Nortel Networks WEB OS 212777 - Manual (Page 375)

Web OS 10.0 Application Guide
Chapter 15: Content Intelligent Switching n 375
212777-A, February 2002
Content Intelligent Server Load Balancing
Web OS allows you to load balance HTTP requests based on different HTTP header informa-
tion, such as “Cookie:” header for persistent load balancing, “Host:” header for virtual hosting,
or “User-Agent” for browser-smart load balancing.
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URL-Based Server Load Balancing on this page
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“Virtual Hosting” on page 380
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“Cookie-Based Preferential Load Balancing” on page 383
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“URL Hashing for Server Load Balancing” on page 387
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“Header Hash Load Balancing” on page 389
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“DNS Load Balancing” on page 390
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“Layer 7 RTSP Load Balancing” on page 392
URL-Based Server Load Balancing
URL-based SLB allows you to optimize resource access and server performance. Content dis-
persion can be optimized by making load-balancing decisions on the entire path and filename
of each URL.
N OTE – Both HTTP 1.0 and HTTP 1.1 requests are supported.
For URL matching you can configure up to 128 strings comprised of 40 bytes each. Each URL
Web request is then examined against the URL strings defined for each real server. URL
requests are load balanced among multiple servers matching the URL, according to the load
balancing metric configured for the real server group (
leastConns is the default).
In Figure 15-2 , the following criteria are specified for content load balancing:
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Requests with “.cgi” in the URL are forwarded to real servers 3 and 4.
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Requests with the string “images” in the URL are sent to real servers 1 and 2.
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Requests with URLs starting with “/product:” are sent to real servers 2, 3, and 5.
Requests containing URLs with anything else are sent to real servers 1, 2, 3, and 4. These serv-
ers have been defined with the “any” string.