Application
Presentation
Session
The three layers that I could think of are User interface, Client side, and server side.
There are many more than three protocols which can operate at the application layer. Some of these are; Telnet FTP TFTP SMTP IMAP POP DNS RARP BOOTP SNMP CMOT
I've always considered it to operate at the transport layer as it;s simply an encrypted version of TCP. However, Wikipedia OSI-model lists it as operating at the presentation layer, as it's concerned with the transformation of data between the application and transport layers.
Layer 5 - Session layer
No, At each layer, protocols perform servers unique to that layer. While performing those services, the protocols also interact with protocols in the layers directly above and below. In addition, at the top of the OSI model, Application layer protocols interact with the software you use. At the bottom, Phsyical layer services act on the networking cables and connectors to issue and receive signals.
Rip and BGP is in Application layer Ospf is in Transport Layer
The Application layer The Presentation layer The Session layer
DNS is an application layer protocol. The application layer of the OSI model is the layer closest to the user and provides network services to the applications of the user. Examples of protocols that operate at the application layer are: DNS, FTP, TFTP, SNMP, TELNET, RLOGIN, SMTP, MIME, NFS, FINGER, BOOTP and SMB.
Application layer protocols: DNS and HTTP Transport layer protocols: UDP for DNS and TCP for HTTP
network layer
application
connectionless protocols - transport layer