In this section:


The SBC Core supports the following Real Time Control Protocol (RTCP) modes for media:

RTCP Modes for Media

RTCP Mode

RTCP Behavior

RTCP Relay for pass-through calls with RTCP enabled on both legs

RTCP is relayed between two end users. The SBC will not terminate the RTCP sessions; however, it will set up the media-path to forward RTCP packets from one party to the other.

This is the default and recommended approach for handling RTCP for pass-through calls.

RTCP termination for a pass-through call with RTCP enabled on only one leg


RTCP for transcoded calls legs

If RTCP is enabled on the leg, the SBC will terminate RTCP.

In either pass-through or termination modes, the SBC collects packet RTCP statistics and reports them for output to CDRs. Configurable parameters include:

  • Media peer inactivity—Configure media peer inactivity time out value. When using this feature, you must also set the flag, peerAbsenceAction, from the Packet Service Profile.
  • Media port range—Use this control to set the UDP media port range for RTP and RTCP.
  • Media RTCP control—Configure sender report interval.


Command Syntax

% set system media
	dedicatedBWForNonRTPMedia (0-50)
	enhancedApplicationMediaSupport <disabled | enabled>
    mediaPeerInactivity
		inactivityTimeout <20-1260, in multiples of 10>
	mediaPortRange 
		baseUdpPort <1024-65534>
		maxUdpPort <1024-65534>
        highPriorityPortRangeLocation <top | bottom>
        highPriorityPortRangeSize <0 to 25)>
	mediaProbe
		dscpValue <0-63>
		encryptionType <None>
		format <rtcp>
		mediaProbeAddressContext <addressContext>
		mediaProbeIpInterfaceGroup <mediaIpInterfaceGroup>
		protocolType <udp>
		reportingInterval <1-8>
		state <disabled | enabled>
	mediaRtcpControl
		sendBYEPacket <disabled | enabled>
		senderReportInterval <5-16>
  		t140RtcpMonitorInterval <2-20>
	tcpPortRange
		baseServerPort <1-65534>
		maxServerPort <1-65534>

Command Parameters

Note

When configuring System Media, the mediaProbe configuration is optional (default state is "disabled"). However, when configuring the parameter mediaProbe, ensure to configure all values (or accept defaults, where applicable).

System Media

Parameter

Length/Range

Description

dedicatedBWForNonRTPMedia

0-50

Use this control to specify (reserve) an amount, as a percentage, of bandwidth usage to limit across all physical interfaces for non-RTP media (default = 0).

NOTE: This feature only applies to TCP media traffic such as MSRP.

enhancedApplicationMediaSupport

N/A

(This flag is specific to application media)

  • disabled (default)
  • enabled

When the flag is enabled, the following functionality is supported:

  1. The SBC initiates and establishes TCP on the egress leg only after the TCP connection is successful on ingress leg.
  2. The SBC supports transmitting URG (urgent) data from one leg to another.
  3. The SBC supports establishing and disconnecting a TCP connection multiple times within the same SIP session.

Refer to SIP over TCP for additional details.

mediaPeerInactivity

N/A

Use this control to set detection of media peer inactivity (inactivityTimeout) which can be used in conjunction with packet loss rate parameter (packetLossThreshold) of Packet Service Profile. 

  • inactivityTimeout – (range: 20-1260 / default = 60)  Set RTP/RTCP inactivity timeout value (in seconds, in multiples of 10) to guard against loss of media connection. The timer is restarted whenever an RTP or RTCP packet is received from the peer.

When both RTP and RTCP are enabled, the timeout will only occur if both packet types remain undetected for the configured inactivityTimeout duration. If RTCP is not enabled, then only the absence of RTP causes the timer to expire.

When mediaPeerInactivity is enabled (configured with an inactivityTimeout value), the SBC detects media inactivity within the configured inactivity timeout value + X, and then executes the configured action (where the X is from 0 - 10 seconds).

INFO: When using this feature, you must also set the "peerAbsenceAction" flag from Packet Service Profile (refer to Packet Service Profile - CLI).

NOTE: If a valid RTP stream does not send enough packets, use mediaPeerInactivity with RTCP only.

NOTE: If the endpoint does not send both RTP and RTCP packets frequently enough within the inactivityTimeout duration, Ribbon recommends to avoid using mediaPeerInactivity. 

