Which TCP/IP sub-protocol operates at the Layer7 of the OSI model?
Which TCP/IP sub-protocol operates at the Layer7 of the OSI model?
The Transmission Control Protocol/Internet Protocol (TCP/IP) suite contains several protocols operating at different layers of the OSI model. Layer 7 is the Application layer, which supports end-user processes and provides services directly to applications. NFS (Network File System), which operates at this layer, facilitates file sharing over a network. Hence, it is the correct answer as it directly involves application-layer interactions. UDP and MAC, on the other hand, do not operate at Layer 7; UDP operates at Layer 4 (Transport layer), and MAC (Media Access Control) functions at Layer 2 (Data Link layer). SNMP (Simple Network Management Protocol) also operates at the Application layer but primarily focuses on network management rather than direct end-user application communication, making NFS a more suitable answer.
● Application (Layer 7 or L7): This layer identifies and establishes availability of communication partners, determines resource availability, and synchronizes communication. ● Presentation (Layer 6 or L6): This layer provides coding and conversion functions (such as data representation, character conversion, data compression, and data encryption) to ensure that data sent from the Application layer of one system is compatible with the Application layer of the receiving system. ● Session (Layer 5 or L5): This layer manages communication sessions (service requests and service responses) between networked systems, including connection establishment, data transfer, and connection release. ● Transport (Layer 4 or L4): This layer provides transparent, reliable data transport and end-to-end transmission control.
● Network (Layer 3 or L3): This layer provides routing and related functions that enable data to be transported between systems on the same network or on interconnected networks. Routing protocols are defined at this layer. Logical addressing of devices on the network is accomplished at this layer using routed protocols such as Internet Protocol (IP). Routers operate at the Network layer of the OSI model. ● Data Link (Layer 2): This layer ensures that messages are delivered to the proper device across a physical network link. ● Physical (Layer 1 or L1): This layer sends and receives bits across the network medium (cabling or wireless links) from one device to another. It specifies the electrical, mechanical, and functional requirements of the network, including network topology, cabling and connectors, and interface types, and the process for converting bits to electrical (or light) signals that can be transmitted across the physical medium.
Correct answer : D