Kelvin Lawson

SJA1105 Support Hairpin Mode

Discussion created by Kelvin Lawson on Apr 7, 2020
Latest reply on Apr 8, 2020 by jamesbone

Can anyone from NXP advise whether the SJ1105 Ethernet switch supports "hairpin" / VEPA mode?


This is helpful for some modes of macvlan networking, which you can see in the VEPA diagram here: Introduction to Linux interfaces for virtual networking - Red Hat Developer 


In VEPA mode, for comms within the host you need the switch to be able to reflect back packets for a different MAC address on the same host, the green line below:

  VEPA mode


Alternatively there is Bridge mode, where the host manages packets itself within the host, as can be seen from the Bridge mode diagram from the same site, the green line showing that packets for within the same host do not go out to the physical network: Bridge mode


It would be helpful to understand whether the SJA1105 supports the former VEPA "hairpin" mode, but I haven't been able to confirm this from the datasheet.


Many thanks.