On Thu, Nov 3, 2016 at 6:24 AM, Gal Pressman <galp....@gmail.com> wrote: > > > On 25/10/2016 05:50, Vidya Sagar Ravipati wrote: >> SET FEC option: >> root@tor: ethtool --set-fec swp1 encoding [off | RS | BaseR | auto] autoneg >> [off | on] >> >> Encoding: Types of encoding >> Off : Turning off any encoding >> RS : enforcing RS-FEC encoding on supported speeds >> BaseR : enforcing Base R encoding on supported speeds >> Auto : Default FEC settings for divers , and would represent > > divers? :) Drivers :) > >> asking the hardware to essentially go into a best effort mode. >> >> Here are a few examples of what we would expect if encoding=auto: >> - if autoneg is on, we are expecting FEC to be negotiated as on or off >> as long as protocol supports it >> - if the hardware is capable of detecting the FEC encoding on it's >> receiver it will reconfigure its encoder to match >> - in absence of the above, the configuration would be set to IEEE >> defaults. > > Not sure I follow, why do we need an autoneg option if encoding type can be > set to auto? Auto is one of the FEC configuration modes which indicates the drivers to set the IEEE defaults based on speed/duplex combination of the port. i.e. RS FEC mode will be set in case of 100G/full
Auto negotiation is the configuration for the link to negotiate the FEC capabilities and different FEC modes with other endpoint using encoded bits D44:47 in base link code word.