Note: On the PSX Manager > Packet Service Profile screen, the field "Media Peer Inactivity Timeout (s)" allows the user to reduce the timeout duration to 0-1260 seconds for specific zones during emergency calls such as 911 calls. By default it is set to 0 (disabled). The value set on the PSX Manager takes precedence over the value set on the SBC side. When the field "Media Peer Inactivity Timeout (s)" on the PSX is set to 0 (disabled), the SBC uses the configuration value set on the SBC side.

mediaPortRange

N/A

Use this control to set the UDP media port range for RTP and RTCP.

  • baseUdpPort – Base UDP port number (inclusive) for RTP/RTCP media. (range: 1024-65534 / default = 1024).
  • maxUdpPort – Maximum UDP port number (inclusive) for RTP/RTCP media. (range: 1024-65534 / default = 65148). An error message appears if you set the range to a value greater than 65148 because that overlaps a Linux reserved port range (65150 to 65535). Do not specify a value greater than 65148.
  • highPriorityPortRangeLocation – Specifies whether the high priority port range, if specified, occurs at the top or the bottom of the media port range.
    • bottom – high priority ports are at the bottom of the range.
    • top – high priority ports are at the top of the range.
  • highPriorityPortRangeSize – Specifies the percentage of the configured port range to include in the high priority range. Specifying 0 disables having a high priority range.(range: 0-25)

High priority port range is optional configuration that divides the media port range into a high-priority port range and a low-priority port range. Under congestion conditions, all the packets received on ports outside the high priority media range are dropped automatically by the network processing layer. Therefore, if you choose to configure SIP signaling ports within the media port range, Ribbon recommends they reside within the high priority port range so that packets are not dropped.

Note:

  • Starting with SBC Core 8.1, the SBC supports configuring the parameters highPriorityPortRangeLocation and highPriorityPortRangeSize across all supported hardware, software, and cloud platforms.
  • The configuration for the parameters highPriorityPortRangeLocation and highPriorityPortRangeSize defines the High Priority Media Port Range (HPMPR) as a subset of the overall MPR. The SBC uses the configuration to quickly identify UDP packets (both media and non-media) arriving within the overall MPR, and prioritizes them while processing ingress UDP packets. For GETS/HPC applications, Ribbon recommends reserving 10% of the MPR as HPMPR. If additional SIP Signaling Ports (besides the default port 5060), and/or other Control UDP ports are within the overall MPR, Ribbon recommends configuring them within the HPMPR. Such configuration ensures that during congestion, they are prioritized while processing ingress packets.
    For example, if the overall MPR is defined as 1024-65535, and the High Priority Port Range is 10% (starting with the lower limit of MPR), then the HPMPR is 1024-7475. Ribbon recommends configuring additional SIP Signaling and other Control UDP ports within the range 1024-7475. In case of congestion, such configuration ensures that while processing ingress packets, packets received at ports within the range configured for HPMPR are prioritized. Normal calls are allocated local UDP ports ranging from 7476-65535, and GETS/HPC calls are allocated local UDP ports ranging from 1024-7475.
mediaProbeN/A

To facilitate monitoring and management of voice quality by the SBC Core and Ribbon Analytics, the SBC supports the following functionality to allow service providers to see discrete variations in voice quality, as well as monitor SLA and network operations.

  • Communicate with Ribbon Analytics
  • Report media quality statistics (RTP/RTCP) and DTMF packets to Ribbon Analytics using the Media Probe configuration

NOTE: Ribbon Protect is rebranded to Ribbon Analytics. Any references to 'Ribbon Protect' and 'Protect' in the SBC Core documentation apply to the Ribbon Analytics product.

NOTE: To establish communication to Ribbon Protect, refer to Protect - CLI.

Configure mediaProbe with the following values to capture and report media quality statistics (RTP/RTCP) and DTMF packets to Ribbon Protect. 

