All experiments were performed in a testbed consisting of 4 Sun Microsystems SPARCstation 20 model 61 workstations (60MHz SuperSPARC+, 36KB L1, 1MB L2, SPECint92 98.2) as the client machines. The workstations are equipped with 32MB of memory and run SunOS 4.1.3_U1. Our server is a dual processor SPARCStation 20 constructed from 2 erstwhile SPARCStation 20 model 61 machines. This machine has 64MB of memory and runs Solaris 2.5.1. A 155 Mbit/s ATM local area network connects the machines, using FORE Systems SBA-200 network adaptors. For our HTTP server, we used the NCSA httpd server software, revision 1.5.1. In our experiments we used no artificial delay in the router connecting the clients and the server. We have not yet quantitatively evaluated the effect of WAN delays on server performance.
The server's OS kernel was tuned using Web server performance enhancing tips advised by Sun. That is, we increased the total pending connections (accept+SYN-RCVD queues) limit to 1024 and decreased the TIME-WAIT period to 3 seconds.