Andrew S. Tanenbaum Edition 5 Exercise 4 Question 2 (Page No. 351)

Question

A group of N stations share a 56-kbps pure ALOHA channel. Each station outputs a
1000-bit frame on average once every 100 sec, even if the previous one has not yet
been sent (e.g., the stations can buffer outgoing frames). What is the maximum value
of N?

Answer 1

There are N Stations Sharing 56kbps Pure ALOHA Channel

so with pure ALOHA Usable Bandwidth = 0.184* 56kbps=10.3kbps

1 Station Outputs 1000 bits in every 100sec

so in 1sec One station will ouput at rate 1000/100=10bits/sec

so For N stations in 1 sec Total Output Data is 10*N bits this should be equal to the Channel Capacity in pure ALOHA

N*10=10300

N=1030 it is the maximum value of Number of Station Possible.

Comments

so with pure ALOHA Usable Bandwidth = 0.184* 56kbps=10.3kbps

What do you mean by that PLZZ explain It would be a great help

---

that’s the maximum throughput in Aloha mechanism you can get. 18.4%.

You can’t utilize the bandwidth more than that.

In slotted Aloha it’s double.