Networking Fundamentals

Match each device to the addressing layer it uses and the job it does.

• Router: moves packets between networks using routing tables (IP addresses).
• Switch: forwards frames inside one network using its MAC address table.
• Hub: repeats every bit to every port — no intelligence.
• Firewall: blocks unwanted traffic with ACL rules (permit/deny).
• Managed switch: the only listed device that can create VLANs.
• Punchdown block: attaches bare wires (110/66 style) — no connector.
• ONT (Optical Network Terminal): where fiber Internet terminates instead of a cable or DSL modem.

• Cat 5e is the lowest UTP grade rated for 100 Mbps.
• Single-mode fiber (SMF) offers the longest segment lengths — kilometers vs 100 m for UTP.
• 10GBaseER = extended-range 10 Gbps fiber; a 5 km run fits easily.
• Ethernet NICs use CSMA/CD: sense the cable and transmit only when it is clear.
• Bluetooth is the standard described as a wireless personal area network (WPAN).

• SAN advantages per the guide: more storage space on the network and more efficient data storage.
• Backups are a policy you run, not an automatic property of a SAN.