| Federation (IM) | Linkage of both IM ID's and presence information with similar information in other systems/networks listed below. (Federated presence information may not match the level of detail available to users of each vendor's UC client). |
| Linkages to other systems/networks | |
| · Microsoft Live Communications Server 2005 | |
| · Microsoft Office Communications Server 2007 | |
| · IBM Lotus Sametime | |
| · Microsoft Live Messenger | |
| · AOL Instant Messaging | |
| · Yahoo! Messenger | |
| · Google Talk | |
| · Other IM systems/networks | |
| Federated users visible in IM and presence lists | Degree to which federated users are visible to one another |
| Federated and internal users included in single IM conversation | Ability to mix internal users and federated users in a single IM conversation. |