Solution:

In Instant Messaging (IM), federated IM networks are those that allow communications across different IM clients and platforms, similar to the way email allows people to communicate regardless of which email client they choose to use.

There two types of IM Federation:

• Inter-Domain Federation: Federation between IM using different domains (Example: between ABC.com, XYZ.com and 123.com) - SUPPORTED
• Intra-Domain Federation: Federation between IM services servicing the same domain (Example: OCS on XYZ.com and Cisco Jabber on XYZ.com) - NOT SUPPORTED

A federated IM network meets the following criteria:

• They have an operational IM network.
• They maintain an open directory, allowing all other IM networks to message their users.
• The instant messaging clients communicate using the Jabber/XMPP protocol. (an open standard)