Hi everyone, I have some questions about 802.11 module (i.e., mac-802_11.cc). 1. Where is physical carrier sensing? It seems *is_idle()* only checks* tx_state_, rx_state_* and *nav_*, but does not check physical carrier state. 2. What's the difference between defer timer (*mhDefer_*) and backoff timer (*mhBackoff_*)? Why not just use one such as backoff timer? 3. When the channel is sensed busy, the backoff timer should refrain from counting down. But I only see *mhBackoff_.start()*. Does the timer freeze when channel is busy? If yes, which part of the code shows this?
I will be truly grateful if you can help me clarify these questions. p.s. My apology if you receive this message twice. The system asked me to re-send because this is my first message. -Xiaohui Liu
