SIP Carrier Peering: SIP Trunk Group - Media

When enabled, SBC sends only the main audio/image stream in the SDP offer.

• Disabled (default)
• Enabled

When enabled on a trunk group, this flag includes the b=AS attribute in the SDP outgoing offer or answer sent on that trunk group.

• Disabled (default)
• Enabled

This flag does not insert the b=AS SDP attribute for non-audio streams or at the session level. The b=AS SDP attribute does not apply to the H.323 signaling interface.

Comedia Connection Role

• Active – The SDP offer will include "a=direction: active" attribute line.
• None – The SDP offer will not include a direction attribute line.
• Passive – The SDP offer will include "a=direction: passive" attribute line.

Data Path Mode Passthru

Determines whether the SBC will transmit media direction (Data Path Mode) received from a peer in the Offer SDP RTP IP.

• Disabled (default)
• Enabled

If enabled, attempt to set up a direct-media path so that media flows directly between endpoints in the same direct-media group.

• Disabled (default) 
• Enabled

If enabled, attempt to set up a direct-media call for endpoints behind NAT.

• Disabled (default)
• Enabled

Enable flag on trunk groups facing AS to allow direct media using C-line trigger (e.g. media anti-trombone).

• Disabled (default)
• Enabled

Note: Direct Media configuration (directMediaAllowed flag) must be enabled on trunk groups facing the endpoints for this feature to function.

This identifies the direct media group to which this trunk group belongs.(default = 0).

Determines whether the SBC forwards SRTP streams on egress when they are received in the incoming SDP, or if it sets the port to zero, thus disabling the SRTP stream. The options are:

• Disabled (default)
• Enabled

Note: Users no longer have to enable the multipleAudioStreamSupport flag to configure the disallowSrtpStream flag. You can enable the disallowSrtpStream flag independently. However, the disallowSrtpStream flag will have an impact on the call flows only when any one of the two flags below are enabled:

• selectCoreStreamForMultiStreamAudioOrImageCall under IPSP. Refer to Common IP Attributes - Flags for details about this flag.
• multipleAudioStreamSupport under TrunkGroup

When enabled, the disallowSrtpStream flag takes the first precedence.

Late Media Support

Determines whether a SIP late media (reverse offer) INVITE should be converted to a forward offer on egress or else allowed to transparently pass through. Set this flag at the Ingress leg of the Trunk Group.

• Convert (default)
• Passthru

NOTE:

• If you configure Packet Service Profile Packet To Packet Control for “Transcode Free Transparency” (see System Provisioning - Packet Service Profile), ensure you also set Late Media Support to Passthru.
• When Late Media Support is set to Convert and the Direct Media Allowed flag is enabled for the same call, late media Convert takes precedence for the original egress INVITE being generated. Eventually, the call transitions to a direct media call.
• The SBC gives precedence to SIP Adaptive Transparency Profile over this flag.

This flag supports Lync/Desktop sharing application media streams.

• Disabled (default) – lyncShare media streams are not allowed for the specified Trunk Group.
• Enabled – lyncShare media streams are allowed for the specified Trunk Group.

Refer to Configuring SBC and LYNC in Media Environment for configuration details.

Determines whether the SBC processes multiple audio m-lines, or a combination of audio and image m-lines, in SDP.

• Disabled (default)
• Enabled

Max Ptime Default

This field indicates the default packet size in milliseconds. The value ranges from 10 to 150 and the default value is 150.

Media IP Interface Group Name

Name of the IP interface group for media.

Each trunk group can have a media IP address configured to specify a specific IP address to use when allocating UDP or TCP media. The default value is 0.0.0.0.

Note: Does not apply to D-SBC.

If you prefer to choose an IP address from a range of values configured in Media Port Range (UDP) or TCP Port Range, set this parameter to the default value.

Configure the Media IP Address as either an IPv4 or IPv6 address (except for H.323, which does not support IPv6 addresses). The configured IP address must belong to the IP Interface Group configured as the Media IP Interface Group for the trunk group. For additional details, refer to SIP over UDP and SIP over TCP.

Media Addr Type

The media address type attribute determines the type of IP address the SBC uses in an offer.

