In this section:
IMPORTANT
Ribbon recommends using the Transparency Profile to configure transparency on the SBC Core for new deployments, as well as applying additional transparency configurations to existing deployments. Do not use IP Signaling Profile flags in these scenarios because the flags will be retired in upcoming releases.
Refer to the SBC SIP Transparency Implementation Guide for additional information.
Use the Flags window to configure IP attribute flags within an IP signaling profile. Different sets of flags apply to H323 and SIP trunk groups.
To View and Edit Flags
On the SBC main screen, go to Configuration > System Provisioning > Category: Trunk Provisioning > IP Signaling Profile > Common IP Attributes > Flags.
H323 Flags
On the Flags window, choose the IP Signaling Profile as DEFAULT_H323 to view the flags for H323 trunk groups.
The Edit Flags window opens showing flags that apply to H323 trunk groups.
Figure 1: Trunk Provisioning - Common IP Attributes H323 Flags
H323 Trunk Group Flags
Parameter | Description |
|---|---|
Audio Codec Change Through Empty Tcs | Enable flag to perform audio codec change (e.g. G.711 fax fallback) using empty Terminal Capability Set (TCS). When disabled, the Unable to show "metadata-from": No such page "_space_variables" performs audio codec change using request mode.
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| Clearmode For Data Calls | This parameter is used to enable the clearmode function for data calls. When enabled, the SBC enables clearmode. When disabled, the SBC provides legacy G.711 behavior.
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| Disable Constrained Capacities | Set this flag to present a full TCS to its peer during call setup or media modification. When disabled, the Unable to show "metadata-from": No such page "_space_variables" presents only the selected codec in the TCS, and follows up with a full TCS after media establishment.
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| Include G729With G729a When Offer Psp Has G729a | Use this flag to control whether the H.323 Service Group includes G.729 along with G.729A in the network offer when the Unable to show "metadata-from": No such page "_space_variables" offer Packet Service Profile has G.729A.
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| Map Dpm To Sendrecv For Initial Dialog | When this parameter is enabled, direction attribute a=sendrecv is sent in the outgoing initial invite when a=inactive is received in the Invite from other side, or a=sendrecv is sent in responses to initial invite when the response from other side is received with a=inactive.
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| Send Empty Tcs | Enable this flag to send an empty TCS to the peer to restart the peer’s forward channel if there is an address update in a direct media case.
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| Send RTCP Port In SDP | When enabled, the SBC adds the attribute,a=rtcp:<rtcpPort> to the audio and video m-lines in the outgoing SDP (RTCP port mentioned will be the SBC RTP port + 1). When disabled, the SBC does not add the attribute a=rtcp:<rtcpPort> to the audio and video m-line in the outgoing SDP.
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| Select Core Stream For Multi Stream Audio Or Image Call | When enabled, the SBC selects the core stream based on the Route PSP from multiple audio or image streams received in the incoming offer. The dependent flag Disable Non Core Audio And Image Streams is visible for configuration only when this flag is enabled.
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| Disable Non Core Audio And Image Streams | This dependent flag is visible only when the flag Select Core Stream For Multi Stream Audio Or Image Call is enabled. Use this option to disable all non-core audio and image streams by setting the port to "0" irrespective of codecs allowed by the Route PSP and T.38 configuration. If enabled, the SBC relays all non-core audio and image streams with port set to "0".
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| Terminal Portability Interworking | Controls Terminal Portability Interworking service between ISUP and SIP. When enabled, Terminal Portability Interworking service is enabled. When disabled, Terminal Portability Interworking service is disabled. The service enables a terminal to be moved from one socket to another or a call to be moved from one terminal to another within one call while the call is active.
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SIP Flags
On the Flags window, choose the IP Signaling Profile as DEFAULT_SIP to view the flags for SIP trunk groups.
The Edit Flags window opens showing flags that apply to SIP trunk groups.
