Is my understanding about ***Ethernet - MII & MDI*** correct?

* **MII** - Media Independent Interface is about the connectivity between MAC and PHY. In other words, it is about TXD and RXD signals from MAC to PHY.
* **MDI** - Media Dependent Interface is about the connectivity between PHY and Connector/Jack(RJ45). In other words, it is about TX+/- and RX+/- signals from PHY to RJ45.

Also, I noticed that for 10/100Mbps Ethernet, only 2 differential pairs are needed between PHY transceiver and RJ45 whereas for 10/100/1000Mbps Ethernet, 4 differential pairs are needed between PHY transceiver and RJ45. Is that correct?

It would be really nice if you could post a link to a resource or app note that illustrates the basics of Ethernet connectivity that discusses the concepts above.