Associating a SSP with a web application - Shared Service Provider (SSP)
One SSP is meant to offer certain services like Search, BDC etc. There can be one or more SSPs configured in a farm. Ideally each SSP should be hosted on its own web application and render services to the web applications which are associated with SSP in question.
In this article, we created BDC SSP which is meant to offer BDC services to its clients (web applications in this case). Now, we need to associate web applications which need to utilize these services. We do that using "Manage this Farm's Shared Services" option in "Application Management" tab in Central Administration. So, go ahead and select this option in Central Administration as shown in the following image.
After selecting "Change Associations" option above, a new page will be displayed with list of available SSPs and already configured web applications. Make sure, you select the SSP in question and check all the web applications which need the services offered by the SSP (BDC SSP in this case). So observe the check box checked next to "SharePoint - 9999" web application and "BDC SSP" selected in the drop down.
Once web applications selection is made, click OK. After a warning page, associations should be configured appropriately.
If everything goes well, you should see a page something similar to the following.
Now "SharePoint - 9999" web application is associated with BDC SSP, and can consume the services offered by BDC SSP.
Next I will cover How to Configure SSP to offer BDC services