Thanks everyone for sharing your experience!
Saturday Feb. 14th 2015, we brought home an 8 weeks old puppy: Pix.
Alf who is 2 years old was really great at introducing himself to the puppy.
4 days later, he litteraly is educating Pix, teaching him good manners and snipping him gently from time to time.
I wasn't sure if all the noise was normal, but I for sure know that Alf never really hurts the puppy. He never had any troubles with any dogs, and I think Pix is probably a really good actor 🙂