Will@cup.portal.com (Will E Estes) (01/23/91)
I would like some opinions and/or test results that would give me a basis for comparing performance of a client server application under one of two configurations. In both configurations the client side is a 386 PC running MS-DOS and connecting to the host using a 2400 bps modem. Configuration One: Server is an IBM mainframe running VM/CMS accessed through a protocol converter or, alternately, accessed through a TCP/IP Ethernet and router that supports asynchronous TCP/IP access. Configuration Two: Server is a multi-processor UNIX machine (e.g., a Sequent S81 with 20 386 processors) accessed through direct modem connections or, alternately, accessed through a TCP/IP Ethernet and router that supports asynchronous TCP/IP access. The application is similar in concept to CompuServe's Informatino Manager (CIM) or Connect Inc.'s Connect software: the user interface is on the PC and E-mail, conferencing, and database engines are on the host side. The protocol used to exchange messages between client-server may be built from scratch (in the case of using protocol converters or direct-connect modems) or based on something standard like TCP (in the case of an Ethernet attachment to the host). I have been told that the application's performance is likely to be poor under Configuration One if we use the protocol converter, but no one has been able to quantify the response time difference. Does anyone have any opinions regarding the four options? (i.e., 1) IBM host w/protocol converter, 2) IBM host w/Ethernet connection and asynch TCP router, 3) UNIX host with direct modem connections, 4) UNIX host w/Ethernet connection and asynch TCP router) I'm also interested in anyone's thoughts on how asynch TCP/IP (e.g., SLIP or PPP) is likely to perform over on a 2400 bps line in both configurations, and are there preferred alternatives? Thanks, Will Estes (apple!cup.portal.com!Will)