Ethernet – point-to-point VS point-to-multipoint

ethernetinternetpoint-to-point

I readed some articles but I still don't undestand the difference,
is point-to-point transmites unicast messages, so point-to-multipoint uses broadcasts ?
is point-to-point consist of one dedicated physical cable, so point-to-multipoint consist of shared routes ?….
and wich topology is used in Internet and Ethernet ?

Best Answer

Most of time, the terms point to point or point to multipoint refer to logical topology, not physical topology. One can configure P2P or P2MP on various type of media, and the ability to use broadcasts depends on the type of media you have.

Ethernet is usually considered a broadcast media, where every station can hear every other station, but modern switched Ethernet makes it act like P2P, because the switch connects a sender and receiver with a single logical connection. And when you have a single Ethernet cable connecting two devices, that can also be considered a P2P connection although the media is still broadcast.

In the context of OSPF configuration, again it's a logical topology, so you get to decide how it's configured.