So-called second-tier vendors of local area network Ethernet switches are beginning to make inroads into a market currently dominated by the 3Com Corp, Cisco Systems Inc and Bay Networks Inc, hears Natick, Massaachusetts-based Sage Research Inc. The big three, with Cabletron Systems Inc as a distant fourth, are seeing a new challenge from companies such as Digital Equipment Corp, Intel Corp and Madge Networks NV, particularly in sales to smaller companies and those focused on vertical markets. DEC is making an impact selling its Ethernet switch lines to the Government and insurance industry, while Madge has done well in manufacturing and health care. Hewlett-Packard Co and Intel Corp have concentrated their efforts on smaller-sized companies of less than 1,000 employees. Others gaining market share include UB Networks Inc (now owned by Newbridge Networks Inc) IBM Corp and Compaq Computer Corp. Sage has produced a report, culled from interviews with 700 user organizations, on the Ethernet Switch market.