Exam 4: Data Link Layer

What is media access control and why is it important? What are two examples of controlled access methods and contention based media access methods? When might one access method be preferred over another in a network, and why? Under what conditions do contention-based media access control techniques outperform controlled-access techniques i.e., have lower response time)? Explain.

The probability of detecting an error, given that one has occurred, using parity checking is about:

In an odd parity-checking scheme, the parity bit is set to make the total number of ones in the byte including the parity bit) an even number.

_____________ is an effective way to prevent attenuation.

As part of the five-layer network model used in this textbook, the data link layer sits directly between:

Which of the following is not an error detection method used in the data link layer?

Which of the following is true about the data link protocol, PPP?

Transmission efficiency refers to the percentage of bits transmitted without errors.

With __________ ARQ, the sender immediately sends the next message or packet of data.

Briefly define noise.Describe five types of noise and the underlying causes of this noise.Which type of noise is likely to pose the greatest problem to network managers? What does error look like in a data network?

HDLC is very similar to the SDLC synchronous data link protocol.

One type of forward error correction is the Hamming code.

Forward error correction is commonly used in satellite transmission.

Contention is commonly used with Ethernet local area networks.

Synchronous transmission:

Ethernet has been refined over the years and is now formally standardized as IEEE802.3ac.

In ARQ, a NAK:

Which of the following is true about the data link protocol, SDLC:

Asynchronous transmission:

The primary source of error in data communications is: