CLC/TR 50510:2007

SLOVENSKI STANDARD
01-januar-2008
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Fibre optic access to end-user - A guideline to building of FTTX fibre optic network
Lichtwellenleiterzugang zum Endkunden - Leitfaden für die Erstellung von FTTX
Lichtwellenleiternetzen
Ta slovenski standard je istoveten z: CLC/TR 50510:2007
ICS:
33.180.99 'UXJDRSUHPD]DRSWLþQD Other fibre optic equipment
YODNQD
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CLC/TR 50510
RAPPORT TECHNIQUE
October 2007
TECHNISCHER BERICHT
ICS 33.180.99
English version
Fibre optic access to end-user -
A guideline to building of FTTX fibre optic network

This Technical Report was approved by CENELEC on 2007-07-06.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TR 50510:2007 E
Foreword
This Technical Report was prepared by the Technical Committee CENELEC TC 86A, Optical fibres and
optical fibre cables.
The text of the draft was submitted to vote in accordance with the Internal Regulations, Part 2,
Subclause 11.4.3.3 (simple majority) and was approved by CENELEC as CLC/TR 50510 on 2007-07-06.
__________
– 3 – CLC/TR 50510:2007
Contents
Executive summary. 6
1 Network Structure and Nodes – A guideline .8
1.1 Introduction . 8
1.2 Levels. 9
1.2.1 Physical routing .9
1.2.2 Passive transmission media . 9
1.2.3 Transmission-, IP- and application level . 10
1.2.4 Ownership, operating and maintenance . 10
1.3 Network topology – Terminology . 10
1.3.1 Infrastructure parts . 10
1.3.2 National network. 11
1.3.3 Regional network. 11
1.3.4 Municipality connecting network . 11
1.3.5 Metropolitan or urban network . 12
1.3.6 Access network . 12
1.4 Node topology – Terminology. 13
1.4.1 National node . 14
1.4.2 Regional node . 14
1.4.3 Community main node. 14
1.4.4 Municipality node. 14
1.4.5 Fibre cross connect node (fccn). 14
1.4.6 Access node. 14
1.5 Examples of FTTX topologies. 15
1.6 Access network . 18
1.6.1 FTTX in access networks . 18
1.6.2 Size of an FTTX-network. 18
2 Passive network solutions. 20
2.1 Choice of fibre type – Single-mode/multimode. 20
2.2 Number of fibres for each end-user . 22
2.3 Connectors in the FTTX-network. 23
2.4 Fibre splicing . 25
2.5 Link dimensioning. 25
2.6 Calculation of an optical budget. 25
2.7 Fibre optic cabling . 26
2.8 Pulling, burying and blowing. 28
2.8.1 Fibre volume. 28
2.8.2 Fibre length .28
2.8.3 Installation conditions . 28
2.9 Dimensions for microducts and multi ducts. 29
2.10 Hybrid cables and ducts for blowing . 30
2.11 Installation of FTTX . 31
2.11.1 Outdoor . 31
2.11.2 Indoor. 31
2.12 Right of Way (RoW) solution . 31
2.12.1 Fibre optic cables in sewer systems (sanitary and stormy ones). 32
2.12.2 Fibre optic cables in gas pipes (fibre-in-gas). 33
2.12.3 Fibre optic cables in drinking water lines . 34

