Which of the following correctly identifies a layer-specific function that differs between the TCP/IP and OSI models?

This statement accurately describes the functional correspondence between the TCP/IP and OSI models. The TCP/IP model's Internet layer is directly comparable to the OSI model's Network layer. Both layers are fundamentally responsible for logical host addressing (e.g., using IP addresses) and determining the best path for routing packets from a source to a destination across multiple networks. While the models differ in their structure and terminology (e.g., "Internet layer" vs. "Network layer"), the core functions described—addressing and routing—are correctly attributed to their respective layers in this option. The other options contain factual inaccuracies regarding the functions of the specified layers.

A. Error detection is primarily a function of the OSI model's Data Link and Transport layers, not the Physical layer, which deals with the raw bitstream transmission.

B. In the OSI model, encryption and decryption are functions of the Presentation layer (Layer 6), not the Session layer (Layer 5).

D. Packet sequencing is a key function of the connection-oriented protocol TCP, which operates at the Transport layer of the TCP/IP model, not the Application layer.

1. Kurose, J. F., & Ross, K. W. (2021). Computer Networking: A Top-Down Approach (8th ed.). Pearson. In Chapter 1, Section 1.5, "The Internet Protocol Stack," the text explicitly maps the OSI Network Layer to the TCP/IP Internet Layer, stating both are responsible for "routing of datagrams from source to destination." This supports the functions described in option C. The text also assigns sequencing to the Transport Layer (refuting D) and encryption to the Presentation Layer (refuting B).

2. Stallings, W. (2017). Data and Computer Communications (10th ed.). Pearson. In Chapter 2, Section 2.2, "The OSI Model," and Section 2.3, "The TCP/IP Protocol Suite," the author compares the two models. The text confirms that the OSI Network Layer and the TCP/IP Internet Layer both provide the service of routing packets across networks and handling logical addressing.

3. Tanenbaum, A. S., & Wetherall, D. J. (2011). Computer Networks (5th ed.). Prentice Hall. Chapter 1, Section 1.4.3, "The TCP/IP Reference Model," describes the Internet Layer's main function as handling routing. Section 1.4.1, "The OSI Reference Model," describes the Network Layer's key function as determining how packets are routed from source to destination. This directly validates the claims in option C.

4. IETF RFC 1122, Requirements for Internet Hosts -- Communication Layers, October 1989. Section 1.3.3, "INTERNET LAYER -- IP," states, "The internet layer handles the routing of packets for the transport layer." This official document confirms the function of the TCP/IP Internet layer.