Access Networks

Done byBader Al-Mugren ID: 201067Naser Al-Dossary ID: 216867Nezar Al-Ubaiyed ID: 981526

Agenda

1. INTRODUCTION

2. OPTICAL NETWORKS

5. Fiber-To-The-Home (FTTH)

3. Hybrid Fiber Coax (HFC)

4. CONCLUSION

4. Fiber-To-The-Curb (FTTC)

INTRODUCTION

• Access Networks are just the last step that will provide the service from the service provider up to the end user. As the network application is varied, ranging from transferring files, video files, video conferencing, and so on, this will require huge bandwidth which is available using fibre based access technologies.

• This leads to the existence of fiber based network such as HFC, FTTC,FTTH which will discussed later.

OPTICAL NETWORKS

• An optical network is a network in which the physical layer technology is fiber-optic cable. Cable trunks are interconnected with optical cross-connects (OXCs), and signals are added and dropped at optical add/drop multiplexers (OADMs).

• In addition, most optical networks have implemented OEO (optical-electrical-optical) switches, which convert optical signals to electrical signals for processing, and then back again to optical signals.

Hybrid Fiber Coax (HFC)

• Introduction• Overview of HFC• Historical Background• HFC Network Structure• HFC Network Features• Network Management System• Conclusion

Introduction

• Hybrid Fiber Coax (HFC) is a combination of optical fiber and coaxial cable.

• HFC offers reliability, availability, power, and potentially disruptive upgrades, as well as scalability, cost and data rate symmetry.

Overview of HFC

• An HFC network is a cable network that includes a combination of fiber-optic and coaxial cable, with fiber-optic cable running from the cable company's facility to a location near a home and coaxial cable running from there into the home.

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• The fiber cable provides high bandwidth to multiple users in a single neighbourhood.

• It forms what is called the "trunk line" that stretches from cable office to neighbourhoods.

• The coaxial cable is called the "feeder circuit." • An upgrade to an HFC system usually requires

replacement of existing coaxial trunk lines with fiber trunk lines.

• In addition, equipment is needed at the neighbour-hood junction to join the coaxial and fiber cables.

Historical Background

• During the late 1980s, cable television operators in the United States reached a critical point where bandwidth demands to their coaxial-based stressed the technical limits for signal quality and platform reliability.

• In response to the cable operators’ demand for a solution that addressed both signal quality and reliability.

• The result was development of The HFC network.

HFC Network Structure

• Head-End: Where the CMTS [Cable Modem Termination System] sits which feeds an RF signal on the "downstream" to the fibre optic node.

• The fibre node: converts the fibre optic light signal back to RF signal for the forward path and from RF to fibre optic light for the return path.

HFC Network Features

• Reuse existing cable TV coax.• 500 to 1200 homes per HFC link.• 45 Mbps downstream, 1.5 Mbps upstream.• MAC protocol required to share upstream bandwidth.• Several homes share the cable TV.• Better quality pictures.• More bandwidth possible with lower investment.• Improved reliability.

Network Management System

• For an HFC based network to be successful, features to ensure reliability, availability and the capability of scaling to large numbers must be managed in efficient way.

• The network management functions classified as:– Configuration configure parameters for: network

infrastructure & hosts attached to it.– Security Privacy of user data must be maintained.– Performance management provide sufficient info to

monitor network performance in order to resolve problems and to plan for growth.

– Fault managementkind, place, time of the problem.– Accounting provide billing for the resources used.

Conclusion

• Consumer needs for interactive residential services.• The convergence of cable TV, computers and

telecommunications.Resulted in the migration from unidirectional coax

Cable TV infrastructure to HFC networks.• The data throughput required for two directional

interactivity and digital video downstream, required a fiber and coax architecture.

• Hybrid Fiber Coax networks have proven to be successful and low cost.

END OF PART I

Q & A

Fiber-to-the-curb (FTTC)

• Introduction & Definition.• The structure of FTTC network.• Some Advantages and disadvantages.• Some Characteristics of FTTC network.• Similar Concepts.• Conclusion.

