snmp-trap bootps bootpc https finger 33434 traceroute Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Transport Technologies Chapter 7 The Transmission Control Protocol (TCP) TCP provides a connection-oriented communication service across the network. It stipulates rule sets for message formats, establishing virtual circuit establishment and termination, data sequencing, flow control, and error correction. Most applications designed to operate within the TCP/IP protocol suite use TCP's reliable, guaranteed delivery services. In TCP, the transmitted data entity is referred to as a segment because TCP does not operate in message mode: It simply transmits blocks of data from a sender and receiver. The fields that make up the segment, shown in Figure 7-39, are described in this section. The source port and the destination port identify the originating and terminating connection points of the end-to-end connection as well as the higher-layer application. The sequence number identifies this particular segment's first byte in the byte stream, and since the sequence number refers to a byte count rather than to a segment, the sequence numbers in sequential TCP segments are not, ironically, numbered sequentially. Figure 7-39 Source Port Destination Port The TCP header Sequence Number Acknowledgment Number Header Reserved Window Size Length Flags TCP Checksum Urgent Pointer TCP Options Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Transport Technologies Transport Technologies The acknowledgment number is used by the sender to acknowledge to the transmitter that it has received the transmitted data. In practice, the field identifies the sequence number of the next byte that it ex