My boyfriend shows me off to his friends all the time

We just started dating but know each other for a long time. In college whenever he's with his friends and I am just walking by, doing my stuff, he'd call me and talk with me and touch me on my arm etc. in front of them.

When he's out with his friends, he'd phone me and tell them that he's talking to me and then talk for a long time loudly.

He tells his guy friends about how we went out to eat and what happened etc. when I'm around.

Why is he doing this? Should I be concerned?