What are Gateways?

In our day-to-day life, we use the Internet on our computers which may be connected to a LAN network. Internet is an example of a WAN network, it may implement some other protocols or have a different architecture from a LAN. Have you ever wondered, how it is possible?

In such cases, there is a need for a network connecting device, known as Gateways. Gateways are the most intelligent and highly configurable network connecting devices. It operates in all the layers of the OSI(Open System Interconnection) model, which is also depicted in the image below. So in this blog, we'll learn about Gateways in detail. We'll also see the working, features, advantages, and disadvantages of using a Gateway.


Gateway is a network connecting device that can be used to connect two devices in two different networks implementing different networking protocols and overall network architecture. In other words, a gateway is a node on a network that serves as an entrance to another network.

A Gateway is the most intelligent device among the network connecting devices. Intelligent in terms of its working, error control, data packet routing, transmission speed, etc. It is a combination of both hardware as well as software components.

One of the main features of using a gateway is that we can have routing controls for different networks through gateways. This way, the traffic flow in the transmission channels for different networks can be easily controlled by gateways.

A gateway operates on all the layers of the OSI model, so it can be used as a one-stop solution for all kinds of network device connectivities. But the major disadvantage of using a gateway is its implementation cost. So, it will not be so effective to be used for small networks, or for a single network. Also, the implementation of gateways is very complex. These things constraint the wide use of gateways for small purposes.

A Gateway is also called as 'Protocol Converter' because it can convert the data packets as per the destination network protocol requirement. It can also translate the data format as per the destination needs or architecture. A gateway is used either at the starting or endpoint of the network. It is an intelligent device that can be used to connect a local node with an external node having a completely different structure(protocols/architecture/languages/data formatting structures). In other words, a gateway acts as a 'gate' between two networks and enables traffic to flow(in and out) of the network.

Gateways are often associated with both Routers and Switches. A Router routes the data packets(arriving at the gateway) to the correct node in the destination network. While a switch specifies the actual path of the data in and out of the gateway. In general, a gateway expands the router's functionality by performing data translation and protocol conversion. For Example, a router can act as a gateway in a single network. In similar ways, Switches, Servers, Firewalls, etc. can also be used as a gateway at different places, as per the needs.

A default gateway passes the local subnet to devices on other subnets. In other words, a default gateway connects a local network to the internet or some other network. Actually, each network has an internal default gateway in order to connect its devices to the dissimilar network. A gateway can also have multiple NIC's(a chip that allows the nodes to communicate to another computer on a network) connected to it. Unlike routers, it does not supports dynamic routing. It mostly uses a packet switching technique to transmit data from one network to another. A gateway mainly works on IP(Internet Protocol) Addresses for dissimilar network communication. It has control over both collisions(inside a network) as well as broadcast(outside the networks) domain. It can also encapsulate and decapsulate the data packets when they send and receive the data packets respectively.

For Example, Electronic Mail Gateway(X.400), etc.

Need: To establish an intelligent communication between two dissimilar networks.

Working: When a data packet arrives at the gateway, it first checks the header information. After checking the destination IP address and any kind of errors in the data packets. It performs data translation and protocol conversion of the data packet as per the destination network needs. Finally, it forwards the data packet to the destination IP address by setting up a specific transmission path for the packet.

Following are the advantages of using a Gateway:
  1. It can connect the devices of two different networks having dissimilar structures.
  2. It is an intelligent device with filtering capabilities.
  3. It has control over both collisions as well as a broadcast domain.
  4. It uses a full-duplex mode of communication.
  5. It has the fastest data transmission speed amongst all network connecting devices.
  6. It can perform data translation and protocol conversion of the data packet as per the destination network's need.
  7. It can encapsulate and decapsulate the data packets.
  8. It has improved security than any other network connecting device.
Following are the disadvantages of using a Gateway:
  1. It is complex to design and implement.
  2. The implementation cost is very high.
  3. It requires a special system administration configuration.

This is all about the most intelligent network connecting device, i.e., Gateways. Hope you learned something new today. That's it for this blog.

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