2.13 Fibres for blowing . 34
2.14 Microduct optical fibre cables for blowing . 34
2.15 Cables for blowing. 35
2.16 Pre-connectorised fibre . 35
2.17 Optical splitters. 35
2.18 Closures. 36
2.18.1 Fibre management system closures (FMSC). 36
2.18.2 Air blown fibre closures (ABFC). 37
2.18.3 Air blown fibre microduct connectors . 37
2.19 Access and jointing chambers . 38
2.20 Optical Distribution Frame (ODF) .38
2.21 Design of a room for an access node . 39
2.22 Power feeding an access node. 41
2.23 Earthing in an access node . 42
3 Network design. 42
3.1 Areas with block(s) of flats (multi-tenants buildings) . 42
3.2 Areas with detached and terraced houses. 43
3.3 Sparsely built-up areas. 44
3.4 Summary of network design . 45
4 Planning and installation – General advice and instructions. 45
4.1 Planning . 45
4.1.1 Rough planning . 45
4.1.2 Ownership circumstances. 46
4.1.3 Housing and property owners. 47
4.1.4 Legal issues – Something to think about . 47
4.1.5 Investigating availability. 47
4.1.6 A study of documents . 47
4.1.7 Detailed planning. 47
4.2 Installation – General advice . 48
4.2.1 Drilling . 48
4.2.2 Cover strips .48
4.2.3 Lift shaft. 48
4.2.4 Messages to residents. 48
4.2.5 Insurance and compensation for damage. 48
4.2.6 Certificate . 48
4.3 Installation in node areas. 48
4.3.1 Access node. 48
4.3.2 Area for splice cabinet – Fibre concentration point . 48
4.3.3 In a flat, a house or similar area (user node – subscriber node). 48
4.4 Work with digging, installation of ducts and pulling of cables and microduct optical fibre
cables. 49
4.4.1 Material for ducts, cables and microduct optical fibre cables . 49
4.4.2 Ploughing for installation of ducts (cables). 50
4.4.3 Digging and milling for installations of ducts (cable). 51
4.4.4 Warning tape or ribbon . 51
4.4.5 Installation in ducts. 52
4.4.6 Sub-ducts .52
4.4.7 Different techniques to install cables into ducts . 53
4.4.8 Traditional installation with pulling rope . 53

– 5 – CLC/TR 50510:2007
4.4.9 Installation of cable into ducts with compressed air or floating with water . 55
4.4.10 Preventive protection of ducts and cables in manholes. 55
4.4.11 Installation of hanging optical cables or microducts . 56
4.4.12 Self-supported cables/microducts. 56
4.4.13 Hanging of cables with lashing and wrapping . 56
4.4.14 Traditional indoor installation of FTTX . 56
4.4.15 Splicing and its environment. 57
4.4.16 Splice boxes & closures. 57
4.5 Handing over finished installation, inspection . 57
4.6 Safety, risks and risk elimination. 57
5 Measurements, documentation and operation. 59
5.1 Measurements. 59
5.2 Labels and marking . 60
5.3 Final documentation . 61
5.4 Operation and maintenance . 63
6 Quality. 63
7 Glossary. 64
References. 66
Annex A List of standards . 67
Annex B Ducts and microducts. 73
Annex C Block of flats . 75
Annex D Areas with private detached or terraced houses . 82
Annex E Aerial installation of FTTX . 88

Executive summary
FTTX normally refers to networks that deploy fibre directly into the customer residences, which can be either
single dwelling units (houses) or multi dwelling units (blocks of flats).
Most FTTX networks are designed without any active equipment in the external network and are therefore
classified as passive optical networks. The only active equipment is at the central office and the customer
premises. FTTH - PON networks can be designed around different architectures.
The purpose of this Technical Report is to be a first guideline for those considering to install a high
bandwidth (high bit-rate) FTTX-network. After studying the Technical Report operators, communities, energy
companies, installers and other will understand the necessary steps to take to plan and install
FTTX-networks with high quality and cost effectiveness, and to secure a uniform structure and a high quality
level on such networks.
The main part of this Technical Report describes the FTTX-networks, but Clause 1 also contains more
general information to give an understanding how these networks fit into the planning of the fibre
infrastructure.
FTTX has for many years been regarded as the most future-proof technique for transmission of broadband
multi-media applications. The building of FTTX-networks has previously been prevented by high costs. New
investigations show, however, that the cost to install a new fibre based network (100 Mbit/s) is a little less
than to install a new copper network. The FTTX-network is also the only structure, which with certainty can
offer both the present and the future needs, which broadband access services require. At the same time the
technique allows efficient operating maintenance and cost savings.
The networks to be presented used to be called FTTH, but with the strategy described here fibre networks
can reach anywhere (X). The end-user can be separate homes, houses, office environments, optoelectrical
transitions in equipment for alarms, surveillance, monitoring devices etc.
The Technical Report also describes recommendations and gives basic requirements to be fulfilled by a fibre
installation in an FTTX-network to satisfy present and future requirements on capacity, transmission distance
and quality. As a target, the minimum capacity is set to 1 Gbit/s (1 000 Mbit/s) up to 10 km distance; for
certain access applications (e.g. flats or multi-tenants buildings) a shorter distance can be targeted, e.g.
500 m to 2 000 m. Relevant types of optical fibres (single-mode and multimode) are specified in
EN 60793-2-50 and EN 60793-2-10. However, in the industry a single-mode fibre is typically called by its ITU
terminology (e.g. G.652). The physical network should have an expected lifetime of 25 years.
The recommendations are written for a general audience, but in particular for people involved in private and
public enterprises, people responsible for broadband decisions, planning and installations.
The Technical Report is divided into six independent clauses:
• Clause 1 is an introduction and gives a view of the IT-infrastructure and a survey of the basic structure
for the fibre optical broadband.
• Clause 2 describes system solutions for FTTX including requirements on capacity and installation
techniques.
• Clause 3 is a guideline on how to create a network and gives an overview of applicable network
topologies.
• Clause 4 gives basic information about installation and planning before installation.
• Clause 5 treats measurements and documentation.
• Clause 6 treats quality issues.

