In an 802.11 WLAN, suppose the duration of the propagation delay is k, transmission time for RTS, CTS or ACK frames is 5k, SIFS is k, and DIFS is 3k. Assume the sender and the receiver use CSMA/CA with RTS/CTS enabled.

Once the sender finishes sending an RTS (say at time 0), the earliest time before it can completely receive the corresponding CTS is _____ k.

suppose the sender sends a frame that is 100k long (transmission time). The minimum total time that elapses in the exchange of RTS/CTS/data/ACK is ______ k.

Measure time at the sender, from the beginning of the transmission of the RTS until the complete receipt of the ACK.