In a Token Ring network (IEEE 802.5), what is the formula for channel efficiency when 2a < 1 (where $a = Tp / Tx$)?
For the stated Token Ring model with 2a < 1, the standard efficiency expression is eta = 1/(1+a), where $a = Tp/Tx$.
In HDLC (High-Level Data Link Control), which frame type is used to carry user data?
HDLC uses I-frames for user data transfer, S-frames for flow/error control (ACK/NACK), and U-frames for link management.
What is Piggybacking in Data Link Layer flow control?
Piggybacking is the technique of temporarily delaying outgoing ACKs so they can be embedded into the header of the next outgoing data frame.
Which medium access control protocol uses Inter-Frame Spaces (IFS) such as SIFS and DIFS to prioritize transmissions?
IEEE 802.11 Wireless LANs use CSMA/CA with SIFS (Short IFS) for high priority ACKs and DIFS (DCF IFS) for normal data frame contention.
In CSMA/CA, what is the main purpose of sending RTS (Request to Send) and CTS (Clear to Send) control frames?
RTS/CTS reservation handshake mitigates the Hidden Terminal Problem in wireless networks by reserving the medium around both sender and receiver.