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With this parameter you can configure multiple SAP systems for the Web Dispatcher.

Prerequisites

<xx> stands for a number. The numbers must be used in acendending order from 0.

For more information, see Generic Profile Parameters with Ending _<xx>

Structure

Work area

SAP Web Dispatcher

Unit

Character string

Standard value

-

Dynamically changeable

No

Value Range and Syntax

The character string has the following syntax:

Syntax Syntax

  1. wdisp/system_<xx> = SID=<sap-sid>, 
    [MSHOST=<ms-host>, [MSPORT=<ms-http-port> | MSSPORT=<ms-https-port>] | 
    SILOC=<info-file> | EXTSRV=<external-server-list>], [SRCSRV=<src-host>:<source-ports>,] 
    [SRCURL=<source-urls>,] [NR=<scs-sys-no>,] [SCSHOST=<scs-host>]
End of the code.

You must specify the following options to describe the connected system.

  • SID=<sap-sid>: Three letter SAP system ID

  • Specifies where the Web Dispatcher obtains the meta information about the system.

    Normally, the Web Dispatcher fetches its metadata (which application servers are logged on, which services they provide, what capacity they have, and so on) from the message server of the connected system. Alternatively, you can also set up a file with the information, or configure the data to be forwarded to an external system.

    To do this, you have to specify one of the following variants:

    • MSHOST=<ms-host>, MSPORT=<ms-http-port>: The host name and HTTP port of the SAP Message Server that provides the information about the system in question. If you want to configure the metadata exchange through SSL, use option MSSPORT=<ms-httpS-port> to specify the HTTPS port of the message server. You then have to set parameter wdisp/server_info_protocol = HTTPS.

      For more information, see Metadata Exchange Using SSL

    • SILOC=<config-file-name>: Name of the configuration file containing the metadata of the system's application servers. The parameter corresponds to parameter wdisp/server_info_location for systems in which information is stored in a file.

      For more information, see Overview of Parameters

    • EXTSRV=<external-server-list>: You can use this to send requests to an external (non-SAP) system. The URLs, separated by semicolons in the list, are treated by the Web Dispatcher as instances of a system.

      Example Example

      wdisp/system_2 = SID=EXT, EXTSRV=http://websrv1:8080;http://websrv2:8888, SRCSRV=*:8093

      This sends all requests (“round robin”) arriving in port 8093 on to the two Web servers.

      End of the example.

      Caution Caution

      If an external system is configured with more than one server, you can only use stateless requests, since there is no mechanism in the Web Dispatcher for stickiness for external systems.

      End of the caution.

The remaining specifications are optional.

Description of HTTP Requests for this System

The following options specify which requests the Web Dispatcher forwards to this system. URL prefix and the host/port combination of the incoming request are available as criteria.

  • SRCSRV=<source-services>: Specifies the possible host/port combinations in a list separated by semicolons: <source-services> = <host1>:<port1>[;<host2>:<port2>;…], whereby the wildcard character * can be used for the host name and port to specify every possible host name or every possible port.

    Note Note

    Each port specified here is configured in the Web Dispatcher as the HTTP port (parameter icm/server_port_<xx>).

    End of the note.

    Example Example

    • SRCSRV=*:8073 means: All requests arriving through the Web Dispatcher port 8073 should be forwarded to this system.

    • SRCSRV=*:8083;*:8073 means: All requests arriving through the Web Dispatcher ports 8073 and 8083 should be forwarded to this system.

    End of the example.
  • SRCURL=<source-url-prefixes> specifes the possible URL prefixes in a list separated by semicolons: <source-url-prefixes>=<prefix1>[;<prefix2>;…].

    If the incoming request contains one of the specified URL prefixes, the request is forwarded to this system.

    Example Example

    SRCURL=/sap/;/myapp/ means: Requests whose URL starts with “/sap/” or “/myapp/” are forwarded to this system.

    End of the example.

Caution Caution

  • If both SRCSRV and SRCURL are specified, the port and the URL prefix must correspond for selecting the system.

  • If you omit SRCSRV and SRCURL, the Web Dispatcher only works if you have set rules in the action file for forwarding requests to the connected systems (modification handler). If you explicitly want the ambiguity between the systems you have to set SRCSRV=*:* or SRCURL=/, and change a profile parameter (wdisp/system_conflict_resolution = 2).

For more information, see SAP Web Dispatcher for Multiple Systems – System Selection Using the Web Dispatcher

End of the caution.
Optional Specifications for the Connected System
  • NR=<scs-sys-no> (optional): System number of the message server

    You can use the option NR to specify the SAP system number of the message server. This is required to identify the backend system in the System Landscape Directory (SLD), if the Web Dispatcher is to register with the SLD.

    Note Note

    Use the NR option to specify the system number of instance that contains the message server. This can be an SCS instance (AS Java), an ASCS instance (AS ABAP), or a classic central instance (DVEMGS).

    End of the note.
  • SCSHOST=<scs-host> (optional): Host name of the SCS instance.

    The option SCSHOST specifies the host name of the SCS instance, as does option MSHOST.

    Option SCSHOST is then only required if the host name specified in MSHOST does not correspond to parameter SAPLOCALHOST in the SCS instance (or central instance).

    In this case, option SCSHOST contains the value of parameter SAPLOCALHOST in the SCS instance (or central instance). The host name of the SCS instance is required for registering the Web Dispatcher in the SLD data model.

Example Example

wdisp/system_0 = MSHOST=ms.external.sap.com, MSPORT=8101, SID=ERP, SRCSRV=*:*, NR=01, SCSHOST=ms.internal.sap.corp

In this example, the parameter wdisp/system_0 contains both optional parameters NR and SCSHOST, which identify the back-end system in the SLD, in the case of SLD registration.

The Web Dispatcher uses the name ms.external.sap.com for the network connection to the message server, while the message server itself uses the host name ms.internal.sap.corp (parameter SAPLOCALHOST of the message server).

End of the example.