I am not an expert using SFP.

I got a Cisco SG500X L3 switch with 4 SFP+ 10G ports.

I got 2 mini-gbic HP AJ718A (8Gbps) and 1 fiber (HP 3PAR-10G-10M 850-200029 10Gbps). I plug the fiber into XG1 & XG2 ports (I know it's a loop but STP is enabled), and I got 2 ports at 1000Mbps according to the webconsole.

I got 1 all-in-one cable 10G (10Gtek SFP-DAC) and in the same ports i got 10Gbps connected ports.

I don't understand why. The switch is unable to works at 8Gbps ? It's 1 ou 10 Gbps ? Thank you

  • 1
    8 Gbps is not ethernet.
    – Ron Maupin
    Dec 12, 2019 at 19:23

1 Answer 1


There simply is no 8 Gbit/s Ethernet. That transceiver is probably for Fibre Channel. Since it doesn't support 10G the switch falls back to the next lower speed it supports, 1 Gbit/s. (2.5 and 5 Gbit/s PHY standards also exist but they're not universally supported yet.)

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