In a dynamic situation, where entities appear and disappear in the network, a strong policy is usually used to protect entities from direct input connection. In a virtual organisation, it is difficult to control all these local policies and to force them to open an input port. Therefore, this decision depends of internal security policy. A solution to this situation, is to provide a mechanism that permits two entities to connect using a bridge which receives the input connection and forwards network messages from one entity to another.

This situation happens often when there is different firewall blocking input connection. A connection bridge is thus needed when a distributed system is composed by heterogeneous entities with their own security policy.