Figure 2: Trunk Provisioning - Common IP Attributes SIP Flags
SIP Trunk Group Flags
Parameter | Description |
|---|---|
| Accept Alert Info | Enable this flag to have the SBC process the URI specified in the Alert-info header received in a 180 Ringing message, and to use the tone specified in the Alert-Info header as the Local Ring Back Tone to play. Note:
When this flag is enabled, the tones processed override any incoming tones in the media stream. For example, when Accept Alert Info is enabled, the SBC plays the tone specified in the Alert-info header of the 180 ringing message overriding the in-band tones included in the 180 Ringing message.
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| Add Path Service Route | Enable this flag to allow the Note:
When the No Service Route Hdr For Emergency Registration flag is enabled, the SBC does not add Service-Route headers for emergency registrations even if the Add Path Service Route and Create Service Route Header flags are enabled.
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| Add PCharging Func Addr | Specifies whether or not to add a P-Charging Function Address header.
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| Ai To Pem Interworking | Use this flag is configure interworking between Alert-Info and P-Early Media headers.
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| Call Holding Interworking | Controls the Call Hold Interworking service between ISUP and SIP is enabled or disabled. The service converts an ISUP call hold to an SIP call hold, or vice-versa. Call holds are invoked by ISUP or SIP/ H.323 endpoints. When disabled, call hold indications are dropped.
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| ClearMode for Data Calls | This parameter is used to enable the clearmode function for data calls. When enabled, the SBC enables clearmode. When disabled, the SBC provides legacy G.711 behavior.
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| Contact Transparency For Is Focus Media Tag | Enable this flag to transparently pass the Contact header in outgoing messages when the "isFocus" parameter is received in the Contact header.
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| Create Path Header | Controls whether or not the SBC creates a Path header in outgoing SIP REGISTER messages.
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| Create PCharging Vector | Controls whether or not a P-Charging-Vector header is created in outgoing SIP messages. Creating P-Charging-Vector headers is supported in INVITE and REGISTER messages. It is also supported in SUBSCRIBE, OPTIONS, and NOTIFY messages when received from the same direction as the REGISTER message.
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| Create PVisited Network Id | Specifies whether or not to create the P-Visited-Network-ID header.
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| Create Service Route Header | Controls whether or not the SBC creates a Service-Route header in outgoing SIP messages. Note:
When the No Service Route Hdr For Emergency Registration flag is enabled, SBC does not add Service-Route headers for emergency registrations even if the Add Path Service Route and Create Service Route Header flags are enabled.
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| Customized Session Timer Behavior | Specifies the session timer behavior expected by the remote peer. When enabled, the remote peer expects customer-specific session timer behavior. When disabled, the remote peer expects the standard session timer behavior.
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| Disable Also Header | Specifies whether to use the Also header. When enabled, the SBC ignores the Also header if received from the remote peer and the SBC does not send the Also header to the remote peer. When disabled, the SBC uses the Also header for call forwarding as usual.
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| Disable Host Translation | Specifies whether to enable or disable host name translation. This applies to all URL style headers that require transparency and defines the processing that the SBC is to apply to the host name portion of these headers before forwarding.
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| Disable Media Lock Down | If the SBC offers both pass-thru and transcode codecs, the Minimize Relaying Of Media Changes From Other Call Leg flag effectively suppresses Re-INVITEs to peers when the peer answers with a single codec. However, if the peer has multiple codecs, the Minimize Relaying Of Media Changes From Other Call Leg flag in certain situations cannot suppress the Re-INVITEs because change in one of the common codecs is detected. In these situations, if the SBC’s most preferred codec matches the peers most preferred codec, the Disable Media Lock Down flag can be used to suppress this Modify Offer. The Disable Media Lock Down flag controls the modified offer initiated by the SBC to lock down the codec. If this flag is disabled, the SBC sends a modified offer to lock down the codec. If enabled, the SBC will not initiate a modified offer to lock down the codec. See examples following the table.
