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Component documentationSAP Web Dispatcher Locate this document in the navigation structure

 

The SAP Web dispatcher lies between the Internet and your SAP system. It is the entry point for HTTP(s) requests into your system, which consists of one or more NetWeaver application servers. As a “software web switch”, the SAP Web dispatcher can reject or accept connections. When it accepts a connection, it balances the load to ensure an even distribution across the servers. The SAP Web Dispatcher therefore contributes to security and also balances the load in your SAP system.

You can use the SAP Web Dispatcher in ABAP/Java systems and in pure Java systems, as well as in pure ABAP systems.

Recommendation Recommendation

It is also useful to use the SAP Web Dispatcher if you only want to cover one aspect (security functions or load balancing). We also recommend that you use the SAP Web dispatcher if you do not need security functions (entry point in the DMZ, SSL, URL filtering), but you simply want to balance the load between several SAP NetWeaver AS instances.

End of the recommendation.

Implementation Considerations

The SAP Web dispatcher is recommended when you use an SAP system with several SAP NetWeaver AS instances for Web applications.

The SAP Web dispatcher is a program that you can run on the machine that is connected directly to the Internet. It requires minimal configuration - you just have to enter the following data in the profile file:

  • Port, on which the HTTP(s) requests are to be received (parameter icm/server_port_<xx>)

  • Host and HTTP port of the SAP Message Server (parameter rdisp/mshost and parameter ms/http_port or wdisp/system_<xx>)

    Example Example

    If you should be able to call the Web application externally, for example using the URL www.shop.acme.com, this host name must be mapped internally to the SAP Web dispatcher. This then forwards the HTTP(S) request to a suitable application servers.

    End of the example.
Downward Compatibility

Although the SAP Web Dispatcher is downward-compatible to older releases of SAP systems, there may be restrictions with release combinations of SAP Web Dispatcher and SAP system that are supported by SAP. The released release combinations are documented in Note 908097.

In principle, SAP Web Dispatcher is released for older releases of SAP systems at the latest when the kernel release that the SAP Web Dispatcher is based on is released for use as the downward-compatible kernel for the SAP system.

Features

The SAP Web dispatcher performs the following tasks:

Constraints

The SAP Web dispatcher is only useful in the Web environment. In the classic SAP system, load is balanced by the message server.

The SAP Web dispatcher forwards incoming HTTP(S) requests to the application servers and returns the responses from the back end to the client.

Outgoing requests (such as requests to a different SAP Web Application Server) are not sent via the SAP Web dispatcher. They are sent via the proxy server for the appropriate intranet.

More Information

The documentation is split up into the following sections:

You can find details of the change history of the SAP Web Dispatcher in collective note SAP Web Dispatcher (SAP note 538405).