– 7 – CLC/TR 50510:2007
A number of annexes are included to give deeper knowledge in certain areas. They are broad examples and
can be used to give a better view on the principles for installation of FTTX-networks with cables, microduct
optical fibre cables, microducts and microduct fibre unit cables (blown fibres). To some extent these annexes
are company specific, which the reader should be aware of. Annex A (reference [1]) gives a comprehensive
list of standards. References [2], [3] and [5] give a good overview of the present status in both ITU-T, IEC
and the general CENELEC view.
Some of the requirements put forward in this Technical Report are unique for an FTTX-network and should
not be used in a general sense for optical networks.

1 Network Structure and Nodes – A guideline
1.1 Introduction
This Technical Report describes the FTTX-network. As a guideline other parts of the fibre optic infrastructure
are given in this clause.
First some basics: sound, pictures, voice, data carried by networks are digital data expressed in terms of bit,
bytes and their multiples (kilo (k), mega (M), giga (G), tera (T)). A bit (binary digit) is the smallest digital unit
and has only two values: 0 or 1. A byte includes 8 bits and defines the size of a data file. Transmission
capacity of networks and terminals is not expressed by using bytes, but using bit per second (bps). When a
data file is transferred in a network two supplementary bits are necessary. It means that 10 bits are required
for 1 byte.
In the case of a VDSL subscriber with 10 Mbit/s, who wants to upload a pdf data file, the Web provider
indicates for instance the following size: 20 Megabytes. It should then take 20 s. However, for any Mbit/s
subscription the fact is that the real final data flow is about a quarter of the notified data flow, because the
data flow is shared between subscribers and its quality depends on the activity of the other subscribers. It
means that the 20 Megabytes data file will need 1 min 20 s to be uploaded. For instance a 15 Mbit/s ADSL
system gives only 1 Mbit/s for uploading. The following table gives some further examples of transmission
times for uploading a quality DVD-movie, if there is no data flow sharing.

Transmission speed Uploading time
0,128 Mbit/s 5 days, 8 h
10 Mbit/s 8 h
100 Mbit/s 0,8 h
1 000 Mbit/s 50 s
We do not know the new tools that will be created by the real high bit rate networks. New applications (not
invented today) will appear and applications originally dedicated to professionals will be extended to all in a
similar way as it happened with the mobile phone.
It is important to define the meaning of « low, medium and high bit rate transmission ». One possible
classification is presently the following:
− low bit rate transmission: up to 1 Mbit/s
− medium bit rate transmission: 1 up to 10 Mbit/s
− high bit rate transmission: 10 up to 100 Mbit/s and more.

– 9 – CLC/TR 50510:2007
1.2 Levels
For a level-designed view on the components in the build-up of the infrastructure, see Figure 1.

