What are Gateways in Computer Network (Fully Explained)
A gateway is a network node that creates a connection between two networks that use different transmission protocols. The most prevalent type of gateway, known as the network gateway, functions at layer 3, which is the network layer of the OSI (Open Systems Interconnection) model. However, depending on its purpose, a gateway can function at any of the seven layers of the OSI model. It serves as the entry and exit point for a network, as all traffic that traverses the networks must go through the gateway. The only exception is the internal traffic between nodes within a LAN, which does not pass through the gateway.
Features of Gateways
- A gateway is positioned at the edge of a network and oversees all data that enters or exits that network.
- It establishes a connection between two distinct networks that operate on different transmission protocols.
- A gateway functions as a protocol converter, ensuring compatibility between the various protocols utilized in the two networks.
- What sets a gateway apart from other network devices is its ability to operate at any layer of the OSI model.
- It also retains information regarding the routing paths of the networks that are communicating.
- In an enterprise context, a gateway node may also serve as a proxy server or firewall.
- Typically, a gateway is implemented as a node equipped with multiple NICs (network interface cards) linked to different networks. However, it can also be set up using software.
- It employs packet switching techniques to transmit data across the networks.
Types of Gateways
Based on the direction of data flow, gateways can be broadly classified into two categories:
- Unidirectional Gateways: These allow data to flow in only one direction. Changes made in the source node are reflected in the destination node, but not the other way around. They can serve as archiving tools.
- Bidirectional Gateways: These permit data to flow in both directions. They can function as synchronization tools.
Based on their functionalities, various types of gateways exist, with the most notable ones being as follows:
- Network Gateway: This is the most prevalent type of gateway, serving as an interface between two distinct networks that operate on different protocols. When the term 'gateway' is used without further specification, it typically refers to a network gateway.
- Cloud Storage Gateway: This is a network node or server that converts storage requests into different cloud storage service API calls, such as SOAP (Simple Object Access Protocol) or REST (REpresentational State Transfer). It enables the integration of private cloud storage into applications without requiring the applications to be moved to any public cloud, thereby streamlining data communication.
- Internet-To-Orbit Gateway (I2O): This gateway connects Internet devices to satellites and spacecraft that are in orbit around the Earth. Two notable I2O gateways include Project HERMES and the Global Educational Network for Satellite Operations (GENSO).
- IoT Gateway: IoT gateways gather sensor data from Internet of Things (IoT) devices in the field and convert between different sensor protocols before transmitting the data to the cloud network. They serve as a link between IoT devices, the cloud network, and user applications.
- VoIP Trunk Gateway: This gateway enables data transmission between traditional telephone service (POTS) devices, such as landline phones and fax machines, and a VoIP (Voice over Internet Protocol) network.
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