This attribute indicates the Customer Identifier (CID) assigned to
the userid. The CID is used in Customer Network Management
(CNM). A CNM operator may only send commands to components
provisioned with the same CID as the operator. A CNM operator
will only receive event data, such as alarms, which is generated by
components provisioned with the same CID as the operator.
The special CID of 0 is reserved for the network owner, known as
the Netman.
The Passport CID attribute is compatible with DPN-100 Netman
and Basic CIDs.