Coyote Point Systems Equalizer GX Series, Administration Manual

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Overview
Layer 7 Load Balancing and Server Selection
Equalizer’s support for Layer 7 content-sensitive load balancing enables administrators to define
rules for routing HTTP, HTTPS, and special Layer 7 TCP 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. A match rule might, for example, route requests based on whether the request
is for a text file or a graphics file. For example, you may want to:
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load balance all requests for text files (html, etc.) across servers A and B
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load balance all requests for graphics files across servers C, D, and E
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load balance all other requests across all of the servers
Match Rules are constructed using match functions that make decisions based on the following:
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HTTP protocol version; for HTTPS connections, the SSL protocol level the client uses to con-
nect.
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Client IP address
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Request method (GET, POST, etc.)
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All elements of the request URI (host name, path, file name, query, etc.)
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Pattern matches against request headers
Match functions can be combined using logical constructs (AND, OR, NOT, etc.) to create
extremely flexible cluster configurations. See
"Managing Match Rules"
on page 402 for an overview
of Match Rules, a complete list of match functions, and usage examples.
34 Copyright © 2014 Coyote Point Systems, A Subsidiary of Fortinet, Inc.