A gas transportation system that delivers gas to industrial, commercial and domestic customers. GDNs are supplied with gas from the national transmission system (NTS) but may also have gas entry points. There are currently eight GDNs which typically operate at lower pressures than the NTS. For more information, see Practice note, Downstream gas industry: overview. The operator of a GDN may be referred to as a distribution network operator (DNO) or a gas transporter. DNO is also used for an electricity distribution network operator.