What is piggybacking ?
Piggybacking on Internet access is the
practice of establishing a wireless Internet connection by using another
subscriber's wireless Internet access service without the subscriber's
explicit permission or knowledge. It is a legally and ethically
controversial practice, with laws that vary by jurisdiction around the
world. While completely outlawed or regulated in some places, it is
permitted in others.
Name the two sub layers of Data link layer. Specify their protocols.
1. Logical link control(LLC)
Protocols : SDLC, NetBIOS, NetWare
2. Media access Control (MAC)
Protocols : CSMA/CA, Slotted-ALOHA, CDMA, OFDMA
How we arrived 7 layers of OSI reference model? Why not less than 7 or more than 7 ?
The ISO looked to create a simple model
for networking. They took the approach of defining layers that rest in a
stack formation, one layer upon the other. Each layer would have a
specific function, and deal with a specific task. Much time was spent in
creating their model called "The ISO OSI Seven Layer Model for
Networking". In this model, they have 7 layers, and each layer has a
special and specific function.
Why network standardization is done ?
Computer networking is a great way of
connecting the computers and sharing data with each other. There are
many vendors that produce different hardware devices and software
applications and without coordination among them there can be chaos,
unmanaged communication and disturbance can be faced by the users. There
should be some rules and regulations that all the vendors should adopt
and produce the devices based on those communication standards.
Difference between unacknowledged connection less services and acknowledged connection less services ?
Unacknowledged connectionless
service consists of having the source machine send independent frames to
the destination machine without having the destination machine
acknowledged. Most LAN's use this service.
Acknowledged connectionless service
in this service there are no logical connections used but each frame
sent individually acknowledged. In this way the sender knows whether a
frame has arrived correctly. It is useful on wireless systems
What is frame ?
In computer networking and
telecommunication, a frame is a digital data transmission unit or data
packet that includes frame synchronization, i.e. a sequence of bits or
symbols making it possible for the receiver to detect the beginning and
end of the packet in the stream of symbols or bits.
What is bit stuffing?
Ans: Bit stuffing is the insertion
of one or more bits into a transmission unit as a way to provide
signaling information to a receiver. The receiver knows how to detect
and remove or disregard the stuffed bits.
What is encryption and decryption ?
Ans: Encryption is an algorithm
which converts the message into a form that is unreadable known as
scrambled message and decryption is the process which converts the
encrypted message into readable form known as unscrambled message.
Actually this is a method to transfer message from one side to other in a
secure manner.
What are the various types of key used in cryptography ?
Ans: here are two main types of cryptography:
-
Secret key cryptography
-
Public key cryptography
Secret key cryptography
is also known as symmetric key cryptography. With this type of
cryptography, both the sender and the receiver know the same secret
code, called the key. Messages are encrypted by the sender using the key
and decrypted by the receiver using the same key.
Public key cryptography also
called asymmetric encryption, uses a pair of keys for encryption and
decryption. With public key cryptography, keys work in pairs of matched
public and private keys.
