Faster rollouts of new technologies with multi-vendor Gfast interoperability test coverage

Faster rollouts of new technologies with multi-vendor Gfast interoperability test coverage

By Herman Verbueken, Director of Broadband Forum’s Physical Layer Transmission Work Area

The rollout of Gfast is key to enabling delivery of gigabit services to the end user through fiber-to-the-extension point architectures, avoiding the need to install additional fiber.

The Broadband Forum’s Physical Layer Transmission Work Area has published new revisions of the Gfast interoperability test suite and the Gfast performance test plan in support of the rollout of Gfast over coaxial infrastructures.

By providing multi-vendor interoperability, Broadband Forum is ensuring that new services and technologies are introduced quickly, reliably and effectively, enabling the broadband industry to deploy equipment that will provide a better quality of experience for their end users while tapping into new revenue streams.

Gfast interoperability test suite TP-337

The Broadband Forum Gfast Certification Test Plan TP-337 is used for the highly successful  Broadband Forum BBF.337 Gfast Certification Program and provides a set of functional, stability and basic performance test cases and related pass/fail requirements for Gfast implementations.

With an initial release in 2017, the test plan has undergone some major evolutions. The issue 2 (ATP-337i2) added testing of multivendor interoperability for the following:

• Support for 212 MHz profile (212a) over twisted pair;
• Support for 106MHz (106c) and 212 MHz profile (212c) over coaxial cables;
• Support for increased bit loading.
• Support for 106 MHz profile with increased maximum transmit power (106b) over twisted pair.

These are all capabilities that increase the rate and reach of Gfast, as well supporting rollout of Gfast over coax.

The issue 3 (TP-337i3; TP-337i3c1), published recently, adds:

• Support for ITU-T G.9701 Annex X – Operation in a crosstalk free environment, including dynamic time assignment (DTA);
• Support for ITU-T G.9701 Annex D – Operation in a crosstalk environment, including dynamic time assignment (DTA);
• Support of ITU-T G.9701 Annex S – software download to NTs;
• Support for extended Fast Rate Adaptation settings (FRA-TIME).

The Dynamic Time Assignment capability addresses the dynamic nature of internet traffic, providing the highest throughput for the end-user at any time, being for download or upload.

The software download enables the service operator to provide seamless software upgrades to the Gfast terminal, thus ensuring optimal operation all the time. The extended FRA setting handles quickly repeating long duration impulsive noises without degrading the quality of the Gfast connection.

For additional details about the BBF.337 Gfast Certification Program, including requirements for participation in the program or to view the list of currently certified devices, please refer to the Broadband Forum website. 

Gfast performance test plan TR-380

This technical report provides a set of functional, stability and performance test cases with related pass/fail requirements for Gfast implementations. The first issue focused on the single twisted pair Gfast performance delivering data rates beyond 1Gb/s.

Supporting the rollout of Gfast over coax, the Physical Layer Transmission Work Area has also developed a new revision of the Gfast performance test plan.

Issue 2 of this Technical Report (TR-380i2)  adds single-line coax throughput tests, updates to the physical layer test setup and noise accuracy verification procedures, and a correction to the attainable net data rate test.

The coax throughput tests provide service operators with a view on the minimal throughput that can be reached over coaxial cable, either in a point-to-point environment, or in an environment where the coaxial cable is shared with SATV services.

What’s next?

The next issue of TP-337 is being developed. Issue 4 intends to add Robust Management Channel Recovery (RMCR) and sub-carrier masking tests, tests for Low power operation and tests for accuracy and updating of reported Gfast parameters.

To power the DPU, power will come from the customer premises location over the copper pair; this is referred to as Reverse Power Feed (RPF). In support of the deployment of Gfast over coax, a new revision of TR-338i2 Reverse Power Feed (RPF) test plan is also underway.

TR-338i3 plans to address the interoperability pass/fail requirements for reverse powering (RPF) of remote network nodes (Gfast DPUs, single-port or multi-port) from customer premises equipment (one or multiple CPEs) over coaxial cable. It will define a set of RPF-over-coax functional and safety test cases for the Power Source Equipment (PSE) implemented according to ETSI specification TS 101 548-2, either as a stand-alone device or as a function integrated in the Gfast (G.9700 and G.9701) network termination. It is planned to include also RPF integrated into G.hn Access and MoCA Access network terminations.

To gain further insight into what the Physical Layer Transmission Work Area is doing, visit: https://wiki.broadband-forum.org/display/BBF/Physical+Layer+Transmission.