MENLO PARK, Calif., Aug. 30, 1993 -- Cisco Systems has successfullytested its high-end routers with ATM (Asynchronous Transfer Mode) switchesfrom five vendors, and has announced that it will support the ATM DataExchange Interface (DXI), a standard for routers operating in ATM networks.

Cisco 7000 and AGS+ routers, in combination with Digital Link DL3200Digital Service Interfaces and ADC Kentrox DataSMART T3/E3 ADSUs (ATM DataService Units), were tested with ATM switch products from Fore Systems,GTE, NEC, Newbridge Networks and TRW. The router decides where on the ATMnetwork each packet should go, then passes it to the ATM DSU. The ATM DSUsegments the packet into fixed-length cells and transmits them at DS3 or E3speeds (45 or 34 megabits per second) over an ATM network.

Developed by the ATM Forum, the ATM DXI specification describes howrouters communicate with ATM DSUs. Support for the ATM DXI will begenerally available as part of Cisco 7000 and AGS+ software in mid-1994.

The ATM DXI is an open specification that will be offered by the ATMForum to vendors and users, according to Larry Lang, Cisco ATM productmanager and chairman of the ATM Forum's DXI Working Group. A preliminaryversion of the proposed specification was used in Cisco's interoperabilitytesting with ATM switches.

"The extensive interoperability tests we've done should put users'minds at rest about being locked to any one vendor's AT switch," Lang said."We've proven that data can be sent over our router to any of fiveswitches. And our support for the ATM Forum's DXI specification will ensurea further level of interoperability between routers and DSUs."

Delivery of the ATM DXI will complete Phase II of Cisco's three-partATM development program, Lang said. In Phase I, Cisco and ADC Kentroxjointly developed a router/DSU combination that supported an interface toSMDS (Switched Multi-Megabit Data Service), the first available cell-basedservice. Phase II replaced the SMDS DSU with an ATM DSU. In Phase III, cellprocessing will be moved inside the router in the form of a directrouter-switch interface, eliminating the need for a stand-alone DSU; thisinterface is being demonstrated in Cisco's booth at the Interop 93 Augustconference.