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| Disable Non Core Audio And Image Streams | This flag is visible only when the flag Select Core Stream For Multi Stream Audio Or Image Call is enabled. Use this option to disable all non-core audio and image streams by setting the port to "0" irrespective of codecs allowed by the Route PSP and T.38 configuration. If enabled, the SBC relays all non-core audio and image streams with port set to "0". |
| Disable Refer To Uri Parameters | By default, parameters in the SIP URI Refer-To header are passed through to the outgoing INVITE. When this option is enabled, this pass through does not occur. When disabled, the URI parameters are copied to the Refer-To field in the outgoing INVITE.
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| Discard Received Reason Header | Specifies whether to use the cause code in the Reason header received from the remote peer. When enabled, the SBC ignores the cause code in the received Reason header. When disabled, the SBC uses the cause code in the received Reason header.
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| Do not Include Ss Attribute In Re Invite | Specifies whether the SBC sends silence suppression to the remote peer. When enabled, the SBC does not send silence suppression (no a=silenceSupp is sent) in the SDP to the remote peer. When disabled, and when silence suppression is off, the SBC sends a=silenceSupp:off in the SDP to the remote peer. Note that a=silenceSupp:on is never sent to the remote peer in the
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| Enable Default PUIProcedures | Specifies whether or not to enable the Default PUI Procedure flag.
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| Enable Dial String Handling | This flag is primarily used to enable/disable transparency of dial string (i.e username) received in request URI of INVITE message. Transparency does not occur, however, if PSX/ERE returns globalized or non-private called address. SBC performs dial string identification based on RFC 4967.
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| End To End Bye | Controls whether the SBC will issue an end-to-end BYE on the side initiating the disconnect, depending on the receipt of a BYE from the other leg. When enabled, for SIP-SIP calls, the SBC does not issue the 200 BYE on the side initiating the disconnect until the 200 BYE is received from the other leg. When disabled, for SIP-SIP calls, the SBC issues the 200 BYE on the side initiating the disconnect regardless of whether a 200 BYE is received from the other leg.
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| End To End Re Invite | When this flag is enabled, the SBC forwards Re-INVITEs received from one leg (with or without SDP) to the other leg.
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| End To End Update | When this flag is enabled, the SBC forwards UPDATEs (With SDP) received from one leg to the other leg.
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| Suppress E2ESession Refresh | Enable this flag to prevent the SBC from relaying an end-to-end session refresh UPDATE/RE-INVITE locally (The SBC terminates the session without relaying it). This flag is only available when the "End To End Update" and/or the "End to End re-INVITE" flags are enabled. The SBC applies this flag on both the ingress and egress legs even if it is enabled on just one IPSP.
Refer to UPDATE and reINVITE Suppression for additional feature details. |
| End To End Prack | When this flag is enabled, the SBC forwards the received reliable provisional response without generating a PRACK locally. It waits for the PRACK from the ingress peer to generate a PRACK towards egress peer.
Note:
This flag must be enabled when both endpoints support PRACK and the 100rel header extension. |
| From Header Anonymisation | Enable this flag to prevent the From header of INVITE messages from being anonymized. The SBC always relays the From header of INVITEs.
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| Include Ip Ports in From And To Headers | When enabled, port numbers are included with IP addresses in the From and To headers of SIP messages. When disabled, port numbers are not included with IP addresses.
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| Include Reason Header | When enabled, the SBC includes the Reason header in 18x, 4xx, 5xx, Cancel, and Bye messages in the forward direction. It is provisioned on the egress trunk group.
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| Include Ss Attribute In Initial Invite | Specifies whether the SBC sends the SS attribute in the initial Invite to the remote peer. When enabled, the a=silenceSupp:off is sent in the Initial Invite SDP to the remote peer when Silence Suppression is OFF. When disabled, a=silenceSupp is not sent in the Initial Invite SDP to the remote peer. Note that a=silenceSupp on is never sent to the remote peer in the
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| Include Transport Type In Contact Header | This flag is used by an SBC configured for an external PSX. When this flag is enabled, the SBC includes the transport type parameter in the Contact headers of 3XX responses. The PSX sends the value of this flag in a DIAMETER response to the SBC. When this flag is disabled, the SBC does not include the transport type parameter.