Figure 1 – Network levels
From the bottom up, Figure 1 shows:
• Physical routing: Duct for cables, for microduct optical fibre cables, and for microduct fibre unit cables
(blown fibre products) and for structures for antennas
• Passive transmission and interconnecting media: optical fibre cable, connectors, antennas, boxes,
closures and their physical interconnections
• Active transmission systems: Logical connections over a physical connection
• IP: The internet operator network service to the user
• Application: Equipment, program and data bases of the user
Designing the infrastructure in levels makes it possible for different ownership of individual levels. This
creates possibilities for open networks and competition, but also presents risks regarding responsibilities and
long-term interaction.
1.2.1 Physical routing
The lowest level in the physical network is the physical routing. It consists of ducts in standard dimensions,
antenna structures, network material and microducts among others. Also existing infrastructure tubing as
sewer-, gas-, and drinking water tubes may be used. It should have an expected lifetime of 25 years.
A large part of this level belongs to the FTTX and will be thoroughly described in this book. Most of the cost
for a broadband network is in the planning and installation of the routing layer. It is therefore important to be
accurate in planning, installation and documentation, and that the material of the parts is of high quality.
Normally the network owner owns this level.
1.2.2 Passive transmission media
Level 2 contains optical fibres and cables, interconnecting devices (connectors, splices, closures, …), copper
cables (not treated here) and antennas (also not treated here) for radio networks (FWA, WLAN, 2G, 3G, 4G,
LMDS).
The optical fibre and cable have a mechanical lifetime that corresponds to the ducting level. However, the
transmission lifetime depends on required future services on the fibres. These future requirements may
demand more capacity compared to present planning prediction. If that is the case, the fibre may need to be
replaced by a fibre with better transmission performance. It is therefore proposed in this guideline to use
single-mode fibre in the FTTX-networks, since it has by far the largest capacity well above the 1 Gbit/s over
long distances up to 40 km. In cases where the length is limited to 500 m – 2 000 m (e.g. multi-tenant
buildings) also multimode fibres can be considered. By installing optical fibres and cables in ducts the costs
for replacements and repair are substantially lower than without ducts. The network owner normally owns
cable and fibre.
1.2.3 Transmission-, IP- and application level
Transmission-, IP- and application level will not be described in this Technical Report.
1.2.4 Ownership, operating and maintenance
When all parts in the infrastructure fulfil specified quality requirements regarding transmission and
installation, different ownerships could be possible. Ownership and operation could be split by different
governmental or community companies, jointly owned companies between different communities, energy
companies, building enterprises. Housing co-operatives, house-owner associations, private persons and
landowners may also own the local network closest to the end-users.
Considering operation and maintenance the network level owners have to specify acceptable downtimes.
1.3 Network topology – Terminology
1.3.1 Infrastructure parts
To get an overall picture about optical fibre networks it is necessary to explain some of the terminology and
concepts used.
The higher the network is in a network topology, the higher traffic volume, capacity, requirements on function
and availability and therefore also the strategic significance and need for protection and security in the
network. All IP-traffic can be distributed, which means that this hierarchy may be flattened in a few years.
The present network is a combination of a traditional telephone- and a future IP-network, which can be
described as in Figures 2 to 7. This means that the information can find the best route when alternative
routes are available.
National network
Regional network
Municipality connecting
network
Metropolitan or
urban network
Access network
Figure 2 – The new infrastructure is based upon both old and new network hierarchy
The highest level is the national network, see Figure 2 and the lowest is the network for connecting end-
users or subscribers.
– 11 – CLC/TR 50510:2007
1.3.2 National network
The national network connects all regions in the country and is connected to international networks. This
type of network has a very high security level. A national network has normally few owners.
1.3.3 Regional network
A regional network or a community-connecting network connects networks within a region. Networks within a
region often consist of municipality-connecting networks from different communities. A regional network is
then connected to the national network.

Figure 3 – A regional network, e.g. in a county
Some of the main communities can be connected to nearby regions (Figure 3).
1.3.4 Municipality connecting network
Municipality-connecting networks connect different municipalities (places) within a community. These
networks are in turn connected upwards to regional networks or community-connecting networks and
downwards to access networks. The connection is made through the community main node.

