Data Link Layer

Question 1

Does the Data link layer encapsulate Layer 3 packets into Layer 2 frames? Where do Layer 3 packets come from?

Answer 1

Yes. IPv4, IPv6

Question 2

T/F - The data link layer does not do error detection

Answer 2

False

Question 3

Name the 2 Data link layer sublayers

Answer 3

Logical Link Control (LLC) and Media Access Control (MAC)

Question 4

Name this: Responsible for data encapsulation and its name

Answer 4

MAC

Question 5

Name this: Communicates between the networking software at the upper layers and device hardware at the lower layers

Answer 5

LLC

Question 6

At each hop along a path within a packet exchange the router will perform 4 layer 2 functions

A
D
R
F

Answer 6

Accepts the frame
De-encapsulates the frame to expose the packet
Re-encapsulates the packet in a new frame
Forwards the new frame

Question 7

Name this topology: the simplest and most common WAN topology. Consists of a permanent link between two endpoints.

Answer 7

point-to-point

Question 8

Name this topology: similar to a star topology where a central site
interconnects branch sites through point-to-point links

Answer 8

Hub and spoke

Question 9

Name this topology: provides high availability but requires every end system to be connected to every other end system.

Answer 9

Mesh

Question 10

Name this: All nodes operating in half-duplex, competing for use of each medium

Answer 10

Contention-based access

Question 11

What are some examples of contention-based access? What do the final 2 characters in each stand for?

Answer 11

CSMA/CD and CSMA/CA. Collision detection, collision avoidance.

Question 12

Name this: When transmitting, devices also include the time duration needed for the transmission. Other devices on the shared medium receive the time duration and know how long the medium will be unavailable.

Answer 12

Collision Avoidance