NOTE: Ensure the Pass Complete Contact Header flag is disabled (except for the REGISTER method) to obtain the desired behavior. |
| Insert PAccess Network Info | Enable this flag to have the SBC construct and send a P-Access-Network-Info header using received location info.
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| Insert Peer Address As Top Route Header | When enabled, the SBC SIPE inserts the IP address of the next hop in the top Route header of the egress INVITE. This is required when the SBC is acting as an IMS BGCF proxy. It is also used to support SIPConnect compliance for direct inward dialing.
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| Insert UEFlow Info | Enable this flag to send a P-UE-Flow-Info header towards the core.
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| Lock Down Preferred Codec | Enable this flag to maintain using the most preferred codec of the leg on which it is enabled even if it requires transcoding. This feature also suppresses triggering a Re-INVITE on the leg (on which it is enabled from the SBC) due to a Modify Offer received from the other leg as part of mid-call codec modification.
Note:
This flag must be enabled in conjunction with Minimize Relaying Of Media Changes From Other Call Leg All flag. Note:
When this flag is enabled, the flag Relay Data Path Mode Change From Other Call Leg must also be enabled to propagate HOLD Modify Offers (any modify offer that changes the data-path-mode). |
| Map Cause Location | Specifies whether or not to enable the Map Cause Location flag.
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| Map Suspend Resume Event In PSvc Info Header | Controls whether or not the SBC maps the suspend/resume event in the P-Svc-Info header of SIP messages.
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| Map Uui In PSig Info Header | Specifies whether or not the SBC maps the UUI parameter and includes it in the SIP P-Sig-Info header.
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| Map Dpm To Sendrecv For Initial Dialog | When this parameter is enabled, direction attribute a=sendrecv is sent in the outgoing initial invite when a=inactive is received in the Invite from other side, or a=sendrecv is sent in responses to initial invite when the response from other side is received with a=inactive.
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| Mime Cause Precede Reason Header Cause | When enabled, the cause value is mapped from the MIME body of the incoming message based on the Q.1912 standard. When disabled, the cause value is mapped from the Reason header based on the RFC3398 standard.
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| Minimize Relaying Of Media Changes From Other Call Leg All | The advertised SIP SDP is described as a set of capabilities that the SBC can receive. The SBC by default issues a Modify Offer ( Re-INVITE, UPDATE) whenever it detects a change in receive capabilities. In certain scenarios, the Modify Offer can be perceived as redundant. Enabling Minimize Relaying Of Media Changes From Other Call Leg All flag suppresses redundant Modify Offers being sent from the SBC. When enabled, the SBC suppresses modify offers that have no changes to the “common codecs” that impact the end-user experience. “Common codecs” are codecs that exist both in the initial offer and answer. Changes to common codecs imply changes to DTMF, packetization time, codec specific FMTP attributes and data-path-mode. See examples following the table.
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| No Content Disposition | Specifies whether including a Content Disposition header in SIP messages is expected by the remote peer. When enabled, the remote peer expects no Content Disposition header. When disabled, the remote peer expects the standard SIP message format, which includes the Content Disposition header.
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| No Port Number5060 | This parameter is used by the SBC to control whether port number 5060 is sent to the remote peer in the Request-URI of PRACK, ACK, and BYE messages. When enabled, the outgoing SIP URI does not include the port number 5060 (sip:user@host). In addition, the SBC only sends out port numbers in the Record-Route and Route headers of SIP request and response messages if it receives a port number in Record-Route headers. When disabled, the outgoing SIP URI includes the port number 5060 (sip:user@host:5060). In addition, if the SBC does not receive a port number in the Record-Route headers of SIP request and response messages, the SBC inserts the port number 5060 in outgoing Record-Route and Route headers.
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| No Service Route Hdr For Emergency Registration | Enable this flag to stop the SBC from adding Service-Route headers for emergency registrations even if the Add Path Service Route and Create Service Route Header flags are enabled.