Figure 4 – The municipality-connecting network connects the larger places within a community

In each place there are one or more nodes, access nodes (possibly also distribution nodes), which connects
the end-user – the subscriber (Figure 4).
1.3.5 Metropolitan or urban network
City (metropolitan) or urban networks are networks within a city or in a sparsely populated area. The function
is to give a broadband infrastructure, which can satisfy a long-term need. It shall be easy to establish
cost-effective solutions of access networks to reach subscribers. This can be achieved by using existing or
planned networks of different kinds. These networks are directly connected to the main node or to a
distribution node (redundancy), which could be a possible fibre optic cross-connect node (fccn) to another
main node, if so required.
Figure 5 – The metropolitan or urban network, the red lines, connects areas in a thinly populated area
Access nodes are connected along the ring structure (Figure 5).
1.3.6 Access network
The access network connects subscribers or group of subscribers to an access node. Earlier described
networks have normally been installed on public land. The opposite is normally valid for the access network.
A large number of the access networks will be installed on private properties or land. Subscribers from
houses, terraced houses, blocks of flats, companies, hospitals and authorities can be connected to the
access network. Also masts for FWA (Fixed Wireless Access) or WLAN (Wireless LAN) and antennas for the
mobile network can be connected. Furthermore equipment for security, surveillance, fire-alarms and control
equipment can be connected.
– 13 – CLC/TR 50510:2007
FTTX-network
FWA
Fibre to the
home
Mobile
network
Metropolitan or
urban network
Fibre
concentration
spot
Figure 6 – The access network connects a large number of end-users
1.4 Node topology – Terminology
There are a number of junctions (also known as nodes) in a broadband network, where single traffic flows
are mixed, multiplexed and de-multiplexed to create an efficient flow through the network. In the nodes data
packages are given a choice of route to make the distribution. Joint traffic between different network owners
or operators is also possible. The largest number of nodes will be used for the connection of the
end-customers.
The nodes are spaces filled with transmission equipment, cross-connect devices, splice boxes, uninterrupted
power supplies and equipment for climate control.
The design of the access node will be briefly described in the following but other types of nodes will not be
discussed, except for a few comments.

National nodes
Regional nodes
Community main nodes
and Municipality nodes
fccn
Access node
End-use nodes
Figure 7 – Node hierarchy
1.4.1 National node
A national node is connected to several national and international networks.
The security level is very high.
1.4.2 Regional node
A regional node is connected to a national network, regional and municipality-connecting network.
1.4.3 Community main node
The main node in a community is connected to a regional network, municipality-connecting network in the
same community. This node should always be redundant.
1.4.4 Municipality node
The municipality node is connected to the municipality-connecting network and the metro/urban network.
In small places the end customers may be connected directly to the municipality node through the access
network.
1.4.5 Fibre cross connect node (fccn)
This is not a node in the true sense. It is more like a cross connect field to create redundancy in the premises
network in case the main node will not function. In the distribution node the metro and municipality networks
can be relocated to other main nodes, which will replace the original node. The distribution node can be
localized next to the community main node or to the municipality node as a cross connect node, but not in
the same room as the main node.
1.4.6 Access node
The access node is connected on one side to the metropolitan network and on the other side to the access
network and can be connected directly to the end-user.
It will be described more in detail later in the Technical Report.
Municipality
node
Other Community
Main node
Municipality
connecting
network
fccn
Metropolitan Metropolitan
network network
FTTX-network FTTX-network
Community Main
node
Figure 8 – A comprehensive picture over a community network –
The access network is here defined as FTTX

EE hh ee
xxcc aanngg
– 15 – CLC/TR 50510:2007
1.5 Examples of FTTX topologies
The following four pictures give some simple illustrations to point-to-point (PTP) and passive optical networks
(PON). PTP is in general passive, where one fibre from central office is routed directly to the customer and
does not use splitters. For PON (in general point to multi point) one fibre from the central office is shared
among a number of customers (usually 32) by the use of one passive splitter located within the network. For
example, in a “converged PON” a number of passive splitters are located together, whilst in a “distributed
PON” each passive splitter is located separately within the network.
The pictures are examples from different countries in Europe. See also the Glossary. PON can also be
explained as power splitting point-to-multipoint.

