The transmission links connect the nodes together. The nodes use circuit switching, message switching or packet switching to pass the signal through the correct links and nodes to reach the correct destination terminal.
Examples of telecommunications networks are:
- computer networks
- the Internet
- the telephone network
- the global Telex network
- the aeronautical ACARS network
In general, every telecommunications network conceptually consists of three parts, or planes (so called because they can be thought of as being, and often are, separate overlay networks):
- The control plane carries control information (also known as signalling).
- The data plane or user plane or bearer plane carries the network's users traffic.
- The management plane carries the operations and administration traffic required for network management.
Example: the TCP/IP data network
The data network is used extensively throughout the world to connect individuals and organizations. Data networks can be connected to allow users seamless access to resources that are hosted outside of the particular provider they are connected to. The Internet is the best example of many data networks from different organizations all operating under a single address space.
Terminals attached to TCP/IP networks are addressed using IP addresses. There are different types of IP address, but the most common is IP Version 4. Each unique address consists of 4 integers between 0 and 255, usually separated by dots when written down, e.g. 126.96.36.199.
TCP/IP are the fundamental protocols that provide the control and routing of messages across the data network. There are many different network structures that TCP/IP can be used across to efficiently route messages, for example:
- wide area networks (WAN)
- metropolitan area networks (MAN)
- local area networks (LAN)
- Internet area networks (IAN)
- campus area networks (CAN)
- virtual private networks (VPN)
There are three features that differentiate MANs from LANs or WANs:
- The area of the network size is between LANs and WANs. The MAN will have a physical area between 5 and 50 km in diameter.
- MANs do not generally belong to a single organization. The equipment that interconnects the network, the links, and the MAN itself are often owned by an association or a network provider that provides or leases the service to others.
- A MAN is a means for sharing resources at high speeds within the network. It often provide connections to WAN networks for access to resources outside the scope of the MAN.