The following are the types of numbering:
Enterprise Canonical Number (ECN): ECN is unique to Session Manager and can be a public long number, a private long number, or a short or internal number.
Public number: A public number must begin with a plus (+) sign.
Private alias: A private alias is required for public numbering when telephones, such as Avaya deskphones, are unable to register with a plus (+) sign.
Off-PBX Telephony Integration and Mobility (OPTIM) table: This table converts a registration number to a short number. The registration number can be an ECN.
Public numbering table: This table converts a short number to a public long number. Communication Manager adds the short number as an avext parameter to the PAI header and the Contact header for messages to the deskphone.
Private numbering table: This table converts a short number to a private long number. Communication Manager adds the short number as an avext parameter to the PAI header and the Contact header for messages to the deskphone.
Incoming Call Handling Treatment (ICHT); ICHT converts a public or a private long number to a short number.