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Author's profile photo Michael Albrecht

Little known ways to create a load balanced Consumer – Producer connection in a FPN scenario

With this blog I want to create a short guide describing how to configure a Federated Portal Network (FPN) connection between two portals by using a Load Balancer. It’s not difficult at all but maybe this guide can help you to avoid pesky documentation reviewing. For load balancing you can use a multitude of hardware or software products but in this blog I want to concentrate on the SAP Web Dispatcher and SAP Message Server.  As described in the SAP help library  (http://help.sap.com/saphelp_nw70/helpdata/EN/43/289ad33ff80b19e10000000a1553f6/frameset.htm) the workflow to create a FPN scenario is to configure the user repository, configure the proxy settings, set up trust, define initial caching configuration, define initial consumer profile settings and set the user permissions and UME actions to the local portal roles.However, today we are not interested to configure a simple direct communication between consumer and producer portal but a load balanced communication. So if you want to use the SAP Web Dispatcher or a non-SAP load balancer you should enter the URL of the load balancer in the Host Name and the appropriate port number. SAP recommends to use the SAP Web Dispatcher as the entrance point for HTTP load balancing so for the HTTP/HTTPS FPN communication we should enter the SAP Web Dispatcher host and port number. However, *the SAP Web Dispatcher is not able to load balance the P4 communication*. That means with the SAP Web Dispatcher it is not possible to load balance RDLs. If you want to use a non-SAP load balancer you should at first check if it supports the P4-RMI protocol.   Let’s assume the product support of our non-SAP Load Balancer told us that our load balancer doesn’t support P4 redirection. So we have to fall back on the SAP Message Server. Okay, but how to obtain host name and port information of a SAP Message Server? Don’t worry. Do the following: Use the Visual Admin tool to access the property sheet of the Message Info service Maybe this service is not yet running. To start the service you just choose the service and then start the service with the ‘Runner’ icon on the toolbar.  is   Now you can open the Runtime tab > Parameters tab. The host name and port are listed in the sever host and ms/http_port parameters, respectively. Back to the portal we now have to define the Producer URL. By using the Message Server we should obviously use “Load-balanced via Message Server” in the P4 Communication Host Name

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      Author's profile photo Former Member
      Former Member
      Michael, I came across your blog and noticed that your recommendation is in direct conflict with SAP note 1040325 which states that:

      It is not possible if there is another component between the
      browser and the message server (for example, a portal).

      Essentially we are having this issue as well - where the message server connection from the consumer to the producer for http/https using RRA breaks our FPN functionality.

      Author's profile photo Michael Albrecht
      Michael Albrecht
      Blog Post Author
      Hi Patrick,

      I double-checked it with the FPN development department and you are absolutely right. You should use the Web Dispatcher for the HTTP/HTTPS communication. I corrected that in the blog. Thanks a lot for that hint.

      Regards, Michael

      Author's profile photo Former Member
      Former Member
      Hi,
      We are also trying to use the load balancer URL for the Producer- Consumer communication in the federated portal model.

      But the portal is not accepting the value. We also checked on the firewall the communication is being alllowed.

      The HTTPS port on which we are trying to communicate is 443 & the load balancer URL string is like https://abc.xyz.edu:443/

      Could you please advise if there is anything else where we should be looking.

      Thanks,
      Pushkar

      Author's profile photo Michael Albrecht
      Michael Albrecht
      Blog Post Author
      Hello Pushkar,

      Such questions are maybe better posted in a thread of the SDN Forum.

      Anyway, check if the connection is working without the Load Balancer (LB). If so then you can definitely say that it is a LB problem. Reproduce the issue and check the LB logs. In case you can't interpret the logs you should contact the support organization of the LB. If it is a SAP LB then please open a customer message for component BC-CST-WDP regarding the Web Dispatcher or BC-CST-MS concerning the Message Server.

      Best regards, Michael