About $802\mathrm{.}3$ Ethernet, hubs and switches$($i$)$ Early $10$Mbps $802\mathrm{.}3$ Ethernet is $1-$Persistant CSMA$/$CD $($CSMA:Carrier Sense Multiple Access, CD: Collision Detection$).$ Briefly explain how $1-$Persistant CSMA$/$CD functions. $1-$Persistent CSMA$/$CD station detects the channel constantly to verify its status, for example idle or active, so that data can be transmitted or not. In the event that the channel is busy, the station will wait until the channel is idle. It transmits the frame to the channel without any delay when the station has detected an idle channel. It transmits a frame with a probability of $1.-$If the channel is busy, listen until the channel is clear, then transmit immediately.$-$If two or more stations is waiting for a free signal, so there would certainly be a collision with a free channel.$-$If the collision happens, wait a random period of time, then try again $($ii$)$ Briefly explain how an $802\mathrm{.}3$ Ethernet hub that supports spanning trees operate? Spanning tree bridges$/$switches$/$hubs are self configuring. They configure themselves after power$-$on to be part of a Spanning Tree $($ST$)$ according to the distributed ST algorithm of Radia Perlman, as defined in the IEEE $802\mathrm{.}1$ D specification. $($iii$)$ Briefly explain how the receiver MAC layer acknowledges a MAC frame sent by the sender MAC layer.