Computer_Networking_-_Chapter_6.2

What is the role of the link layer in the protocol stack?

The link layer combines hardware and software to handle data transmission over a link, responding to controller interrupts and managing error conditions.

What are the primary services provided by the link layer?

Error detection and correction for bit corruption in frames sent between physically connected nodes.

What is forward error correction (FEC)?

A technique that allows the receiver to detect and correct errors without needing retransmission from the sender.

What is a single parity bit used for?

It is a basic error-detection method that indicates whether an odd number of bits are corrupted in the data.

What is the limitation of using single parity checks?

It may fail to detect errors if an even number of bits are corrupted, hence undetected errors can occur.

How does two-dimensional parity improve error detection?

It allows the detection and correction of single bit errors by using row and column parity checks.

What is the Internet checksum?

A checksumming method that sums 16-bit integers of data and uses the 1's complement to detect errors.

Why are checksumming methods generally used at the transport layer?

Because they are simple and fast, suitable for implementation in software.

What is cyclic redundancy check (CRC)?

An error-detection technique that uses polynomial arithmetic to detect errors in transmitted data.

What is the function of the generator pattern G in CRC?

It is a predetermined bit pattern that the data must be divisible by to confirm correctness in received data.

What is the main advantage of CRC over simple checksumming?

CRC provides stronger protection against errors and detects burst errors more effectively.

What types of links are discussed in the context of network protocols?

Point-to-point links and broadcast links.

Can nodes on an Ethernet network both send and receive messages?

Yes, nodes can both send and receive messages on a broadcast channel.

What real-world analogy is used for understanding broadcast channels?

A cocktail party, where many people (nodes) can both talk (send) and listen (receive).