Bandwidth Management

Microsoft Unified Communications Managed API (UCMA) 2.0 and Microsoft Office Communications Server 2007 / Microsoft Office Communications Server 2007 R2 did not allow for any capacity management or ‘bandwidth control’. Calls were routed without regard to consumption of LAN and WAN links. To address this, Microsoft Unified Communications Managed API (UCMA) 3.0 and Microsoft Lync Server 2010 offer a bandwidth-management solution that allows calls to be selectively declined and re-routed based on the consumption of the network links. UCMA 3.0 will automatically adopt server settings for bandwidth control, and based on those settings, UCMA 3.0 will make a request for bandwidth automatically on call placement or receipt. If bandwidth is oversubscribed, and sufficient resources cannot be allocated for this call, the call establishment or acceptance might fail, or be re-routed through the PSTN link, if available.

If the application allows the call to be redirected to PSTN, be aware that any rich information associated with the call will be lost. In particular, if an application must be able to pass contextual data, or perform modalities other than voice, the application should not enable redirection to PSTN.

For more information, see Call Admission Control (CAC).