3 - D.L.L Protocols Flashcards
1
Q
D.L.L Services (3)
A
- bundling groups of bits into frames for P.L
- throttling the flow of frames between sender and receiver
- detecting and correcting “higher-level” transmission errors
2
Q
The three levels of D.L.L Complexity
A
- Simplex Connectionless
- Half-Duplex Connectionless
- Full-Duplex Connection-orientated
3
Q
Used to detect frame corruption
A
Checksums
4
Q
Detecting Frame Loss
A
Use ACK
5
Q
Benefits of Network Simulations (3)
A
- different aspects can be controlled and examined on very dynamic networks
- need to test for errors
- centralised control of a network
6
Q
StopandWait Protocol
A
- Sends packet and waits for ACK to be received before sending the next one off
7
Q
Frame Pipelining
A
Sender transmits many frames until the medium is full and then wait for ACK indicating that frames have been received correctly,
“permit multiple outstanding frames
8
Q
Go-back-N Protocol
A
Requires receiver to simply discard all frames after bad one, corresponding to window size of 1
9
Q
Selective Repeat Protocol
A
Receiver buffers all frames and waits for the bad frame to be retransmitted
10
Q
Problem with selective repeat
A
Disaster when the ACK frame is sent from receiver but not received by transmitted
Soln - make window sizes half the size of the max seq number
