TCP and IP Chapter 03
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TCP provides reliable, ordered delivery of data through the use of sequence numbers and acknowledgments. It accumulates data into segments and ensures delivery through retransmissions. UDP is a simpler protocol that does not ensure delivery or order, making it faster but unreliable. IP handles addressing and fragmentation of packets to accommodate networks with different maximum sizes. IPv6 was developed to support more devices, longer addresses, extension headers and simplified header processing.
TCP and IP Chapter 03
- 1. Chapter 3 TCP and IP Chapter 3 TCP and IP 1
- 2. Introduction • Transmission Control Protocol (TCP) • User Datagram Protocol (UDP) • Internet Protocol (IP) • IPv6 Chapter 3 TCP and IP 2
- 3. TCP • RFC 793, RFC 1122 • Outgoing data is logically a stream of octets from user • Stream broken into blocks of data, or segments • TCP accumulates octets from user until segment is large enough, or data marked with PUSH flag • User can mark data as URGENT Chapter 3 TCP and IP 3
- 4. • Similarly, incoming data is a stream of octets presented to user • Data marked with PUSH flag triggers delivery of data to user, otherwise TCP decides when to deliver data • Data marked with URGENT flag causes user to be signaled Chapter 3 TCP and IP 4
- 5. Checksum Field • Applied to data segment and part of the header • Protects against bit errors in user data and addressing information • Filled in at source • Checked at destination Chapter 3 TCP and IP 5
- 6. Options • Maximum segment size • Window scale factor • Timestamp Chapter 3 TCP and IP 6
- 7. Figure 2.1 Chapter 3 TCP and IP 7
- 8. UDP • RFC 768 • Connectionless, unreliable • Less overhead • Simply adds port addressing to IP • Checksum is optional Chapter 3 TCP and IP 8
- 9. Appropriate Uses of UDP • Inward data collection • Outward data dissemination • Request-response • Real-time applications Chapter 3 TCP and IP 9
- 10. IP • RFC 791 • Field highlights: – Type of service, defined in RFC 1349, see Figure 3.1 – More bit – Don’t fragment bit – Time to live (similar to a hop count) Chapter 3 TCP and IP 10
- 11. Figure 2.2 Chapter 3 TCP and IP 11
- 12. Figure 3.1 Chapter 3 TCP and IP 12
- 13. Fragmentation and Reassembly • Networks may have different maximum packet size • Router may need to fragment datagrams before sending to next network • Fragments may need further fragmenting in later networks • Reassembly done only at final destination since fragments may take different routes Chapter 3 TCP and IP 13
- 14. Figure 3.2 Chapter 3 TCP and IP 14
- 15. Type of Service TOS Subfield • Set by source system • Routers may ignore TOS • Router may respond to requested TOS value through: – Route selection – Subnetwork service – Queuing discipline Chapter 3 TCP and IP 15
- 16. Table 3.1 Chapter 3 TCP and IP 16
- 17. Type of Service Precedence Subfield • Indicates degree of urgency or priority • Like TOS subfield, may be ignored and there are 3 approaches to responding • Intended to affect queuing discipline at router – Queue service – Congestion control Chapter 3 TCP and IP 17
- 18. IPv4 Options • Security • Source routing • Route recording • timestamping Chapter 3 TCP and IP 18
- 19. IPv6 • Increase IP address from 32 bits to 128 • Accommodate higher network speeds, mix of data streams (graphics, video, audio) • Fixed size 40-octet header, followed by optional extension headers • Longer header but fewer fields (8 vs 12), so routers should have less processing Chapter 3 TCP and IP 19
- 20. IPv6 Header • Version • Traffic class • Flow label • Payload length • Next header • Hop limit • Source address • Destination address Chapter 3 TCP and IP 20
- 21. IPv6 Addresses • 128 bits • Longer addresses can have structure that assists routing • 3 types: – Unicast – Anycast – multicast Chapter 3 TCP and IP 21
- 22. Figure 3.3 Chapter 3 TCP and IP 22
- 23. Optional Extension Headers • Hop-by-hop options • Routing • Fragment • Authentication • Encapsulating security payload • Destination options Chapter 3 TCP and IP 23
- 24. Figure 3.4 Chapter 3 TCP and IP 24