Hi, I read an article in documentation: When for example u want to use service applications you need to connect your service applications to the WFE’s. This is done using a proxy (don’t think WCF/ASMX proxy… think of it in the more generic term for now (as compared to 2007)). I donnt exactly undestand this - so what is this proxy and what is communication Protocol between WFE and the application server? Second question is if it is truth, then if there are two farms or more then could you search content through all of them using one Search Service Application? And would it be enough to have ONE search server in total and on the other farm there would be only some proxy to search sevice?

Although the scenario in your second question is possible, it's not what the service proxy is all about. The point is that a specific service application may be running on any server or on multiple servers in a SharePoint farm, but it needs to be addressable on any of the farm's WFE servers. So the connection point to the service app is actually a proxy that is available on the WFE. The client can connect through the proxy to a specific instance of the service application without needing to specify or know where that specific service is running. For a regular WCF service you need to know which server the service is running on.Paul Stork SharePoint Server MVP

Thanks, So I have more questions - 1. what are exactly these serives? dlls, webservices or windows services? 2. Do they use Sharepoint API to communicate in Sharepoint? 3. How you would create such service? Is there a template for it in visual studio 2010 ? 4. Then how it is compiled? To what format? And is it deployed on IIS or what? 5. And what is the communication protocol with such service? 6. What if some service application database will crash - can u install only this application or the whole server? Lets take search service as an example

It's a bit more complicated than just a simple dll or webservice. There are a number of classes and at least one .SVC file involved. Take a look at the following set of blog posts. It may help with answers to your questions. http://blogs.code-counsel.net/Wouter/Lists/Posts/Post.aspx?ID=149Paul Stork SharePoint Server MVP