The following diagram illustrates the message flow and server connections of the different components required to deploy Internal domain federation combined with Inter-PS federation.

Avaya Aura® users in domain 1 can watch Microsoft users in domain 2 using the Presence Services in domain 2 as a tandem server. Avaya Aura® users in domain 1 can also watch Avaya Aura® users in domain 2 using Inter-PS federation.

Similarly Microsoft users in domain 2 can watch Avaya Aura® users in the external domain 1 via the tandem Presence Services in domain 2. They can also watch Avaya Aura® users in domain 2 using Microsoft Internal Domain federation.

Using the concepts and configuration details described below, the Microsoft Front End server could be deployed in either domain, or one in each domain. For simplicity, the steps will cover a Front End server deployed only in domain 2.