Problem (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. Explain how CSMA/CD operates and describe how Ethernet deals with collisions.

ii. Give the structure of a typical Token Ring frame and explain how communication is effected in a Token Ring Network.

Problem (b) A datagram of 3000 bytes has to travel over a network with a MTU size of 1000 bytes. Explain how fragmentation can be used to solve this problem.

You should give the value of the 3 key fields used in fragmentation for each fragment created.

Problem (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.