The primary functions of an Internet Information Server are to establish connections for its clients, to receive and interpret requests, and to deliver files, all as quickly as possible. The pace at which these vital functions are performed depends, in large part, on two factors: the effective bandwidth of the link between the server and the network and on the capacity of this link and the server to support network resources.
This chapter examines bandwidth and network capacity on an Internet Information Server and suggests methods you can use to measure and improve transmission rates and connection handling on your server. This chapter is not intended as a comprehensive guide to network monitoring. Instead, it is a limited presentation of the network-related issues that are important on servers running Internet Information Server (IIS).
This chapter includes the following sections:
"Defining Bandwidth and Network Capacity." This section defines the terms bandwidth and network capacity.
"Monitoring Transmission Rates." This section describes the Performance Monitor counters available for measuring transmission rates. Transmission rates are a primary measure of bandwidth on an Internet Information Server.
"Monitoring File Transfers." This section describes the Performance Monitor counters that display the number of files and directory listings sent and received by each IIS service. These counters can be used to determine the level of a particular service's network activity or the effect of file activity on server components.
"Monitoring TCP Connections." This section describes the Performance Monitor counters on the TCP object that monitor the rate at which Transmission Control Protocol (TCP) connections are established, failed, and reset. The ability to establish and maintain connections is a primary indicator of the effective network capacity of a server.
"Using Network Monitor to Monitor Bandwidth." Network Monitor enables you to examine the packets sent and received by the local computer. It is an optional tool included with Windows NT Server. This section suggests some Network Monitor fields to watch when measuring bandwidth.
"Limiting Bandwidth." On multipurpose servers, you might want to limit the proportion of the server's bandwidth used by IIS services. Doing so prevents Internet Information Server from consuming network capacity required by other services. This section explains how to limit the share of the network used by the Internet Information Server, and how to monitor the results.
"Suggestions for Maximizing Bandwidth." This section provides some suggestions for improving the performance of your server with its current equipment.