Question:

(a) The IEEE 802 series of standards describe both the Physical and Data Link layers of their respective technologies. Two important standards are 802.3 and 802.5, respectively known as CSMA/CD (Ethernet) and Token Ring.

i. Describe 3 differences between Token Ring and CSMA/CD technologies.

ii. Explain the structure of a typical Ethernet II frame.

(b) Asynchronous Transfer Mode (ATM) is a high-speed network technology. ATM has a physical layer, an ATM layer and an ATM Adaptation Layer (AAL). Four protocols at the AAL layer allow for the creation of a variety of service classes.

i. What are the factors that determine the service classes and what is the purpose of such a distinction?

ii. Give briefly the structure of an ATM NNI cell.

(c) Nowadays many companies are shifting towards the IEEE 802.11x standard for extending their network.

i. Outline two popular flavours of this wireless standard. Elaborate on the operating frequency, range and speed of each flavour.

ii. What are the two modes of operation of this standard and explain the difference between the two.

iii. Mention one security issue with this wireless technology and explain how this issue can be addressed.