Networking / Beginners

The Network Layer

Also called layer 3, this is concerned with controlling the operation of the network, including the question of how to route a packet from source to destination. This might include the problem of congestion control: if too many packets are trying to use one line we might reroute some, or use flow control to slow some sources down.

We can also deal with internetwork problems at this layer. Perhaps a packet is routed from one network to another that has a smaller frame size so some action must be taken, such as breaking the frame into smaller frames or perhaps simply refusing to pass on the frame.

The network layer also deals with things like accounting: counting the number of bits sent by a user so we can bill them later.

[Previous] [Contents] [Next]

In this tutorial:

  1. Layering Models
  2. The Seven Layer Model
  3. The Physical Layer
  4. The Data Link Layer
  5. The Network Layer
  6. The Transport Layer
  7. The Session Layer
  8. The Presentation Layer
  9. The Application Layer
  10. How the Layers Fit Together
  11. Why Layers and Encapsulation?
  12. The Internet Model
  13. The Link Layer
  14. Models and Protocols
  15. Comparing OSI and Internet Models