'Legacy DNS architectures are inadequate for 5G'

Oct 17, 2019
According to Neil Cook, VP DNS and Security Products at Open-Xchange, outdated DNS will cause 5G bottlenecks.

By 2024, an estimated 1.9 billion people across the globe will be connected to superfast 5G networks - while in the same timeframe, 5G is set to represent 26% of total mobile subscriptions in the UK. Yet while many people today look forward to being able to utilise faster browsing and improved download speeds, it’s important to remember that this is not the sole purpose of the next generation of wireless technology.


5G has been specifically designed to support smart devices that make up the Internet of Things (IoT). These “things” currently include everything from Alexa-style voice assistants and Apple watches, to smart fridges and robotic vacuum cleaners. Once linked up to a network, these devices “talk” to each other through the use of machine-to-machine (M2M) connections, which increases their ability to assist users in a variety of ways.   

Supporting smart devices 

With 5G, networks can support a much higher number of smart devices. And for this reason, many technologists are hoping to usher in a new age of IoT, with networks of self-driving cars in constant communication with one another, as well as medical devices that can monitor the body and administer treatment accordingly.

In the UK, 5G is currently available - albeit in select cities across the country. But it will take time before many of the promised benefits of 5G come to pass, as operators re-architect their core networks around 5G. Part of that re-architecture is changing the way that DNS is deployed to ensure that it is not a bottleneck for 5G use-cases such as eMMB and urLLC.

One of the most significant differences of a 5G network compared with the previous generations is that the latency of the RAN, i.e. the time it takes to connect a device to a network, is dropping from around 30-50 milliseconds to between 1 and 4 milliseconds. This might sound like a good thing (and it is!), but it then exposes other parts of the network which may become a bottleneck, such as the Domain Name System (DNS).


DNS is the “phonebook of the internet” 


The DNS, sometimes described as “the phonebook of the internet”, converts user-friendly domain names (e.g. www.5Gradar.com) into computer-readable IP addresses (e.g. “”). Almost all network connections necessitate a DNS lookup, making it one of the backbone universal standards of the internet.


If a DNS lookup is slow to return a result, the network will begin to “feel” slow and frustrate users, while for smart devices on the network this high latency may impact time-critical M2M connections.


Until recently, network providers haven’t had to worry too much about the latency of DNS because it could simply “hide” within the relatively higher RAN latency. But this all changes when the RAN latency drops significantly in a 5G network, causing the DNS service to become a painfully apparent bottleneck. The main reason for this is that DNS servers are typically located fairly deep within the network core; this makes them relatively easy to manage, particularly considering the typical appliance model of many DNS servers, but makes them poorly suited to the task of delivering extremely low-latency answers to connected devices.


Moving to the edge 


When data is processed at the “edge” of a network, this means that it’s brought closer to the location where it’s needed, minimising the need for high-latency long distance communications. These types of edge computing solutions are expected to play a significant role in 5G networks, ensuring high quality user experience. And this is also how you solve an issue like DNS latency in a 5G network.


By locating the DNS service as close to the edge as practically possible, network providers can reduce latency and be confident that their 5G service will meet the expected boost in performance and functionality. But in order to achieve this, network providers will require a new vision and architecture for how their DNS services are run. Instead of a small number of large regional data centres, DNS servers should utilise a much higher number (potentially thousands) of smaller centres, distributed depending on customer location; this presents much more stringent requirements for orchestration, management and monitoring.


Solving these requirements requires building on a huge range of supporting (and open) technologies, which together make up the “Cloud Native” architecture (see https://www.cncf.io). DNS is no exception, which is why your DNS deployment must support “Cloud-Native” deployment, either today or on the near-term roadmap. 

Network providers must act 


Earlier this year EE 5G and Vodafone 5G launched in select locations across the country, with O2 5G and Three 5G also pressing ahead now. However, at the moment the investment in 5G is mainly around the RAN, with much less attention directed at the core network behind it.


As that new network is built out, we will quickly discover that legacy DNS architectures are inadequate for 5G, and that they will be unable to meet its new latency requirements. And with customers looking forward to hyped-up browsing and download speeds, there will be a lot of people in for a nasty shock. Therefore, it is vital that network providers invest in DNS solutions that can be deployed at the edge of the network, whilst using open Cloud Native technologies to do it.

About the author

Neil Cook

Neil Cook

PowerDNS Head of Product

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