Computer Science - Networking - Discussion

May any one please describe Network User Address (NUA) ?

The address is made up of the international data number (IDN) , which consists of two fields: the 4 digit data network identification code (DNIC) and the (up to) 10 digit national terminal number (NTN).

The DNIC has three digits to identify the country (one to identify a zone and two to identify the country within the zone) and one to identify the PDN (allowing only ten in each country). The NTN identifies the exact network device (DTE, data terminal equipment) in the packet-switched network (PSN) and is often provided as an NUA. There are no rules to the structure of the NTN.

IP addresses can be mapped to X.121 as described in RFC 1236. The 14.0.0.0/8 block used to be reserved for X.121 use but was returned to IANA in 2008 to stave off IPv4 address exhaustion.

The X.25 DTE Address is often referred to as the Network User Address (NUA), although strictly speaking the NUA is the base address allocated by a network to a subscriber, not including the sub-address. The first 4 digits are known as the DNIC, which identifies the particular network.

Network User Address (NUA) is having 4 digits, but 5, 6, 7 are only 3 digits. Can anyone explain this to me?

1 - 4:DNIC.
5 - 7:Area code(zone).
8 - 12:Terminal number.
13 - 14:Sub address digits(for use by the user).