Answer - If you are not sure where to send messages then addresses play an important role here. This is a Uniform Resource Locator (URI) that will identify the location of the receiver. It is similar to the network address and highly useful to send or receive messages. It can be divided into four parts – Scheme, Machine, Port, and path. Each address is unique in itself and finds out the location of the receiver accurately without any error. There are plenty of protocols are used to exchange messages in WCF. These are HTTP, TCP, MSMQ, etc.