ICM Load balancing

[#1]

I have some doubts on basics of ICM and web architecture...

If we have multiple app servers for an SAP system, we'll have multiple ICMs for one sap system... ? Pl. correct if this is wrong.

In such case, will our incoming HTTP request come through message server ? Can MS do load balancing between ICM's as well ?

Lastly, if we have one sap webdispatcher interfacing ERP and EP system both (say, total of four ICM.. two each), how will the dispatcher decide if an incoming request, is for BSP running at ERP server or a portal page at EP ?

Thanks,

[Former Member]

Hi,

If we have multiple app servers for an SAP system, we'll have multiple ICMs for one sap system... ? Pl. correct if this is wrong.

You, the basis admin, decides to activate the ICM (or not) on each instances (CI or DIA) with parameter rdisp/start_icman.

The most common configuration is to put the parameter in the DEFAULT profile to start the ICM on each instance

In such case, will our incoming HTTP request come through message server ? Can MS do load balancing between ICM's as well ?

MS can do http load balancing but it is not a good practice because it uses http redirects and does not hide the app servers from the user browser.

Lastly, if we have one sap webdispatcher interfacing ERP and EP system both (say, total of four ICM.. two each), how will the dispatcher decide if an incoming request, is for BSP running at ERP server or a portal page at EP ?

To use the same web dispatcher for 2 different systems, you need at least release 7.2 and you have to configure it to choose the back end system. One possibility is for exmple to use a URL prefix.

All of these informations is explained in details in help.sap.com...

Regards,

Olivier