111444444………324 SM324 SM324 SM Tr Tr Trunununk k k CaCaCablblbleee
(((LLLononong dig dig distststaaannnccceee)))
14144…4…332244 SM SM Fi Fibrbree Di Diststrriibutbutiion on CaCablblee
2…2…8 SM8 SM Fi Fibbrre e DDrrop Caop Cablblee
114444 SSMM Fi Fibrbre Die Dissttrriibubuttiionon Ca Cablblee
DDDDiiiiststststrrrriiiibubububuttttiiiionononon No No No Nodededede
MiMiMiMinnnniiii Po Po Po PoPPPP
MDUMDU
22……2424 S SMM F Fiibrbre De Diissttrriibubuttiionon Ca Cablblee

Figure 9 – Example for a Point-to-Point/Access Network

ooPP
PP
ONTONT atat e eaacchh prpreemmiissee

EExxcchhaannggee
48…48…114444 fifibresbres T Trrunkunk C Cablablee
(Long di(Long dissttancance)e)
PoPoPP
48…48…60 S60 SMM Fi Fibre bre
MMiinini R Riingng
PoPoPP
4488……660 S0 SMM FiFibre bre
32…32…44 (44 (SSM+MMM+MM) )
MiMinini R Riingng
FiFibre Dbre Diissttriributibution on
CaCabbllee
100 / 2100 / 200 S00 SMM FiFibre bre
RiRinngg
2…2…24 MM24 MM F Fiibre bre
DDrrop Cop Cablablee
48…48…6600 S SMM FiFibre bre
MiMinini R Riingng
DDDDiiiissssttttriririributibutibutibution Non Non Non Nodeodeodeode
MiMiMiMinnnniiii P P P PooooPPPP
PoPoPP
Figure 10 – Example of a Metro/Access Network

EEExxxccchhhaaannngggeee
OOOLLLTTT
– 17 – CLC/TR 50510:2007
144144144………33324 S24 S24 SMMM T T Trrrunununk Ck Ck Cablablableee
EExchanxchangege
(((LonLonLong dig dig dissstttancancance)e)e)
48 48 SMSM Fi Fibrebre M Miinini Ri Ringng
48 S48 SMM Fi Fibre bre MMiinini R Riinngg
2 SM2 SM F Fiibrbre De Drroopp C Cablablee
14144 SM4 SM F Fiibrbre Re Riingng
24 S24 SMM Fi Fibrebre Di Diststrriibutbutiion Con Caabbllee
MDUMDUMDU
FiFibbrre De Diissttriributbutiion Pon Pooiinntt
48 S48 SMM FiFibbrre Me Miinini R Riinngg
DiDiDiDiststststrrrriiiibutbutbutbutiiiion Non Non Non Nooooddddeeee
ConConConConnecnecnecnecttttiiiion Nodon Nodon Nodon Nodeeee

Figure 11 – Second example of a Metro/Access Network

144…144…144…3232324 S4 S4 SMMM T T Trrrunkunkunk C C Cableableable
……144 S144 SMM F Fiibbrre e DDiissttrriibutbution Cion Cableable (((LonLonLong dig dig dissstttancancance)e)e)
1…1…2 F2 Fiibrbre e DDrrop Cop Caableble
MDMDUU
48 S48 SMM F Fiibrbre e DDiissttrriibutbution ion CCableable
2…2…24 S24 SMM F Fiibrbre e DDiissttrriibutibution on CCablablee
DDDDiiiissssttttrrrriiiibutibutibutibution Non Non Non Nodeodeodeode
PPPPaaaassssssssiiiive Ove Ove Ove Oppppttttiiiicacacacal Sl Sl Sl Spppplitlitlitlittttteeeerrrr
DDDDiiiissssttttrrrriiiibution bution bution bution NNNNooooddddeeee w w w wiiiitttthhhh S S S Spppplitlitlitlitterterterterssss
CCCConnonnonnonnecececectititition Non Non Non Node wode wode wode wiiiith Sth Sth Sth Spppplllliiiittttttttererererssss

Figure 12 – Example for a Passive Optical Network (PON)
ONONONTTT atatat eac eac eachhh pr pr premememisisiseee

