Multiple Contacts per AoR

The

maintains registration information using a data structure called Registration Control Block (RCB). If the SBC maintains a single RCB per Address of Record (AoR), 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).

When the ‘Multiple Contacts per AOR’ feature is enabled, the

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 SBC fetches the corresponding RCB based on source IP-port of the UE.

Registration/De-Registration Support

The

, 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

sends all contacts towards UE. Otherwise, the  sends only the UE’s contact in the 200 OK response.

The 

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

The 

supports following security mechanisms:

• IMS AKA
• Digest with TLS
• Digest without TLS
• GIBA (GPRS-IMS-Bundled Authentication)

The

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 (e.g. GIBA authentication), the does not reject the registration.

The

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

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

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

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').