Part A:

No books or other source material are allowed in this part of the exam! Make sure that there is sufficiently time left for part B!

1. Explain briefly:

a) What is ICMP?        (2 p.)
b) There are several classes of IP networks: Describe the classes and the types of addresses in them. How many hosts can there be in each class?       (4 p.)
c) IP header structure and field definitions    (4 p.)

2. Link layer protocols

a) Describe: Error control options?      (4 p.)
b) Draw a timing diagram of Idle RQ and calculate the average transport time of a data frame (= the throughput formula of Idle RQ).  (6 p.)

3. List problems (10 different problem is enough)  that may occur while data frames are transferred from one place to another. Give also some possible remedies for each case! (10 p.)

Part B:

You may use a textbook (Tanenbaum, Halsall…) while answering these questions, but no lecture notes etc.

4. An old ad-hoc network (based on serial interfaces and mostly used to share a printer) that connects about 20 computers in an office is to be entirely replaced by Ethernet (of the 10baseT variety). There is a mixed lot of computers. Some PCs use Windows while others use Linux and the graphic artists in marketing want to keep their Macs. Internet connectivity is needed as well. Which new protocols (communications programs) and which other changes are needed to realise the new network? (10 p.)

5. A large company has several offices and factories all over Finland and even some sales offices abroad. Besides e-mail, WWW and the usual office programs such as Word, they also have some proprietary applications such as a product data base and order handling system and an accounting system tailored to their needs. To be able to communicate between the offices, they intend to connect each office to an Internet service provider and use the Internet. Consider the strengths and weaknesses of this approach. Could You propose an alternative solution? (10 p.)