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| No Userinfo In Contact Header | Specifies whether including userinfo in Contact headers in SIP messages is expected by the remote peer. When enabled, the remote peer expects no userinfo component in the Contact header URI. When disabled, the remote peer expects the standard format of the Contact header, which includes the userinfo component.
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| Only Selected Codec In Session Refresh | When this flag is enabled, the SDP in a session keep-alive Re-INVITE message will only include the currently-selected codec for the call. When disabled, the SDP in a session keep-alive re-INVITE message will be identical to that in the last offer. See example below.
Example: --> The SBC sends an INVITE including Codec-A and Codec-B <-- An 18x message is received identifying Codec-B. --> The SBC sends a keep-alive Re-INVITE depending upon the flag setting:
Note:
The o-line of the SDP will be identical to that in the last offer. |
| P Called Party IDSupport | Specifies whether or not to enable P-Called-Party-ID header support.
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| P Chg Msg Info | When enabled, the SBC adds a P-ChgMsg header to a SIP INFO or a 183 Session Progress message (which it selects depends on the call state). The P-ChgMsg header contains the interworked ISUP CHG with TLEC information. When disabled, this function is disabled.
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| Publish IPIn Hold SDP | Enable this flag to include the SBC's IP address in the SDP on-hold.
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| Reject Refer | When enabled, the SBC rejects SIP REFER messages from the peer and responds with a 405 Method Not Allowed message.
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| Replace Host On Via Header | When enabled, the SBC will replace the IP address of the top-most Via header in the initial outbound INVITE or REGISTER request with the IP address or hostname it received in the top-most Via header of the incoming request. When disabled, the SBC defaults to B2BUA behavior where the VIA header contains the local SIP signaling address.
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| Re Query Psx On Register Refresh | When enabled, the SBC will re-query the PSX when it receives a REGISTER refresh message, which may result in a new or updated result for the REGISTER relay. When disabled, the SBC does not re-query the PSX on a REGISTER refresh. This setting must be made on the ingress trunk group profile facing the registered endpoint.
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| Restrict History Info Header | Specifies whether to restrict the HistoryInfo header, depending on the Privacy header or Privacy URI header parameter values.
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| Route Using Recvd Fqdn | Enable this flag to use the FQDN received in the Contact header of a Refer-To or 3xx message for routing.
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| SDP Oline Only Compares | When enabled, the SBC checks only the o-line when comparing SDPs. When disabled, the SBC checks the entire SDP body when comparing SDPs.
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| Send RTCPBandwidth Info | Enable this flag to send the RR and RS bandwidth information, as well as "b=RR:" and "b=RS:" in the SDP offer.
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| Send All Allowed Codecs For Late Media Invite Or Re Invite | When enabled, the SBC sends all allowed codecs in the SDP offer in response to a late media INVITE or Re-INVITE. When disabled, the SBC sends the codec selected in the Offer SDP in response to a late media INVITE or Re-INVITE.
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| Send Direct Media Info In SDP Attribute | Used by the SBC to enable encoding direct media information in signaling. When enabled, the SBC sends direct media information in the SDP attribute X-dmi. When disabled, the SBC does not send direct media information.
Note
The 'directMediaAllowed' flag must be disabled on the associated trunk group. Caution
You must enable the "Send Direct Media Info In Sdp Attribute" flag for
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| Send Ptime In SDP | This parameter takes effect only when the trunk group parameter, Direct Media Allowed, is disabled. When enabled, the SBC sends an a=ptime attribute in the SDP. When disabled, the SBC does not send a=ptime in the SDP.
Note: If the flag is enabled in the ingress IP signaling profile only, the SBC only sends the ptime attribute in the SDP in the ingress signaling. However, if the flag is enabled in the egress IP signaling profile, the SBC sends the ptime attribute in the SDP in both the ingress and egress signaling. |
| Send Rtcp Port In Sdp | When this flag is enabled, the SBC adds the attribute,a=rtcp:<RTCPPort> to the audio and video m-lines in the outgoing SDP (RTCP port mentioned will be SBC RTP port + 1). When disabled, the SBC does not add the attribute a=rtcp:<RTCPPort> to the audio and video m-line in the outgoing SDP.