Involved product standards (for details, see Annex A)
O. F. Cables EN 187105, EN 60794-x-y
Connectors EN 50377-x-y
Closures/ODFs EN 50411
Splices EN 61073
Connector devices EN 61753
RoW-solutions CLC/TS 50429 … 50431

1.6 Access network
The network, which connects each end-user to the access node, is called the access network. The network
is normally part of the real property. The access network may consist of a network inside a house and/or a
network between several buildings. It can therefore include an area with block of flats, houses, industrial
areas, schools, hospitals or offices.
The access network is the most complex network within the fibre optic IT-infrastructure. Each access
network is unique and requires special planning to be optimised in all aspects. Anyway there are a number of
solutions, which can be used as a base, see Annexes B, C and D.
1.6.1 FTTX in access networks
FTTX is often called the fibre access network. Here it is defined as the connection from a USER NODE in
e.g. a private home to an ACCESS NODE. It is therefore the part of the IT-structure, where there is not a
general redundancy requirement the fibres can be connected like a star from the access node to the user,
see Figure 6.
Note that in many areas with privately owned access networks the active equipment is placed close to the
building in a house property node. This network will therefore be rather short. A number of property nodes
are then concentrated to an access node. This structure implies in many cases lower costs. Even working
and maintenance expenses will increase for an area with active equipment in several nodes.
1.6.2 Size of an FTTX-network
The distance between the user and the access node can vary depending on the area from 10 m to 10 km.
In most cases the FTTX-network varies between 100 m and 2 000 m.
To be able to handle these distances with desired capacity of 1 Gbit/s a single-mode fibre (SM) is required.
Multimode-fibres can also be used in FTTX, but these networks are normally shorter, up to (500 – 2 000) m,
and they need more active equipment. Multimode fibres can form sub-optimized solutions in particular for
dense populated areas, like multi-tenants buildings, which can be compared in a way to business like LAN
applications, where multimode fibres are the preferred fibre types because they offer cheaper active
equipment.
– 19 – CLC/TR 50510:2007
Figure 13 – A complex picture of a small community network with the main node in the centre

To other community main nodes
To other community main nodes
or municipality nodes
or municipality nodes
Community Main
node
Regional network
Municipality or
distribution node
Municipality network
Access node
City or urban network
Access network
To other community main nodes To other community main nodes
or municipality nodes
or municipality nodes
Distribution point for
microducts at house level
Distribution point for
microducts at floor level
End-user node
End-users
2 Passive network solutions
In this clause we will present some information about optical fibres, connectors, splicing, link designs and
optical power budgets. Cable technology and various installation techniques will also be given. Although
optical cables look similar to copper cables there are many differing details both in design and handling.
2.1 Choice of fibre type – Single-mode/multimode
The choice of fibre is determined by several parameters. The most important are:
• system costs,
• distance,
• transmission bit-rate.
The advantages of a single-mode fibre are high transmission capacity and low optical attenuation. If a
single-mode fibre is used in FTTX, the same type can be used throughout the network, which gives
transparency and uniformity. This also simplifies service, maintenance and new developments. Another
advantage is that only tools and instruments for single-mode fibres need to be procured.
Multimode fibre allows simpler opto-electrical components and the costs for such networks will be slightly
lower. However, such a fibre can only be used for shorter distances, depending on type, maybe 2 km, see
more below.
NOTE Compilation of single-mode fibre types as defined in ITU and EN/IEC.

Single-mode (SM) ITU EN/IEC 60793-2-50 Comment
Unshifted dispersion G.652A,B B1.1 Most common
Cut-off-shifted G.654 B1.2 Low attenuation
Low water peak G.652C,D B1.3 Also common
Bending loss insensitive New types for the Access
G.657A,B - (tbd)
unshifted dispersion Network
Dispersion-shifted G.653 B2 Old, not recommended
Nonzero dispersion-shifted G.655, G.656 B4 Newer type for DWDM

For future developments in FTTX-infrastructures it is therefore recommended to use single-mode such as
G.652B, C, D or G.657A, B, see more below.
The types G.652B, C and D are basically the same fibre ty
...