Connectionless demux: example DatagramSocket DatagramSocket serverSocket new DatagramSocket DatagramSocket mySocket2 new mySocketl new DatagramSocket (6428): DatagramSocket (9157); application (5775); application (P1 application P3 (P4 t币印ot transport nerwork transport network link 水 physical physical physical source port:6428 source port: dest port:9157 dest port: source port:9157 source port: dest port:6428 dest port:? Transport Layer 3-11
Transport Layer 3-11 Connectionless demux: example DatagramSocket serverSocket = new DatagramSocket (6428); transport application physical link network P3 transport application physical link network P1 transport application physical link network P4 DatagramSocket mySocket1 = new DatagramSocket (5775); DatagramSocket mySocket2 = new DatagramSocket (9157); source port: 9157 dest port: 6428 source port: 6428 dest port: 9157 source port: ? dest port: ? source port: ? dest port: ?
Connection-oriented demux TCP socket identified server host may by 4-tuple: support many source IP address simultaneous TCP ■source port number sockets: ■dest IP address each socket identified dest port number by its own 4-tuple demux:receiver uses web servers have all four values to different sockets for direct segment to each connecting client appropriate socket non-persistent HTTP will have different socket for each request Transport Layer 3-12
Transport Layer 3-12 Connection-oriented demux TCP socket identified by 4-tuple: source IP address source port number dest IP address dest port number demux: receiver uses all four values to direct segment to appropriate socket server host may support many simultaneous TCP sockets: each socket identified by its own 4-tuple web servers have different sockets for each connecting client non-persistent HTTP will have different socket for each request
Connection-oriented demux: example application application (P4 (P5(P6 application P3 P2) (P3 ransport transport etwork transport netvork network link hysical link physical server: physical IP address B host:IP source IP,port:B,80 host:IP address dest IP,port:A,9157 source IP,port:C,5775 address A dest IP,port:B,80 C source IP,port:A,9157 dest IP,port:B,80 source IP,port:C,9157 dest IP,port:B,80 three segments,all destined to IP address:B, dest port:80 are demultiplexed to different sockets Transport Layer 3-13
Transport Layer 3-13 Connection-oriented demux: example transport application physical link network P3 transport application physical link P4 transport application physical link network P2 source IP,port: A,9157 dest IP, port: B,80 source IP,port: B,80 dest IP,port: A,9157 host: IP address A host: IP address C network P5 P6 P3 source IP,port: C,5775 dest IP,port: B,80 source IP,port: C,9157 dest IP,port: B,80 three segments, all destined to IP address: B, dest port: 80 are demultiplexed to different sockets server: IP address B
Connection-oriented demux: example threaded server application application P4 application (P3) rangport transport retwork transport netwvork link network link physical link physical server: physical IP address B host:IP source IP,port:B,80 host:IP address dest IP,port:A,9157 source IP,port:C,5775 address A dest IP,port:B,80 C source IP,port:A,9157 dest IP,port:B,80 source IP,port:C,9157 dest IP,port:B,80 Transport Layer 3-14
Transport Layer 3-14 Connection-oriented demux: example transport application physical link network P3 transport application physical link transport application physical link network P2 source IP,port: A,9157 dest IP, port: B,80 source IP,port: B,80 dest IP,port: A,9157 host: IP address A host: IP address C server: IP address B network P3 source IP,port: C,5775 dest IP,port: B,80 source IP,port: C,9157 dest IP,port: B,80 P4 threaded server
Chapter 3 outline 3.1 transport-layer 3.5 connection-oriented services transport:TCP 3.2 multiplexing and segment structure demultiplexing reliable data transfer 3.3 connectionless ■flow control transport:UDP ■connection 3.4 principles of management reliable data 3.6 principles of transfer congestion control 3.7 TCP congestion control Transport Layer 3-15
Transport Layer 3-15 Chapter 3 outline 3.1 transport-layer services 3.2 multiplexing and demultiplexing 3.3 connectionless transport: UDP 3.4 principles of reliable data transfer 3.5 connection-oriented transport: TCP segment structure reliable data transfer flow control connection management 3.6 principles of congestion control 3.7 TCP congestion control