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| Session Timer Refresh Update | This flag controls the session timer refresh method used with SIP peers. When enabled, the SBC sends UPDATE messages. When disabled, the SBC resends INVITE messages.
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| Set Accept Header To Application Sdp Only | Specifies whether including a short Accept header in SIP messages is expected by the remote peer. When enabled, the remote peer expects a short Accept header format that contains the application/ SDP value only. When disabled, the remote peer expects the standard Accept header format containing all of the standard parameters.
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| Set Oline Dash | Specifies what SDP o-line format is expected by the remote peer. When enabled, the remote peer expects an o-line format in which the username component is set to a "-" (dash). When disabled, the remote peer expects the standard o-line format containing all of the o-line parameters, including the username.
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| Set Session Version Zero | Controls the session version used in outbound SDP. When enabled, the SBC sets the session version to zero in the o-line of the outbound SDP. When disabled, the SBC assigns a session version randomly.
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| Set Sline Dash | Specifies what SDP s-line format is expected by the remote peer. When enabled, the remote peer expects a short s-line format that contains a dash only (s=-). When disabled, the remote peer expects the standard s-line format containing all of the s-line parameters.
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| Skip Psx Query For Refer | Specifies whether to skip the PSX query for REFER requests.
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| Store Path Header | Controls whether a Path header received in an incoming SIP message is stored/cached locally on the SBC. When enabled, the received Path header is stored. When disabled, the received Path header is not stored.
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| Store Service Route Header | Controls whether a Service-Route header received in a 200-class response to a REGISTER request is stored/ cached locally on the SBC. When enabled, the received Service-Route header is stored. When disabled, the received Service-Route header is not stored.
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| Store PCharging Func Addr | Specifies whether or not to store the P-Charging-Function-Addresses header.
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| Store PCharging Vector | When this flag is enabled, the SBC stores the P-Charging-Vector (PCV) header it received in requests. When the response is forwarded back, the stored PCV is inserted and sent. If the SBC receives the PCV when this flag is disabled, the SBC ignores the PCV and does not log it in the CDR.
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| Send Only Preferred Codec | Use this flag to have the SBC send a single preferred codec in an answer to an initial offer or Re-INVITE.
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| Send SBCSupported Codecs For Late Media Re Invite | Enable this flag to have the SBC include all pass-through and transcodable codecs supported on that leg in the SDP offer sent in the 200 OK response to a late media Re-INVITE request.
Note:
This flag takes precedence over the Send All Allowed Codecs For Late Media Invite Or Re Invite flag and the Send Only Preferred Codec flag. The SIP trunk group media flag Late Media Support must be set to Convert for the behavior enabled by the Send SBCSupported Codecs For Late Media Re Invite flag to apply. |
| Select Core Stream For Multi Stream Audio Or Image Call | When enabled, the SBC selects the core stream based on the Route PSP from multiple audio or image streams received in the incoming offer. The dependent flag Disable Non Core Audio And Image Streams is visible for configuration only when this flag is enabled.
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| Suppress Min Se If Not Received | When this flag is enabled, the Min-SE header is added to Re-INVITEs/UPDATEs only if it exists in the previous offer/answer. When this flag is disabled, Min-SE is always added to session refreshes.
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| Suppress Refer Relay From Other Leg | This flag is significant only when the
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| Support Call Info With SIP Cause 608 RFC 8688 | Enable this flag to process the Call-Info in a 608 SIP response code from the PSX, and then set the value in to the outgoing SIP response message (in support of RFC 8688).
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| Support SCSCFRestoration Procedures | When enabled, the SBC, acting as P-CSCF, rejects a request with a 504 (Server Time-out) response that carries a MIME body of type application/3gpp-ims+xml, if the SBC does not receive any response to a request from the S-CSCF network or the next hop address is blacklisted as part of ARS (Address Reachability Service) service (see IMS Restoration Procedures for additional details).
