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What’s a Gateway?

A gateway is a network device that translates between different protocols, enabling communication across dissimilar technologies. Routers, modems, voice gateways, wireless LAN controllers, and firewalls can all function as gateways depending on their role in the network.

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About this video

A gateway is a network device that translates between two or more different protocols, making communication possible across otherwise incompatible technologies. The term describes a functional role rather than a specific device type, which distinguishes it from more narrowly defined equipment like switches or routers. Any appliance that bridges dissimilar communication technologies can be classified as a gateway, and a single network may include several of them serving different purposes. The edge router is the most familiar example, sitting at the boundary between a private LAN and an external WAN connection and handling the protocol translation required to pass traffic between the two. A router bridging an Ethernet LAN and a T1 circuit is a clear case of this, since those two technologies operate very differently at the protocol level. A router with a built-in modem extends this further, as the modem itself is a modulator-demodulator that translates between digital and analog signaling. Beyond the network edge, gateways appear in other specialized roles throughout an organization's infrastructure. A voice gateway connects VoIP phones to external voice services, a wireless LAN controller acts as a bridge between the wireless and wired portions of a network, and a firewall that performs routing functions also qualifies as a gateway. Recognizing the gateway as a functional classification rather than a product category helps in understanding how traffic flows across boundaries between different network technologies.

What you'll learn

What's covered

Network Gateways

Aligned to

CompTIA Network+
1.2 Compare and contrast networking appliances, applications, and functions.
Cisco CCNA
1.1 Explain the role and function of network components
Cisco CCST Networking
1.1 Identify the fundamental conceptual building blocks of networks
3.3 Describe endpoint devices
CompTIA A+ Core 1
2.2 Compare and contrast common networking hardware.

Key terms

Gateway
A network node that connects two networks using different protocols, translating between them.
Router
A network device that forwards data packets between networks based on IP addresses.
Switch
A network device that connects devices within a LAN and forwards traffic based on MAC addresses.
Firewall
A network security device that monitors and controls incoming and outgoing traffic based on predefined security rules.
Modem
A device that modulates and demodulates signals to translate between different transmission protocols, enabling communication between a local network and an external service such as DSL or cable.
Voice Gateway
A network device that translates between Voice over IP (VoIP) protocols and traditional telephony protocols to provide voice services on a network.
Wireless LAN Controller
WLC
A network device that provides centralized management of multiple lightweight wireless access points, handling functions such as client authentication, roaming, radio frequency management, and security policy enforcement. WLCs communicate with APs using CAPWAP and allow network-wide wireless configuration from a single management point.
Protocol
A set of rules governing the format and transmission of data between devices.

Transcript

What a Gateway Is

The term gateway can be applied to many different types of appliances. What a gateway is, is it's translating between different protocols.

One thing to note is that when we're talking about a switch, it performs a very specific function. When we're talking about a router, it performs a very specific function. When we're talking about a gateway, it more describes a type of equipment. So a gateway can be thought of as a type of equipment.

So what type of equipment is it? It's like a translator. It's going from one protocol to another. For instance, our router right here is usually connected to the outside world, which has a very different type of connection to it. We're connecting to our internet service provider, and this WAN connection right here is maybe DSL, or maybe it's a cable connection, or it's some other type of connection. So what this router is doing is it's functioning as a gateway between our network and this other type of connection that uses a different type of protocol. A lot of times what we refer to as routers are a gateway, or at least the ones that we see at the edge of our network.

We may have multiple gateways on our network. For instance, maybe we have some voice over IP phones on our network, and we set up a separate box that is our voice gateway, and our voice gateway gives us access to voice services. That's one thing that I've set up on a network before, so this is just another example of a type of gateway that's out there.

Examples of Gateways

Here are some examples of gateways. The best example of a gateway would be this router right here, because with the router we have these two LAN connections, these two Ethernet connections right here, and then we have the T1. So it's translating between this Ethernet LAN and also a T1, which are very different types of technologies. So this router is a great example of a gateway.

And then this is an example — this is a router as well, so this is an example of a gateway — especially if this had a built-in modem. This one doesn't particularly have a built-in modem to it, but a modem is a modulator-demodulator, translating between two different protocols. So that would be another great example.

I also have a wireless LAN controller here, so we're going between the wireless network and also the regular network. This would be an example of a gateway.

And then we also have this firewall as well. It's all Ethernet that's right here, but this performs some router functionality, so we would consider a firewall a type of gateway as well.

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