1. What layer of the OSI model is responsible for determining the availability of the receiving program and checking to see if enough resources exist for that communication? a) Transport b) Network c) Presentation d) Session Answer: a) Transport Rationale: The transport layer ensures that messages are delivered errorfree, in sequence, and with no losses or duplications. It relieves the higher layer protocols from any concern with the transfer of data between them and their peers. 2. A network administrator uses a network utility to test the reachability of a host on an adjacent network. Which of the following utilities did they most likely use? a) netstat b) ping c) tracert d) nslookup Answer: b) ping Rationale: The ping utility is used to test the reachability of a host on an IP network and to measure the round-trip time for messages sent from the originating host to a destination computer. 3. Which of the following best describes the function of a router? a) It connects multiple IP subnets. b) It controls access to hardware on a network. c) It broadcasts data to all devices on a network. d) It serves as the endpoint for data transfer. Answer: a) It connects multiple IP subnets. Rationale: Routers are devices that forward data packets along networks. They connect at least two networks together and determine the best path for data to travel. 4. In the context of TCP/IP model, which protocol is responsible for ensuring the reliable delivery of data?