G.fast Fundamentals – The G.fast migration path
Migrating to G.fast is the most economical way to bring Gigabit speeds to customers because the existing copper or coax infrastructure is reused between the DPU to the customer’s client. This avoids rewiring for the last 250 to 300 meters. All segments of the hybrid network: fiber, copper line, interior twisted pair or coax wiring, and WiFi need to be tested.
So how does G.fast differ from traditional xDSL?
- G.fast relies on deeper fiber (FTTx: Fiber to the Cabinet, Curb or Building) and a short segment of fault free copper up to 250 meters. Beyond 250 meters, rate reach will decline below a Gigabit.
- The signal is sent via time division duplexing (TDD) instead of utilizing frequency division duplexing (FDD) to allow more bandwidth per time slot.
- G.fast is a high frequency service and copper faults that were not noticeable before can impair the service experience. Viavi’s OneExpert OneCheck TDR ™ helps techs auto identify and locate multiple faults, such as an open or a splice, saving your team thousands of hours per year.
- Two key communication components –
- The DPU connects the fiber segment to the copper G.fast segment. It’s critical to ensure the fiber connection is clean and correctly powered.
- New modems contain a proprietary Broadcom or Sckipio G.fast chipset. Viavi’s OneExpert DSL is the only solution that tests for both.
- G.fast systems can be configured to vary in the upstream or downstream bandwidth allotment to make a full Gigabit. To distinguish between service and equipment problems, test the G.fast layer and Ethernet layer with TrueSpeed™.