1. Lecture 1 Overview of Socket Programming Erick Pranata © Sekolah Tinggi Teknik Surabaya 1

2. » Hosts and Routers » Communication Channel » Packets » Protocol » TCP/IP as Protocol Suite ˃Internet Protocol (IP) ˃Transmission Control Protocol (TCP) ˃User Datagram Protocol (UDP) 2 © Sekolah Tinggi Teknik Surabaya

3. 3 David Makofske, Michael J. Donahoo, Kenneth L. Calvert, TCP/IP Sockets in C#: Practical Guide for Programmers, Morgan Kaufmann, 2004, p. 3

4. GUI being Displayed Application TCP UDP Transport Internet Protocol Datagram Service Internet Routing Network Interface 4 © Sekolah Tinggi Teknik Surabaya

5. » Datagram Service ˃Each IP packet has destination address ˃Best-effort Protocol +May lose +Needs to be reordered +Duplicate packets » TCP and UDP utilize Port Numbers » TCP and UDP are called end-to-end transport » TCP provides error recovery on host-to- host channel ˃UDP doesn’t 5 © Sekolah Tinggi Teknik Surabaya

6. » Internet Address (IP) ˃32-bit (e.g. 10.1.2.3, dotted-quad notation): IPv4 ˃128-bit: IPv6 » Port Number (TCP and UDP) ˃16-bit unsigned binary (1 to 65.535) 6 © Sekolah Tinggi Teknik Surabaya

7. » Example: host.example.com » IP deals with numerical addresses, not names » TCP/IP doesn’t need names ˃It requires extra work to resolve name into address » Advantages: ˃Easier to remember ˃Insulates users from IP address changes » Name-resolution Service ˃DNS ˃Local Configuration Database 7 © Sekolah Tinggi Teknik Surabaya

8. » Client program initiates communication » Server program ˃Waits passively ˃Responds to clients that contact it » Example: ˃Database Application ˃Web Application ˃Directory Services 8 © Sekolah Tinggi Teknik Surabaya

9. » Client needs to know server’s address and port, not vice versa » Server’s address: through name or IP Address » Server’s port number ˃Convention (Internet Assigned Number Authority) +21: FTP +80: HTTP ˃Custom port number 9 © Sekolah Tinggi Teknik Surabaya

10. » An abstraction which allow an application to send and receive data » Different types of socket correspond with different types of protocol suites » TCP/IP Sockets: ˃Stream Sockets (TCP) ˃Datagram Sockets (UDP) 10 © Sekolah Tinggi Teknik Surabaya

11. 11 © Sekolah Tinggi Teknik Surabaya David Makofske, Michael J. Donahoo, Kenneth L. Calvert, TCP/IP Sockets in C#: Practical Guide for Programmers, Morgan Kaufmann, 2004, p. 7

12. » David Makofske, Michael J. Donahoo, Kenneth L. Calvert, TCP/IP Sockets in C#: Practical Guide for Programmers, Morgan Kaufmann, 2004 12 © Sekolah Tinggi Teknik Surabaya