Polycom DOC2702A User Manual

Appendix H-Setting the MCU for Integration Into Microsoft Environment

Polycom, Inc.

Microsoft RTV FEC (Forward Error Correction) is supported in the MCU to control and 

correct packet loss when receiving and sending video streams using the Microsoft Lync 

Server 2010 communications software. All RTV resolutions and options, including B Frame, 

are supported.
Redundant video packets are sent over the network during video stream transmission. 

When packet loss occurs, FEC is automatically activated and the redundant packet is used to 

recover the lost packet.
When receiving video transmissions, packet loss automatically triggers FEC in the MCU. 

When sending video transmissions, MCU sends FEC packets when the RTCP RX report 

contains packet loss that is greater than or equal to 1 percent.

In previous MCU versions, media such as video, audio, content and FECC is transmitted 

using the UDP transport protocol. In version 7.7, media is automatically transmitted 

through TCP when UDP, the default transport protocol, is not available. Media over TCP is 

supported using the Microsoft ICE environment. 
The media transport protocol type (UDP/TCP) is displayed in the Participant Properties - 

Channel Status - Advanced dialog box.
The media transport protocol type is displayed for the following IP addresses:
•

MCU IP Address

•

Participant IP Address

•

ICE MCU IP Address - only when ICE is functional

•

ICE Participant IP Address - only when ICE is functional

When a short network error occurs, for example 5 seconds, MCU automatically recovers, 

enabling calls in Microsoft Lync to continue the video or audio conference without 

disconnecting. However, when a longer network error occurs, the call is disconnected. The 

presence status mode is correctly updated from Busy to Available. There is no configuration 

required for this procedure.

MCU has the ability to automatically recover from a SIP dialog failure, which can occur in 

long duration calls in Meeting Rooms using the Microsoft Lync client. There is no 

configuration required for this procedure.