You can greatly increase the benefits of your investment in Microsoft Communications Server 2010 conferencing by enabling your users to communicate with external users. External users can include:

• Your organization’s own users, when they are working outside your firewalls and are using their laptops or other Communications Server devices.
  
  
• Users from companies you work with who also run Communications Server; to enable your users to easily contact these users, you create federated relationships with these companies.
  
  
• Users of Public IM services, such as IM services provided by the MSN network of Internet services, Yahoo!, and AOL. (Public IM connectivity required a separate license.)
  
  

To enable any or all of these scenarios, you deploy an Edge Server to enable secure communications between your Communications Server deployment and external users. Your organization’s remote users, as well as users at federated organizations, will be able to see each other’s presence and communicate using secure IM. For more information about enabling communication with external users, see External User Access.

Communications Server provides features you can use if your organization must follow compliance regulations. You can use the Archiving Server to archive the content of IM messages for all users in your organization, or only certain users. For details, see Archiving Server.