Low latency numbers are a moving target. They're higher for applications with low-throughput requirements than they are for applications with higher-throughput requirements. In general, latency is a function of the proper network design. Radio latency must be considered alongside end-to-end IP latency and the round-trip delay. One major factor that contributes to latency is shared by 5G, Wi-Fi, and Cisco Ultra-Reliable Wireless Backhaul (URWB) technologies: The closer applications are located to where data is being processed in data centers, clouds, or at the network edge, the lower the possible latency.

Low Latency Requirements Vary by Application

In VoIP, 150 milliseconds of latency in one direction is not noticeable by users and therefore perfectly acceptable. With collaboration applications like WebEx or Microsoft Teams and augmented and virtual reality (AR/VR), sub-50 millisecond bi-directional response times are required. If you're using wireless connections to run an Autonomous Mobile Robot (AMR) or an Automated Guided Vehicle (AGV) in a factory, sub-20 ms response times in a high-throughput network are necessary, while some closed-loop process control traffic requires 10 ms or less end-to-end latency.

How Latency is Usually Calculated

End-to-end IP latency is usually calculated in one direction: from the wireless device to the wireless network, IP transport network, and application server. Round-trip Time (RTT) is the calculation of bi-directional latency (e.g., the time required for a network ping). Achieving lower RTT latency is simplified with the closer proximity of applications hosting the wireless devices.

In calculating end-to-end IP latency, it's important to consider the typical round-trip time (RTT) latency between an end user and a cloud provider or content distribution network (CDN) provider. In a network design aiming for 150 ms of RTT latency, the time split between each network segment or building block from the local device to its application must be estimated. A device attaches to a local wireless network with its over-the-air latency, then data is transited over public and private IP infrastructure, including switches, routers, and firewalls in the round-trip path. This often incurs unpredictable Internet latency before reaching the application.In addition, the processing time required before a response is sent back must also be considered in calculating overall latency.

How Different Wireless Technologies Handle Latency

Advanced types of 5G service