In a small scale multiplayer online game (MO or casual), one of methods that is used for communicated between peers is having just one member from P2P group takes care sending and receiving of all game play related messages for all members. This method is called P2P Networking for Super Peer (Super Peer or host).
In P2P Networking for Super Peer (Super Peer or host) method, each peer doesn't send their message to all members within the same P2P group directly during the gameplay. Instead, all messages get sent only to one designated super peer (a.k.a host) who directly passes them to all other members in the same P2P group.
In the assumption that member A in P2P group has better internet connection than the other then client A is most likely to be the best candidate for Super Peer in terms of performance. The amount of data receiving traffic for client A (Super Peer) and other clients will be equal but the amount of data sending traffic for client A will be square of other clients' amount.
Since this has a large dependency on the internet connection speed, when none of members in P2P group has high speed connection, it would even make the gameplay experience worse and more lagging. Thus when you apply P2P Networking for Super Peer (Super Peer or host) method, you need to carefully choose who will carry out the role of Super Peer as considering the quality of internet of all peers. Here are some of ways to decide who should be Super Peer.
ProudNet has functions that automatically calculate everything listed in above. Please refer to Proud.CNetServer.GetMostSuitableSuperPeerInGroup and Proud.CNetServer.GetSuitableSuperPeerRankListInGroup for more details.