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| Terminal Portability Interworking | Controls whether Terminal Portability Interworking service between ISUP and SIP is enabled. The service enables a terminal to be moved from one socket to another or a call to be moved from one terminal to another within one call while the call is active.
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| Use PSX Routefor Registered Invite | Enable this flag to route INVITEs from the core to the received PSX route for registered users, but not to the Contact address of the RCB.
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| Validate Access Nw Info Header | Specifies whether to forward the P-Access-Network-Info header when the network-provided parameter is present.
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Make the required changes and click Save at the right hand bottom of the panel to save the changes made.
Note
The SBC gives precedence to SIP Privacy handling when the SIP Adaptive Transparency Profile is enabled. For example, if the incoming SIP message has "privacy: Id" and the flag Apply Privacy Id under Profiles > Services > Privacy Profile is set to Enabled, the SBC does not include P-ASSERTED-ID header in the egress message.
Several flags prevent the SBC from relaying a re-INVITE, or an UPDATE, to the other leg of the call. When you enable such flags, the behavior is contradictory to that of the SIP Adaptive Transparency Profile.
To resolve such conflicts, the SBC gives precedence to the SIP Adaptive Transparency Profile over the following flags:
- Parent Object:
Profiles > Signaling > IP Signaling Profile > Common IP Attributes > FlagsRelay Data Path Mode Change From Other Call LegMinimize Relaying Of Media Changes From Other Call Leg AllDisable Media Lock DownLock Down Preferred CodecCall Hold Interworking
- Parent Object:
Address Context > Zone > SIP Trunk Group > SignalingSdp 100rel Iwk For PrackRel100 Support
- Parent Object:
Address Context > Zone > SIP Trunk Group > MediaLate Media Support
For more information, refer to Services - SIP Adaptive Transparency Profile.
Call Flow Examples
Call Flow Examples for 'Disable Media Lockdown' Flag
Example1:
In the following call flow, the Modify Offers (in green) are suppressed if the Minimize Relaying Of Media Changes From Other Call Leg flag is enabled:
Ingress Peer |
| SBC |
| Egress Peer |
G711U | -> | SBC offers G711U as pass-through codec and G729A as a transcode option by reserving a DSP channel | -> | G711U,G729A |
G711U | <- | SBC releases the DSP channel resulting in a G711U pass-thru call | <- | G711U |
Receive capabilities of SBC have changed as a codec G729A was removed and the DSP channel de-allocated. | -> | G711U | ||
<- | G711U |
Example 2:
The messages (in green) can be suppressed if the Disable Media Lock Down field is enabled.
Ingress Peer |
| SBC |
| Egress Peer |
G711U | -> | SBC offers G711U as pass-through codec and G729A as a transcode option by reserving a DSP channel | -> | G711U,G729A |
G711U | <- | SBC releases the DSP channel resulting in a G711U pass-thru call | <- | G711U,G729A |
Receive capabilities of SBC have changed as a codec G729A was removed and the DSP channel de-allocated. | -> | G711U | ||
<- | G711U |
Ingress Peer |
| SBC |
| Egress Peer |
G711U | -> | SBC offers G711U as pass-through codec and G729A,G726 as transcode options by reserving a DSP channel | -> | G711U,G729A,G726 |
G711U | <- | Transcode G711-G729A call. Egress codec is locked down to G729A | <- | G729A,G726 |
Receive capabilities of SBC have changed to G729A due to transcode. | -> | G729A | ||
<- | G729A |
Example 3:
Scenario in which Disable Media Lockdown field can not suppress the media lock down messages (in green).
The codecs configured at Egress route PSP are G711U, G726, G729A with HRP disabled.
Ingress Peer |
| SBC |
| Egress Peer |
G711U | -> | SBC offers G711U as pass-through codec and G726,G729A as transcode options by reserving a DSP channel | -> | G711U,G726,G729A |
G711U | <- | Transcode G711-G726 call. Egress codec is locked down to G726 | <- | G729A,G726 |
Receive capabilities of SBC have changed to G726 ( i.e. HRP is disabled). Since, the codec selected by SBC is different from Peer’s preferred codec (G729), though the flag DML is enabled SBC sends a Modify Offer to lockdown to G726. | -> | G726 | ||
<- | G726 |
Call Flow Examples for 'Minimize relaying of Media Changes From Other Call Leg All' Flag
Example1:
The re-INVITEs (in green) are suppressed if the Minimize Relaying Of Media Changes From Other Call Leg flag is enabled.
