FAQ

Why move from a Hybrid Fiber-Coax (HFC) to a Fiber to the Home (FTTH) network?
In many cases, it is possible to upgrade networks and achieve savings using existing HFC technology. Existing broadcast television, telephony services and internet connection will continue to be the main revenue generators for the years to come. They represent the safe business that need to be protected to ensure current and future revenue. Operators must also know that as the use of more intelligent home devices such as PCs, multimedia and entertainment consoles, set-top boxes grows, the trend for more service and technolgy convergence will be accelerated and operators will be forced to provide new ways of communicating. That's why taking the long-term approach, operators may be better advised to invest gradually in FTTH network solution that will cover both their existing and future needs.

With FTTH, existing copper infrastructure will have to be replaced by fibre optic. Is n' t too expensive?
With the introduction of the Internet over the HFC infrastructure, old coax cables have been gradually replaced by new coax cables. The drawback of deploying FTTB/FTTH networks was primary associated with the high cost for construction and the lack of pragmatic and realistic solutions. Today with the introduction of advanced installation systems and the availability of cost effective network equipment that ensures a graduated migration toward digital services without jeopardising existing revenues make the fiber based access solution economically more feasible. Why not just build FTTB/FTTH future-proof networks today?

What is the cost difference between full fiber access network versus a traditional coax access network?
While it is always difficult to define exact number, we estimate that the fiber access solution in term of equipment cost per subscriber compares favourably with a traditional coaxial infrastructure. Today cost effective technologies are available allowing fast and economical deployment of the fiber in the outdoor as well as indoor environment. Because of its small dimensions, the fiber can easily be deployed in existing ducts or canalisation avoiding extensive civil works. Network planners should take full advantage of existing infrastructures when FTTH networks have to be deployed.

PON vs. distributed point to point architecture?
The main advantages of a PON network is no intermediate electronics or powering is necessary between the HE and the subscriber's home and consequently its operational simplicity. A distributed point to point network topology is essentially designed to cover the "last mile" and normally requires power at the node. However because the nodes of existing CATV networks are already powered no additional power supplies are necessary. PON solution whereas is based on ATM (APON) or Ethernet technology (EPON), are proprietary systems and provides a shared communication architecture. The distributed switched network architecture completely support the Ethernet standard and have all its advantages (no sharing, low-cost components and large availability of data transmission equipment such as transceiver, switching, plug and play facilities). It provides nearly unlimited bandwidth and is entirely open to various technologies. Optical node-based infrastructures can be quickly and easily deployed, allowing a gradual migration from traditional HFC structures to future-proof FTTB or FTTH systems.

Point to point star topology is a fiber rich infrastructure. Is it not a handicap?
The point to point star topology represents the universal solution as it is used in the traditional telephony. It is the most flexible and reliable network topology, even it is also the fiber richest solution. This disadvantage is largely compensated by the advantages in term of network simplicity, transmission security especially for data communication, operating costs, facility of network management and ease of maintenance. It is interesting to note that although point-to-point architecture is a fiber rich infrastructure, it is currently the preferable access architecture design used in fiber-to-the-home deployments in Korea, and scandinavian countries.

Why choosing a ribbon fibre solution instead of one single fibre system?
Since the distances between optical node and the end user are usually less than 1 km the cost impact of a ribbon fibre solution becomes negligible compare to all advantages its offers. The ribbon fiber solution is characterised by a clear separation of services permitting a highly robust transmission system resulting in high network reliability and a cost effective maintenance. Furthermore with ribbon fiber systems the use of additional passive devices are not needed allowing a cost effective network infrastructure.

Why is DOCSIS still required on FTTH infrastructure?
DOCSIS provides today HFC system operators with a standard for internet services to residential users. Offering DOCSIS on a FTTH infrastructure it allows cable operators to take full advantage of their existing investment, generating the revenues from today's services. However, at some point in the future, applications requiring 10/100Mbs of interactive bandwidth will become more common and CATV operators will be able to provide the necessary bandwidth demanded by its customers. Both HFC-DOCSIS and high speed data capabilities over fiber can coexist, with each one doing what it is designed to do.

Is a fiber infrastructure still needed with DOCSIS 2.0?
Although DOCSIS 2.0 will bring some advantages in term of bandwidth and signal robustness compare to DOCSIS 1.0 its high capital cost and bandwidth limitation makes the future of this technology questionable, especially in its ability to deliver next generation broadband services.

Is broadcast Television really needed?
From various marketing studies, it results that video based services are the most requested by residential users in compare to internet services. According to marketing research institute the ratio between video based services to Internet services is around 4:1. In EU roughly 100 Mio. subscribers are used to receive TV programs over the cable. Therefore delivering analogue and digital TV programming on a FTTH architecture will still represent for next decade a significant income revenue for cable operators.

Are active cabinets a real problem?
In a coax access network active cabinets have been widely deployed along the distribution. With SUBONET existing cabinet infrastructures can be re-used to deploy fiber-based access systems where needed.

Will digital TV gradually replace the traditional analogue programming? Why fiber technology does still need to support analogue TV?
Yes Digital Video Broadcasting DVB is increasingly becoming reality. However it must be clearly stated that Digital TV signals as defined by DVB (Digital Video Broadcasting) Standard are transported by modulating radio frequency carriers much as in the case of analogue TV signals. In other words, DVB signals should be considered as analogue signals so far the transportation is concerned.