In certain instances, we may earn revenue when a reader makes a purchase or completes a form through our pages or on a partner’s website. We adhere to a strict 
What Is a Gateway?
In networking, a gateway is a network node that has the ability to route traffic between incompatible networks. Gateways allow devices on a local area network (LAN) to communicate with other devices on external networks like the Internet.
Key Takeaways
- Gateways are network nodes that can route traffic between incompatible networks.
- They work by translating communication protocols, normalizing data formats, and/or mapping IP addresses.
- Gateways use a mechanism called network address translation (NAT) to ensure devices on a local network can access the Internet.
- In the early days of networking, gateways were specialized hardware devices.
- Today, gateway functionality is often built into routers.
How Gateways Work
Network nodes determine whether they need to use gateway functionality by checking a data packet’s destination IP address to see if it belongs to the same local network. If it does, the gateway is bypassed, and devices communicate directly using their MAC addresses. If the destination IP address is outside the local network, however, the node sends the packet to the gateway so it can be processed and forwarded to the appropriate destination.
To ensure devices on a local network can access the Internet, gateways often use a function called network address translation. NAT replaces a private IP address and port number in an outgoing packet with a public IP address and a different port number. It also reverses this process for incoming traffic to ensure that responses reach the correct device on the LAN.
Gateway Types
In the past, gateways were always physical network appliances, but software-defined networking (SDN) network architectures have made it easier than ever to program gateway functionality into other types of network appliances.
SDN decouples the control plane (where decisions about traffic flow are made) from the data plane (where traffic is actually forwarded). The separation allows gateway functionality to be implemented virtually in firmware and software and integrated into Layer 3 switches, routers, and firewalls.
Virtual gateways are important in cloud computing environments because they can be managed from a central location and scaled up or down as needed. It should be noted, however, that while virtual gateways are often integrated into other virtual network devices, they can also exist as standalone software components that can be called on to provide gateway services when required.
Virtual Gateway Features
Virtual gateways can be programmed with a range of features that enhance network performance and security.
Many virtual gateways are able to collect and analyze network traffic data, cache frequently accessed data closer to users to reduce latency, and distribute network traffic across multiple servers for bandwidth shaping and load balancing purposes.
Some are able to implement stateful packet inspection just like anti-virus apps, isolate sensitive parts of the network to limit the impact of security breaches, and use techniques like data compression and deduplication to optimize performance over wide-area networks (WANs).
Gateway vs. Router
Gateways are designed to translate communication protocols, data formats, and/or addressing schemes so that data packets can be forwarded to the correct destination across different networks.
Routers, on the other hand, use routing tables and algorithms to forward data packets between devices within the same network or between different subnets within a larger network.
Gateways and routers are often confused because they are both used to direct network traffic. To add to the confusion, gateway functionality is frequently integrated into commodity routers used in small to mid-sized businesses and home networks.
Gateway Use Cases
The flexibility that virtual gateways provide allows them to be used for a wide variety of use cases.
For discussion purposes, networking gateways are often referred to by the use case they are designed for:
Gateway Pros & Cons
Organizations can determine how and when to use gateways by looking at both the pros and cons of each type of gateway and then balancing functionality with cost and security needs:
Pros
- Bridge different network architectures for data exchange
- Can be integrated with firewalls, intrusion detection, and encryption to protect data and prevent unauthorized access
- Virtual gateways handle additional networking tasks like load balancing
- Physical getaways remain available for specific use cases despite virtualization
Cons
- Can become bottlenecks if not configured correctly
- If not secured properly, gateways can become an entry point for attackers
- Setting up and maintaining a gateway can require significant technical expertise
- Gateway outages can disrupt communication between connected networks
The Bottom Line
While the definition of gateway has become more nuanced over time because of virtualization, the label “gateway” is still a useful metaphor. Whether you are talking about driveways or networks, a gateway is an access point that’s used to manage traffic.
FAQs
What is a gateway in simple terms?
What is a default gateway?
What is a gateway used for?
What is the gateway on my Internet bill?
What is the difference between a router and a gateway?
What is the gateway IP address?
Why is 502 a bad gateway?
References
- Just a moment… (Images.techopedia)
