Routers perform routing at which OSI layer?
Physical
Data Link
Network
Transport
Application
Front
A router is specified at the Network layer and a router routes packets. Routers can also be called layer‐3 switches.
Back
Which layer chooses and determines the availability of communicating partners along with the resources necessary to make the connection, coordinates partnering applications, and forms a consensus on procedures for controlling data integrity and error recovery?
Front
The Application layer is responsible for finding the network resources broadcast from a server and adding flow control and error control (if the application developer chooses).
Back
Which layer specifies voltage, wire speed, and connector pinouts and moves bits between devices?
Front
The Physical layer is responsible for the electrical and mechanical connections between devices.
Back
Which layer of the OSI model is responsible for code and character‐set conversion as well as recognizing data formats?
Application
Presentation
Session
Network
Front
The Presentation layer makes data "presentable" for the Application layer
Back
Which IEEE standard specifies the protocol for CSMA/CD?
802.2
802.3
802.5
802.11
Front
The 802.3 standard, commonly associated with Ethernet, specifies the media‐access method used by Ethernet, which is known as Carrier Sense Multiple Access with Collision Detection (CSMA/CD).
Back
At which layer is routing implemented, enabling connections and path selection between two end systems?
Front
The Network layer provides routing through an internetwork and logical addressing.
Back
Acknowledgments, sequencing, and flow control are characteristic of which OSI layer?
Layer 2
Layer 3
Layer 4
Layer 7
Front
A reliable Transport‐layer connection uses acknowledgments to make sure all data is received reliably. A reliable connection is defined by the use of acknowledgments, sequencing, and flow control, which is characteristic of the Transport layer (Layer 4).
Back
Which of the following mnemonic devices can you use to remember the first letter of the name of each layer of the OSI model in the proper order?
All People Seem To Need Processed Data
Always Should People Never Threaten Dog Police
Please Do Not Throw Sausage Pizza Away
All Day People Should Try New Professions
Front
The phrase "Please Do Not Throw Sausage Pizza Away" contains the first letters of the layers in order from Layer 1 through Layer 7.
"All People Seem To Need Data Processing" works from the top down, but that's not exactly how the option that looks similar, reads.
Back
Which layer manages the transmission of data across a physical link and is primarily concerned with physical addressing and the ordered delivery of frames?
Front
PDUs at the Data Link layer are called frames. As soon as you see frame in a question, you know the answer
Back
Which layer defines how data is formatted, presented, encoded, and converted?
Front
The Presentation layer makes sure that data is in a readable format for the Application layer.
Back
Which layer is responsible for converting data packets from the Data Link layer into electrical signals?
Front
The Physical layer takes frames from the Data Link layer and encodes the 1s and 0s into a digital signal for transmission on the network medium.
Back
Which layer of the OSI model provides a user interface in the form of an entry point for programs to access the network infrastructure?
Application
Transport
Network
Physical
Front
The top layer of the OSI model gives applications access to the services that allow network access.
Back
At which layers of the OSI model do bridges, hubs, and routers primarily operate, respectively?
Physical, Physical, Data Link
Data Link, Data Link, Network
Data Link, Physical, Network
Physical, Data Link, Network
Front
Data Link, Physical, Network
Bridges, like switches, are Data Link‐layer devices. Hubs, like repeaters, are Physical‐layer devices. Routers are Network‐layer devices
Back
Which layer provides logical addressing that routers use for path determination?
Front
The Network layer provides logical addressing, typically IP addressing, and routing.
Back
Which layer combines bits into bytes and bytes into frames and uses MAC addressing?
Front
The Data Link layer is responsible for the framing of data packets.
Back
Which layer is used for reliable communication between end nodes over the network and provides mechanisms for establishing, maintaining, and terminating virtual circuits as well as controlling the flow of information?
Front
The Transport layer uses virtual circuits to create a reliable connection between two hosts.
Back
Which Layer 1 devices can be used to enlarge the area covered by a single LAN segment? (Choose two.)
Switch
NIC
Hub
Repeater
RJ‐45 transceiver
Front
Hub
Repeater
Not that you really want to enlarge a single collision domain, but a hub (multiport repeater) will provide this functionality for you.
Back
A receiving host has failed to receive all the segments that it should acknowledge. What can the host do to improve the reliability of this communication session?
Send a different source port number.
Restart the virtual circuit.
Decrease the sequence number.
Decrease the window size.
Front
A receiving host can control the transmitter by using flow control (TCP uses windowing by default). By decreasing the window size, the receiving host can slow down the transmitting host so the receiving host does not overflow its buffers.
Back
Host 1 sent a SYN packet to Host 2. What will host 2 send in response?
ACK
NAK
SYN‐ACK
SYN‐NAK
SYN
Front
To set up a connection‐oriented session, called a three‐way handshake, the transmitting host sends a SYK packet, the receiving host sends a SYK‐ACK, and the transmitting host replies with the last SYN packet. The session is now set up.
Back
TCP and UDP reside at which layer of the OSI model?
1
2
3
4
Front
TCP and UDP are Transport‐layer protocols. The Transport layer is Layer 4 of the OSI model
Back
Which of the following are types of flow control? (Choose all that apply.)
Buffering
Cut‐through
Windowing
Congestion avoidance
VLANs
Front
Buffering
Windowing
Congestion avoidance
The common types of flow control are buffering, windowing, and congestion avoidance.
Back
What is the purpose of flow control?
To ensure that data is retransmitted if an acknowledgment is not received
To reassemble segments in the correct order at the destination device
To provide a means for the receiver to govern the amount of data sent by the sender
To regulate the size of each segment
Front
To provide a means for the receiver to govern the amount of data sent by the sender
Back
What are two purposes for segmentation with a bridge?
To add more broadcast domains
To create more collision domains
To add more bandwidth for users
To allow more broadcasts for users
Front
To create more collision domains
To add more bandwidth for users
Bridges and switches break up collision domains, which allow more bandwidth for users.
Back
Which layer of the OSI model is responsible for converting data into signals appropriate for the transmission medium?
Application
Network
Data Link
Physical
Front
The Physical layer's job is to convert data into impulses that are designed for the wired or wireless medium being used on the attached segment.
Back
You are connected to a server on the Internet and you click on a link on the server and receive a time‐out message. What layer could be the cause of this message?
Application
Transport
Network
Physical
Front
If the remote server is busy or does not respond to your web browser request, this is an Application layer problem.
Back
Segmentation of a data stream happens at which layer of the OSI model?
Physical
Data Link
Network
Transport
Front
The Transport layer receives large data streams from the upper layers and breaks these up into smaller pieces called segments
Back
Of the following, which is the highest layer in the OSI model?
Transport
Session
Network
Presentation
Front
The Presentation layer is the sixth layer of the model. Only the Application layer is higher, but it is not listed. Session is Layer 5, Transport is Layer 4, and Network is Layer 3.
Back
Which layer is responsible for creating, managing, and terminating sessions between applications?
Front
The Session layer sets up, maintains, and terminates sessions between applications.
Back
When data is encapsulated, which is the correct order?
Data, frame, packet, segment, bits
Segment, data, packet, frame, bits
Data, segment, packet, frame, bits
Data, segment, frame, packet, bits
Front
The encapsulation order is data, segment, packet, frame, bits