Contents

	Welcome Note
	FTTX The next broadband wave
	Creating the Green Data Centre
	Protection systems in the Communications Network
	Patch-Free Cabling Solution
	Cat 6A is now Ratified

FTTX – The next broadband wave

Fibre to the “X” (FTTX) covers many architectures like Fibre to the Premises (FTTP), Fibre to the Home (FTTH), Fibre to the Curb (FTTC), Fibre to the Business (FTTB) or Fibre to the Node (FTTN). FTTP is considered to be the next step in access network in India. Broadband application requirements are going beyond regular voice and data applications. High speed data, IP applications and Video on demand kind of application requirements are the reason why some of the service providers are conducting field trials and are in the initial implementation phase for FTTP / FTTH in India. In this architecture, an optical fibre is deployed till the customer premise, either to the business or to the home. A Network Interface device (NID) is located at the customer premise as the Optical Network Termination (ONT) or Optical Network Unit (ONU) and this act as the termination point for optical access network providing direct connectivity to high bandwidth applications.

Investment requirements in Optical fibre deployment are still on the higher side and can be implemented only if there are that many takers for the high bandwidth applications. An optical to electrical conversion at each premise itself is an expensive proposition. An alternate cost effective approach is fibre to the Node (FTTD) which can be considered to be a “phase-by phase approach”. In this configuration, an optical link is deployed to the ONU in a Service Area Interface (SAI) cabinet located near a housing colony or business park. The ONU will convert the optical signal to electrical signal and services get transmitted to existing copper network. In this method, because of the shorter reach of copper, service providers are able to offer high bandwidth services without fibre going directly till the premises. There can be an upgrade to Fibre to the Premise as a second phase as bandwidth and service requirements increase.

Depending on the deployment, an optical network implementation can be termed as “greenfield”, “overbuild” or “rehabilitation”. Greenfield is a newly built area where there is no existing broadband infrastructure and no constructions exist. Since infrastructure cost difference for fibre and copper are negligible and construction cost for the deployment are very similar, FTTP investments are well justified in green field projects. Fibre deployment reduces future maintenance costs of the physical plant also considerably. Typical Greenfield customers will include Independent houses, Multi-storied apartments, Small business units and Multi- tenant business parks. A relatively high take rate for second phone lines, data and video services can be expected creating higher revenues and lowering the cost of deployments. Another advantage of green field implementation is because of the typical dense population. Fibre can be cost-effectively run from central office (CO) to the local convergence point (LCP) where the first passive split can be made. The overbuild is an FTTP application where market demand for advanced data and video services exists in a serviced neighborhood. It may be desirable to deploy fibre along with the existing copper network. Some of the factors that contribute to a decision to overbuild an existing plant are aging infrastructure and requirement for higher bandwidth than available bandwidth through current copper technologies. The objective of the full overbuild with fibre is to gradually transition all customers to the FTTP system, while concurrently retiring the aging copper plant and the active infrastructure such as digital loop carrier. The third scenario “rehabilitation” aims to minimize capital expense when there is insufficient justification. The difference in the case of rehabilitation is that it involves existing customers and all services are served through the existing copper plant. Optical Network Units are installed in close proximity to customer premise and if there is a need for high-speed data, it can be provided directly from ONU based on customer requirement.

Passive Optical Network (PON) Standards

There are different PON standards to consider while planning a network.

APON (Asynchronous Transfer Mode PON). This was the first PON standard which uses ATM encapsulation of transported data and is aimed at small business applications. APON was soon replaced by the BPON technology.

BPON(Broadband PON). Most popular form of PON standard being rolled out today is BPON. It is a robust network that includes WDM support for video overlay, higher upstream bandwidths and upstream bandwidth allocation.

EPON (Ethernet PON) is an IEEE standard ratified in 2004 and is highly suitable for data services. EPON uses Ethernet rather than ATM data encapsulation.

GPON (Gigabit PON) is an IP based protocol designed for IP traffic and is the standard choice for high volume FTTP carriers. GPON is often described as combining the best attributes of BPON and EPON at gigabit rates. It recognizes gigabit Ethernet interfaces to enable pure IP transport and does not require active powering points in the access network.

Before selecting architecture, a number of external and internal factors are to be considered .The choice you make early in the planning process have a lasting impact in the network. Stay tuned to the next edition of New Networks from ADC KRONE to discuss about different architectures, design methods, deployment

Dileep Kumar
Director: Enterprise & Carrier Networks
ADC KRONE
INDIA & SAARC