Data Link Layer

A service that the data link layer provides is: (a)   ​ ​ (b)   i

• it defines end-to-end delivery addressing scheme
• provides reliable delivery with flow control
• manages the access of frames to the network media
• packages layer 3 pdus into a frame

What is contained in the trailer of a data-link frame?

• logical address

• physical address

• data

• error detection

Which statement describes a characteristic of the frame header fields of the data link layer?

• They all include flow control and logical connections fields

• Ethernet frame header fields contain Layer 3 source and destination addresses

• They vary depending on protocols

• They include information on user applications

A network team is comparing physical WAN topologies for connecting remote sites to a headquarters building. Which topology provides high availability and connects some, but not all, remote sites?

• 
• 
• 
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Answer explanation

An extended star topology is when:

• end devices connect to a central, intermediary device, which in turn connects to other central intermediate devices.

• end devices are connected together by a bus and each bus connects to a central intermediate device.

• Each end system is connected to its respective neighbor via an intermediate device.

During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?

• An IP Address is added

• The logical address is added

• The physical address is added

• The process port number is added

What three items are contained in an Ethernet header and trailer?​ (a)   ​ (b)   ​ (c)  

• source MAC address
• destination MAC address
• error-checking information
• source IP address
• destination IP address

What type of communication rule would best describe CSMA/CD?

• access method

• flow control

• message encapsulation

• message decoding

Which three basic parts are common to all frame types supported by the data link layer?

• header

• type field

• CRC value

• data

• trailer

Which statement is true about the CSMA/CD access method that is used in Ethernet?

• When a device hears a carrier signal and transmits, a collision cannot occur.

• A jamming signal causes only devices that caused the collision to execute a backoff algorithm

• All network devices must listen before transmitting

• Devices involved in a collision get priority to transmit after the backoff period.