Question

For Networks -> Please tell me about the following:

1. Why are CRCs used over checksums in many cases?
2. What is a sliding window protocol?
3. How does the Go-Back-N sliding window work?
4. How does the Selective Repeat sliding window work?
5. What is PPP?

Answer 1

1) because CFC has greater ability to detect errors because-

it has a math formula based on 16/32 bit encoding whereas checksum gets it value from sum of data(8bits).

Also crc uses hash formula.Crc is basically an improved version of Checksum.

2) This protocol controls the transmission of data packets between two networks computers to ensure realibility and sequential flow of the data packets.

3)Working- Data packets are sent from sender to receiver in sequential format in such a manner that when the acknowledgement of receiving the data packet is not received by the sender from the receiver , the all the packets - starting from the packet(for which acknowledgement is not received ) is sent all over again.

4)sender sends the data in the frames to the receiver.Receiver records the sequence no. Of the incorrect frame and keeps on filling the receiving window with the correct frames. The receiver then sends the sequence no. Of the incorrect/missing frames along with each acknowledgement frame.Sender sends the missing frames after sending the all the existing frames in its sending window.

5) PPP is Point to Point Protocol.It is protocol of data link layer which is used to send multiprotocol data between two directly or point to point connected nodes of the network.