Registration Flow (Registration-Based Trunk)

1. 1
   TLS Connection Initiated

   CUBE initiates a TLS connection toward the Webex Calling access SBC
2. 2
   Certificate Presented and Validated

   Access SBC presents its certificate. CUBE validates it against the Cisco root CA bundle (IdenTrust Commercial Root CA1) imported to the gateway
3. 3
   Persistent TLS Session Established

   Secure session established and reused for both registration and call processing via connection-reuse
4. 4
   SIP REGISTER Sent

   CUBE sends a SIP REGISTER to the access SBC using the registrar configured in voice class tenant
5. 5
   401 Challenge Received

   Access SBC responds with 401 Unauthorized. CUBE replies using credentials from the tenant: username, password, realm
6. 6
   SIP Profile Rules Applied

   sip-profiles 100 converts SIPS URLs back to SIP in response headers as required by Webex proxies
7. 7
   200 OK Received - Registration Complete

   Access SBC sends 200 OK. Control Hub trunk status updates to Online