| Author | Ignatius, Nimalkumar Guy Maritius |
| Call Number | AIT Thesis no. CS-88-9 |
| Subject(s) | Computer networks
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | The purpose of this thesis is to evolve a simulator for performance
analysis, for the bus and ring medium access protocols and also to derive an
analytical model to study the relationships between the simulation and
analytical models. The medium access control protocol considered are tolcen-ring
and CSMA/CD.
Analytical Model for CSMA/CD protocol assumes infinite number of stations
and when there is a collision no specific back-off algorithm is used. Analytical
model for token-ring protocol assumes infinite buffer size. Simulation and
analytical models of both access control mechanisms assume the arrival rate
distribution to be Poisson distribution.
The simulation model is used to compare the performance between
token-ring and CSMA/CD. The performance parameters considered are delay,
throughput and utilisation. The networks compared s h ould be of the same size.
The performance parameters obtained from analytical and simulation models are
compared for both token-ring and CSMA/CD, to find out the relationship and the
range within which the analytical model agrees with the simulation model.
Simulation model simulates the real conditions which prevail in these
respective networks as far as possible, whereas the analytical model makes
assumptions to malce the model simple and possible. These assumptions malce the
analytical model more vulnerable and accounts for the mismatch between this
and the simulation model.
The simulator can be used to predict the delay, throughput or utilisation
of token-ring or CSMA/CD network of any length, with any number of stations
and for any transmission speeds. It can also be used to find the fairness of the
network, because it gives the statistics of each terminal in the network (i.e.
whether each terminal is given fair access to the network).
It was found that for token-ring, the analytical model delay matched with
the simulation model delay when the load is small (less than 60 per ·cent). For
CSMA/CD the analytical model throughput does not match with the simulation
model throughput. In this case simulation throughput is larger than the
analytical throughput because simulation back-off algorithm is more effective
and also by the fact that analytical model does not handle retransmissions.
Both these models together can be used to determine transmission and
retransmission for any given load. The analytical throughput is modified to give
results which are more close to the expected throughput (same as simulation
throughput) |
| Year | 1988 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Computer Science (CS) |
| Chairperson(s) | Skjesol, Trond
|
| Examination Committee(s) | Nanda, Navnit Kumar ;Huynh Ngoc Phien
|
| Scholarship Donor(s) | German Academic Exchange Service
(DAAD) |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1988 |