• What is FTTC?• Fiber to the Curb (FTTC) Network: An access network in

which fiber is used for part, but not the entire link from the OLT to the end-user. An optical to electrical (O/E) conversion takes place somewhere near the end-user. The terminal network segment of a FTTC network is usually twisted copper pairs or coaxial cable. The final optical receiver in a FTTC network typically serves several customers.

FTTC system configurations

• The star-connected architecture is used by both PONs (Passive Optical Networks) and FTTC networks. From the figure, one can see clearly that a dedicated fiber link is running up to the ONU (Optical Network Unit).

• The benefit of this access technology (star connected architecture) that there will a dedicated path running from the ONU up to the Home (end user or customer). Therefore, this technology seems to be better rather than bus architecture in which the connection will be shard among the end users.

Cont’d

• Bus-connected architecture: In this architecture the coax line will be shared among different

homes.

The Structure of FTTC network• Outside plant wiring

• In –House wiring

• Advantages of FTTC System: I- Fewer numbers of active electronic devices which in

turn result in more network interruptions resulting definitely in minimized maintenance cost.

II- Allow for higher bandwidth which can be upgraded to fully optical (FTTH) to allow for more bandwidth.

• Disadvantages of FTTC system: I- Since we are using fiber, then the cost of

implementation will be more. II- The copper which uses VDSL is very short for about

200m.

III- The frequencies used for VDSL have been found to interfere with the existing wireless network devices such as radio signal.

• Of course, the performance of FTTC system can be improved by upgrading the network to FTTH (fiber-to-the-home) which completely optical up to the end user.

Similar Concepts to FTTC network

• FTTH (fiber-to-the-home) = FTTB: "Fiber to the building" (FTTB) refers to installing optical fiber

from the telephone company central office to a specific building such as a business or apartment house.

• HFC (fiber-to-the-neighborhood): “Hybrid Fiber Coax" (HFC) refers to installing the fiber up to

mid node between the network provider and the consumer. You can refer to the figure below to see clearly the difference.

Cont’d

Fiber-to-the-Home (FTTH)

Objectives:• Introduction.• What is FTTH?• The Uses of FTTH.• The Advantages of FTTH.• The Future of FTTH.• FTTH and FTTC.• Conclusion.

Introduction

• Need: high-speed data, dependable voice and high-quality video.

• Problems: how to get lines out to each customer? How to future-proof the architecture put into the ground today?

• Solution: FTTH

What is FTTH?

• Fiber-to-the-home (FTTH) is the installation of optical fiber from a telephone switch directly into the subscriber’s home.

• It is one of the latest access technologies.• FTTH is also referred to as fiber-to-the-

building (FTTB).

The Uses of FTTH

• Broadband Internet/data access, with speeds in excess of 10 Mbps to the subscriber, and if required, speeds in excess of 100 Mbps to 1 Gbps.

• Enhanced video services supporting analog and digital programming, interactive features, Video on Demand, Pay per View and High Definition TV.

The Uses of FTTH

• Telephony, plain old telephone service (POTS) as well as next generation voice services  such as Voice over IP and IP telephony.

• Highly secure and reliable Virtual Private Network (VPN) services, and other enhanced applications.

The Advantages of FTTH

• It is a passive network. There are no active components from the CO to the end user. This minimizes the network maintenance cost and requirements, as well as eliminating the need for a DC power network.

• The FTTH network is a future-proof architecture.

The Advantages of FTTH

• It is a single fiber to the end user, providing revenue-generating services with industry standard user interfaces, including voice, high-speed data, analog or digital CATV, DBS, and video on demand.

• It features local battery backup and low-power consumption.

• It is reliable, scalable and secure.

The Future of FTTH

• The desire for two-way, video-based services such as interactive television, distance learning, motion picture–quality videoconferencing, and videophones is expected to continuously increase. As a result, demand for fiber technologies such as FTTH are on the rise.

FTTH and FTTC

• Many people think that fiber-to-the-curb (FTTC) is more cost-effective than fiber-to-the-home (FTTH). However, the opposite is true.

• FTTH is much more desirable as the infrastructure for the future services than FTTC.

Conclusion