Access Networks
Done by
Bader Al-Mugren
Naser Al-Dossary
Nezar Al-Ubaiyed
ID: 201067
ID: 216867
ID: 981526
Agenda
1. INTRODUCTION
2. OPTICAL NETWORKS
3. Hybrid Fiber Coax (HFC)
4. Fiber-To-The-Curb (FTTC)
5. Fiber-To-The-Home (FTTH)
4. CONCLUSION
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)
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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 fiberoptic 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.
Continue
• 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 neighbourhood 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
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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
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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 managementkind, 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)
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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
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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.
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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.
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Of course, the performance of FTTC system can be
improved by upgrading the network to FTTH (fiber-to-thehome) 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-thebuilding (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, highspeed 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-tothe-home (FTTH). However, the opposite is
true.
• FTTH is much more desirable as the
infrastructure for the future services than
FTTC.
Conclusion