Commands for changing the port speed of optical modules in Linux

With ethtool, we can also change settings like speed, duplexity, and toggling auto-negotiation. It takes the device name (like swp1) as an argument. See man ethtool(8) for details. Not all. ethtool -s devname [speed N] [duplex half|full] [port tp|aui|bnc|mii] [mdix auto|on|off] [autoneg on|off] [advertise N] [phyad N] [xcvr internal|external] [wol p|u|m|b|a|g|s|d. ] [sopass xx:yy:zz:aa:bb:cc] [msglvl N | msglvl type on|off. ] ethtool -n|-u|--show-nfc|--show-ntuple devname [. ethtool is used to query and control network device driver and hardware settings, particularly for wired Ethernet devices. This guide introduces how to read optical module information when it is installed on a network card in a Linux system. [pdf]