Discussion
Suppose two hosts are connected by a point-to-point link and they are configured to use Stop-and-Wait protocol for reliable data transfer. Identify in which one of the following scenarios, the utilization of the link is the lowest.
Answer: B
Utilisation is lowest with a longer link length and higher transmission rate.
In Stop-and-Wait the sender transmits one frame and then idles for a round trip until the acknowledgement returns. With transmission time \(T_{t} = L/R\) and propagation delay \(T_{p} = d/v\):
\[ \begin{aligned} U &= \frac{T_{t}}{T_{t} + 2T_{p}} = \frac{1}{1 + 2a} \\ a &= \frac{T_{p}}{T_{t}} \end{aligned} \]
Utilisation falls as a grows. A longer link raises \(T_{p}\), and a higher transmission rate shrinks \(T_{t}\); both increase a, so together they give the lowest utilisation. A shorter link with a lower rate is the best case, and the two mixed options lie in between.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development