G.fast semiconductor provider Sckipio Technologies says it will soon offer dynamic bandwidth allocation (DBA) capabilities through its current G.fast silicon. The feature, which a company source says will be available "imminently," will enable support of symmetrical 750-Mbps services, Sckipio asserts.
G.fast has been touted as a pathway toward 1-Gbps services over existing copper infrastructure. However, the technology's bandwidth capacity traditionally is quoted in aggregate (upstream and downstream). So how carriers would divvy that bandwidth (which may not be a full 1 Gbps initially, depending upon the distance the signals need to travel and the quality of the copper infrastructure) between upstream and downstream and still offer services similar to those provided by fiber and DOCSIS-based services has been an open question.
The availability of DBA would enable operators to give their networks flexibility in terms of doling out bandwidth based on expected usage patterns. They therefore could offer larger-scale symmetrical services than they could without it.
And operators have taken notice. "DBA is a G.fast game-changer," said Tim Fell, vice president of video and broadband services at Canadian service provider TELUS, via a Sckipio press release. "In the race to deliver ultra-fast broadband, the ability to offer affordable symmetrical services will give telcos the flexibility required to meet our customers evolving high-speed Internet needs."
The press release also referenced a recent interview Light Reading conducted with Eddy Barker, assistant vice president of Technical Design & Architecture at AT&T, in which Barker stated that DBA would enable AT&T to offer the symmetrical 750-Mbps speeds over coax using first-generation G.fast silicon. Future chip generations are expected to operate over a greater spectral range, which Barker speculated could enable as much as 1.5 Gbps symmetrically.
Sckipio Vice President of Marketing Michael Weissman agrees with Barker's assessment of the capabilities of future G.fast silicon. In the nearer term, Weissman sees the higher-rate services DBA would enable as a significant weapon for telcos who want to use their copper infrastructures to compete head-to-head with alternative providers using fiber to the home (FTTH) as well as cable operators offering DOCSIS-based services. In particular, Weissman noted that DOCSIS 3.0 networks' traditional inability to support symmetrical high-speed services would make G.fast-enabled networks potentially competitively superior.
Cable operators have begun to roll out DOCSIS 3.1 technology, which is designed to support 10 Gbps downstream and 1 to 2 Gbps upstream (see "CableLabs releases DOCSIS 3.1 chip specifications" and "Comcast starts DOCSIS 3.1 field trials"). A symmetrical 750-Mbps service could remain competitive when faced with competition from a DOCSIS 3.1 enabled network, depending upon how the cable operator split its capacity.
While operators such as BT have active field trials of G.fast in the last mile underway (see "BT connects first G.fast trial customers"), several sources have suggested it will initially make its mark as an in-building option to deliver high-speed services to apartment units and business tenants over existing wired infrastructure. Most trials of such applications have focused on networks with twisted-pair copper. The fact that AT&T believes it can support symmetrical high transmission rates over coax would seem to extend the range of buildings in which G.fast would offer a viable option. Weissman admits that G.fast would not work on coax networks based on a tree architecture, however.
Weissman expects Sckipio will be the first to market with DBA capabilities. However, he notes that the ITU-T is working on a standardized version of the capabilities, which it calls "dynamic timeslot allocation." The ITU-T could finish this effort by the end of the year, he says.
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Stephen Hardy | Editorial Director and Associate Publisher
Stephen Hardy has covered fiber optics for more than 15 years, and communications and technology for more than 30 years. He is responsible for establishing and executing Lightwave's editorial strategy across its digital magazine, website, newsletters, research and other information products. He has won multiple awards for his writing.
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