y SM&AML, such as packaging systems, cooling systems, powering sys- items, mechanical cross-connects, cabling systems and antenna systems. If we dis- regard these parts of a concrete network, physical network remains, where the physical nodes are connected by physical media connections that terminate in physical media connection endpoints. These endpoints are only specified with regard to their electromagnetic properties. If we focus only on those parts that are not included in a physical network model, we are talking about a spatial network. Mechanical and spatial aspects of physical media are described in spatial network models. The effect of separating 2 Foundations of Sysnet Modelling physical and spatial models is that a physical network model is transparent to where physical nodes reside in spatial network. 2.2.4 The Physical Network View on Telecom Systems There are numerous ways the physical nodes of a telecom system could be designed, based on the logical network model of the system. However, since termi- nals can be assumed to be remote to the network side, the top-level physical struc- ture of any sysnet network looks the same for all kind of telecom systems, see Fig. Telecom System Terminal Systems Operator Network End-users Network Terminations TE-TPC Teleservice Access Protocol Access Transport Network (ATN) TE-UDT Teleservice Network Transport Network Teleservice Protocols (NTN) Distribution Protocol TE-UDT Teleservice Access Protocol TE-TPC Fig. 2.5 The physical structure of all telecom systems The physical structure consists of two types of physical nodes: an operator net- work (often referred to as "the network") and a number of terminal systems (on the terminal side). The model shows two terminal systems, connected to two different access transport networks. The operator network contains a network transport net- work that supports two distributed network process controllers and the telecom resources (TR, TRC) they use for service provisioning. The access transport net- works and the network tra