3 Connection-Oriented and Connectionless protocols
3. Connection-Oriented and Connectionless Protocols
Figure 2-6: Connection-Oriented and Connectionless protocols Connection-Oriented Protocol Connectionless Protocol A A Open connection Message (No Sequence Number) Message 1(Seg. Num=A1) Connection-oriented protocols have Message 3 (Seq Num B Formal openings and closings like Telephone calls Message 2 (Seq Num= A2) Also have sequence numbers so that the receiver can put Close Connection messages in order And so the receiver can send Acknowledgments for specific messages
2-17 Figure 2-6: Connection-Oriented and Connectionless Protocols Message (No Sequence Number) Connectionless Protocol A B Message 1 (Seq. Num = A1) Message 2 (Seq. Num = A2) Close Connection Connection-Oriented Protocol Open Connection A B Message 3 (Seq. Num B1) Connection-oriented protocols have Formal openings and closings like Telephone calls Also have sequence numbers so that the receiver can put messages in order And so the receiver can send Acknowledgments for specific messages
Figure 2-6: Connection-Oriented and Connectionless Protocols continued Client PC Webserver Browser Application Http Request Http is connectionless No Openings No Closings No Sequence Numbers No Acknowledgments 2-18
2-18 Figure 2-6: Connection-Oriented and Connectionless Protocols, Continued Client PC Browser Webserver Application HTTP Request HTTP is connectionless No Openings No Closings No Sequence Numbers No Acknowledgments
Figure 2-6: Connection-Oriented and Connectionless Protocols continued In tcP Client pc Webserver TCP Process TCP Process Connection-Opening Messages Messages During the Connection Ime Connection-Closing messages 2-19
2-19 Figure 2-6: Connection-Oriented and Connectionless Protocols, Continued Client PC TCP Process Webserver TCP Process Connection-Opening Messages Time Connection-Closing Messages Messages During the Connection In TCP
Figure 2-7: Advantages and Disadvantages or Connection-Oriented protocols Advantages Thanks to sequence numbers the parties can tell if a message is lost Error messages, such as acKs can refer to specific messages Long messages can be fragmented into many smaller messages that can fit inside packets Fragmentation followed by reassembly on the destination host is an important concept in networking 2-20
2-20 Figure 2-7: Advantages and Disadvantages or Connection-Oriented Protocols • Advantages – Thanks to sequence numbers, the parties can tell if a message is lost. – Error messages, such as ACKs can refer to specific messages. – Long messages can be fragmented into many smaller messages that can fit inside packets. • Fragmentation followed by reassembly on the destination host is an important concept in networking