The shift is from a single collision domain towards the multiple collision domain which is possible because of evolution of network technology such as switch and the 100 base-T form of media.
This has has isolated as transmission and reception on two separate wires. No collision hence no need for CSMA/CD.
There is a requirement of multi-port switches. This brings the capability for increased port density to enable the connection of a greater number of end system devices within a single local area network
Each end system or host within a local area network is required to be connected as part of the same IP network in order for communication to be facilitated at the network layer. The IP address however is only relevant to the host systems since switch devices operate within the scope of the link layer and therefore rely on MAC addressing for frame forwarding.