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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.

 

The SBC Coremaintains registration information using a data structure called Registration Control Block (RCB). When the flag multipleContactsPerAor  is disabled, the SBC maintains single RCB per Address of Record (AoR) and any existing binding information is overwritten on receipt of REGISTER from a new contact for the same AoR.

This is applicable to non-IMS case as well as IMS cases with Public User Identity not having any associated PUIs (or having an implicit set of size 1).

The SBC supports validating the source IP address and the port even if multipleContactsPerAor flag is disabled. The SBC also supports locating the RCB using the AoR to perform additional validation on the source IP address and port if the parameter requireRegistration is set to "required" or "required-non-priority". This is applicable for both calls and OOD requests that are originated from the IAD.

In case of refresh registration that is originated from a different IP/port, the SBC forwards the request to the registrar and move the sate to "UPDATING". Any calls or OOD requests that are originated from the IAD while the RCB is in updating state must be validated using the previously authenticated IP/port.

When the flag multipleContactsPerAor is enabled, the SBC maintains different RCBs for each new registration. A registration is considered new when the source IP/port of the REGISTER request is different from earlier registration for the same AoR. Any of the registered UEs may initiate a communication on behalf of the AoR, and the SBC fetches the corresponding RCB based on source IP port of the UE.

Registration/De-Registration Support

The SBC Core, being a B2BUA by nature, inserts its own egress SIP Signaling address as Contact header in the egress REGISTER request if contact header transparency is not enabled. On receipt of 200 OK response, the Contact header in the response is replaced with the contact header of the UE before forwarding the 200 OK.

When multiple contacts register for the same IMPU, from the second registration onwards, 200 OK response received from the registrar (S-CSCF) may contain more than one contact. If contact header transparency is enabled, the SBC sends all contacts towards UE. Otherwise, the SBC sends only the UE’s contact in the 200 OK response.

The SBC allows multiple UEs to register for same IMPU independent of the IP version supported by the UE. The SBC allows registrations from UEs with different authentication mechanisms for same IMPU.

The SBC supports following security mechanisms:

  • IMS AKA
  • Digest with TLS
  • Digest without TLS
  • GIBA (GPRS-IMS-Bundled Authentication)
For GIBA authentication procedures, UE registers for an IMSI-based temporary AOR which any other UE is not allowed to use. As a result, multiple contacts per AOR feature is not applicable for IMSI-based AoRs.

The SBC supports up to eight UEs simultaneously registering for the same IMPU. Refresh Registration request processing for any of the existing registrations for the same IMPU is not impacted by presence of multiple registrations. If a new registration from a different IP address comes from the same AoR (for example, GIBA authentication), the SBC does not reject the registration.

The SBC allows de-registering any contact without impacting the registration status of other contacts registered for the same IMPU. Similarly, registration timer expiry of any binding (contact) does not impact the registration status of other bindings (contacts) registered for the same IMPU.

SUBSCRIBE/NOTIFY Support

The SBC allows different UEs registered for the same IMPU to subscribe through it, and processes/routes the SIP requests (SUBSCRIBE/NOTIFY)/responses related to those subscriptions independent of whether  or not multiple contacts are registered for the same AoR.

The SBC supports the following OOD non-INVITE requests originated from registered UEs even when multiple UEs are registered for the same IMPU.

  • PUBLISH
  • REFER
  • MESSAGE
  • OPTIONS

The SBC supports the following OOD non-INVITE requests destined to registered UEs even when multiple UEs are registered for the same IMPU.

  • REFER
  • MESSAGE
  • OPTIONS

To support multiple contacts per AOR, the "multipleContactsPerAor" system-level flag must be enabled as shown in the example below (default configuration is 'enabled').

% show global signaling sipSigControls multipleContactsPerAor

multipleContactsPerAor enabled;
Info

For configuration details, refer to:

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