Creating and Modifying SIP Signaling Groups

Specifies the number of SIP channels available for calls in this Signaling Group.

Valid entry: 1 - 960.

SIP Mode

Specifies the SIP Registration Mode to use in this Signaling Group.

• • Basic Call: Sends INVITEs to the selected server table.
  • Forward Reg. After Local Processing: Forward the REGISTER request after inserting it to the local registrar.
  • Local Registrar: Maintains local registrar only. Uses registrar bindings to terminate a call.

See also: Configuring the SBC Edge Portfolio for Site Survivability.

SIP Mode (SBC SWe Edge only)

Specifies the way in which SIP-SIP signaling will be handled by the SBC. Valid entries:

Access Mode: When Access Mode is enabled, the SBC allows certain SIP functions to be sent in passthrough mode:

• • Authentication handling
  • Non-call-related methods (Register, Subscribe and Notify)
  • Refer and Update

When Agent Mode is set to Access Mode, the Signaling Group service status will always show as "green" or "up" to allow for pass-through messaging. Also, when Agent Type is set to Access Mode, the options Office 365 and Office 365 with AD PBX are disabled.

Back-to-Back User Agent. The SBC will maintain the state and participate in all SIP signaling between both endpoints. 

In Access Mode, the following options are available: Standard, BroadSoft Extension, Header Transparency

Default selection: Back-to-Back User Agent.

The SIP SG configuration Agent Type configuration on the ingress SG decides whether the OPTIONS message is forwarded. 

• The OPTIONS Mode configuration is applicable/visible only when the Agent Type is selected as B2B UA.
• Configuration under Signaling Group Table OPTIONS Mode controls the decision of passthrough message or not. 

Indicates if the SBC should interoperate in a proprietary manner for certain functionality. Multiple SIP Signaling Groups can enable this mode, but this mode can only be enabled once for each SIP Signaling Group/SIP Server combination.

Valid entries:

BroadSoft Extension. The SBC will support BroadSoft-related extensions. Specifically, the SBC will use BroadSoft’s subscriber data (BroadWorksSubscriberData) while in remote survivability mode. This feature allows the SBC to retrieve and store alternative user information for use when the BroadSoft server is unreachable.

Office365. Indicates the Signaling Group is communicating directly with the Skype for Business Front End Pool. Applicable to SBC 1000/2000 only.

Office 365 w/AD PBX. Indicates the Signaling Group is communicating directly with the Skype for Business Front End Pool. The SBC retrieves AD records (based on the entry in the AD Attribute field) and uses that to register on-premises PBX endpoints to Skype for Business Front End Pool. Applicable to SBC 1000/2000 only.

Standard. Standard interop mode works in conjunction with Agent Type - Access mode. When configured in Standard interop mode, SBC passes through standard SIP headers to peer according to RFC standards while locally processing authorization and session refresh headers.

Header Transparency. Header transparency mode works in conjunction with Agent Type - Access mode. When set in Header transparency mode, the SBC passes through non-dialog related headers such as AlertInfo, CallInfo, ProxyAuthorization, Authorization, and Warning headers without locally processing them. To allow subsequent requests and responses to go through the SBC modifies the contact, from, and to headers appropriately.

Default selection: Standard.

The FQDN is used in the Signaling Group to communicate directly with the Skype for Business Front End Pool.

This field is visible when the Interop Mode is set to Office 365 or Office 365 w/AD PBX.

This field can be NULL; if so, the address of the SIP Server will be used.

Specifies any desired Active Directory attribute name in which the PBX number to be Registered is located; this field is dependent on how AD is configured. Default entry: =pager=.

This field is visible when Interop Mode is set as Office 365 w/AD PBX.

Controls the frequency (in days) for how often SIP queries Active Directory for all records with the specific AD attribute populated. Valid entry: 1 - 30 days.

This field is visible when Interop Mode is set as Office 365 w/AD PBX.

Specifies the time of first AD query update in hh:mm:ss (24-hour format). Valid entry: hh (hour), mm (minute), ss (seconds).

This field is visible when Interop Mode is set as Office 365 w/AD PBX.

Specifies the load balancing method used for SIP Server registration and redundancy in the Signaling Group.

• • First: The initial request goes to the first available server.
  • Priority: Register Active Only: Used with the Failover SIP Registration feature. The initial request goes to the SIP Server with the highest priority. If the registration fails, the SIP Server becomes unreachable, or the registration expires, and a re-register fails, the SBC falls back to the next available SIP Server.
  • Priority: Register All: The request goes to the SIP Server with the highest priority (this is configured in the SIP Server) as long as it is available.
  • Round Robin: Each initial INVITE is sent to the next SIP Server in the pool. As the basic algorithm, the scheduler selects a resource pointed to by a counter from a list, after which the counter is incremented and if the end is reached, returned to the beginning of the list. Round-robin selection has a positive characteristic of preventing starvation, as every resource will be eventually chosen by the scheduler.

The type of the SIP Server: IP/FQDN or DNS-SRV determines the available options for Load Balancing:

Load Balancing Option	IP/FQDN	DNS-SRV
Round Robin
Priority: Register All
Priority: Register Active Only
First

In the event of a call release due to the No Channel/Circuit available release cause code, the specified cause code is sent to the relevant protocol module. For more information, refer to the list of Cause Codes.

See below for an example of this behavior:

Specifies the interval of time, in seconds, after a call is initiated that the SBC Edge Portfolio (SBC) waits for a call to connect before terminating the incoming call.

Enables the QoE (Quality of Experience) reporting feature in the SBC. Valid options: Enabled (enables the feature) or Disabled (disables the feature). This field must be enabled for the QoE options to be available through the QoE Settings. See Configuring Quality of Experience (QoE) Settings

When enabled, the SBC Edge Portfolio ignore a forked leg (disconnect) if that leg is going to a voicemail box, but the rest of the forked legs may connect to the subscriber's other numbers. For details, refer to Forked Calls Answered To Soon (Disconnect on Quick Connect).

