I've got some Intel 82599-based 10 Gbps NICs (using the ixgbe driver). I've plugged some direct-attach cables into these cards. Those cables have SFP+ ends, with a cable part number and serial number. I can query that information from my Cisco switch (show interfaces transceivers) and from hosts with Myricom 10G nics (via the mdio_rw tool). Is there a tool for the ixgbe-based Intel nics that prints out data about the SFP+ modules?
I figured it out. You can extract the serial number from the SFP interface by running ethtool's EEPROM dump command, with the 'raw' extension:
$ ethtool -m eth0 raw on