OB-UDPST paving the way for greater speed and latency measurement

Al Morton, OB-UDPST Project Co-leader at Broadband Forum

Broadband networks are being pushed to their limits, with ultra-fast connectivity no longer just a lofty aspiration, but a necessity for users to truly unlock the full potential of their connected homes. Gigabit services can support a plethora of next-generation applications including gaming, UHD streaming, augmented reality, and virtual reality – all of which are becoming increasingly popular with operators’ consumer bases. Yet these applications not only require reliable Internet connection, but need low latency to achieve the required Quality of Experience.

The industry’s attention has already rightly shifted to recognizing and delivering lower latency in addition to fast speed. Traditional web-based speed tests are regarded as lacking in accuracy, impacted by issues such as slow Wi-Fi and network congestion from background updates or other users consuming bandwidth while the test is being run. There has been a continued push for a common understanding and approach on how industry players can measure performance more accurately, with speed no longer being the sole consideration.

So how does a simple, standardized, and open-sourced User Datagram Protocol-based Speed Test (UDPST) deliver on this promise?

Readiness for the new standard of connectivity

An open source implementation for Internet access measurement has verifiable accuracy and is an integral part of Broadband Forum specifications. UDPST performs the tests defined in TR-471 Issue 3 ‘Maximum IP-Layer Capacity Metric, Related Metrics, and Measurements’, to quantify broadband networks’ ability to achieve consistent low latency along with Gigabit capacity. The specification was developed in coordination with other standards organizations, including ITU-T, IETF and ETSI-STQ/Mobile.

UDPST measures multiple metrics that are critical to Internet services and their support of consumer applications. The measurement of Maximum IP Capacity measures the packet loss, round-trip delay, delay variation, and reordering present. With UDP based tests, we are able to provide calibrated measurements of IP-Layer Capacity and Latency using a unified test stream. Other methods combine two protocols and may introduce inaccuracy because the protocols are treated differently in the network. All of UDPST’s  testing features are needed to support today’s range of latency-sensitive applications and user demands.

Why User Datagram Protocol (UDP)?

UDP is a critical communication protocol for time-sensitive transmissions on the Internet. UDP-based methods are commonly used with user applications and traffic having strict response time requirements. The amount of UDP traffic continues to grow compared to Transmission Control Protocol (TCP) traffic. The UDPST results offer an enhanced and more practical view when compared to alternative TCP-based methods. Simply put, most test tools do not provide as complete a performance picture as UDPST can.

The latest progress on UDPST includes Latency under Load (and Capacity) measurements and capabilities to perform application-layer traffic performance estimation. With these UDPST Latency under Load measurements, end-users can compare their service’s performance to the latency demands of their Internet applications in milliseconds. Latency requirements can be categorized with red, yellow, and green indicators.

The role of Broadband Forum’s OB-UDPST project

Broadband Forum’s Open Broadband – User Datagram Protocol Speed Test (OB-UDPST) project was initially launched in response to growing fiber deployments with low latency and gigabit service rates. The OB-UDPST project utility applies to both mobile and fixed radio access.

OB-UDPST has been used by the industry to measure the capacity and latency of networks with increasing capabilities, such as 5G and higher speed PON. With mobile services, there can be more performance variation as transmission capacity reaches new highs, and UDPST manages these challenging circumstances.

The team has produced ten public releases of the open source implementation, with the latest major release of version 8.0.0 completed in April 2023. The primary new feature in this release was support for multiple test connections (UDP flows) between the client and one or more server instances (i.e., distributed servers). This feature provided server redundancy and resiliency to busy or unavailable servers.

Get involved in the OB-UDPST project, by reaching out to: info@broadband-forum.org.