Quality of Service
Ethernet volume will drive price low. This and compatibility with legacy Ethernet networks will be the key to its success compared to alternative network solutions such as ATM.
Network size is not an issue with full duplex point-to-point links implemented using fiber channel. Buffered distributor/repeater will deal with collisions and, to the extent that the buffers can handle, there will be fewer collisions.
Guaranteed quality of service will always be an issue. However, in practical situations, just as with present Ethernet, FDDI, etc., network traffic load will be kept low by keeping the number of nodes per subnet low.
Support for real-time services cannot be entirely addressed by protocols. The physical layer of a network that provides guaranteed quality of service should offer connection admission control and predictable packet arrival. Gigabit Ethernet is a connectionless technology that transmits variable length frames and so cannot guarantee that time sensitive packets get priority.