QUESTIONS WITH DETAILED EXPLANATIONS
2026
◉ Physical Layer.
Answer: network interface or some device that can connect to a
network, LANs broadcast frames
◉ Data Link Layer.
Answer: responsible for data transmission in a LAN.
◉ LLC.
Answer: Logical Link Layer. services for flow control, acks, and
correcting physical error.
◉ MAC.
Answer: Medium Access Control. defines protocol for data transfer.
◉ Network Layer (IP Layer).
Answer: responsibilities are routing and delivery. connectionless
and unreliable. can send messages in mulitple packets.
,◉ Transport Layer.
Answer: TCP in TCP/IP. adds guarantees and quality of service, acks
and checksums, message sequencing.
◉ 3 Way Handshake.
Answer: TCP has it. Client requests connection by sending out a SYN
packet, server responds by sending a SYN/ACK packet, an ack for the
connection, client responds w/ ACK to the server establishing
connection
◉ Application Layer.
Answer: One of 3 upper layers. closest to end users, HTTP for web.
adds TCP information, each layer adds its metadata.
◉ Protocol.
Answer: Defines rules for communication between computers.
◉ Connectionless.
Answer: send out data as soon as able to transmit, typically stateless
◉ Connection-oriented.
Answer: provides reliable connection stream between two nodes
, ◉ Internet Protocol.
Answer: connectionless, encapsulate TCP and UDP packets into link
layer frames, unreliable, best effort service, no acks, packets can be
lost or reordered.
◉ IP Header.
Answer: source and destination addresses, header checksum, packet
length, time to live, protocol version, protocol information
◉ IP Routing.
Answer: router bridges two or more networks. maintains tables to
forward packets to correct network.
◉ Internet Control Message Protocol.
Answer: used for network testing and debugging. simple messages
encapsulated in single IP packets. ICMP
◉ ICMP Tools.
Answer: ping - sends echo requests and gives states on RT times and
packet loss. Traceroute - sends ICMP packets w/ increasing TTL
value to discover routes
◉ Network Address Translation (NAT).