Anycast Networks: What Are They and Why Do They Even Matter?


We talk about our Anycast network a lot. With over 100 points of presence in globally redundant locations, what’s not to be proud of?

What is an Anycast network and why does it even matter?

Before we get into Anycast, let’s talk about a routing scheme called Unicast. Unicast is how most DNS networks work. An easy way to think of Unicast networks is one-to-one. Unicast is taking an IP address and assigning it to one unique nameserver. If you have the following nameservers: ns1, ns2, ns3, each one of those nameservers will be responsible for answering certain queries. If ns2 goes down due to power outage or severe weather, the server will move on to the next available unicast server. If the second server goes down due to being overloaded, your domain will be fully inaccessible.

So, what is Anycast?

If Unicast is one-to-one, Anycast is one-to-many. Anycast is taking the same IP address and assigning it to multiple locations across the network. In the same scenario as above, your website isn’t just hosted at one location (or on one nameserver), it is hosted on multiple name servers, in multiple locations. So, if one server in the Anycast cluster goes down, your website won’t go down with it. The queries will just be answered by the next server instead. It is used to help distribute traffic and query load across the entire network, so one point isn’t always doing all of the work. This helps keep the network fast and reliable. Anycast also helps to ensure that someone visiting your website from Tokyo, Japan, queries the server that is closest to their location. This helps to ensure that the website loads quickly.

Anycast helps ensure that the network is flexible and reliable. It helps the traffic find the quickest path. If one of our points of presence is having problems and we take it offline, that traffic will be routed to our next point of presence on the network that is nearby.

Outsourcing your Managed DNS for your domains to a reliable and trusted Managed DNS provider with a robust Anycast network is essential for small and large businesses.

If you depend on your website for customer leads and e-commerce, not thinking strategically about your Managed DNS network will do more harm than good. Ready to learn more or get started, add Plus Managed DNS to your domain now.