RealPresence Collaboration Server (RMX) 1500/1800/2000/4000 Administrator’s Guide
Polycom®, Inc. 432
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.
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.
Monitoring ISDN/PSTN Participants
Using the Participant Properties dialog box, you can monitor and verify the properties of an ISDN/PSTN
participant. The dialog box’s tabs contain information that is relevant to the participant’s status only while
the conference is running and is used to monitor the participant’s status when connection problems occur.
The table below lists the audio algorithms that are supported for ISDN participants according to their
connection bit rate
Maximum line rate at which ISDN endpoints can connect to a conference is 768 kbps.