1. Computer Networks and Operating Systems UFCFQ4-30-2 Lecture-1

2. Introduction to Module Team
Module Tutors
Dr Mazhar H Malik
Contact: P.8,

3. Outline of Lecture Introduction Module Specification
Basic Concepts of Networks and IP
Static and Dynamic IP
IP vs MAC
DNS, DHCP,FTP, ARP and MAC
To Do List

4. Resources
Burgess, M (2000). Principles of Network and Systems Administration, Wiley
Comer, D.E. (2008) Computer Networks and Internets: International Version (5th Edition), Pearson.
English, J (2004), Introduction to Operating Systems, Palgrave.
Tanenbaum, A, David J. Wetherall (2010). Computer Networks: (5th Edition) PrenticeHall
Tanenbaum, A (2007). Modern Operating Systems: International Version, PrenticeHall
Tanenbaum, A, Maarten van Steen (2006). Distributed Systems: Principles and Paradigms, Prentice-Hall
Tanenbaum, A, Todd Austin (2012). Structured Computer Systems: International Edition, Prentice-Hall.

5. Resources
Other resources
UWE BlackBoard

6. Module Structure 3 hours of lecture 3 hours of practical
Main topics, illustrative programs
3 hours of practical
Tutorials, program exercises, class tests, group assignment
6 hours of self study
Textbook chapters, lecture slides, program examples, class test preparation, group assignment

7. Assessment Structure Component A 50% of Total Marks
Exam 2 Hours (Operating Systems) in Week-7 50% Marks of Component A.
Exam 2 Hours (Computer Networks) in Week 15 50% Marks of Component A
Component B 50% of Total Marks
Weekly worksheets, signed off on regular basis by the lab tutor , Individual work 50% marks of component B
Group Practical Assignment 50% marks of component B
You would need to attend every lecture and practical session in order to learn and fully understand all the topics to be assessed in the class tests.
The structure and content of the class test will be very similar to the corresponding practical exercises. You would need to do those exercises with full understanding. 7

8. The Computer Network
I especially liked this graphic. I felt it would be good for an introduction. While it wasn’t really in the color scheme, it was modern and caught people’s eye.
Arguably, the greatest advancement in technology and communication over the past 20 years has been the development and advancement of the computer network. From ing a friend to on-line bill paying to downloading data off the Internet to e-commerce, networking has made our world much smaller and changed the way we communicate forever.

9. The Internet
The simplest definition of the Internet is that it's a network of computer networks
I used three slides to go over the Internet. I wanted to start of the first slide with a basic statement but, it would have an impact on the viewer.

10. An IP address is a 32-bit address. The IP addresses are unique.
What is an IP Address?
An IP address is a bit address.
The IP addresses are unique.

11. Address space rule 2N ………….. addr1 addr15 addr2 …………..
The address space in a protocol
That uses N-bits to define an
Address is: 2N
…………..
…………..
…………..
addr41
addr226
addr31
…………..
…………..

12. The address space of IPv4 is
IPv4 address space
The address space of IPv4 is
or 4,294,967,296.

13. Binary Notation

14. Dotted-decimal notation
Figure 4-1
Dotted-decimal notation

15. Example 1
Change the following IP address from binary notation to dotted-decimal notation.
Solution

16. Example 2
Change the following IP address from dotted-decimal notation to binary notation:
Solution

17. Example 3 Solution Find the error in the following IP Address
Solution
There are no leading zeroes in
Dotted-decimal notation (045)

18. Example 3 (continued) Solution
Find the error in the following IP Address
Solution
In decimal notation each number <= 255
301 is out of the range

19. Finding the class in binary notation

20. Finding the address class

21. Example 5
Show that Class A has
231 = 2,147,483,648 addresses

22. Solution Example 6 Find the class of the following IP addresses
Solution
1st is 0, hence it is Class A
1st and 2nd bits are 1, and 3rd bit is 0 hence, Class C

23. Finding the class in decimal notation

24. Solution Example 7 Find the class of the following addresses
Solution
1st byte = 158 (128<158<191) class B
1st byte = 227 (224<227<239) class D

25. Millions of class A addresses are wasted.

26. Network Addresses The network address is the first address.
The network address defines the network to the rest of the Internet.
Given the network address, we can find the class of the address, the block, and the range of the addresses in the block

27. In classful addressing, the network address (the first address in the block) is the one that is assigned to the organization.

28. Solution Example 8 Given the network address 132.21.0.0, find the
class, the block, and the range of the addresses
Solution
The 1st byte is between 128 and 191.
Hence, Class B
The block has a netid of
The addresses range from to

29. DNS A lookup mechanism for translating objects into other objects
A globally distributed, loosely coherent, scalable, reliable, dynamic database
Comprised of three components
A “name space”
Servers making that name space available
Resolvers (clients) which query the servers about the name space
February 2003

30. Concept: Resource Records
The DNS maps names into data using Resource Records.
More detail later
Resource Record
… A
Address Resource
February 2003

31. DHCP: Why? More work to set up Much more work to change
Manually assigning IP addresses (the alternative to DHCP) causes:
More work to set up
Much more work to change
IP address conflicts
Unsatisfied users who configure their own machines to cause more conflicts

32. DHCP: Why not?
You notice that every Tuesday afternoon, our laboratories were disrupted by “network failure”
This was caused by project students running DHCP servers on our network,
…and recently, by a small router running a DHCP server accidentally plugged into our campus network
Solution: when detect this, run Ethereal listening on ports 67 and 68

33. What can DHCP do? Current standard DHCP servers can:
Allocate all IP parameters
Divide hosts into classes, based on many criteria, such as:
Manufacturer
Explicitly putting individual machines into different classes
Whether the machine is registered
Offer different parameters to machines in different classes
Dynamically update DNS servers
Support a DHCP failover protocol

34. Characteristics of DHCP
All communication initiated by the client
Uses UDP on port 67 for client, port 68 for server
Uses unicast when client has IP address, [and client is not in REBINDING state — see later]; broadcast otherwise
Addresses offered from
address pools, or
Fixed addresses allocated to particular computers

36. To Do List Before Next Lecture
Read Lecture 1 slides.
Revise IP Classes and Subnetting
Come up with Operating System Definition

37. Questions?