What are the responsibilities of Presentation Layer?
The Presentation layer is concerned with the syntax and semantics of the information
exchanged between two systems.
a. Translation
b. Encryption
c. Compression
What are the responsibilities of Application Layer?
The Application Layer enables the user, whether human or software, to access the network.
It provides user interfaces and support for services such as e-mail, shared database management
and other types of distributed information services.
a. Network virtual Terminal
b. File transfer, access and Management (FTAM)
c. Mail services
d. Directory Services
What are the two classes of hardware building blocks?
Nodes and Links.
What are the different link types used to build a computer network?
a. Cables
b. Leased Lines
c. Last-Mile Links
d. Wireless Links
What are the categories of Transmission media?
a. Guided Media
i. Twisted - Pair cable
1. Shielded TP
2. Unshielded TP
ii. Coaxial Cable
iii. Fiber-optic cable
b. Unguided Media
i. Terrestrial microwave
ii. Satellite Communication
What are the types of errors?
a. Single-Bit error
In a single-bit error, only one bit in the data unit has changed
b. Burst Error
A Burst error means that two or more bits in the data have changed.
What is Error Detection? What are its methods?
Data can be corrupted during transmission. For reliable communication errors must be deducted
and Corrected. Error Detection uses the concept of redundancy, which means adding extra bits
for detecting errors at the destination. The common Error Detection methods are
a. Vertical Redundancy Check (VRC)
b. Longitudinal Redundancy Check (VRC)
c. Cyclic Redundancy Check (VRC)
d. Checksum
What is Redundancy?
The concept of including extra information in the transmission solely for the purpose of comparison.
This technique is called redundancy.
What is VRC?
It is the most common and least expensive mechanism for Error Detection. In VRC, a parity bit is added
to every data unit so that the total number of 1s becomes even for even parity. It can detect all single
-bit errors. It can detect burst errors only if the total number of errors in each data unit is odd.
What is LRC?
In LRC, a block of bits is divided into rows and a redundant row of bits is added to the whole block.
It can detect burst errors. If two bits in one data unit are damaged and bits in exactly the same positions
in another data unit are also damaged, the LRC checker will not detect an error. In LRC a redundant data
unit follows n data units.
What is CRC?
CRC, is the most powerful of the redundancy checking techniques, is based on binary division.
What is Checksum?
Checksum is used by the higher layer protocols (TCP/IP) for error detection
The Presentation layer is concerned with the syntax and semantics of the information
exchanged between two systems.
a. Translation
b. Encryption
c. Compression
What are the responsibilities of Application Layer?
The Application Layer enables the user, whether human or software, to access the network.
It provides user interfaces and support for services such as e-mail, shared database management
and other types of distributed information services.
a. Network virtual Terminal
b. File transfer, access and Management (FTAM)
c. Mail services
d. Directory Services
What are the two classes of hardware building blocks?
Nodes and Links.
What are the different link types used to build a computer network?
a. Cables
b. Leased Lines
c. Last-Mile Links
d. Wireless Links
What are the categories of Transmission media?
a. Guided Media
i. Twisted - Pair cable
1. Shielded TP
2. Unshielded TP
ii. Coaxial Cable
iii. Fiber-optic cable
b. Unguided Media
i. Terrestrial microwave
ii. Satellite Communication
What are the types of errors?
a. Single-Bit error
In a single-bit error, only one bit in the data unit has changed
b. Burst Error
A Burst error means that two or more bits in the data have changed.
What is Error Detection? What are its methods?
Data can be corrupted during transmission. For reliable communication errors must be deducted
and Corrected. Error Detection uses the concept of redundancy, which means adding extra bits
for detecting errors at the destination. The common Error Detection methods are
a. Vertical Redundancy Check (VRC)
b. Longitudinal Redundancy Check (VRC)
c. Cyclic Redundancy Check (VRC)
d. Checksum
What is Redundancy?
The concept of including extra information in the transmission solely for the purpose of comparison.
This technique is called redundancy.
What is VRC?
It is the most common and least expensive mechanism for Error Detection. In VRC, a parity bit is added
to every data unit so that the total number of 1s becomes even for even parity. It can detect all single
-bit errors. It can detect burst errors only if the total number of errors in each data unit is odd.
What is LRC?
In LRC, a block of bits is divided into rows and a redundant row of bits is added to the whole block.
It can detect burst errors. If two bits in one data unit are damaged and bits in exactly the same positions
in another data unit are also damaged, the LRC checker will not detect an error. In LRC a redundant data
unit follows n data units.
What is CRC?
CRC, is the most powerful of the redundancy checking techniques, is based on binary division.
What is Checksum?
Checksum is used by the higher layer protocols (TCP/IP) for error detection
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