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Chapter 7 - Transport layer protocols. Chapter 7 provides knowledge of TCP, UDP, SPX, and NCP. This chapter includes contents: Connection-oriented protocol; provides packet acknowledgment and flow control, much like TCP; used for NetWare file sharing traffic, among many other functions | Chapter 7 Transport Layer Protocols 1 Chapter Overview A. TCP and UDP B. SPX and NCP Chapter 7 Lesson 1 TCP and UDP 1. TCP 2 A. TCP characteristics 1. TCP is the acronym for Transmission Control Protocol. 2. Connection-oriented protocol 3. Reliable 4. Used to carry relatively large amounts of data such as entire files 5. Complements Internet Protocol IP by providing services that IP lacks 6. Defined in Request for Comments RFC 793 published by the Internet Engineering Task Force IETF 3 7. TCP functions a. Guaranteed delivery b. Packet acknowledgment c. Flow control d. Error detection e. Error correction B. The TCP header 1. TCP encapsulates application layer data by applying a header. 4 2. Segmentation a. TCP splits the message received from the application layer into datagram-sized segments and encapsulates each segment with its own header. b. The collection of segments that make up an application layer message is called a sequence. c. The destination end system reassembles the segments into the original sequence. d. The segmentation process is completely separate from the network layer fragmentation process. 1 In other words the segments produced by TCP can later be fragmented by IP. 5 3. The TCP message format a. Source Port 2 bytes . Identifies the process on the transmitting system that generated the information carried in the Data field b. Destination Port 2 bytes . Identifies the process on the receiving system for which the information in the Data field is intended c. Sequence Number 4 bytes . Identifies the location of the data in this segment in relation to the entire sequence d. Acknowledgment Number 4 bytes . In acknowledgment ACK messages this field specifies the sequence number of the next segment expected by the receiving system. e. Data Offset 4 bits . Specifies the number of 4-byte words in the TCP header 6 f. Reserved 6 bits . Unused g. Control Bits 6 bits . Contains 6 flag bits that identify the functions of the message h. Window 2 bytes . .
