Curs PC si internet cap 12.2 TCP and UDP

12.2 TCP and UDP 12.2.1 TCP Instructor Note The purpose of this target indicator is to identify the key properties of TCP. It also locates TCP on the protocol graph of the TCP/IP stack. The purpose of this target indicator is not that the student memorize all of the fields of a TCP segment. Rather, if they can describe the most important features of segments that is sufficient. Also, it is important to relate segments to the other PDUs -- segments are encapsulated into packets which are encapsulated into frames which are converted to a bit stream on the media. The students have already seen Ethernet, Token Ring, and FDDI frame formats; and IP datagrams -- relate the TCP segment format explicitly to those diagrams. Transmission Control Protocol (TCP) is a connection-oriented Layer 4 (transport layer) protocol that provides reliable full-duplex data transmission. TCP is part of the TCP/IP protocol stack. - Following are the definitions of the fields in the TCP segment:source port -- number of the calling port destination port -- number of the called port sequence number -- number used to ensure correct sequencing of the arriving data acknowledgment number - next expected TCP octet HLEN -- number of 32-bit words in the header reserved -- set to zero code bits -- control functions (such as setup and termination of a session) window -- number of octets that the sender is willing to accept checksum -- calculated checksum of the header and data fields urgent pointer -- indicates the end of the urgent data option-one option -- maximum TCP segment size data -- upper-layer protocol data 12.2 TCP and UDP 12.2.2 UDP Segment Format Instructor Note The purpose of this target indicator is to identify the key properties of UDP. It also locates UDP on the protocol graph of the TCP/IP stack:The purpose of this target indicator is not that the student memorize all of the fields of a UDP segment. Rather, if they can describe the most important features of segments that is sufficient. Also, it is important to relate segments to the other PDUs -- segments are encapsulated into packets which are encapsulated into frames which are converted to a bit stream on the media. The students have already seen Ethernet, Token Ring, and FDDI frame formats; and IP datagrams -- relate the TCP segment format explicitly to those diagrams. User Datagram Protocol (UDP) is the connectionless transport protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams, without acknowledgments or guaranteed delivery. Error processing and retransmission must be handled by other protocols. UDP uses no windowing or acknowledgments, therefore application layer protocols provide reliability. UDP is designed for applications that do not need to put sequences of segments together. Protocols that use UDP include: TFTP SNMP DHCP DNS (Domain Name System)