Topic Last Modified: 2011-03-23

Determining which conferencing capabilities to deploy depends not only on the features you want available to your users, but also on your network bandwidth capabilities.

The following list of questions guides you through the conferencing planning process to determine what features of conferencing you should deploy, based on your organization’s requirements.

A/V Conferencing Network Bandwidth Requirements

To plan for A/V conferencing, you need to understand the network bandwidth required by the type of conferencing media that your organization requires.

Before you enable users for A/V conferencing, you should ensure your network can handle the resulting load. Without sufficient network bandwidth, the end-user experience may be severely degraded. Anew feature in Lync Server 2010, call admission control, can help you manage the network bandwidth used by A/V Conferencing. For details, see Overview of Call Admission Control.

For information on media bandwidth requirements, see Media Traffic Network Usage.

Client A/V Devices

If you deploy audio conferencing on your network, your users will need audio devices such as headsets to participate. If you also deploy video conferencing, you will need to roll out video devices, such as webcams for users and the RoundTable device for conference rooms.

We recommend that you use unified communications (UC) devices that are certified by Microsoft for all device types, to ensure an optimal end-user experience. For details about UC-certified devices, see "Phones and Devices for Microsoft Office Communicator" at

For either audio or video devices, device rollout and user training are important issues for you to consider and plan for, to maximize your return on investment in conferencing.

Enabling External Participation in Conferences

You can greatly increase the benefits of your investment in Lync Server conferencing by enabling external users to also participate in conferences when invited. External users can include:

  • Remote Users   Your organization’s own users, when they are working outside your firewalls and are using their laptops or other Lync Server devices.

  • Federated Users   Users from companies you work with who also run Lync Server. To enable your users to easily contact these users, you create federated relationships with these companies.

  • Anonymous Users   Any other external users who are invited specifically by your users to join specific conferences. A meeting organizer in your company can send an email invitation for a conference to an external user. The email includes a link that the outside user can click to join the conference.

To enable any or all of these scenarios, you deploy an Edge Server to help enable secure communications between your Lync Server deployment and external users. The Lync Server solution using Edge Servers provides higher quality media than other solutions such as a virtual private network (VPN). For details, see Planning for External User Access.

Additionally, whether or not you deploy Edge Servers, you can enable users (either inside or outside your organization) to dial in from standard PSTN phones to join on-premises audio conferences. This is accomplished by deploying Lync Server dial-in conferencing.

Compatibility Among Meeting Types and Client Versions

Lync Server 2010 includes many improvements and enhancements to conferencing capabilities. For details about these changes, see New Conferencing Features.

However, these changes require you to be aware of some conferencing interoperability issues in Lync Server 2010. If you are going to have Lync Server 2010 interoperate with previous versions of Office Communications Server and its clients, you must be aware of the following issues:

  • Users using Lync 2010 cannot schedule Live Meeting online conferences, or modify any migrated meetings of this type.

  • Users using Lync 2010 who need to attend Live Meeting online conferences hosted on servers running Office Communications Server 2007 R2 must have the Live Meeting client installed on their computer (in addition to Lync 2010) to attend these meetings.

  • When Live Meeting online conferences are migrated to Lync Server 2010, meeting content does not migrate. If this content is needed, it must be uploaded again.

  • Users who are migrated from previous versions of Office Communications Server to Lync Server 2010 and who use Lync 2010 will receive a new assigned dial-in conference ID the first time they schedule an assigned dial-in conference meeting. They can use this new assigned dial-in conference ID to both schedule and attend meetings. The old ID will continue to work for previously scheduled meetings, but newly scheduled meetings are assigned the new ID.

  • Users in federated organizations who are using Microsoft Office Communicator 2007 or Microsoft Office Communicator 2005 clients cannot join Lync Server 2010 meetings in your organization unless the admission type for the meeting is set to Everyone. Federated users cannot join closed (company and invitation-only participants) meetings or meetings locked by the organizer, unless they use a Lync 2010 client.