In search of the perfect Anycast locations

The RcodeZero DNS Anycast service provides optimal load balancing with more than 40 locations worldwide. In the following text, we reveal why placing the locations correctly is a challenge, why the traffic hubs may not be as expected, and why sending out the first servers was so nerve wracking.

Complicated customs formalities in the USA, difficulties with local authorities, and bureaucratic obstacles: The first servers that ipcom (sister company of the Austrian domain registry for the .at TLD) shipped around the world ten years ago presented the company with logistical challenges. "There were so many imponderables. If you don't do this every day, you must learn the hard way," says Robert Schischka, technical managing director of nic.at and ipcom. Alexander Mayrhofer, Head of Research & Development, also remembers: "Back then, we didn't fly to the sites ourselves, but instructed technicians on site which cable to plug in where." ipcom's Anycast service started with seven servers – today there are more than 40 worldwide. Not only has the number of servers grown, but the structure of the industry has also changed in the meantime: "We no longer ship hardware, but order infrastructure that is then made available to us," explains Mayrhofer.

Johannesburg, Tokyo or Singapore

The Anycast servers for RcodeZero DNS are distributed all over the world and ensure that online services are continually available under one and the same IP address. If a server fails, the topologically closest one steps in. This reduces response time and spreads the overall load across the network. The goal of a new site is always to improve speed. "Before that, a lot of analysis goes into what impact a new site will have on network traffic," Mayrhofer explains. “It's often a matter of fractions of a second”. Across Europe, he says, you can reach any location in 20 milliseconds. "The distances are not as great in Europe as they are in North America, for example, where we need locations on the West Coast and the East Coast." In addition to servers in the U.S. and Europe, there are locations in Sao Paulo, Johannesburg, Tokyo and Singapore. "Many of our clients have European customers themselves, so good European coverage is important to us. However, we also want to offer reliable service to customers outside Europe, so it is essential that we venture into other continents as well," says Mayrhofer.

A constant process of optimization

The servers are placed where the traffic flows. But placing the sites correctly is no easy task: "The topology of the Internet is a secondary structure covering the globe, but which does not follow any geographical boundaries. Placing sites in the right place so that users within a geographical radius access the fastest server is a challenge," Mayrhofer says. “Changes in network topology are taking place all the time. Something that worked well two weeks ago may not work today. We may find that traffic from a nearby node switches to a node farther away, wiping out our optimization efforts. So it's imperative that we constantly measure and check where performance is coming from and then adjust accordingly."

Perceived centers

The conventional centers of the world are not necessarily the centers of the Internet. "There are big nodes where traffic comes together, which are Frankfurt, London or Amsterdam. In Germany, the capital Berlin is rather insignificant from a network topology perspective," Mayrhofer says. Nevertheless, it is "prettier" if the servers are evenly distributed. Robert Schischka also confirms this: "What looks good on the map is not automatically good for the network. But we have the advantage that our size means we can respond to requests to a certain extent."

Two clouds for the RcodeZero DNS Anycast service

As more and more customers use RcodeZero DNS, and the traffic therefore continues to increase, the locations relating to the Anycast service are being expanded. ipcom is increasingly using server capacities in the cloud. "We are well positioned in terms of the number of sites we have," says Klaus Darilion, Head of Operations. "We are operating on two tracks: in the first cloud, we have many locations where our physical servers are located. Our second cloud, on the other hand, is completely virtual. That's a good combination, because we don't have infinite resources in the cloud." For sites with a lot of traffic, ipcom therefore still has its own servers to absorb peak loads. "After all, size, stability and performance are key success factors for a successful Anycast service," says Darilion.

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