RTP, RTCP and T.38 Parameters

'RTP Redundancy Depth'

configure voip > media rtp-rtcp > RTP-redundancy-depth

[RTPRedundancyDepth]

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.

'RFC 2198 Payload Type'

configure voip > media rtp-rtcp > RTP-redundancy-payload-type

[RFC2198PayloadType]

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

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

Note:

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The parameter is applicable only if you configure the [RTPRedundancyDepth] parameter to 1.

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The device ignores this parameter for Rx payload types and uses the payload type determined during SDP negotiation. For using this configured payload type, see the [BackwardPTBehavior] parameter.

'Forward Invalid RTP Packets'

[RTPFWInvalidPacketHandling]

Defines the device's handling of invalid RTP and RTCP packets.

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[0] Forward Packets = Forwards the invalid packets as is.

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[1] Forward Packets and Issue Warnings = (Default) Forwards the invalid packets and issues warnings (sent to the syslog) to notify of the invalid packets.

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[2] Drop Packets and Issue Warnings = Drops the invalid packets and issues warnings to notify of the invalid packets.

Note:

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The parameter is applicable only if the IP Profile parameter 'Mediation Mode' is configured to RTP Forwarding.

'Forward Unknown RTP Payload Types'

[RtpFWNonConfiguredPTHandling]

Defines the device's handling of RTP packets that are received with non-configured (unknown) payload types.

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[0] Handle as Invalid Packet = (Default) Handles the packet as an invalid packet, according to the RTPFWInvalidPacketHandling parameter.

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[1] Handle as Valid Packet = Handles the packet as a valid packet.

Note:

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The parameter is applicable only if the IP Profile parameter 'Mediation Mode' is configured to RTP Forwarding.

'RTP Base UDP Port'

configure voip > media rtp-rtcp > base-udp-port

[BaseUDPport]

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.

configure voip > media rtp-rtcp > udp-port-spacing

[UdpPortSpacing]

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

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[2] = The device allocates ports in "jumps" of 2 ports.

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.

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[4] = (Default) The device allocates ports in "jumps" of 4 ports.

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[5] = The device allocates ports in "jumps" of 5 ports.

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[10] = The device allocates ports in "jumps" of 10 ports.

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.

'T.38 Fax Session'

configure voip > sip-definition settings > t38-sess-imm-strt

[T38FaxSessionImmediateStart]

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

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[0] Disable (default)

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[1] Immediate Start on Fax = Device activates T.38 fax relay upon receipt of a re-INVITE with T.38 only in the SDP.

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[2] Immediate Start on Fax & Voice = Device activates T.38 fax relay upon receipt of a re-INVITE with T.38 and audio media in the SDP.

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.

configure voip > sip-definition settings > t38-use-rtp-port

[T38UseRTPPort]

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

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[0] = (Default) Use the RTP port +2 to send/receive T.38 packets.

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[1] = Use the same port as the RTP port to send/receive T.38 packets.

Note:

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

'T38 Fax Max Buffer'

configure voip > sip-definition settings > t38-fax-mx-buff

[T38FaxMaxBufferSize]

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.

[QoEMediaStatisticTimer]

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:

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The parameter is applicable only to the SBC application.

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

no-operation-enable

[NoOpEnable]

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.

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[0] = Disable (default)

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[1] = Enable

Note: You can also enable the feature per IP Profile , using the 'Generate No-Op Packets' IP Profile parameter.

[NoOpInterval]

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.

no-operation-interval

[RTPNoOpPayloadType]

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:

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The parameter is applicable only if the IP Profile parameter 'Generate No-Op Packets' is enabled, or the [BackwardPTBehavior] parameter is enabled.

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When configuring the parameter, make sure that its settings don't cause collisions with other payload types.

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The device ignores this parameter for Rx payload types and uses it only for Tx payload types.

'Enable RTCP XR'

configure voip > media rtp-rtcp > voice-quality-monitoring-enable

[VQMonEnable]

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

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[0] Disable (default)

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[1] Enable Fully = Calculates voice quality metrics, uses them for QoE calculations, reports them to OVOC (if configured), and sends them to remote side using RTCP XR.

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[2] Enable Calculation Only = Calculates voice quality metrics, uses them for QoE calculations, reports them to OVOC (if configured), but doesn't send them to remote side using RTCP XR.

'Minimum Gap Size'

[VQMonGMin]

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

The default is 16.

'Burst Threshold'

[VQMonBurstHR]

Defines the voice quality monitoring - excessive burst alert threshold.

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

'Delay Threshold'

[VQMonDelayTHR]

Defines the voice quality monitoring - excessive delay alert threshold.

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

'R-Value Delay Threshold'

[VQMonEOCRValTHR]

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

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

'Tx RTCP Packets Interval'

configure voip > media rtp-rtcp > rtcp-interval

[RTCPInterval]

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.

'Disable RTCP XR Interval Randomization'

configure voip > media rtp-rtcp > disable-RTCP-randomization

[DisableRTCPRandomize]

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

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[0] Disable = (Default) Randomize

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[1] Enable = No Randomize

'Publication IP Group ID'

publication-ip-group-id

[PublicationIPGroupID]

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

By default, no value is defined.

'SBC RTCP XR Report Mode'

configure voip > sip-definition settings > sbc-rtcpxr-report-mode

[SBCRtcpXrReportMode]

Enables the sending of RTCP XR reports of QoE metrics at the end of each call session (i.e., after a SIP BYE). The RTCP XR is sent in the SIP PUBLISH message.

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[0] Disable (default)

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[1] End of Call