Chapter 2:Application Layer Our goals: learn about protocols ▣conceptual,. by examining popular implementation application-level aspects of network protocols application protocols *HTTP transport-layer FTP service models ÷SMTP/POP3/IMAP *client-server DNS paradigm ▣programming network peer-to-peer applications paradigm socket API 2:Application Layer 32: Application Layer 3 Chapter 2: Application Layer Our goals:  conceptual, implementation aspects of network application protocols ❖ transport-layer service models ❖ client-server paradigm ❖ peer-to-peer paradigm  learn about protocols by examining popular application-level protocols ❖ HTTP ❖ FTP ❖ SMTP / POP3 / IMAP ❖ DNS  programming network applications ❖ socket API