Explain WCF Features.

Transactions A transaction is a unit of work. A transaction ensures that everything within that transaction either succeeds as a whole or fails as whole. For example, if a transaction contains three items of work to perform, and during the execution of that transaction one of those items fails, then all three fail. The transaction succeeds only if all three statements of work succeed, unless a Checkpoint is issued. You commonly see this in database operations.
WCF incorporates this same transactional processing into its communication.
Hosting WCF hosting allows services to be hosted in a handful of different environments, such as Windows NT Services, Windows Forms, and console applications, and well as IIS (Internet Information Services) and Windows Activation Services (WAS).
Hosting a service in IIS has added benefits in that the service can take full advantage of many of the native IIS features. For example, IIS can control the starting and stopping of the service automatically.
Security What good would Windows Communication Foundation be without security? Trust me on this, WCF certainly isn’t lacking in this department. Everything from messages to clients and servers get authenticated, and WCF has a feature that ensures messages aren’t messed with during transit. WCF includes message integrity and message confidentiality.
WCF also enables you to integrate your application into an existing security infrastructure, including those that extend beyond the standard Windows-only environments by using secure SOAP messages.
Queuing If you are at all familiar with MSMQ (Microsoft Message Queuing), this topic will sound familiar. WCF provides queuing, allowing messages to be safely stored, providing a consistent state of communication. Queuing collects and stores sent messages from a sending application and forwards them on to the receiving application. This provides a safe and reliable message delivery mechanism.