RTP, RTCP and T.38 Parameters

Global parameter defining the minimum delay (in msec) of the device's dynamic Jitter Buffer.

You can also configure the feature per specific calls, using IP Profiles ('Dynamic Jitter Buffer Minimum Delay' parameter) or Tel Profiles ('Dynamic Jitter Buffer Minimum Delay' parameter). For a detailed description of the parameter and for configuring the feature, see Configuring IP Profiles or Configuring Tel Profiles.

Note: If the feature is configured for a specific profile, the settings of the global parameter is ignored for calls associated with the profile.

Global parameter defining the Dynamic Jitter Buffer frame error/delay optimization factor.

You can also configure the feature per specific calls, using IP Profiles ('Dynamic Jitter Buffer Optimization Factor' parameter) or Tel Profiles ('Dynamic Jitter Buffer Optimization Factor' parameter). For a detailed description of the parameter and for configuring the feature, see Configuring IP Profiles or Configuring Tel Profiles.

Note: If the feature is configured for a specific profile, the settings of the global parameter is ignored for calls associated with the profile.

Global parameter that enables the device to generate RFC 2198 redundant packets. You can also configure this feature per specific calls, using IP Profiles ('RTP Redundancy Depth' parameter). For a detailed description of the parameter and for configuring this feature in the IP Profiles table, see Configuring IP Profiles.

Note: If you configure this feature for a specific IP Profile, the device ignores this global parameter for calls associated with the IP Profile.

Enables the device to include the RTP redundancy dynamic payload type in the SDP (according to RFC 2198).

a=rtpmap:<PT> red/8000

Where <PT> is the payload type as defined by the [RFC2198PayloadType] parameter. The device sends the SIP INVITE message with "a=rtpmap:<PT> red/8000" and responds with a 18x/200 OK containing "a=rtpmap:<PT> red/8000" in the SDP.

Note:

Defines the RTP redundancy packet payload type (according to RFC 2198).

The valid value is 96 to 127. The default is 104.

Note:

N/A (controlled internally by the device according to the selected coder).

Defines the Tx RFC 2833 DTMF relay dynamic payload type for outbound calls.

The valid range is 96 to 127. The default is 96.

Note: When RFC 2833 payload type negotiation is used (i.e., the parameter FirstTxDTMFOption is set to 4), this payload type is used for the received DTMF packets. If negotiation isn't used, this payload type is used for receive and for transmit.

Defines the Rx RFC 2833 DTMF relay dynamic payload type for inbound calls.

The valid range is 96 to 127. The default is 96.

Note:

Determines whether the device changes the RTP packets according to the MAC address of received RTP packets and according to Gratuitous Address Resolution Protocol (GARP) messages.

Note:

Global parameter that defines the lower boundary of the UDP port used for RTP, RTCP (RTP port + 1) and T.38 (RTP port + 2). For more information on configuring the UDP port range, see Configuring RTP Base UDP Port.

The range of possible UDP ports is 6,000 to 65,535. The default base UDP port is 6000.

Note: For the parameter to take effect, a device restart is required.

Defines the port spacing ("jumps") of local UDP ports allocated by the device to media channels (legs) within the configured port range.

Note: For UDP port spacing of 2, you must configure the device to use the same port for RTP and T.38, by configuring the [T38UseRTPPort] ini file parameter to 1.

For more information on configuring the UDP port range, port allocation and spacing, see Configuring RTP Base UDP Port.

Note: A device restart is required for the parameter to take effect.

Disables RTCP traffic when there is no RTP traffic. This feature is useful, for example, to stop RTCP traffic that is typically sent when calls are put on hold (by an INVITE with 'a=inactive' in the SDP).

Note: The parameter is applicable only to the Gateway application.

Enables fax transmission of T.38 "no-signal" packets to the terminating fax machine.

The parameter is used for transmission from fax machines connected to the device and located inside a NAT. Generally, the firewall blocks T.38 (and other) packets received from the WAN, unless the device behind NAT sends at least one IP packet from the LAN to the WAN through the firewall. If the firewall blocks T.38 packets sent from the termination IP fax, the fax fails.

To overcome this, the device sends No-Op (“no-signal”) packets to open a pinhole in the NAT for the answering fax machine. The originating fax doesn't wait for an answer, but immediately starts sending T.38 packets to the terminating fax machine.

Note: To enable No-Op packet transmission, use the [NoOpEnable] and [NoOpInterval] parameters.

Defines the port (with relation to RTP port) for sending and receiving T.38 packets.

Note:

Defines the maximum size (in bytes) of the device's T.38 buffer. This value is included in the outgoing SDP when T.38 is used for fax relay over IP.

The valid range is 500 to 3000. The default is 3,000.

Defines the interval (in msec) for QoE collection and report generation.

The valid value range is 0 to 65,535. The default is 30,000 (i.e., 30 seconds).

For more information, see Configuring Interval for QoE Report Collection and Generation.

Note:

Enables the device to send RTP or T.38 No-Op packets during RTP or T.38 silence periods. This mechanism ensures that the NAT binding remains open.

Note: You can also enable the feature per IP Profile (for SBC calls only) , using the 'Generate No-Op Packets' IP Profile parameter.

Defines the interval (msec) between each RTP or T.38 No-Op packet sent by the device during the silence period (i.e., no RTP/T.38 traffic).

The valid range is 20 to 600,000. The default is 1,000.

Note: To enable No-Op packet transmission, use the [NoOpEnable] parameter.

Defines the payload type of No-Op packets.

The valid range is 96 to 127. For the range of Dynamic RTP Payload Type for all types of non hard-coded RTP Payload types, refer to RFC 3551. The default is 120.

Note:

Enables voice quality monitoring and RTCP XR, according to RFC 3611.

Defines the voice quality monitoring - minimum gap size (number of frames).

The default is 16.

Defines the voice quality monitoring - excessive burst alert threshold.

The default is -1 (i.e., no alerts are issued).

Defines the voice quality monitoring - excessive delay alert threshold.

The default is -1 (i.e., no alerts are issued).

Defines the voice quality monitoring - end of call low quality alert threshold.

The default is -1 (i.e., no alerts are issued).

Defines the time interval (in msec) between adjacent RTCP XR reports. This interval starts from call establishment. Thus, the device can send RTCP XR reports during the call, in addition to at the end of the call. If the duration of the call is shorter than this interval, RTCP XR is sent only at the end of the call.

The valid value range is 0 to 65,535. The default is 5,000.

Determines whether RTCP report intervals are randomized or whether each report interval accords exactly to the parameter RTCPInterval.

Enables the device to send RTCP XR in SIP PUBLISH messages and defines the interval at which they are sent.

Note: The parameter is applicable only to the Gateway application.

Defines the IP Group to where the device sends RTCP XR reports.

By default, no value is defined.