Master OSI model vocabulary: the 7 layers, their responsibilities, and how to describe networking concepts in each layer.
0 / 5 completed
1 / 5
Which OSI layer is responsible for end-to-end connection and reliability (TCP/UDP operate here)?
Layer 4 (Transport) handles end-to-end communication: TCP provides reliable, ordered delivery; UDP provides fast, connectionless delivery. Port numbers also live here.
2 / 5
The PDU (Protocol Data Unit) at Layer 3 (Network) is called a:
Layer 3 PDU = Packet (or datagram). Layer 2 = Frame. Layer 4 = Segment (TCP) or Datagram (UDP). Knowing these terms is essential for precise network troubleshooting vocabulary.
3 / 5
The purpose of ARP (Address Resolution Protocol) is to:
ARP maps IP addresses to MAC addresses within a local network segment — when a device knows the IP it wants to reach but needs the MAC address to send the frame.
4 / 5
A subnet mask of /24 means:
/24 (or 255.255.255.0) gives a 256-address block: 254 usable hosts (minus network and broadcast addresses). CIDR notation is used everywhere in networking documentation.
5 / 5
NAT (Network Address Translation) allows:
NAT enables private IP address spaces (192.168.x.x, 10.x.x.x) to communicate externally through a single public IP — conserving IPv4 addresses and providing implicit firewall functionality.