IoT Network Categories
The previous post in the IoT 101 series described the types of system architectures common with IoT. This post will describe the network categories and topologies. The network categories are divided mainly by the region they enable access, and often interface with other networks to provide additional features and services. For example, personal area network (PAN) mesh IoT smart home systems are often connected to a LAN and WAN through an IoT gateway device.
Near-Field Communications (NFC) and RFID
NFC, of which RFID is a subset of technologies and applications, is an extremely short range communication network that predominantly uses resonant magnetic coupling or other low power transmission technologies. This type of network is generally between two NFC capable devices, or an RFID tag and a tag reader, and has a limited range of only several centimeters to around a meter. This type of network is considered extremely secure, as the range of communication of these technologies is intrinsically limited, and are hence often used for secure inventory management and banking systems.
Body Area Network (BAN)
BAN are a new medical application network that involves the interconnection of medical and diagnostic systems worn on the body, or as internal implants. This type of network is being developed and prototyped to work with sensitive medical monitoring systems and health assistant devices. There are some BAN technologies that can also communicate with external medical equipment for information retrieval and analysis purposes. Future BAN technologies may also provide real-time monitoring of human vitals using gateways to WAN technology.
Personal Area Network (PAN)
PANs are networks that are often employed with IoT technology and consist of two or more directly communicating devices. For example, Bluetooth communication from a smartphone to a headset uses a device-to-device PAN, where Zigbee mesh network devices create a mesh network PAN in order to relay control and sensor data. IoT gateways are often used to interface securely between PANs and LANs/WANs.
Local Area Network (LAN)
A LAN is a common home or business network where devices can be observed and accessed over the internal network. LANs are bridged with external WAN networks via routers and NAT firewalls, and can be based on Ethernet and switch wired connections or WiFi routers. WiFi routers are often used as LAN connections with IoT gateways, and these routers are often connected to modems that have access to WANs, such as the Internet. Network switches are the most common interconnect for LAN devices, of which, many WiFi routers have several external LAN ports along with their WiFi LAN interconnectivity features.
Metropolitan Area Network (MAN)
A MAN is similar to a LAN, but covers a large metro area, such as a city or town. MAN often consist of large cable deployments, racks of networking equipment (routers and switches), and possibly even microwave backhaul for areas where last-mile networking infrastructure installation is infeasible.
Intranet & Extranet
An intranet is a form of private local network (PLN), and typically uses standard networking protocol, such as Ethernet, WiFi, TCP/IP, and web services. Intranets can use MAN and WAN services, such as the internet, to create much larger intranets of various sites. Intranets are commonly used this way by businesses. An Extranet is an augmentation of an Intranet that allows for controlled access to entities outside of the Intranet.
Wide Area Network (WAN)
A WAN is a large-scale network covering a wide geographical area. Often a WAN connects several LANs or individual devices and computing clusters to each other over common protocols, such as the internet. The internet is a WAN that is composed of ISPs that offer internet services to a multitude of MANs and LANs. There are also a variety of proprietary, government, and military WANs and WAN technologies currently deployed. Fiber optic networking and/or high-speed coax lines are necessary to deploy WANs over larger regions. Satellite communications is also used to support WAN availability in areas where terrestrial, or wired, network infrastructure is infeasible to install.
IoT Network Topologies
Though IoT networks often communicate with outside networks, they often require gateways to perform this task. The use of a gateway is a trade-off of capabilities for individual IoT devices, in order to make them smaller, cheaper, and more energy efficient. Hence, IoT networks are typically arranged in either fixed node, relay, or mesh networking topologies.
Fixed Node Networks
A fixed node network, such as a star network, where each node is connected to a central node, and communications are all handled through the central node.
A relay network uses a fixed configuration of nodes that send messages to designated nodes in a relay structure. Such structures include, rings, trees, lines, buses, and other configurations.
A mesh network is a more intelligent networking topology that uses algorithms to determine the most effective network configuration to use at a given time. Mesh networks are typically designed to minimize the number of hops a message uses to reach its destination in order to conserve power and to lower transmission latency. Though many Mesh networks are made of similar devices, some are designed with gateways that also operate within the Mesh in order to communicate between the PAN Mesh network and outside networks.