This attribute specifies a secondary address to which the primary
address is redirected.
The address attribute includes the Numbering Plan Indicator (NPI)
and the digits which form a unique identifier of the customer
interface. The address may belong to the X.121 or E.164 addressing
plan. Address digits are selected and assigned by network operators.
The address attribute takes the form:
x.<X.121 address> or e.<E.164 address>