CNT 4007

1. Let us assume that we have a CSMA/CD network with n stations. For any time slot, the probability that a station has a frame to send is p. Now the question is what is the probability that a time slot is used successfully (with no collision)?

(Hint: use Bernolli Trials to solve this problem)

2. Consider a slotted ring of length 20 km with a data rate of 100 Mbps and 1000 repeaters, each of which introduces a 1-bit delay. Each slot contains room for one source address byte, one destination address byte, two data bytes, and 8 control bits for a total length of 40 bits. How many slots are on the ring?

3. Imagine a LAN with a bus topology in which each station is given permission to send a fixed-size frame. However, other stations are not allowed to send data until this frame reaches the destination. What is the efficiency of this LAN?

Assume:

Medium length = 10,000 m

Capacity = 10 Mbps

Propagation speed = 200,000,000 m/s

Frame length = 100 bits

4. Numerically Calculate the efficiency of a typical CSMA/CD using the following information:

Medium length = 5000 m

Capacity = 100 Mbps

Propagation speed = 200,000,000 m/s

Frame length = 1000 bits

5. Calculate (Numerically) the efficiency of a Token Ring network using the following information:

Medium length = 3000 m

Number of stations: 100

Capacity = 16 Mbps

Propagation speed = 200,000,000 m/s

Frame length = 8000 bits