Ingress Peer |
| SBC |
| Egress Peer |
G711U | -> | SBC offers G711U as pass-through codec and G729A as a transcode option by reserving a DSP channel | -> | G711U,G729A |
G711U | <- | SBC releases the DSP channel resulting in a G711U pass-thru call | <- | G711U |
Receive capabilities of SBC have changed as a codec G729A was removed; send Modify Offer to Peer to advertise the latest set of capabilities | -> | G711U | ||
<- | G711U |
Example2:
SBC suppresses a Modify Offer from the ingress peer. The offer changes the maxptime from 10 to 20ms. An increase in maxptime can be suppressed – a device that advertises a maxptime of 20ms can also receive 10ms packets.
Ingress Peer |
| SBC |
| Egress Peer |
G711U 10ms | -> | -> | G711U 10ms | |
G711U | <- | <- | G711U | |
re-INVITE (G711U 20ms) | -> | Suppress the re-INVITE if minimize media is enabled and respond to ingress peer; else forward the re-INVITE to egress | -> | G711U 20ms |
G711U | <- | <- | G711U |
Conversely, irrespective of the state of the Minimize Relaying Of Media Changes From Other Call Leg flag All field cannot suppress a change of maxptime from 20ms to 10ms.
Ingress Peer |
| SBC |
| Egress Peer |
G711U 20ms | -> | -> | G711U 20ms | |
G711U | <- | <- | G711U | |
re-INVITE (G711U 10ms) | -> | -> | G711U,10ms | |
G711U | <- | <- | G711U |
Example3:
A change of data-path-mode from sendrecv to sendonly ( HOLD request) can also be suppressable. The rational is that SBC can always ignore the media received from the peer and continue to send it media.
Ingress Peer |
| SBC |
| Egress Peer |
G711U sendrecv | -> | <- | G711U sendrecv | |
G711U | <- | -> | G711U | |
re-INVITE (G711U sendonly) | -> | Suppress the re-INVITE if minimize media is enabled and respond to ingress peer; else forward the re-INVITE to egress | <- | G711U sendonly |
G711U | <- | -> | G711U |
Conversely, SBC irrespective of the state of the Minimize Relaying Of Media Changes From Other Call Leg flag, cannot suppress a change of data-path-mode from sendonly to sendrecv.
Ingress Peer |
| SBC |
| Egress Peer |
G711U sendonly | -> | -> | G711U sendonly | |
G711U | <- | <- | G711U | |
re-INVITE (G711U sendrecv) | -> | -> | G711U sendrecv | |
G711U | <- | <- | G711U |
Call Flow Examples for 'Relay Data Path Mode Change From Other Call Leg' Flag
Example1:
When Minimize Relaying Of Media Changes From Other Call Leg flag is enabled, and when Relay Data Path Mode Change From Other Call Leg is disabled:
Ingress Peer |
| SBC |
| Egress Peer |
G711U,G729A sendrecv | -> | -> | G711U,G729A sendrecv | |
G711U | <- | <- | G711U | |
re-INVITE (G711U sendonly) | -> | Suppress the re-INVITE and respond to ingress peer. Discard media received from the egress peer | ||
G711U | <- |
Example2:
When the Minimize Relaying Of Media Changes From Other Call Leg flag is enabled, and when Relay Data Path Mode Change From Other Call Leg is enabled:
Ingress Peer |
| SBC |
| Egress Peer |
G711U,G729A sendrecv | -> | -> | G711U,G729A sendrecv | |
G711U | <- | <- | G711U | |
re-INVITE (G711U sendonly) | -> | -> | G711U sendonly | |
G711U | <- | <- | G711U |
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