Question $1$

$[25$ marks$]$

$1\mathrm{.}1$ Robert is establishing a small office network for his startup and aims to ensure smooth communication between devices and efficient future troubleshooting. He has acquired a router, a switch, several computers, and a network printer. Robert has segmented his network into the Sales, Marketing, and Development departments, planning to use wired and wireless connections. He wants a clear understanding of data flow within the network and the function of each network device according to the Open Systems Interconnection $($OSI$)$ model.

Robert has connected the computers and the printer to the switch using Ethernet cables. Explain which OSI model layers are primarily responsible for addressing and routing data within this local network setup.

$[6$ marks$]$

$1\mathrm{.}2$ When a router receives multiple route advertisements for the same destination from various routing protocols, it uses a specific feature to determine the preference or trustworthiness of different routing sources or protocols. Discuss this feature, its purpose, and its implementation.

$[9$ marks$]$

$1\mathrm{.}3$ The fundamental responsibility of a router is to select the best path for transferring data packets from one network to another. Explain how routers make forwarding decisions.

$[10$ marks$]$