Interfaces -Bridges
  Hub - (Ethernet/Arcnet) unites multiple devices in a physical location to 
    a common access point. Star configuration. Very dumb, high chance of 
    collision.

  Network Bridge - Unites two or more sub-nets of a LAN.
    Point to point connections.
 
    Aware of all devices on network (usually via mac id) and makes them 
    part of 1 logical network. List of devices small < 20.
  
    Can connect ethernet systems where 1 subnet is twisted pair and the
    other is wireless or coax. (Same protocol but disimilar physically)
   
    Sometimes used to connect two sub-nets via p to p over a distance 
      using a dis-similar technology.
   
    Attempts to optimize traffic by not passing frames that will not 
    be processed on other sub-net.  Distinguished at the mac @ level.

    
  Switch
    Switch is a single connection port or intelligent hub.

    Isolates the line, provides some buffering and thus lowering collisions.

    Can perform like a hub, bridge, or even simple gateway/router.