For network with many nodes and a desire to have advanced features you would set up an Infrastructure. This type of network has an access point (or access points) which coordinates traffic.
Multiple Access Points can be used to have a large amount of nodes in an area by each broadcasting on its own know Frequency Hopping Spectrum (Channelization).
Also an Access point can link the wireless network to a wired LAN or to other wireless LANs via a wireless bridge.
A series of Access Point forming several Cells connected by a backbone is called a "Distributed System".
Roaming is a method of allowing a node to wander through cells by accessing different Access Points. Overlapping coverage of Cell is vital to ensure seamless roaming between Cells.
Load Balancing allows nodes to communicate with the least busy Access Point within a Cell thereby reducing the overall traffic within a cell. Load Balancing is also called Load Sharing.
Point-to-Point refers mainly to WAN configurations. One of the configurations possible in a "Distributed System" The other of course is a wired backbone.
