Data link layer

Question 1

what are the several protocols that can be used by layer 2 to direct traffic to network?

Answer 1

Ethernet
* Frame Relay
* High-Level Data Link Control (HDLC)
* Multi-Protocol Label Switching (MPLS)
* and others
* Ethernet is the default Protocol at Layer 2. Any other
protocol would be specified.

Question 2

logical link control

Answer 2

Communicates between
the networking software
at higher layers and the
device hardware
* Deals with addressing,
multiplexing, and
acknowledgment
messages

Question 3

Media Access Control

Answer 3

Responsible for data
encapsulation/de-
encapsulation and access
to the physical media
* Controls interaction
between devices
* Provides frame
synchronization

Question 4

sublayers of the datalink layer

Answer 4

Media access control
logical link control

Question 5

Data link layer frame structure

Answer 5

Frame Header
* Data Link Header (HD)

Payload
* Usually upper-layer data
* May include control information for the Layer 2 protocol
* Encapsulates the layer 3 PDU (Packet)

Frame Trailer
* Data Link Trailer (TD)
* Optional
* When present usually error-checking information

Question 6

header

Answer 6

frame start - indicates the start of the frame