1	(a)	Give examples of real-time and non-real-time traffic and explain how ATM copes with the transmission of both types of profile. Explain why ATM does not provide reactive end-to-end flow control? (9)
	(b)	Explain the structure of an ATM cell header and the importance of each part. (6)
	(c)	Using an example, show how ATM cells are routed and explain how the VCI virtual paths and circuits route cells. (10)
2	(a)	Outline the structure of an IEEE 802.3 Ethernet data frame and identify the usage of each field. (12)
	(b)	What advantages do switches have over conventional hubs? Discuss both cut-through and store-and-forward switches. Explain their differences and incorporate the advantages and disadvantages of each. (13)
3	(a)	With reference to the functions of the transport layer of the OSI model, explain why the transport layer can be described as implementing a reliable, connection-oriented protocol. (9)
	(b)	Explain, with reference to TCP and UDP headers, why TCP fits the description of being a reliable, connection-oriented protocol, but UDP does not. (9)
	(c)	How does a TCP connection know when a remote connection has crashed, and why is it not possible for a previous connection to be confused with a current connection? (7)
4	(a)	Explain the difference between a static IP address and a dynamically-allocated IP address. How might a network manager use dynamically-allocated IP addresses to access to a network and/or the Internet?(7)
	(b)	For a Class B address, derive the maximum number of hosts and the maximum number of subnets for a subnet mask of 255.255.252.0. State all the assumptions made. (8)
	(c)	When a computer is to be connected to a network and to the Internet, what networking parameters need to be set for it to communicate using TCP/IP? Also, briefly outline how a node is able to determine the MAC addresses of the hosts on a network, and how data packets are able to get passed a router and onto the Internet? (10)
5	(a)	Outline a set of best practices for creating a high-security network. (8)
	(b)	Explain how a firewall could be used to create a secure network, and outline the parameters in TCP data segments and in IP data packets which the firewall would filter with. (10)
	(c)	Explain the operation of an encryption tunnel using public-key encryption to create a secure connection. (7)
6	(a)	Illustrate the different layers of the OSI 7-layered model, and provide an example of each layer. Also, with reference to the OSI model, identify the function of the three lower layers and discuss the function of the repeaters, bridges and routers.(13)
	(b)	Outline the operation of the HTTP protocol and how WWW caches are used in the transfer of WWW pages. What advantages does a cache-based system have over one without caches? Also explain why a WWW client knows that the file has been received correctly, or not. (12)