Ch. 6 | Data Link Layer

Routers are responsible for encapsulating a frame. This process is done in five steps, arrange these steps from first to last. Forwards the new frame appropriate to the medium Re-encapsulates the packet into a new frame De-encapsulates the frame Determines the best path to forward the packet Accepts a frame from a medium

1. Accepts a frame from a medium 2. De-encapsulates the frame 3. Determines the best path to forward the packet 4. Re-encapsulates the packet into a new frame 5. Forwards the new frame appropriate to the medium

Which of the following are data link layer protocols? (choose three) A. 802.11 B. Ethernet C. IP D. PPP E. UDP

A. 802.11 B. Ethernet D. PPP

What Layer 2 function does a router perform? (choose three) A. Accepts a frame from a medium B. De-encapsulates the frame C. Re-encapsulates the packet into a new frame D. Refers to its Layer 3 routing table for a matching destination network

A. Accepts a frame from a medium B. De-encapsulates the frame C. Re-encapsulates the packet into a new frame

Which data link layer media access control method does Ethernet use? A. CSMA/CD B. Determinism C. Turn taking D. Token passing

A. CSMA/CD

What is the function of the last field in a data link layer frame? A. To determine whether the frame experienced transmission errors. B. To identify special flow control services C. To identify the beginning and end limits of the frame D. To identify the Layer 3 protocol in the data field

A. To determine whether the frame experienced transmission errors.

Which LAN topology is a hybrid topology? A. Bus B. Extended star C. Ring D. Star

B. Extended star

The media access control method used depends on which two criteria? A. Layer 3 IP protocol B. Media sharing C. Topology D. Transport layer protocol E. Type of data

B. Media Sharing C. Topology

A legacy topology system where all systerms were chained to each other and terminated in some form on each end.

Bus

What method is used to manage contention-based access on a wireless network? A. CSMA/CD B. Priority ordering C. CSMA/CA D. Token passing

C. CSMA/CA

What does the data link layer add to a Layer 3 packet to create a frame? (Choose two.) A. Flags B. Sequence number C. Header D. Trailer E. Nachos

C. Header D. Trailer

What are two services performed by the data link layer of the OSI model? (Choose two.) A. It encrypts data packets B. It determines the path to forward packets C. It accepts Layer 3 packets and encapsulates them into frames D. It provides media access control and performs error detection E. It monitors the Layer 2 communication by building a MAC address table.

C. It accepts Layer 3 packets and encapsulates them into frames D. It provides media access control and performs error detection

What attribute of a NIC would place it at the data link layer of the OSI model? A. Attached Ethernet cable B. IP address C. MAC address D. RJ-45 Port E. TCP/IP protocol stack

C. MAC address

A technician has been asked to develop a physical topology for a network that provides a high level of redundancy. Which physical topology requires that every node is attached to every other node on the network? A. Bus B. Hierarchical C. Mesh D. Ring E Star

C. Mesh

What is the responsibility of the MAC sublayer? A. Adds Layer 3 address to the frame B. Communicates with the network layer (Layer 3) C. Provides the method to get the frame on and off the media D. Transmits the bits on the media.

C. Provides the method to get the frame on and off the media

What type of physical topology can be created by connecting all Ethernet cables to a central device? A. Bus B. Ring C. Star D. Mesh

C. Star

________ does not detect collisions but attempts to avoid them by waiting before transmitting. Each device that transmits includes the time duration that it needs for the transmission. All other wireless devices receive this information and know how long the medium will be unavailable.

Carrier Sense Multiple Access/Collision avoidance (CSMA/CA)

In _________-____ multiaccess networks, all nodes are operating in half-duplex, competing for the use of the medium.

Contention-based

Portion of a frame that identifies special flow control services such as quality of service (Qos).

Control

In a ________-_____ multiaccess network, each node has its own time to use the medium.

Controlled-Based

Which media access control method is used in legacy Ethernet LANs? A. Carrier sense multiple access/collision annoyance B. Carrier sense multiple access/collision avoidance C. Carrier sense multiple access/collision destruction D. Carrier sense multiple access/collision detection

D. Carrier sense multiple access/collision detection

Which lists the Layer 2 and Layer 3 address fields in the correct order? A. Destination NIC, Source NIC, Destination IP, Source IP B. Source NIC, Destination NIC, Destination IP, Source IP C. Source NIC, Destination NIC, Source IP, Destination IP D. Destination IP, Source NIC, Source IP, Destination IP

D. Destination IP, Source NIC, Source IP, Destination IP

What kind of network would use point-to-point, hub and spoke, or mesh topologies? A. PAN B. LAN C. WLAN D. WAN

D. WAN

What two pieces are contained within the trailer portion of a frame?

Error detection Frame stop

What four pieces are contained within the header portion of a frame?

Frame start Addressing Type Control

Which duplex communication method is used in WLANs?

Half-duplex

What are the three basic parts of each frame type?

Header Data Trailer

A WAN version of the star topology in which a central site interconnects branch sites through the use of point-to-point links.

Hub and Spoke

Which organization defines standards for the network access layer (i.e., the OSI physical and data link layers)?

IEEE

Which two engineering organizations define open standards and protocols that apply to the data link layer? (Choose two.)

International Organization for standards (ISO) International Telecommunication Union (ITU)

This sublayer communicates between the networking software at the upper layers and the device hardware at the lower layers. It places information in the frame that identifies which network layer protocol is being used for the frame.

Logical Link Control (LLC), (IEEE 802.2)

This type of topology refers to the way a network transfers frames from one node to the next. It identifies virtual connections using device interfaces and Layer 3 IP addressing schemes.

Logical topology

What identifier is used at the data link layer to uniquely identify an Ethernet device?

MAC address

This sublayer controls the NIC and other hardware that is responsible for sending and receiving data on the wired or wireless LAN/MAN medium.

Media Access Control (MAC)

This topology provides high availability but requires that every end system is interconnected to every other system.

Mesh

This type of topology identifies how end devices and intermediary devices (i.e., routers, switches, and wireless access points) are interconnected.

Physical topology

The simplest and most common WAN topology. It consists of a permanent link between two endpoints.

Point-to-point

A flow control service that gives forwarding priority to certain types of messages.

Quality of Service (QoS)

A legacy topology system where end systems were connected to their respective neighbor forming a circle.

Ring

True or False? The MAC sublayer also provides media access control, allowing multiple devices to communicate over a shared (half-duplex) medium. Full-duplex communications do not require access control.

True

True or False? There is no one frame structure that meets the needs of all data transportation across all types of media?

True

True or False? Today, Ethernet networks operate in full-duplex and do not require an access method.

True

A transmitting node creates a logical summary of the contents of the frame, known as the ___ value.

cyclic redundancy check (CRC)

The CRC valur is placed in the ___ field to represent the contents of the frame. This provides a method for the receiving node to determine whether the frame experienced transmission errors.

frame check sequence (FCS)

In computer networks, a ____ is a device that can receive, create, store, or forward data along a communications path.

node