Web dispatcher load balancing

[Former Member]

Hi

We are in the process of implementing UCES, and have been advised to use two clustered UCES servers, and two non-clustered Web Dispatcher servers to load balance traffic to UCES. My question is this; if the Web Dispatcher servers are not clustered, to which IP address to I direct incoming connections? It has been suggested that we use switches to load balance the connections to the Web Dispatchers, but this doesn't seem right.

Has anyone come across this before?

Thanks

Paul.

[Former Member]

Hi Andreas,

Thanks for your reply. Yes, UCES is Utility Customer E-Services. We're fine with the setup from the Web Dispatchers onwards. My question was how traffic is routed from the Internet to the Web Dispatchers.

If they were clustered, then the cluster would have a virtual IP address to which we could route traffic from the internet facing router. But as they are not clustered, I am unsure how to use two web dispatchers rather than one?

Please see link to document of how routing will occur between the internet and SAP. We are trying to fill in the gap currently occupied by the question mark.

[Routing Diagram|http://uk.geocities.com/cruwyser/DMZRouting.jpg]

Thanks again

Paul

[Former Member]

Hello Paul,

you could use as well multiple sap web dispatchers on the same host, but they need

to use different TCP/IP ports.

As for high availabilty for SAP web dispatchers please see as well the following document

which might answer some of your questions:

http://help.sap.com/erp2005_ehp_04/helpdata/EN/5f/7a343cd46acc68e10000000a114084/frameset.htm

If you need to run 2 unclustered web dispatchers (the sap web dispatcher does not need

much ressources, it is just forwarding/rejecting http(s) requests with some additional

functions) then I'd say the external browser clients type the adress as follows :

http://<servername1-IP>/<port>;

http://<servername2-IP>/<port>;

In regards to the clustered web dispatchers : if you route external traffic to the virtual IP

please note that the external traffic will only be routed to the current active cluster server.

There is as well the possibility of NAT (network adress translation) adresses so the

external parties can not determine the real ip of the backends, but that is just additional

information.

Hope this helps.

Kind regards,

Andreas

[Former Member]

Hello Paul,

I guess UCES = Utility Customer E-Services 6.0

All incoming requests from the internet will be filtered by the web dispatchers.

They will then redirect the requests to the backend systems and application

servers. You will need to tell the web dispatcher the ip adresses of the

application servers.

Please see the following help page from sap :

http://help.sap.com/erp2005_ehp_04/helpdata/DE/1c/ba295ee20fcd41b6804f1bc602de68/frameset.htm

Hope this helps.

Kind regards,

Andreas