Possible entries:

• • Disabled: The forked leg is not ignored (disconnected) if that leg is going to a voicemail box.
  • Enabled: The forked leg is ignored (disconnected) if that leg is going to a voicemail box, but the rest of the forked legs may connect to the subscriber's other numbers.

Determines the streaming mode for audio, fax, and media transmission.

• • Direct: Audio/fax stream is passed directly from one compatible end-point to another, this uses neither the SBC processor or a DSP resource.
  • DSP: Audio/fax stream is processed using a DSP resource, and consumes a DSP license.
  • Proxy: Audio/fax stream is processed using the SBC internal processing resources and does not require a DSP resource or license.

All options are enabled by default.

Determines the streaming mode for audio, fax, and media transmission.

• • Direct: Audio stream is passed directly from one compatible end-point to another, using neither the SBC processor nor a DSP resource.
  • DSP: Audio stream is processed using a DSP resource, and consumes a transcoding license if the codecs are different.
  • Proxy Relay: Audio stream is processed using the SBC internal processing resources and does not require a DSP resource or transcoding license. Refer to Node-Locked Licensing. SRTP is untouched locally by the SBC.
  • Proxy with Local SRTP: Media stream is switched between endpoints using SRTP media encryption on a call-leg basis. Note: Support of Proxy with Local SRTP (encryption/decryption) requires licensing up to 1,000 signaling sessions. See Node-Locked Licensing.

All options are enabled by default.

Determines whether a call crypto file is used with SRTP media negotiation.

• • Crypto File: Indicates the crypto file profile used to negotiate SRTP.
  • None: SRTP is not used for media negotiation.

Specifies how ringback plays on a channel.

• Auto on 180 (applies to 180/Alert only) or Auto on 180/183 (applies to 180/Alert and 183/Progress): Configured for Auto, the SBC operates in the nominal RFC 3960 pattern
  
  • SBC generates ringback until in-band media arrives.
  • SBC-generated ringback is discontinued in the presence of in-band ringback.

  • Additionally, any ALERT is sent with PI=8 regardless of whether or not an SDP was received on the SIP side. Doing so allows the SBC to send in-band audio without signaling PROGRESS.

Enables RTCP Multiplexing to combine two parts of the Real-Time Transport Protocol (RTP) for data traffic and RTCP (for control information) onto a single multiplexed UDP port. RTCP Multiplexing is supported according to RFC 5761, in which the SDP contains the value of a=rtcp-mux. RTCP Multiplexing is supported for DSP mode only.

Valid entries: Enable ( SDP contains an a=rtcp-mux attribute, and RTP and RTCP are able to be combined on a single multiplexed port if the far end is capable ) or Disable ( SDP does not contain an a=rtcp-mux attribute and  RTP and RTCP consume two ports).

Default value: Disable.

Media Codec Latch

Specifies the Logical IP address at which SIP messages are received. This address is used as the source IP for all SIP messages leaving the SBC SWe Edge or SBC 1000/2000 through this Signaling Group. The physical interface on which these messages leave the system is determined by the System IP routing configuration. The IP version (IPv4 or IPv6) for the SIP Server used by this Signaling Group determines the IP version used for all outgoing messages leaving the SBC through this Signaling Group.

• • Auto: The node automatically selects the IP address used as the source address of all outgoing SIP messages leaving the SBC through this Signaling Group. The IP address is based on the physical interface selected by the IP routing configuration.
  • Ethernet IP: Allows you to select a specific source IP address for outgoing SIP messages through this Signaling Group.
    
    

Specifies whether or not the Signaling Group uses a third-party entity IP address inside the SIP message to support network address translation (NAT). Only visible when NAT Traversal is set to Static NAT.

• • None: Specifies that network address translation is not used.
  • Static NAT: Specifies that network address translation is used.

Specifies whether ICE support is enabled/disabled. Enable/disable is displayed only when SIP Mode is configured to Basic Call.

• • Disable: When the ICE Support option is disabled, the SBC Edge Portfolio SBC Edge Portfolio does not support ICE for both incoming and outgoing calls. If ICE is disabled on a Signaling Group and if the incoming offer contains ICE, the SBC Edge Portfolio responds with no ICE attributes in the SDP.
  • Enable: When ICE support option is enabled on the signaling group, SBC Edge Portfolio allows SIP to propose ICE candidates in INVITE and 183/200 responses based on the call direction for that Signaling Group. If no candidate is proposed by the other side, the call proceeds as if ICE was not enabled.

Specifies the Interactive Connection Establishment (ICE) Mode that is enabled/disabled. This field is displayed only when ICE Support is enabled.

For SBC 1000/2000:

Two ICE Modes are available:

• • Full: The SBC operates as an ICE (full) agent endpoint.
  • Lite: The SBC operates as an ICE-Lite agent endpoint (for SIP calls involving NAT devices) with a full ICE agent in the role of controlling agent.    

• • Lite: For theSBC SWe Edge, only Lite mode is supported. The SBC operates as an ICE-Lite agent endpoint (for SIP calls involving NAT devices) with a full ICE agent in the role of controlling agent. 

If the selected Outbound NAT Traversal is Static NAT, you must enter the field NAT Public IP (Signaling/Media) appears.

This section defines a listening port and protocol for the SIP Signaling Group.

The Listen Ports populated in this screen are derived from the configuration in the Listen Port Table. The Signaling Group uses this port for communication with external peers. 

• • Add/Edit. Displays a drop-down list of available message tables. Select an entry and click Apply.
  • Remove. Removes the port entry from the list.