SAN JOSE, Calif., May 16, 1994 -- Cisco Systems has enhanced its SNAintegration solutions with a suite of new router features that willsignificantly improve the performance and reliability of integrated SNA-LANinternetworks.
The key new feature, custom queuing, brings advanced prioritization andbandwidth reservation capabilities to integrated SNA-LAN internetworks,assuring predictable performance and response times for all networkprotocols. Other features include Dynamic Spanning Tree, SDLC broadcastcapability and two-way simultaneous SDLC transmission.
Nick Francis, director of Cisco's IBM product marketing, said, "Withthis new set of features we are going beyond basic market requirements toaddress a number of advanced, specific needs. By fine-tuning our SNAimplementation, we improve our industrial-quality, robust performance."
Custom Queuing: All Protocols Considered
Cisco is the first major router vendor to offer custom queuing, whichaddresses a critical issue in SNA-LAN integration: ensuring that allprotocols running on the network -- not just the one given highest priorityin today's priority output queuing -- receive sufficient bandwidthavailability.While priority output queuing permitted users to assign a specificprotocol absolute priority in obtaining network bandwidth, other protocolscould become "bandwidth starved" in the process. For example, a company'sSNA-based transaction processing data might use up 100 percent of thebandwidth at a given time, bringing the response time for IP-basedengineering data down to zero. Custom queuing solves this problem byguaranteeing a minimum level of service for every protocol.
Cisco routers can now define up to 10 queues and specify the percentageof bandwidth allocated to each queue. If SNA is allocated 50 percent ofthe bandwidth but uses only 30 percent, other protocols can take up theslack until the allocated bandwidth is required by SNA.
A further prioritization refinement allows Cisco routers to distinguishbetween IBM's SNA and NetBIOS protocols. "While SNA and NetBIOS are bothsource-route bridged protocols," Francis said, "they differ radically inthe way they are used: NetBIOS for file transfers, electronic mail,printing, and so on, and SNA for more mission-critical applications such astransaction processing, financial and database. Now a user can ensure thatSNA applications have the priority they need."
Dynamic Spanning Tree: Protecting Source-Route Bridge Investment
Dynamic spanning tree protects the user's installed base of bridges bygiving Cisco routers enhanced interoperability with IBM source-routebridges. It also reduces administration time by eliminating the need tostatically configure a Cisco router and shortens recovery time after linkfailures by making reconfiguration unnecessary.SDLC Broadcasting Supported Across Virtual Multidrop Lines
Cisco currently supports the ability to make multiple physical SDLClines appear as a single virtual multidrop line, simplifying theconfiguration of front-end processors. Today Cisco is enhancing thatsupport with the addition of the SDLC Broadcast feature. With thisfeature, if a front-end processor sends an SDLC Broadcast to a "virtualmultidrop" line, the Cisco router will propagate that broadcast to eachphysical SDLC line associated with the virtual multidrop line. This featureis key in organizations that require the same message to be simultaneouslysent to multiple destinations; for example, a financial institution may belegally required to deliver stock quotations to many locations at the sametime.Two-Way Simultaneous SDLC for Improved Throughput
Two-way simultaneous transmission allows both ends of an SDLC line tosend or receive data concurrently, increasing throughput and reducingresponse time. In multidrop 3270 controller environments, the 3745 can bereceiving data from one device while polling other devices, improving theoverall throughput of the network and response time. In cases where anSDLC line connects two IBM 3745 front-end processors, neither processor hasto wait while the other transmits data.Availability
Available in June, custom queuing will be included with Cisco's basicsoftware offering. All other new features will be shipped this fall andare included with Cisco's bridging software option.Cisco Systems, Inc., is the leading worldwide supplier ofhigh-performance, multimedia and multiprotocol internetworking products,including routers, bridges, workgroup systems for 10-Mbps/100-Mbps datatransmission, ATM switches, communication servers, and router managementsoftware. Cisco technology is used to build enterprise-wide networkslinking an unlimited number of geographically dispersed LANs, WANs and IBMSNA networks. In the United States, Cisco is traded over the counter underthe NASDAQ symbol CSCO.
Posted: May 16 08:29:57 1994
