Definition of Web Dispatcher back-end systems
With this parameter you can configure multiple SAP systems for the Web Dispatcher.
If it is configured, the parameters rdisp/mshost and ms/http_port are not evaluated.
[xx] stands for a number without a leading 0. You do not need to use the numbers successively without gaps.
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]:,][SRCURL=,] [NR=[SCS system number],] [SCSHOST=[SCS host]]
You must specify the following options to describe the connected system.
• SID=[SAP SID]: three-character 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.
• 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.
• 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.
wdisp/system_2 = SID=EXT, EXTSRV=http://websrv1:8080;http://websrv2:8888, SRCSRV=*:8093
This sends all requests arriving in port 8093 on to the two Web servers (round robin).
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.
The following 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=: Specifies the possible host/port combinations in a list separated by semicolons: = [host1]:[port1][;[host2]:[port2];…]. For the host name and port, you can use the wildcard character * to specify every possible host name and port.
Each port specified here is configured in the Web Dispatcher as an HTTP port (parameter icm/server_port_[xx]).
• SRCSRV=*:8073 means: All requests arriving through the Web Dispatcher port 8073 should be forwarded to this system.
• SRCSRV=*:8083;*:8073 means: All requests that are received through the Web Dispatcher ports 8073 and 8083 should be forwarded to this system.
• SRCURL= specifies the possible URL prefixes in a list separated by semicolons: =[prefix1][;[prefix2];…].
If the incoming request contains one of the specified URL prefixes, the request is forwarded to this system.
SRCURL=/sap/;/myapp/ means: Requests for which the URL starts with “/sap/” or “/myapp/” are forwarded to this system.
• If both SRCSRV and SRCURL are specified, both the port and the URL prefix must match to select 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).
Optional Specifications for the Connected System
• NR=[SCS system number] (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.
Use the option NR to specify the system number of the 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).
• 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.
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 an 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).
SAP Web Dispatcher
Who is permitted to make changes?
Operating System Restrictions
Database System Restrictions