Interfaces
  Router - Connects LANs or other networks together & translates protocols.
    Multiple input/outputs. Acts as a switching station. 

    Repackages data into appropriate sized units.

    Often includes multiple gateway logic/hardware.
  
  Brouters - a combination of both a bridge and a small local router.
    Often used to create an artificial local Internet.  

  Firewall routers - come with their own DHCP services which allow the user to 
    create a private network behind the router.

    IP@ of device behind firewall appears as a port id of the firewall hub.
    NAT - network address translation
      IP masquerading 
      IP spoofing - when the above is done to deceive.
 
  Because masquerading interrupts the true end to end connectivity, some 
    Internet services may not function well or require some complex 
    configuration.


  Distribution Routers
    Provide node to node connection over "Internet"
    Although only responsible for moving packets to next hop, it has to
      be able to discover the full paths to the destination to pick next
      hop. 
     
      RISC systems with database tables.

     wikipedia   Router(Computing)