WAN Termination

Question 1

Demarcation point

Answer 1

• The point where you connect with the outside world
  
  • WAN provider
  • Internet service provider
  • The demarc
• Used everywhere
  
  • Even at home
• Central location in a building
  
  • Usually a network interface device
  • Can be as simple as an RJ-45 connection
• You connect your CPE
  
  • Customer premises equipment or “customer prem”

Question 2

CSU/DSU - Channel Service Unit / Data Service Unit

Answer 2

• Sits between the router and the circuit
• CSU - Connects to the network provider
• DSU - Connects to the data terminal equipment (DTE)
• Physical device - Or built-in to the router

Question 3

CSU/DSU connectivity

Answer 3

• From the demarc
  
  • RJ-48c wiring
• To the router
  
  • Serial connection, v.35, RS-232
• May also include monitor jacks
  
  • Useful for diagnostic equipment

Question 4

Smartjack

Answer 4

Smartjack
• Network interface unit (NIU)
• The device that determines the demarc
• Network Interface Device, Telephone Network
Interface

• Smartjack
  
  • More than just a simple interface
  • Can be a circuit card in a chassis
• Built-in diagnostics
  
  • Loopback tests
• Alarm indicators
  
  • Configuration, status