A gateway is a piece of networking hardware or software used in

telecommunications network A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, mes ...

s that allows data to flow from one discrete network to another. Gateways are distinct from routers or switches in that they communicate using more than one protocol to connect multiple networks and can operate at any of the seven layers of the

open systems interconnection The Open Systems Interconnection model (OSI model) is a conceptual model that 'provides a common basis for the coordination of SOstandards development for the purpose of systems interconnection'. In the OSI reference model, the communications ...

model (OSI). The term gateway can also loosely refer to a computer or computer program configured to perform the tasks of a gateway, such as a default gateway or router, and in the case of

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...

, gateway is also often used as a synonym for reverse proxy.

Network gateway

A network gateway provides a connection between networks and contains devices, such as protocol translators, impedance matchers, rate converters, fault isolators, or signal translators. A network gateway requires the establishment of mutually acceptable administrative procedures between the networks using the gateway. Network gateways, known as protocol translation gateways or mapping gateways, can perform protocol conversions to connect networks with different network protocol technologies. For example, a network gateway connects an office or home

intranet An intranet is a computer network for sharing information, easier communication, collaboration tools, operational systems, and other computing services within an organization, usually to the exclusion of access by outsiders. The term is used in c ...

to the

Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, p ...

. If an office or home computer user wants to load a web page, at least two network gateways are accessed—one to get from the office or home network to the Internet and one to get from the Internet to the computer that serves the web page. On an

Internet Protocol The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. ...

(IP) network, IP packets with a destination outside a given subnet mask are sent to the network gateway. For example, if a private network has a base

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version d ...

address of 192.168.1.1 and has a subnet mask of 255.255.255.0, then any data addressed to an IP address outside of 192.168.1.0 is sent to the network gateway.

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. I ...

networks work in a similar way. While forwarding an IP packet to another network, the gateway may perform network address translation. In enterprise networks, a network gateway usually also acts as a

proxy server In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource. Instead of connecting directly to a server that can fulfill a reques ...

and a

firewall Firewall may refer to: * Firewall (computing), a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts * Firewall (construction), a barrier inside a building, designed to limit the spre ...

. On Microsoft Windows, the Internet Connection Sharing feature allows a computer to act as a gateway by offering a connection between the Internet and an internal network.

Internet-to-orbit gateway

An Internet-to-orbit gateway (I2O) connects computers or devices on the Internet to computer systems orbiting Earth, such as satellites or crewed spacecraft. Project HERMES, run by the Ecuadorian Civilian Space Agency, was first to implement this kind of gateway on June 6, 2009. Project HERMES has a maximum coverage of 22,000 km and can transmit voice and data. The

Global Educational Network for Satellite Operations The Global Educational Network for Satellite Operations (GENSO) is forming by a worldwide network of ground stations and spacecraft which can interact via a software standard. The GENSO aims to increase the return from educational space missions an ...

(GENSO) is another type of I2O gateway.

Cloud storage gateway

A cloud storage gateway is a network appliance or

server Server may refer to: Computing *Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients Role * Waiting staff, those who work at a restaurant or a bar attending customers and su ...

which translates cloud storage APIs such as

SOAP Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are us ...

or REST to block-based storage protocols such as

iSCSI Internet Small Computer Systems Interface or iSCSI ( ) is an Internet Protocol-based storage networking standard for linking data storage facilities. iSCSI provides block-level access to storage devices by carrying SCSI commands over a TCP/IP ...

Fiber Channel Fibre Channel (FC) is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to servers in storage area networks (SAN) in commercial data cent ...

or file-based interfaces such as NFS or CIFS. Cloud storage gateways enable companies to integrate private cloud storage into applications without moving the applications into a public cloud, thereby simplifying data protection.

IoT gateway

Internet of things The Internet of things (IoT) describes physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other com ...

(IoT) gateway provides the bridge (protocol converter) between IoT devices in the field, the cloud, and user equipment such as smartphones. The IoT gateway provides a communication link between the field and the cloud, and may provide offline services and real-time control of devices in the field. To achieve sustainable interoperability in the Internet of things ecosystem, two dominant architectures for data exchange protocols are used: bus-based ( DDS, REST,

XMPP Extensible Messaging and Presence Protocol (XMPP, originally named Jabber) is an open communication protocol designed for instant messaging (IM), presence information, and contact list maintenance. Based on XML (Extensible Markup Language), i ...

) and broker-based (

AMQP The Advanced Message Queuing Protocol (AMQP) is an open standard application layer protocol for message-oriented middleware. The defining features of AMQP are message orientation, queuing, routing (including point-to-point and publish-and-subsc ...

, CoAP,

MQTT MQTT (originally an initialism of MQ Telemetry Transport) is a lightweight, publish-subscribe, machine to machine network protocol for Message queue/Message queuing service. It is designed for connections with remote locations that have devices ...

, JMI). Protocols that support information exchange between interoperable domains are classified as message-centric (AMQP, MQTT, JMS, REST) or data-centric (DDS, CoAP, XMPP).Bryon Moyer.
All About Messaging Protocols What Are the Differences?
. EE JOURNAL. April 20, 2015 Interconnected devices communicate using lightweight protocols that don't require extensive CPU resources. C, Java, Python and some scripting languages are the preferred choices of IoT application developers. IoT nodes use separate IoT gateways to handle protocol conversion, database storage or decision making (e.g. collision handling), in order to supplement the low intelligence of devices.

References

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