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.

翻译：5G在性能方面为蜂窝网络带来了诸多改进，例如更低的延迟、更高的网络效率和更大的吞吐量，使其成为众多应用领域的有力候选。其中一个领域是工业应用，这类应用可能需要实时保证来传输时间关键的控制消息。考虑到支持大规模机器类通信（mMTC）应用的海量数据交换设备，蜂窝基础设施处理大量实时传输的能力可能不足。针对此类情况，迫切需要尽可能减少一切开销，以确保某些截止时间能够被满足。域名系统（DNS）服务便是其中一个目标，因为几乎每个新网络请求之前都需要进行DNS查询。这会基于响应时间引入额外的通信延迟，而响应时间又受到DNS服务器距离的影响。虽然将DNS服务推向边缘被视为一个合乎逻辑的解决方案，但其与5G系统的集成仍具挑战性。这是由于用户设备（UE）流量通过隧道传输至核心网，导致无法在应用层访问DNS查询信息。为此，我们提出了一种新颖方法，能够通过软件定义网络（SDN）功能在基站处识别DNS查询。具体而言，我们开发了一个SDN控制器，用于在基站处识别和提取DNS查询，并在边缘处理该查询，而无需经过5G核心网。该方法已在虚拟化5G网络中实现，我们证明了其可行性，并显示其可能带来显著的性能提升，尤其是在mMTC应用场景中。