You can only bond interfaces if they are operating with the same settings.   You can bond both together using 1Gb/s ports, giving you 2Gb/s.  Both ports are operating at 1Gb/s in this case.   If you have an MGig switch, you can plug in the 2.5Gb/s port, and get 2.5Gb/s.   You can not bond a 2.5Gb/s MGig Interface and a 1Gb/s port, because they are not operating with the same settings. ... View more