Figure 11-2: Client/Server Computing Client/Server Processing with Request-Response Cycle Request Message Client Program Response Message Server Program Does Light I/O and Post-Download Does Heavy Processing Database and other Heavy Client PC Processing File server Highly scalable: Use larger server as number of clients increases 6
6 Figure 11-2: Client/Server Computing File Server Client PC Highly scalable: Use larger server as number of clients increases Client/Server Processing with Request-Response Cycle Client Program Server Program Request Message Response Message Does Light I/O and Post-Download Processing Does Heavy Database and Other Heavy Processing
Figure 11-3: Web-Enabled Application(E-Mail) Http reQuest Message Client is Browser Http Response mEssage Server program Web-enabled applications Form of client server processing that uses browsers as clients Almost all client Pcs now have browsers Client pc No need to install new software E-Mail server 7
7 Figure 11-3: Web-Enabled Application (E-Mail) E-Mail Server Client PC Client is Browser Server Program HTTP Request Message HTTP Response Message Web-enabled applications: Form of client server processing that uses browsers as clients Almost all client PCs now have browsers. No need to install new software
Figure 11-5: E-Mail Standards SMTP o Send SMTP To Send Sender's mail Receiver's mail Server Server Simple mail Transfer Protocol Sending Receiving E-Mail (SMTP)is used to transmit mail E-Mail Client in real time to a user's mail Client server or between mail servers Sender-initiated
9 Figure 11-5: E-Mail Standards 2. SMTP To Send 1. SMTP To Send Sending E-Mail Client Receiving E-Mail Client Sender’s Mail Server Receiver’s Mail Server Simple Mail Transfer Protocol (SMTP) is used to transmit mail in real time to a user’s mail server or between mail servers Sender-initiated
Figure 11-5: E-Mail Standards POP OI IMAP To Receive Sender's mail Receiver's mail Server Server Sending E-Mail POP or IMAP to download mail to ReceIving Client receiver when the receiver next E-Mail downloads mail Client Receiver-initiated 10
10 Figure 11-5: E-Mail Standards Sending E-Mail Client Receiving E-Mail Client Sender’s Mail Server Receiver’s Mail Server POP or IMAP To Receive POP or IMAP to download mail to receiver when the receiver next downloads mail. Receiver-initiated