Alteon Application Switch Operating System Application Guide
Server Load Balancing
Document ID: RDWR-ALOS-V2900_AG1302
219
HTTP/S Services Features
For HTTP/S services, you can use the following features:
•
Content-Intelligent Server Load Balancing, page 219
•
Content-Intelligent Application Services, page 237
•
Advanced Content Modifications, page 244
•
Content-Intelligent Connection Management, page 277
For HTTPS load balancing with SSL offloading, you must also supply a server certificate and
associate an SSL policy. For more information, see
Offloading SSL Encryption and Authentication,
.
Content-Intelligent Server Load Balancing
Alteon lets you load balance HTTP requests based on different HTTP header information, such as the
"Cookie:" header for persistent load balancing, the "Host:" header for virtual hosting, or the
"User-Agent" for browser-smart load balancing.
Alteon lets you load balance HTTP requests based on different HTTP protocol element information,
such as headers, text, and XML.
Content-intelligent SLB uses Layer 7 content switching rules, which are defined per virtual service.
These rules consist of a protocol-specific matching content class and an action, and are evaluated by
priority based on their ID number. When Alteon matches a rule, the defined action is performed, and
stops searching for matches. If no matching rule is found, Alteon performs the default service action
configured at the service level itself.
Various actions are available per rule to provide further configuration granularity. For example, the
actions for the HTTP rule include selecting a server group for load balancing (default), redirecting to
an alterative location, or discarding the HTTP request altogether. Similarly, the default action
configured at the service level can be any available action.
The content class is a matching object used for Layer 7 content switching rules. You can define a set
of matching criteria that are based on the application type. For example, with an HTTP class, you can
define matching criteria based on HTTP protocol elements such as URL, HTTP headers and so on.
Each element can have multiple matching values, enabling advanced matching decisions to be
evaluated. For example, "if (URL=my-site.com OR URL=my-site2.com) AND (Header=User-Agent:
Internet-Explorer)".
Content classes can be nested using logical expressions. This enables you to use one class as part of
the matching criteria for another class. For example, Class A includes a list of 100 mobile phone
browser types. Classes B, C, and D need to match specific URLs for all the mobile phones from Class
A. To configure this, Class A is defined as a logical expression matching the criteria of Classes B, C,
and D. When you need to add additional mobile phone browsers to the list, you add them to Class A,
and they are then propagated to Classes B, C, and D.
Notes
•
Alteon supports Layer 7 content switching using an additional legacy configuration model that is
based on Layer 7 strings. For related examples based on using Layer 7 strings see
Content-Intelligent Server Load Balancing Not Using Layer 7 Content Switching Rules, page 809
•
To support IP fragment traffic when Layer 7 content switching is defined based on strings, use
the forceproxy command under
/cfg/slb/virt/service/dbind
to force traffic through the
Application Services Engine.
For more information, see
/cfg/slb/virt<server number>/service <virtual port or
application name>/dbind/forceproxy
option in the Alteon Application Switch Operating
System Command Reference.
