CITS3002 Computer Networks  
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Implications for Network Protocols

Therefore, the satellite channel must control its own allocation:


The advantages of this "shared medium" approach are:

  • No Data Link Layer acknowledgements needed, each sender can verify the correctness of their own messages (because they can hear them).
  • No routing problems in the Network Layer subnet (no subnet!).
  • No congestion problems or topology optimization.
  • Mobile users may be supported.

The disadvantages of this approach are:

  • Long propagation delay of at least 270msec.
  • All users receive all messages, introducing security implications, and there can be no central control of unethical users.

Question: How can a single communication channel be efficiently shared between uncoordinated users?

CITS3002 Computer Networks, Lecture 4, Local Area Networks (LANs), p2, 18th March 2020.