OSI model
During the data encapsulation process, theData Link layerof the OSI model is responsible for adding a header that contains MAC addressing information and a trailer used for error checking.The header typically includes the source and destination MAC addresses, while the trailer contains a Frame Check Sequence (FCS) which is used for error detection1.
The Data Link layer ensures that messages are delivered to the proper device on a LAN using hardware addresses and translates messages from the Network layer into bits for the Physical layer to transmit. It also controls how data is placed onto the medium and is received from the medium through the physical hardware.
References:=
* The OSI Model - The 7 Layers of Networking Explained in Plain English
* OSI Model - Network Direction
* Which layer adds both header and trailer to the data?
* What is OSI Model | 7 Layers Explained - GeeksforGeeks

Router
Theshow running-configcommand is used on a Cisco router to display the current operational settings that are actively configured in the router's RAM. This command outputs all the configurations that are currently being executed by the router, which includes interface configurations, routing protocols, access lists, and other settings. Unlikeshow startup-config, which shows the saved configuration that the router will use on the next reboot,show running-configreflects the live, current configuration in use.
References:= The information is supported by multiple sources that detail the use of Cisco commands, particularly theshow running-configcommand as the standard for viewing the active configuration on a Cisco device123.
* show running-config: This command displays the current configuration running on the router. It includes all the operational settings and configurations applied to the router.
* show protocols: This command shows the status of configured protocols on the router but not the entire configuration.
* show startup-config: This command displays the configuration saved in NVRAM, which is used to initialize the router on startup, but not necessarily the current running configuration.
* show version: This command provides information about the router's software version, hardware components, and uptime but does not display the running configuration.
References:
* Cisco IOS Commands: Cisco IOS Commands

Explanation:
Here's how each protocol aligns with the correct TCP/IP model layer:
* TCP (Transmission Control Protocol): This protocol belongs to theTransportlayer, which is responsible for providing communication between applications on different hosts1.
* IP (Internet Protocol): IP is part of theInternetworklayer, which is tasked with routing packets across network boundaries to their destination1.
* FTP (File Transfer Protocol): FTP operates at theApplicationlayer, which supports application and end-user processes.It is used for transferring files over the network1.
* Ethernet: While not a protocol within the TCP/IP stack, Ethernet is associated with theNetwork Interfacelayer, which corresponds to the link layer of the TCP/IP model and is responsible for the physical transmission of data1.
The TCP/IP model layers are designed to work collaboratively to transmit data from one layer to another, with each layer having specific protocols that perform functions necessary for the data transmission process1.
* TCP:
* TCP Model Layer: Transport
* Explanation: The Transport layer is responsible for end-to-end communication and error handling. TCP (Transmission Control Protocol) operates at this layer to provide reliable, ordered, and error-checked delivery of data.
* IP:
* TCP Model Layer: Internetwork
* Explanation: The Internetwork layer, also known as the Internet layer, is responsible for logical addressing and routing. IP (Internet Protocol) operates at this layer to route packets across networks.
* FTP:
* TCP Model Layer: Application
* Explanation: The Application layer provides network services to applications. FTP (File Transfer Protocol) operates at this layer to transfer files between computers over a network.
* Ethernet:
* TCP Model Layer: Network
* Explanation: The Network layer, also known as the Link layer in the TCP/IP model, is responsible for physical addressing and access to the physical medium. Ethernet operates at this layer to provide the physical and data link functions.
* Transport Layer: This layer is responsible for providing communication services directly to the application processes running on different hosts. TCP is a core protocol in this layer.
* Internetwork Layer: This layer is responsible for logical addressing, routing, and packet forwarding.
IP is the primary protocol for this layer.
* Application Layer: This layer interfaces directly with application processes and provides common network services. FTP is an example of a protocol operating in this layer.
* Network Layer: In the TCP/IP model, this layer includes both the data link and physical layers of the OSI model. Ethernet is a protocol used in this layer to define network standards and communication protocols at the data link and physical levels.
References:
* TCP/IP Model Overview: Cisco TCP/IP Model
* Understanding the TCP/IP Model: TCP/IP Layers

The tracert command output shows the path taken to reach the destination IP address, 192.168.1.10. The command output indicates:
*Hops 1 and 2 are successfully reached.
*Hop 3 times out, meaning the router at hop 3 did not respond to the tracert request. However, this does not necessarily indicate a problem with forwarding packets, as some routers may be configured to block or not respond to ICMP requests.
*Hops 4 and 5 are successfully reached, with hop 5 being the destination IP 192.168.1.10, indicating that the server is reachable.
Thus, the correct answer is C. The server with the address 192.168.1.10 is reachable over the network.
References :=
*Cisco Traceroute Command
*Understanding Traceroute
The tracert command output indicates that the server with the address 192.168.1.10 is reachable over the network. The asterisk (*) at hop 3 suggests that the probe sent to that hop did not return a response, which could be due to a variety of reasons such as a firewall blocking ICMP packets or the router at that hop being configured not to respond to ICMP requests. However, since the subsequent hops (4 and 5) are showing response times, it means that the packets are indeed getting through and the server is reachable12.
References :=
*How to Use Traceroute Command to Read Its Results
*How to Use the Tracert Command in Windows

When prioritizing trouble tickets, the most critical issues affecting business operations or high-impact activities should be addressed first. Here's a breakdown of the tickets:
* Ticket 1: Relocation of a printer, while necessary, is not urgent and does not impact critical operations.
* Ticket 2: An ongoing webinar losing internet access is critical, especially if the webinar is time-sensitive and involves multiple participants.
* Ticket 3: Slower response time for a cloud-based application is important but typically not as urgent as a complete loss of internet access for a live event.
* Ticket 4: Wireless access down in the cafeteria affects users but does not have the same immediate impact as a live webinar losing connectivity.
Thus, the correct answer is B. Ticket 2: An online webinar is taking place in the conference room. The video conferencing equipment lost internet access.
References:=
* IT Help Desk Best Practices
* Prioritizing IT Support Tickets