What is Anycast Networking and How Does it Work?

These days, most people take fast networks for granted. As the future of work becomes exponentially more digital, everyone just expects their internet connections to be fast. End users of online services demand a fast, reliable experience – or they’ll cancel subscriptions, buy from other websites, or otherwise take their business elsewhere. One of the foundational technologies driving today’s lightning-fast internet experiences is anycast networking.

Now more than ever, optimized networks are a key driver of employee productivity and overall business success. That’s why it’s critical that  IT leaders know the ins and outs of how their workforce – and customers – get and stay connected.

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The good (or bad) news is that networking technology hasn’t changed much over the last 20 years. Regardless, understanding some basic concepts of anycast network addressing will make sure you can consistently deliver the services and products that your end users rely on. Research shows that it’s costly when you fail to do so. According to a 2020 report by Statista, a single hour of downtime costs enterprises between $300k to upwards of $5 million.

To help you avoid this, we’ll take you through a few key network fundamentals, starting with the basics of anycast networking. However, there are still several factors for any IT leader to consider before making anycast a part of their network strategy.

What is anycast networking?

Anycast, also known as IP anycast or anycast routing, is an approach to IP routing in which incoming requests can be routed dynamically to multiple locations. This approach enables businesses to reach the global edge with multiple servers that share the same IP address.

While anycast routing gives businesses a foundation for creating a fast and reliable network, there are other routing alternatives, including:

• Unicast, where each individual server sits behind a single IP address. With unicast, data is transmitted from a single source to a specific destination.

• Multicast, a group communication method in which data is transmitted to a group of servers at the same time.

While unicast and multicast can be simpler to set up, anycast is the most popular choice among content delivery networks (CDNs), domain name system providers (DNS), and other services that must be as fast and resilient as possible. DNS providers often choose anycast because it offers lower latency, load balancing, and built-in defenses against a DDoS attack. CDNs rely on anycast for its speed, scalability, and security.

Anycast is appealing to operators looking to ensure incoming requests get sent to the highest-performing server—and it does so via the border gateway protocol (BGP).

What is BGP (border gateway protocol) and an autonomous system?

In simple terms, the border gateway protocol (BGP) ensures that Internet traffic is routed by the most efficient routes. BGP evaluates the available paths for data to travel and picks the best route. In most cases, it does so by switching between autonomous systems. Autonomous systems are smaller networks; the internet is broken up into hundreds of thousands of these networks, and each one is a large pool of routers run by a single organization.

BGP anycast simplifies data transmission for DNS and CDN providers because each server broadcasts the same anycast IP address. While this is true for any organization leveraging anycast, it’s particularly the case with NetActuate’s AS, which operates one of the largest peered IPv4 and IPv6 networks in the world.

How does anycast work?

In addition to routing requests to different servers, there are several reasons why anycast drives so many pockets of the internet. Many types of security providers, such as those who operate VPN, SIEM, or WAF services, can leverage anycast to provide highly available solutions with fast, reliable end-user experiences.

Additionally, internet service providers and domain operators can improve browsing experience by using anycast to make their global DNS servers available from a single IP address.

• Recursive DNS: Providers of recursive DNS services leverage anycast to make their global DNS servers available from a single IP address. This enables them to deliver a best-in-class internet browsing experience to end users.

• Authoritative DNS: Anycast routes recursive lookup requests to the authoritative DNS server closest to the end user’s location on the network. This makes resolving DNS requests much faster and more reliable than other routing techniques.

Although most people aren’t familiar with anycast, it’s what makes the best online services as fast and reliable as customers count on them to be. Making anycast a part of your network strategy unlocks several benefits, including:

• Faster Connections: User requests are directed by anycast to the closest server on the network. This often correlates to the data center physically closest to the user.

• Improved Reliability: When any server goes down, anycast automatically sends users to the next closest location on the network.

• Load Balancing: Since users are routed to the closest servers by number of hops, the load across all of your servers is automatically balanced, which improves speed and performance.

• DDoS Mitigation: Anycast reduces the impact of DDoS attacks. If one location is taken offline, users are automatically rerouted to the next nearest online server available at the same IP.

Conclusion

Whenever you enjoy a fast and reliable connection to an essential service, there’s a good chance it’s powered by an anycast network. According to research from the National Science Foundation, 93% of top-level domains (TLDs) were powered by anycast in 2021—and businesses across other industries could benefit from it too, especially as their applications evolve and need to be distributed closer to their end users.

This is just one of many reasons why it’s helpful for today’s IT leaders to understand the benefits of anycast and how it works. Companies with large global deployments need to deliver consistently fast experiences to end users if they want to retain them, especially as the costs of downtime hover around a whopping $9,000 per minute.

You can reduce complexity, ensure resilience, and be available even amid an unexpected traffic spike by working with a leading provider like NetActuate, which operates one of the five largest global anycast networks in the world. Ready to learn more? Schedule a call with an engineer today.