Lecture 19: User Datagram Protocol in Data Communication and Computer Networks, Slides of Data Communication Systems and Computer Networks

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Data Communication

Computer Networks

Lecture # 19

● User Datagram Protocol

Riaz Hussain [email protected] 1

Lecture 18 Review

• W hat is the current IP version?
• W hy do we need IHL (Internet Header Length) when the header is 20 bytes?
• W hat is the purpose of TTL (Time To Live) field?
• W hat is the size of source address and destination address in IP header?
• W hy do we need fragmentation and what is the purpose of fragmentation offset field?
• If
  • flag:More Fragments is 0^ and
  • Fragment offset is is 0 what will you infer from this packet
• W hat is the purpose of option field? Riaz Hussain [email protected] 2

Outline

• (^) User Datagram Protocol Riaz Hussain [email protected] Spring 2008 4

UDP: Introduction

• (^) Connectionless
• Best effort
• Datagram Delivery system
• What does UDP do then?
  • Checksum
    • IP checksum is only for the header
  • Multiplexing
    • IP facilitates communication between hosts
      • (^) IP address (source and destination)
    • Enables applications on the hosts to communicate
      • (^) Port number (source and destination)

http://www.networksorcery.com/enp/protocol/udp.htm

Riaz Hussain [email protected] 5