What are all the available alternatives to WCF?

I would like to use a technology that is used for communication between services and several thousands of clients. I came to know of WCF and read a little about it. While it l开发者_运维技巧ooks attractive and has no interoperability issues, i would like to know about other leading technologies which can give me the same features as WCF ? Are there any open source technologies out there ? Also, which is the most widely used technology? I just want this information before i commit myself to WCF.

EDIT: By alternative to WCF, i mean to say that i am looking for a framework that will help me to implement a webservice in linux or any other platform. For example, the wcf simplifies the process of creating a webservice by the use of hard coded .NET applications. Similarly, i need a tool in linux. I came across mono,but found out that it is not complete and not very reliable.

I also provide an Open Source WCF alternative in ServiceStack A modern, code-first, DTO-driven, WCF replacement web services framework encouraging code and remote best-practices for creating DRY, high-perfomance, scalable REST web services.

There's no XML config, or code-gen and your one clean C# web service is enabled all JSON, XML, SOAP, JSV, CSV, HTML endpoints are enabled out-of-the-box. It includes generic sync/async service clients providing a fast, typed, client/server communication gateway end-to-end.

I don't think there is any .net framework with comparable features. But the core protocols of WCF such as WSDL/SOAP are not Microsoft specific so it's not as if you're tying yourself into a particular protocol, you're just choosing an implementation.

To put it another way if you choose to migrate away from .net in the future then I would say the WCF migration would be one of the easiest parts. But if you stay with .net WCF is almost certainly going to be the best implementation available given the investment Microsoft has in it (Azure is built on WCF for example).