Web Services load balancing with SAP Message Server

[Former Member]

Hi

We want to review the possibility of load balancing Web Services with SAP Message Server as we don't have high availability with Web dispatcher. 

Legacy systems  makes connectieons to ERP/CRP Servers using Web services (not BSP/Web applications) to update Sales Orders or read information from time to time and this is a business critical business process.  All the legacy systems and SAP systems are located in LAN and we have 4 Application Servers each for ERP/CRM. 

These web services are stateless applications.

When we test Web Services using http port of Application Server, it is working fine. But, when we use Message Server port (HTTP) port, it is failing with the following error:

A SOAP Runtime Core Exception occurred in method get_http_headers of class CL_SOAP_HTTP_TPBND_ROOT at position id 6 with internal

error id 1032 and error text SRT: Wrong Content-Type and empty HTTP-Body received (fault location is 1 ).

Are there are any restrictions on usages of Web Services with SAP http Message Server for load balancing ? The intention is not to introduce another risk in the form of Web dispatcher for load balancing, as Web dispatcher is configured with high availability/failover.

Thanks in advance,

[Former Member · Accepted solution]

Hi,

Message Server manages Load Balancing via  HTTP redirect directives ans is therefore intended to be used by web browsers.

Most web services client softwares are not able to understand redirect directives.

In short, I think that it is not possible and that the only possibility is to install a SAP Web Dispatcher whic is just designed for this purpose.

Regards,

Olivier

[Former Member · Accepted solution]

Thanks Olivier.

Forgot to mention that these web services/WSDL are developed with in SAP using SOAMANAGER.

I am surprised HTTP Message Server cannot redirect the requests coming from Web services.

Is it documented anywhere? The documentation of Message Server/Web dispatcher does not say this.

Regards

[Former Member · Accepted solution]

Yes, it does :

"You can only use the SAP Message Server for HTTP load distribution, if the browser is the direct client of the message server. If another component lies between the client (browser) and the message server, (for example, the portal), you cannot use the message server to distribute the load."

The documentation only speaks of a web browser as a web client for message server load balancing...

Regards,

Olivier

[Former Member · Accepted solution]

Yes, I overlooked direct client of message server in the documentation..

Using ICF Server groups (Logon group) is the solution then for the load balancing for the web services then? Any issues with this approach?

[Former Member · Accepted solution]

The solution is to use a SAP Web Dispatcher...