• IPv4 – IPv4 address is selected from the media interface group for the SDP, or else call fails.
• IPv6 – IPv6 address is selected from the media interface group for the SDP, or else call fails.
• IPv4 and IPv6 – Both address types are allowed. Additional configuration options are available using the Anat parameters. Refer to Media - Anat.
• Match Sig Addr Type (default) – Selects media IP based on the signaling IP version used for the call. When the SIP peer IP type is known, the media IP will match. When the SIP peer IP version is unknown, the media IP matches the IP version used for signaling (for example, IPv4 first and IPv6 for resolving an FQDN) for the call attempt. When a “Signaling IP version mismatch” results in a collision crank back, the SBC reselects the media IP to match the new signaling IP version.

Note: The Anat parameter page is only available when the IPv4 and IPv6 option is chosen. The Ice parameter page is available only when the IPv4 and IPv6 option is chosen and the Services NAT Traversal option enables Ice Support. Refer to Services - Nat Traversal.

Enables the MSRP payload relay over TCP connections that will be setup on a successful negotiation of MSRP SDP attributes.

• Disabled
• Enabled (default)

This parameter ensures the role of SBC as B2BUA irrespective of the End Point role. Enable this parameter in both trunk groups to handle the msrp-cema attribute received in request/response messages.

• Disabled (default)
• Enabled

Enable this option to reuse an existing TCP connection with an IP peer for multiple MSRP sessions (MSRP multiplexing). MSRP multiplexing applies only to MSRP sessions established using back-to-back user agent (B2BUA) behavior. Multiplexing cannot be applied to MSRP sessions established based on the RFC 6714 “Connection Establishment for Media Anchoring” (CEMA) type of handling. The options are:

• Disabled (default)
• Enabled

Use this parameter to specify when to apply OMR procedures. (see Configuring SBC to Apply OMR Rules for additional details)

• disabled (default) – If this parameter is disabled OMR procedures are not applied to any call. This parameter is disabled by default for backward compatibility.
• enabled – If this parameter is enabled, OMR procedures are applied to all the calls.
• ravelcallOnly– OMR procedures are applied only to ravel calls.

Note: The omrAllowed and directMediaAllowed parameters are mutually exclusive in a Sip Trunk Group. SBC considers OMR as enabled when omrAllowed parameter in the Trunk Group is not set to 'disabled' and a realm name is associated with the Trunk Group, plus useDirectMedia parameter in the Packet Service Profile is enabled. Even if OMR is enabled on one side but not the other, OMR procedures are applied for bypassing any previous nodes, but are prevented from passing the OMR-specific SDP attributes towards the unsupported side.

Note: The PSX flag Send Direct Media Info In SDP in the IP Signaling Profile is used to control sending the OMR attributes to the peer. If OMR is enabled and Send Direct Media Info In SDP is not enabled, SBC still performs all the OMR procedures, but removes the OMR attributes from the SDP before sending the offer/answer.

NOTE: This configuration is not supported on ERE and is intended for use only with an external PSX.

Use this parameter to choose an Address Context realm name to use as the primary realm for this SIP trunk group.

Note: This configuration is not supported on ERE and is intended for use only with an external PSX.

Recordable

Enable this flag to support the media recording of RTP stream to an external recording device on this SIP trunk group.

• Disabled (default)
• Enabled

 Specifies whether or not to relay of unknown SDP attributes in the core audio stream for transcoded calls. Options are:

• Disabled (default) –  When this option is disabled the SBC drops unknown SDP attributes in messages in the core audio stream for transcoded calls.
• Enabled  – When this option is enabled for the ingress SIP trunk group, the SBC relays unknown SDP attributes in the core audio stream in the egress INVITE request. When enabled for the egress SIP trunk group, the SBC relays unknown SDP attributes in the core audio stream in 18x or 200 OK responses it sends to the ingress leg.

SDP Attributes Selective Relay

Enable this flag to control the selective relay of unknown SDP attributes at the session level and attributes from the core audio stream.

• Disabled (default) – Session level attributes are dropped. Media stream level attributes are dropped unless from a non-core stream.
• Enabled – All qualified session level and media stream level attributes are relayed, which includes attributes from a= and b= lines.

Source Address Filtering

When enabled, incoming media packets that do not match the expected source IP address and UDP/TCP port are filtered out.

• Disabled 
• Enabled (default)

Enable this flag to allow the transmission Medium Requirement Unrestricted 64kbit/s control for SIP-ISUP interworking.

• Disabled (default)
• Enabled