Polycom 3725-74600-004 Manual De Usuario

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Polycom® RealPresence Collaboration ServerVirtual Edition Administrator’s Guide
12-32
Polycom, Inc.
Detecting SIP Endpoint Disconnection
When an abnormal disconnection of SIP endpoints occurs because of network problems or 
client application failures, SIP endpoints remain connected to the conference causing 
connection disruptions. For example, the video freezes in the layout or blocks content for 
SIP endpoints when a quick re-connection is performed. It can take several minutes to detect 
the SIP endpoint disconnection using the SIP standard behavior.
In a normal SIP video call, audio and video (RTP and RTCP) messages are sent from the 
endpoints to the MCU to detect the signaling of connected endpoints. Conversely, SVC 
endpoints might not send video RTP messages to the MCU when a participant is not 
displayed in the video layout of any of the participants in the conference. For SVC 
endpoints, the MCU will only verify audio RTP and RTCP messages and video RTCP 
messages. Video RTP messages will not be checked.
To detect the disconnection of SIP endpoints in a reasonable amount of time, a new system 
flag can be defined to specify the amount of time that the MCU should wait for an RTCP or 
RTP message from the SIP endpoint before the endpoint starts the disconnection process. 
The system default value is automatically set to 20 seconds.
The system flag, DETECT_SIP_EP_DISCONNECT _TIMER, contains the amount of time in 
seconds to wait for an RTCP or RTP message to be received from the endpoint. When the 
time that was set in the system flag has elapsed and no RTCP or RTP audio or video 
message has been received on either the audio or the video channel, the MCU disconnects 
the SIP endpoint from the conference. A CDR event record is created with a Call 
Disconnection Cause of “SIP remote stopped responding”.
The Microsoft Lync add-in endpoint opens audio and content channels. Lync endpoints can 
send RTCP/RTP messages and empty RTP audio messages. When the time that was set in 
the system flag has elapsed and no RTCP or RTP message has been received on the audio 
channel, the MCU disconnects the endpoint from the conference. 
SIP audio only endpoints use the audio channel only. When the time that was set in the 
system flag has elapsed and no RTCP or RTP message has been received on the audio 
channel, the MCU disconnects the SIP audio endpoint from the conference.
Configuring the System Flag
When you want to change the system default value of 20 seconds, the system flag, 
DETECT_SIP_EP_DISCONNECT_TIMER, can be manually added to the System Flags 
configuration to detect the disconnection of SIP endpoints. For more information see 
"Manually Adding and Deleting System Flags” on page
The value range is from 0 to 300 seconds. When the value is set between 0 and 14, the feature 
is disabled and SIP endpoints are not detected for disconnection. When the value is set 
between 15 and 300, the feature is enabled.