  • dscpValue <DSCP value> – The DSCP value for Media Probe RTCP application packets. Range: 0-63. Default = 0.
  • encryptionType – The encryption type used towards the Ribbon Protect server. Currently, the SBC does not support any encryption.
    • none (Default).
  • format – The Media Probe format used to report qCDR (quality CDR capturing QoS statistics associated for a leg for each RTP-based stream). Currently, the SBC only supports RTCP.
    • rtcp
  • mediaProbeAddressContext – Address Context associated with the Media Probe IP Interface Group.
  • mediaProbeIpInterfaceGroup – Media IP Interface Group used to transmit Media Probe packets to the remote Ribbon Protect server.
  • protocolType – The network protocol used to transfer the data to the remote server. Currently, the SBC supports only UDP.
    • udp 
  • reportingInterval <1-8> – The interval at which RTCP application packets are sent to the remote Ribbon Protect server, expressed as an integral multiple of the Media RTCP Control senderReportInterval value (configurable to 5-16 seconds). Default is "1". 
    For example, if senderReportInterval is set to 5 seconds, then
    • set reportingInterval to "1" to send media probe packets every 5 seconds (senderReportInterval x 1).
    • set reportingInterval to "8" to send media probe packets every 40 seconds (senderReportInterval x 8).
  • state – Use this flag to enable/disable the system-wide Media Probe state.
    • disabled (default)
    • enabled

mediaRtcpControl

N/A

Use this control to configure the RTCP session.

  • sendBYEPacket – Use this flag to choose whether or not to send RTCP BYE packet. 
    • disabled – Use this setting to suppress RTCP BYE packet in a pass-through scenario when RTCP terminationForPassthrough option is enabled and the call is not established. This setting is useful to avoid one-way audio when Dynamic LRBT and RTCP are in use at the same time.
    • enabled – When this flag is enabled, the SBC sends the RTCP BYE packet when a call is terminated. This command affects all calls configured with RTCP termination.
  • senderReportInterval – Use this value as the initial interval (in seconds) for SBC to generate sender/receiver report when RTCP is terminated on the SBC. (range: 5-16 / default = 5).

  • t140RtcpMonitorInterval – This value defines the interval for which the SBC monitors the RTCP packets for T140 stream from endpoints. If RTCP is not received within this interval, the SBC starts RTCP generation. (range: 2-20 / default = 6)

tcpPortRange

N/A

This port range is used by the SBC to advertise its TCP port on which it can accept connections. A unique unused port from this range will be included in the SDP media line in the offer or answer towards the MSRP UAs. SBC uses a port from this range per MSRP call leg if it takes up a TCP server role.

To create a TCP port range, use the baseServerPort and maxServerPort to specify the minimum and maximum values as described below.

  • baseServerPort – Base port number (inclusive) for TCP media server (range: 1-65534 / default = 1024).
  • maxServerPort – Maximum port number (inclusive) for TCP media server (range: 1-65534 / default = 65534).

Command Examples

General Media Configuration Example

The following example sets inactivityTimeout value to 90, the baseUdpPort to 6000, the maxUdpPort number to 65100 and the senderReportInterval to 6 seconds and sendBYEPacket to enabled, plus sets the peerAbsenceAction parameter from packetServiceProfile object to send a trap if inactivity is detected.

set system media mediaPeerInactivity inactivityTimeout 90
set system media mediaPortRange baseUdpPort 6000 maxUdpPort 65100
set system media mediaRtcpControl senderReportInterval 6
set system media mediaRtcpControl sendBYEPacket enabled
set system media mediaRtcpControl t140RtcpMonitorInterval 6
set profiles media packetServiceProfile DEFAULT peerAbsenceAction peerAbsenceTrap

show system media  
mediaPortRange {
    baseUdpPort 6000;
    maxUdpPort  65200;
}
mediaPeerInactivity {
    inactivityTimeout 90;
}
mediaRtcpControl {
    senderReportInterval 6;

	sendBYEPaket enabled;
 
	t140RtcpMonitorInterval 6;
}

Media Probe Configuration Example

Command Example: system media mediaProbe
set system media mediaProbe dscpValue 0 encryptionType none format rtcp mediaProbeAddressContext ADDR_CONTEXT_1 mediaProbeIpInterfaceGroup INGRESS_LIG protocolType udp reportingInterval 1 state enabled
commit

show system media mediaProbe
state                      enabled;
reportingInterval          1;
protocolType               udp;
encryptionType             none;
format                     rtcp;
dscpValue                  0;
mediaProbeAddressContext   ADDR_CONTEXT_1;
mediaProbeIpInterfaceGroup INGRESS_LIG;