client).


The cause seems to be a blown cap. Look at C4, the green cap in the foreground. It's gone beyond bulging : the pressure of the boiling electrolyte has begun to pop the can off.

Electrolytic caps in the GS108 :

C4, C21 1000 F 6.3 V 105C, pitch 3.5 mm Teapo SC A3 C4 03/07
C7, C14, C27 330 F 25 V 105C, pitch 3.5 mm Teapo SEK A3 C1 04/07

Others have had the same problem :

Apparently C4 and C21 only see 2.5 V so their rated voltage of 6.3 V seems more than adequate. Perhaps it's a bad batch. One thing is for sure, this value and voltage is available in three sizes (8 11, 8 15 and 8 20) and the one Netgear used is, to quote the data sheet, down size, ripple life is less 1000 hrs than standard.

The road ahead

The GS108 now comes with a switching wall wart in place of the old linear one. It emits a nice high-pitched whine which I think you will find to help your concentration. As for reliability, it is a switch mode power supply. Need we say more ?

This is, last modified 2011-07-01.