1. Essentials Guide
  2. ENUM Based Oracle Communications Unified Session Manager
  3. User Registration based on Reg-ID and Instance-ID (RFC 5626)

User Registration based on Reg-ID and Instance-ID (RFC 5626)

Sometimes a user’s device reregisters from a different network than its original registration. This event should be considered a location update rather that a completely new registration for the Contact. The Oracle Communications Unified Session Manager can perform this way by considering the endpoint’s reg-id and instance-id parameters defined in RFC 5626.

The Oracle Communications Unified Session Manager identifies new REGISTER requests received on a different access network as a location update of the existing binding between the Contact and AoR. Without this feature, the Oracle Communications Unified Session Manager would create a new binding and leave the old binding untouched in the local registration cache/ENUM database. This scenario is undesirable and leads to unnecessary load on various network elements including the Oracle Communications Unified Session Manager itself.

The following conditions must be matched to equate a newly registering contact as a location update:

For a received REGISTER:

  • The message must not have more than 1 Contact header while 1 of those Contact headers includes a reg-id parameter. (failure to pass this condition prompts the Oracle Communications Unified Session Manager to reply to the requester with a 400 Bad Request).
  • The Supported: header contains outbound value
  • The Contact header contains a reg-id parameter
  • The Contact header contains a +sip.instance parameter

After these steps are affirmed, the Oracle Communications Unified Session Manager determines if it is the First hop. If there is only one Via: header in the REGISTER, the Oracle Communications Unified Session Manager determines it is the first hop and continues to perform Outbound Registration Binding processing.

If there is more than 1 Via: header in the REGISTER message, the Oracle USM performs additional validation by checking that a Path: header corresponding to the last Via: includes an ob URI parameter, Outbound Registration Binding may continue.

If the Oracle Communications Unified Session Manager is neither the first hop nor finds an ob URI in Path headers, it replies to the UA’s REGISTER with a 439 First Hop Lack Outbound Support reply.