Information Technology Reference
In-Depth Information
•
LAPB (link access procedure balanced) is used in X.25 packet switched networks;
•
LAPM (link access procedure for modems) is used in error correction modems;
•
LLC (logical link control) is used in Ethernet and Token Ring networks;
•
LAPD (link access procedure D-channel) is used in Integrated Services Digital Networks
(ISDNs).
Node A
Node B
Error in
reception
Figure I.9
Example flow
Node A
Node B
0
1
2
Acknowledgement
up to and including
frame 2
0
Acknowledgement
up to and including
frame 1
3
4
Acknowledgement
up to and including
frame 4
1
5
6
Figure I.10
Example flow with piggy-backed acknowledgement
