Much debate has been made about the medium used in the last mile of the access network. Fiber is attractive because of the low cost/bps of the equipment used to deploy it. However, fiber-to-the-home (FTTH) deployments have demonstrated that deploying fiber in the last hop is expensive. This is primarily due to factors other than the cost of capital equipment such as the cost labor and right-of-way. Fortunately, technologies such as data over cable system interface specification (DOCSIS®) 3.1, full duplex DOCSIS (FDX), and distributed access architecture (DAA) will allow operators to continue to leverage their installed coaxial cable to provide multi-gigabit symmetrical services.
In order to deploy DAAs, such as remote physical layer (R-PHY) and remote media access control (MAC)and PHY (R-MACPHY), operators are pushing the distribution network deeper into the plant to reach DAA nodes. The physical media to reach these nodes has been assumed to be strands of fiber. However, just like in the access network fiber can also be cost prohibitive in the distribution network.
This paper will discuss a technological solution called “virtual fiber.” Virtual fiber will allow operators to leverage the in-place coaxial cable that typically would be bypassed by a fiber link to connect DAA nodes.
The first generation of virtual fiber will soon be available and will be able to achieve symmetrical speeds of 10 Gbps. Future generations of virtual fiber will be able to achieve speeds of 25 Gbps and higher providing operators with a deployment roadmap that can keep pace with demand.
Acknowledgements: Virtual fiber and virtual segmentation are technologies that I stumbled upon and to which I am lucky to have been exposed. Hans Wambach, Director of Access Engineering at Liberty Global and Jan Ariesen, Chief Technology Officer (CTO) at Technetix deserve much credit for incubating the ideas and products upon which this paper is based.