Experimental Analysis of VI Architecture

Abstract

Since the TCP/IP protocol is slow, the Virtual Interface Architecture (VIA) was designed to increase the speed of the connection between machines in a cluster. VIA allows the application program to communicate directly with the Network Interface Card (NIC). It bypasses the TCP/IP protocol stack, therefore decreasing latency and increasing data throughput. VIA was developed to work in a System Area Network (SAN) consisting of a cluster of high volume file servers. This report describes the testing that was done on the Giganet cLAN, the test results, and some comparisons with TCP/IP. The testing that was done with VIA over Giganet cLAN determined the latency for small packet sizes and throughput for large packet sizes. The lowest latency was 14.2 microseconds with a packet size of 288 bytes. The highest throughput was 87.7 MB/second. The report also compares the latency and throughput results with TCP/IP over Giganet cLAN and overGigabit Ethernet using the Intel PRO/1000 Gigabit Server Adapter. An echo program was used to find the latency and throughput of Giganet cLAN and Gigabit Ethernet on the same machines. The average test results of both mediums were close. The lowest latency for TCP/IP over GiganetcLAN was 84 microseconds and the highest throughput was 37.6 MB/sec. The lowest latency forTCP/IP over Gigabit Ethernet was 68 microseconds and the highest throughput was 39.85 MB/sec. For packet sizes over 350 Kbytes, the throughput started to decrease for both Giganet cLAN and Gigabit Ethernet over TCP/IP. Since the throughput decreased with both mediums, the probable cause is the TCP/IP implementation in Windows NT Server 4.0. The average time it takes to make a VI connection was measured at 1.152 microseconds. So in VIA applications, the number of VI connections made should be minimized.