Specifications

Chapter 1: Overview
4 Equalizer Installation and Administration Guide
sticky record, Equalizer proceeds to check all of the other clusters that have the same IP address. If
Equalizer still does not find a sticky record, it connects the user based on the incoming request.
Layer 7 Load Balancing and Server Selection
Equalizer’s support for Layer 7 content-sensitive load balancing (not available for the E250si)
enables administrators to define rules for routing HTTP and HTTPS requests, depending on the
content of the request. Layer 7 load balancing routes requests based on information from the
application layer. This provides access to the actual data payloads of the TCP/UDP packets
exchanged between a client and server. For example, by examining the payloads, a program can
base load-balancing decisions for HTTP requests on information in client request headers and
methods, server response headers, and page data.
Equalizer’s Layer 7 load balancing allows administrators to define rules in the administration
interface for routing HTTP and HTTPS requests according to the request content. These rules are
called match rules. For example, you can use Layer 7 rules to specify routing preferences such as,
• send all requests for graphics files to servers A, B and E
• send all requests for Perl scripts to servers C and D
• send all other requests to server Z
This enables administrators to create extremely flexible cluster configurations. Administrators can
use Layer 7 technology to implement client-server persistence based on HTTP cookies.
For HTTP requests, Layer 7 load balancing can make decisions based on the following:
• HTTP protocol version
• Host name
• Pathname of the request
• Filename of the request
• Pattern matches against arbitrary HTTP request headers
Go to “Match Functions” on page 132 for a complete list of match functions.
For HTTPS requests, load balancing decisions can be based on the SSL protocol level the client
uses to connect.