Network+ Guide to Networks - Chapter 2
Networking Standards and the OSI Model From: Network+ Guide to Networks 5th Edition - Tamara Dean Course Technology, Cengage Learning
Terms in this set (76)
List the seven layers of the OSI model.
Data Link Layer
What is the main function of the Application Layer in the OSI model?
Provides interface between software applications and network for interpreting applications requests and requirements
Logical Link Control:
The IEEE standard for error and flow control in data frames
The IEEE standard for Ethernet networking devices and data handling (using the CSMACD access method
Token Ring LAN:
The IEEE standard for token ring networking devices and data handling
What is the main function of the Presentation Layer of the OSI Model
Allows hosts and applications to use a common language, performs data formatting, encryption, and congestion
What is the main function of the Session Layer of the OSI Model
Establishes, maintains, and terminates user connections
What is the main function of the Transport Layer of the OSI Model
Ensures accurate delivery of data through flow control, segmentation and reassembly, error correction, and acknowledgement
What is the main function of the Network Layer of the OSI Model
Establishes network connections, translates network addresses into their physical counterparts and determines routing
What is the main function of the Data Link Layer of the OSI Model
Packages data in frames appropriate to network transmission method
What is the main function of the Physical Layer of the OSI Model
Manages signalling to and from physical network connections
What are standards?
Standards are documented agreements containing technical specification or other precise criteria that stipulate how a particular product or service should be designed or performed.
What does OSI stand for?
Open Systems Interconnection Model
Who developed the OSI model?
What is the OSI model?
The OSI model is a theoretical representation of what happens between two nodes communicating on a network.
Give an example of the protocol you will find in the Application Layer of the OSI model
HTTP (Hypertext Transfer Protocol)
In which OSI layer is data encryption and decryption managed?
Name two different Transport Layer Protocols
Connection Oriented Protocols
Name the two sublayers of the Data Link Layer
LLC: Logical Link Control
MAC: Media Access Control
The IEEE standard for routing, bridging, and network to network communication
The IEEE standard for wireless networking for many different broadcast frequencies and usage techniques
Wireless personal area networks:
The IEEE standard for the coexistence of wireless personal area networks \with other wireless devices in unlicensed frequency bands
Broadband wireless metropolitan area networks:
The IEEE standard for the atmospheric interface and related functions associated with broadband wireless connectivity, also known as WiMax
Resilient packet rings:
The IEEE standard for access method, physical layer specifications, and management of shared packet-based transmission on resilient rings
Mobile broadband wireless network:
The IEEE standard for packet handling and other specifications for multi vendor, mobile high-speed wireless transmission
Wireless regional area networks (WRAN):
The IEEE standard for wireless broadcast style network to operate in the UHF / VHF frequency bands formerly used for TV channels
Why do the different industries make use of standards?
To ensure that products, processes and services suit their purposes;
Without standards, it would be very difficult to design a network because you would not be certain that software or hardware from different manufacturers would work together.
Which of the following standards organisations has established guidelines for installing network cables in commercial buildings?
a. TIA / EIA
TIA / EIA
Which technology does the IEEE 802.3 specification describe?
Under what circumstances would the transport layer use segmentation?
When the destination node cannot accept the size of the data blocks transmitted by the source node.
Which layer of the OSI model is responsible for issuing acknowledgments (ACKs)?
Which OSI model layer is responsible for keeping open acommunications path between your computer and the server when you dial in to aremote access server?
Suppose your network is connected to another network via arouter. Which OSI model layer provides the information necessary to direct data between the two networks?
In which two layers of the OSI model do NICs belong?
physical and data link layers
Which OSI model layer generates and detects voltage so as to transmit and receive signals carrying data?
What type of address follows a hierarchical format?
If the TCP protocol did not receive an acknowledgment for data it transmitted, what would it do?
retransmit the data to the recipient
You have just installed a new NIC in your computer and see the following stamped on it: 000A5E1A8DA2. This unique identifier is an example of what kind of address?
Which part of a MAC address is unique to each manufacturer?
