I am trying to get my head around ARIMA modelling.
I get the idea of it at least on a superficial level.
Looking around you see a lot about ARIMA(p,d,q) where p is the autoregressive term, d is the differencing and q is the moving average term.
However when I use the auto.arima function in R and plot the result it gives me an output with "ARIMA(2,1,0)(1,0,0) with Drift"
Can anyone explain how this relates to ARIMA(p,d,q) I believe the  might be due to the fact that it is monthly data I am using to build the model so it has frequency 12. But I don't see why there is 6 values (2,1,0)(1,0,0) rather than just 3 in the form (p,d,q).
Can anyone shed any light on this?