5G promises enhanced performance-not only in bandwidth and capacity, but also latency and security. Its ultra-reliable low-latency configuration targets round-trip times below 1 ms, while optional security controls extend protection across all interfaces, making 5G attractive for mission-critical applications. A key enabler of low latency is the disaggregation of network components, including the RAN, allowing user-plane functions to be deployed nearer to end users. However, this split introduces additional interfaces, whose protection increases latency overhead. In this paper, guided by discussions with a network operator and a 5G manufacturer, we evaluate the latency overhead of enabling optional 5G security controls across internal RAN interfaces and the 5G user plane. To this end, we deploy the first testbed implementing a disaggregated RAN with standardized optional security mechanisms. Our results show that disaggregated RAN deployments retain a latency advantage over monolithic designs, even with security enabled. However, achieving sub-1 ms round-trip times remains challenging, as cryptographic overhead alone can already exceed this target.

翻译：5G承诺在带宽和容量之外，在时延与安全性方面也实现性能提升。其超高可靠低时延配置以低于1毫秒的往返时延为目标，而可选安全控制将保护范围扩展至所有接口，这使得5G对关键任务应用具有吸引力。实现低时延的关键在于网络组件（包括RAN）的解耦部署，使得用户平面功能能够更贴近终端用户。然而，这种解耦架构引入了额外的接口，其安全保护会增加时延开销。本文基于与网络运营商及5G设备制造商的研讨，评估了在RAN内部接口及5G用户平面启用可选安全控制所产生的时延开销。为此，我们部署了首个实现解耦RAN架构并采用标准化可选安全机制的测试平台。实验结果表明，即使启用安全机制，解耦式RAN部署仍比单体式设计具有时延优势。然而，实现亚毫秒级往返时延仍面临挑战，仅加密开销就可能已超过该目标值。