Specifications

Equalizer Installation and Administration Guide 1
1 Overview
Introducing Equalizer
This chapter provides an overview of Equalizer’s features and discusses some common
configurations.
Overview of Equalizer
Equalizer™ is a high-performance content switch that features:
• Intelligent load balancing based on multiple, user-configurable criteria.
• Real-time server and cluster performance monitoring.
• Server and cluster administration from a single interface.
• Session persistence using cookies or IP addresses
• Hot-backup configurations (requires a second Equalizer) featuring no single point of failure.
• Layer 7 content-sensitive routing.
• Geographic load balancing (requires the optional Envoy add-in).
This document describes the features and capabilities of the Equalizer units available at the time this
document was prepared. For a current list of products and their features, please visit Coyote Point’s
website at (www.coyotepoint.com).
Intelligent Load Balancing
Equalizer functions as a gateway to one or more sets of servers known as virtual clusters. When a
client submits a request to a site that Equalizer manages, Equalizer identifies the virtual cluster for
which the request is intended, determines the server in the cluster that will be best able to handle the
request, and forwards the request to that server for processing.
To route the request, Equalizer modifies the header of the request packet and forwards the modified
packet to the selected server. When operating in Layer 7 (L7), Equalizer can evaluate and, in some
cases, modify the contents of both the request and response headers.
To determine the best server to route a request to, Equalizer uses intelligent load balancing
algorithms that take into account the configuration options set for the cluster and servers, real-time
server status information, L7 rules, and information from the request itself.
Load Balancing Configuration
When you configure your virtual cluster, you can select one of the following load-balancing
algorithms to control how Equalizer balances the load across your servers: round robin, static
weight, adaptive, fastest response, least connections, or server agent.