As a network technology, ethernet flourished in low-cost, low-end markets. Simple to make and with open standards, many companies created products. The resulting improvement in price, performance, and market acceptance resulted in ethernet replacing the more established and sophisticated token-ring technology that dominated early large corporate LANs. As ethernet gets faster, accelerating from the original 10 Mbps into Gigabit speeds, the technology is poised to challenge the dominant backbone and WAN standard, ATM. A discussion of new ethernet developments is formalized with a decision model used to define a market boundary with data illustrating why and where a technology may dominate.