We can't identify all traffic correctly, some traffic will end up in incorrect queues - there is so much traffic, it's difficult. The usage figures should only really be used as a general point of reference.
It may be that you've watched a video online and the traffic type has fallen into the Broadband Phonecall queue - nothing to worry about. Peer to Peer is generally traffic we've identified where your connection has been possibly used to share files with another user.
Examples of Peer to Peer are things such as uTorrent which is commonly used to transfer files between people. There are many other programs but P2P details can be found here:
http://en.wikipedia.org/wiki/Peer-to-peer
