Networking Fundamentals Practice Question 1: TCP IP Layer Mapping
Networking Fundamentals · Test 1 · question 1 of 10
A new help desk technician is learning to map the seven-layer OSI model onto the four-layer TCP/IP model used on the Internet. The OSI Network layer (layer 3), where IP addressing and routing between networks happen, corresponds to which TCP/IP layer?
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Answer:
The TCP/IP model (as described in RFC 1122) has four layers: Link, Internet, Transport and Application. The Internet layer is where the Internet Protocol (IP) lives; it carries datagrams from the source host to the destination host, across routers if needed. That is the same job as the OSI Network layer (layer 3), so B is correct.
- A. Link layer covers talking on the directly connected network (Ethernet, Wi-Fi, ARP). It maps to OSI layers 1 and 2 (Physical and Data Link), not layer 3. - C. Transport layer provides end-to-end communication for applications with TCP and UDP. It maps to OSI layer 4. - D. Application layer holds protocols such as HTTP, DNS and SMTP. It roughly covers OSI layers 5-7 (Session, Presentation, Application).
Reference: RFC 1122 - Requirements for Internet Hosts: Communication Layers, section 1.3.1