1 Data Communications and Network Programming: Course Introduction Asst. Prof. Chaiporn Jaikaeo, Ph.D. Computer Engineering Department Kasetsart University, Bangkok, Thailand Second Semester, 2014 Most materials in this presentation were prepared by Assoc. Prof. Anan Phoenphoem (

2 Outline Motivation Growth of Computer Networking Data Communication Networks Protocols and Standards Standard Organizations

3 Motivations Efficient way to share resources Cost – less expensive Accessibility – easier Efficient way to exchange information Time – faster Size – bigger Correctness – accurate

4 Example - A Computer Network Media Links Printer Workstation Laptop Scanner Server

5 Data Communication Hi, how are you? Hi, how are you? Computer you? how are Hi, you? how are Hi,

6 Data Comm. Components Hi How are you doing? 5Protocol 4Medium 3Receiver 2Sender 1Message

7 Protocols and Standards Protocol A set of rules governing data communications Syntax: format of data block Semantics: meaning of each section Timing: speed and sequencing Standards De facto (in practice) standards  not approved but widely adopted De jure (in law) standards  approved by a standard organization, e.g., ISO, IEEE

8 Protocols and Standards To communicate, two devices must follow the same set of communication protocols E.g., they must be connected to the same medium understand each other's messages In other words, they comply with the same standard

9 Data Representation Standards Numbers 8/16/32 bit integers floating point Text ASCII, Unicode Images Bit patterns, Graphics formats JPG/GIF/etc Audio  Samples of continuous signal Video  Sequence of bitmap images

10 Connection Standards Company A Company D Network Interface Card (NIC) Company B Company C

11 Internetworking How to allow devices from different standards to communicate Gateways/routers – devices capable of communicating in several standards These become "network of networks"

12 The Internet The largest internetwork (network of networks) in the world Devices communicating with TCP/IP protocol suite at high level UCLAStanford UC Santa Barbara U. of Utah

13 Internet Growth #computers attached to Internet

14 Recent and Future Trends The availability of high-quality teleconferencing systems Some social networking applications such as Facebook Twitter Google+ Many others The Internet of Things (IoT)

15 Future of the Internet

16 Future of the Internet

17 Future of the Internet

Internet of Things 18

Connected Living 19

Connected Living 20

21 Future of the Internet

22 What Will We Learn in this course Data communication concepts Computer networking devices Internet protocol suite (TCP/IP) Capture and analyze network traffic of well- known applications Network programming Standalone socket applications Web-based applications Web services

23 Languages and Tools Basic network tools ping, traceroute (tracert on Windows) Network traffic monitor Wireshark Programming Java (with Groovy shell)

24 Ping

25 Trace Route

26 Monitoring Network Traffic Sample results from Wireshark

27 Application Program Interface (API) Set of operation for application programmer Specify arguments and semantics

28 Berkeley Socket API API for developing applications that perform inter-process communication in C/C++ most commonly for communications across a computer network, especially UNIX Example functions listen – used by server to wait for contact from client connect – used by client to contact server send – used by either client or server to send data recv – used by either client or server to receive data Java,.NET, Python, etc. provide convenient wrappers around socket API Easier to write than C/C++

29 Web APIs (Web Services) APIs defining set of request and response messages via web context (i.e., HTTP) usually in Extensible Markup Language (XML) or JavaScript Object Notation (JSON) format Examples Facebook API Twitter API Various Google APIs

30 Summary Motivations of computer networking Data Communication components Network application programming and APIs