Bringing DNS Service to 5G Edge for Reduced Latencies in mMTC Applications

5G brings many improvements to cellular networks in terms of performance, such as lower latency, improved network efficiency, and higher throughput, making it an attractive candidate for many applications. One such domain is industrial applications that may require real-time guarantees to transmit time-critical control messages. Assuming the immense number of devices exchanging data in support of Massive Machine-Type Communications (mMTC) applications, the capability of the cellular infrastructure to handle a large number of real-time transmissions may be inadequate. For such cases, there exists an acute desire to reduce any overheads as much as possible in order to guarantee certain deadlines. One such target is the Domain Name System (DNS) service, for which queries precede almost every new network request. This incorporates additional communication delays based on the response time, which in turn is affected by the proximity of the DNS server. While bringing DNS service to the edge has been touted as a logical solution, its integration with 5G systems is still challenging. This is due to the inability to access the DNS query information at the application layer since the User Equipment (UE) traffic is tunneled through to the core network. To this end, we propose a novel approach that can identify DNS queries at the base stations through Software-Defined Networking (SDN) capabilities. Specifically, we develop an SDN controller which is used to identify and extract DNS queries at the base station and handle the query at the edge without going through the 5G core network. This approach was implemented in a virtualized 5G network, in which we demonstrate that it is feasible and can potentially bring significant performance gains, especially in the case of mMTC applications.