1. Computer Communication & Networks
Intoduction
Computer Communication & Networks
Course Instructor:
Mr. Asjad Amin
Text Book:
Computer Networks A Top-Down Approach Featuring Internet 3rd Edition
By James F. Kurose && Keith W.Ross

2. Goals of The Course
This course is to provide a combined applied/theoretical background in Data Communications & Networks, focusing the fundamentals of good science and creative engineering

3. Teaching Goals Prepare and Reward good students because
Networks impact quality of life
Unskilled practitioners are dangerous !
Skilled practitioners are valuable
Improve the student skills in
Network design & Analysis
Molding the general minds to Engineering cat
Amplifying IQ

4. Non Goals of the Course This course is not intended to
Train you as a Network Administrator
Focus on the implementation specifics of a particular Vendor
Provide Cisco/Alcatel/3com/Novell certification
But it may make these things easier to learn once you know the general principles and the “Big Picture”

5. Text Book
Why this Text?
In today's time this book is considered as one of the finest equipped with all the modern technology information
Seven of the top 10 engineering universities of the world are using Kurose as Text Book

6. Text Book Stanford University (World Rank # 2)
University of Michigan (World Rank # 4)
University of California – Berkeley (World Rank # 5)
Harvard University (World Rank # 6)
Georgia Institute Technology (World Rank # 7)
University of Texas – Austin (World Rank # 8)
University of California – San Diego (World Rank # 9)

7. Slides Courtesy of Kurose & Ross
Most of the Slides that will be used during the course are provided by Kurose & Ross

8. Data Communication Data Communication Data Compression Error Detection
& Correction

9. Data Compression Objective:
To reduce the size of data so that the usage of storage hardware could be made efficient
There are a hundred of techniques used to achieve the above objective but for our course we will study just two of them. These are the two most commonly used Data Compression techniques

10. Data Compression These two techniques are Lempel-ZIV Algorithm
Run Length Encoding

11. Lempel-ZIV Algorithm At start prefix = NULL Input = 101011011010101011
Divide the Input string into groups with each group containing
A Prefix + one new bit
At start prefix = NULL
The first bit, a 1, has no predecessors, so it has a NULL prefix and one new bit itself 1,
Same goes for the 0 that follows since it can’t be expressed in terms of the only existing prefix
1,0,

12. Lempel-ZIV Algorithm
Continuing in this way we eventually divide the whole string in groups
1,0,10,11,01,101,010,1011
Since we found 8 phrases, we will use a 3 bit code to label the null prefix & the first seven phrases
(000,1) (000,0) (001,0) (001,1) (010,1) (011,1) (101,0) (110,1)
Thus the coded version of Input String is
Output =

13. Run Length Encoding Count + A bit
Input =
Divide the Input string into groups with each group containing
Count + A bit
This can be represented as
(13,1) (17,0) (5,1)
(01101,1) (10001,0)
Output =

14. Thank You