> Hi Andrew, > > Thanks for you explanation, I still don't quite understand what the use case > it is, could you give me more details, thanks a lot! > AFAIK now, there are two connections methods, we can abstract the layer: > MAC <-> MAC, there is no PHY attached. It seems to know as Fixed link, > right?
Yes, this is the most common way of connecting a switch. > MAC+PHY <-> PHY+MAC Switches can be connected like this, but not often. Why pay for two PHYs which you do not need? > From your expression, you should use an external Ethernet switch, if > yes, why Ethernet switch needs to use MDIO bus to access another > MAC's(STMMAC) PHY? The switch is on the same board as the MAC. Take a look at: https://netdevconf.info/2.1/papers/distributed-switch-architecture.pdf It explains the DSA architecture. Andrew
