Diffusion vs migration in solid state

[Oxygenne]

I do not understand the difference between diffusion and migration is case of anion/cations.
Thank you!

[Relena]

Migration is a special case of diffusion, that is ,migration have polarity (from side to another) just as in case of PN junction , electrons diffuse in one direction and holes in the other.

In case of anions and cations , Polarity exists , so the accompanied motion is migration from +ve to -ve and vice versa