Client Architecture (Lync Model API)
A custom Microsoft Lync 2010 SDK client relies upon the client process running within Microsoft Lync 2010. If Lync 2010 is not running on your client, the client cannot obtain an instance of the LyncClient class. When a user signs in to Microsoft Lync Server 2010 using the custom client, it is actually causing the Lync 2010 client process to issue the sign-in request to Lync Server 2010 on behalf of the user.
Lync 2010 can support multiple instances of a custom client running on one computer with some restrictions.
A user can only attempt to sign in to Lync Server 2010 from one client.
Once a user is signed in using a custom Lync SDK application or Lync 2010, other clients must use the established communication session.
If a user signs in to Lync Server 2010 from a custom Lync SDK client, Lync 2010 uses the newly established session to update its UI as though a user had signed in from the Lync 2010 client.
You can suppress the Lync 2010 UI so a user only experiences the UI presented by your custom Lync SDK client. The custom Lync SDK client continues to use the client process that underlies the Lync 2010 UI.
Multiple instances of a custom Lync SDK client can run concurrently. If a user is signed in to Lync Server 2010 using Lync 2010, your custom Lync SDK client must not attempt to sign in again. However, each instance of your custom Lync SDK client still has access to the client process running within Lync 2010.
The following illustration shows the relationship between collaboration processes running on a local client that hosts your application.
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