Signs of Triviality

Opinions, mostly my own, on the importance of being and other things.
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Gigabit Cables

Moving our cluster to a netbooting setup, we replaced the originally purchased Broadcom Gigabit Ethernet devices (which were unable to netboot) with Intel's i82540EM Gigabit Ethernet cards. While installing these cards, a number of them appeared to misbehave: upon bootup, they would display a link light, but as soon as the card was configured by the firmware, the link light turned off and the card would claim that no network link was found.

Some of the cards would maintain the link-light, but refuse to netboot -- they would not be able to get a DHCP lease, even though the server was configured to hand out the right lease to the devices. Some cards, seemed to work out of the box, without any problems whatsoever, but the majority would always loose the linklight soon after the card's firmeware kicked in.

In the end, the problem turned out to be related to the network cables: some of the cables used were regular CAT5 cables, while others were CAT5e cables. After replacing all cables with CAT6 cables, everything worked out fine and all cards were able to netboot.

Note that even though the CAT5e should work fine, some of the cards showed this unexpected and rather frustrating behaviour even with these cables. It seems that these network cards are very particular about the used cables.

November 10, 2005

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