Customers can authenticate via two ways:
REGISTER incl. DIGEST Authentication (username + password)
SIP REGISTER prerequisites:
- The CONTACT and FROM headers must contain the username in the ‘user’ part
- When sending the INVITE:
- the CONTACT header must be identical as with the REGISTER message</BR>
- it must contain the REMOTE-PARTY-ID or P-ASSERTED-IDENTITY header, to include a valid CLI
