We can use messageHeaders to check and authenticate the connection between the Silverlight and WCF service. Operation context of type System.ServiceModel holds the information for the current operation in client and service side.
For sending messages from the client side we will use the OutgoingMessageHeaders of type System.ServiceModel.Channels.MessageHeaders and similarly for receiving header information in service side we will use IncomingMessageHeaders.
Suppose we want to send the username and password from the client and check in the service side we can use messageHeaders.
Here in the client side we can create header with the CreateHeader function with the parameter CreateHeader(name as string,ns as string,value as object)
Dim PersonObj As New Person
PersonObj.UserName = "Soumyap"
PersonObj.Password = "Mindfire"
Dim messageHeadersElementOutgoing As MessageHeaders = OperationContext.Current.OutgoingMessageHeaders
messageHeadersElementOutgoing.Add(MessageHeader.CreateHeader("Authentication", "", PersonObj))