A Tale Of Two Gateways: Bridging The Old And New By Jon Crisler and Thanh Nguyen   With direct TCP/IP to the host, SNA gateways may become a thing of the past. Even IPX, though severely limited, is available on the AS/400. Are these direct communications methods as efficient as SNA on the host? Gateway vendors say no; IBM gives a conditional yes. The customer is caught in the middle. But while the gaps in performance have narrowed between using a gateway and direct protocol support on the ho st, the reasons for using gateways--simplifying desktop protocols, conserving host CPU resources and exploiting existing connection methods--are still valid. To view the Report card. We tested two SNA gateways, Microsoft Corp.'s SNA Server 3.0 and Novell's NetWare for SAA 2.2. Both claim to support at least 1,000 SNA users to both mainframe and AS/400 hosts; run TCP/IP and IPX; have a range of connection options; and run on the Intel platform. Of the many players in the SNA gateway market, only Microsoft and Novell offer products that meet all of the above criteria. Some products were not included in our testing because of limited connection options or host support; others, such as IBM Corp.'s Communications Server for Warp, did not support our required protocols. Our findings surprised us. Although marketed by Microsoft as the superior operating system, Windows NT Server with SNA Server 3.0 was troublesome to install and slower in single CPU configurations. NetWare for SAA was marginally faster in single CPU configurations--and was up and running on the first install. However, Microsoft's Windows NT-based SNA Server offered more features, ease of configuration and management, and scalability with its multiplatform support and superior symmetric multiprocessing (SMP) capabilities. Both gateway options reduced our host CPU utilization by 10 percent or more. In comparison tests with ANYNET, an IBM product that encapsulates SNA traffic inside TCP/IP, the gateways provided up to eight times the throughput, proving that in most cases, gateways still deliver superior performance while reducing CPU load (see "Encapsulating SNA with ANYNET" on Network Computing Online at techweb. cmp.com/nc/812/812r1.html). Microsoft Corp. SNA Server 3.0 Our experience with Microsoft's SNA Server got off to a rough start but finished well. We were impressed with SNA Server's wealth of features, ease of configuration (service pack problems aside), variety of connectivity options and the possibilities offered by its superior SMP support. SNA Server 3.0 will run on NT 3.51 or 4.0, but Microsoft recommends 4.0, and the README file included with SNA server indicates that Service Pack 2 (SP2) for NT Server 4.0 is required. In our tests, SP2 for NT gave us unending grief. Following Microsoft's advice, we finally omitted it and moved on with our testing. But don't confuse Microsoft's service packs: Install the SNA Server 3.0 SP1. It includes a range of fixes and enhancements and reportedly increases the speed of SNA Server by 15 percent. Unlike NetWare for SAA, which comes with a separate Win16 Administration program that runs on a client PC, SNA Server has a well-integrated configuration and administration utility. The Admin program, which has been revised since SNA 2.11, runs only on NT Server or Workstation. Windows 95 and 3.1 Admin programs are not provided. To download an Adobe Acrobat .pdf format version of the SNA Gateways features chart, click here.

How We Tested SNA Gateways For more on IBM's ANYNET, Which provides support for TCP/IP on SNA hosts. ISDN PC Cards Adapters: Tiny Bundles of Remote Connectivity Pack a Punch by Jeffery L . Carrell Updated June 27, 1997