What is the purpose of the trailer field added to a frame in the data link layer?
to mark the end of a frame
Which layer of the OSI model encapsulates network layer packets?
data link layer
Suppose that, at the receiving node, a frame's FCS doesn't match the FCS it was issued at the transmitting node. What happens as a result?
the receiving node's link layer requests a retransmission
Give an example where connectionless protocols would be more efficient than connection oriented protocols.
when data needs to be transferred quickly (i.e. video live streaming)
Given an example where connection oriented protocols would be more efficient than connectionless protocols
when data integrity has to be ensured;
when data has to arrive exactly as it was sent;
when data delivery has to be ensured
List the different standards organisations.
ANSI - American National Standards Institute
IEEE - Institute of Electrical and Electronics Engineers
ISO - International Organization for Standardization
ISOC - Internet Society
List some of the functions performed by the Session Layer
Keeping alive the communications link for the duration of the session
Keeping the communication secure
Synchronizing the dialog between the two nodes
Figuring out when to restart communication if it has been cut off
Monitors the identification of session participants, ensuring only authorized nodes can access the session
A response generated at the Transport layer of the OSI model that confirms to a sender that its frame was received.
API (Application Program Interface)
A set of routines that make up part of a software application.
The first set of six characters that make up the MAC address and that are unique to a particular manufacturer.
A method of error checking that determines if the contents of an arriving data unit match the contents of the data unit sent by the source.
A type of Transport Layer protocol that requires the establishment of a connection between communicating nodes before it will transmit data.
A type of Transport Layer protocol that services a request without requiring a verified session and without guaranteeing delivery of data.
CRC (Cyclic Redundancy Check)
An algorithm used to verify the accurace of data contained in a data frame.
The second set of six characters that make up a network device's MAC address. The device ID, which is added at the factory, is based on the device's model and manufacture date.
The process of wrapping one layer's PDU with protocol information so that it can be interpreted by a lower layer.
FCS (Frame Check Sequence)
The field in a frame responsible for ensuring that data carried by the frame arrives intact. It uses an algorithm, such as CRC, to accomplish this verification.
A method of gauging the appropriate rate of data transmission based on how fast the recipient can accept data.
A Network Layer service that subdivides segments it receives from the Transport Layer into smaller packets.
A package for data that includes not only the raw data or payload, but also the sender's and recipient's addressing and control information.
Where are frames generated?
Frames are generated at the Data Link Layer and issues to the network at the Physical Layer.
HTTP (Hypertext Transfer Protocol)
An Application Layer protocol that formulates and interprets requests between Web clients and servers.
IP (Internet Protocol)
A core protocol in the TCP/IP suite that operates in the Network Layer and provides information about how and where data should be delivered. IP is the subprotocol that enables TCP/IP to internetwork.
The Network Layer address assigned to nodes to uniquely identify them on a TCP/IP network. IP addresses consist of 32 bits divided into four octets, or bytes.
A 12-character string that uniquely identifies a network node. The manufacturer hard codes the MAC address into the NIC. This address is composed of the block ID and device ID.
MTU (maximum transmission unit)
The largest data unit a network will accept for transmission.
A unique identifying number for a network node that follows a hierarchical addressing scheme and can be assigned through operating system software. Network addresses are added to data packets and interpreted by protocols at the Network Layer of the OSI model.
PDU (protocol data unit)
A unit of data at any layer of the OSI model
The process of reconstructing data units that have been segmented
A device that connects network segments and directs data based on information contained in the data packet.
A unit of data that results from subdividing a larger protocol data unit.
The process of decreasing the size of data units when moving data from a network that can handle large data units to a network that can handle only smaller data units.
The process of assigning a placeholder to each piece of a data block to allow the receiving node's Transport Layer to reassemble the data in the correct order.
A connection for data exchange between two parties.
A device with little (if any) of its own processing or disk capacity that depends on a host to supply it with applications and data-processing services.
A special control frame that indicates to the rest of the network that a particular node has the right to transmit data.
A networking technology developed by IBM in the 1980s. It relies upon direct links between nodes and a ring topology, using tokens to allow nodes to transmit data.