OSI: is a layered, abstract representation created as a guideline for network protocol design. Application Layer, provides human interface to the network.
Differnces between the function of OSI application, presentation and session layers.
The two forms of software programs that provide access to the network which are network-aware applications and application layer services.
The difference between applications, services and protocols.
Client Server Model.
Peer-to-Peer (P2P) Networking and Applications.
Application layer Protocols and Port numbers, ex. DNS - TCP/UDP Port 53, FTP - TCP Ports 20 and 21 and SMTP - TCP Port 25.
Root DNS Servers and TLD Servers.
Different Application layer protocols such as HTTP, HTTPS, FTP, Telnet, SSH, DHCP, DNS, SMTP, POP3, SMB and Gnutella Protocol