Duplex in WCF allows clients and server to establish a communication pathway with each independently in which any of the entity can initiate a call to others. In order to establish communication between the source and destination duplex mode of communication would be used. If one entity is sending a message at the time another entity will receive the message. Moreover, in the duplex mode of communication, both source and destination will participate in the communication activity.

BY Best Interview Question ON 14 Sep 2019