EN 50173-5:2007

SLOVENSKI STANDARD
01-januar-2008
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VUHGLãþD
Information technology - Generic cabling systems - Part 5: Data centres
Informationstechnik - Anwendungsneutrale Kommunikationskabelanlagen - Teil 5:
Rechenzentren
Technologies de l'information - Systemes de câblage générique - Partie 5: Centres de
données
Ta slovenski standard je istoveten z: EN 50173-5:2007
ICS:
33.040.50 Vodi, zveze in tokokrogi Lines, connections and
circuits
35.110 Omreževanje Networking
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 50173-5
NORME EUROPÉENNE
May 2007
EUROPÄISCHE NORM
ICS 33.040.50
English version
Information technology -
Generic cabling systems -
Part 5: Data centres
Technologies de l'information -  Informationstechnik -
Systèmes de câblage générique - Anwendungsneutrale
Partie 5: Centres de données Kommunikationskabelanlagen -
Teil 5: Rechenzentren
This European Standard was approved by CENELEC on 2007-04-11. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

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. EN 50173-5:2007 E
Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 215, Electrotechnical
aspects of telecommunication equipment.
The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50173-5 on
2007-04-11.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2008-05-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2010-05-01
The European Standards EN 50173:1995 and EN 50173-1:2002 have been developed to enable the
application-independent cabling to support ICT applications in office premises. Their basic principles,
however, are applicable to other types of applications and in other types of premises.
TC 215 has decided to establish relevant European Standards which address the specific requirements of
these premises. In order to point out the commonalities of these cabling design standards, these EN are
published as individual parts of the series EN 50173, thus also acknowledging that standards users recognize
the designation “EN 50173” as a synonym for generic cabling design.
At the time of publication of this European Standard, series EN 50173 comprises the following standards:
EN 50173-1 Information technology – Generic cabling systems – Part 1: General requirements
EN 50173-2 Information technology – Generic cabling systems – Part 2: Office premises
EN 50173-3 Information technology – Generic cabling systems – Part 3: Industrial premises
EN 50173-4 Information technology – Generic cabling systems – Part 4: Homes
EN 50173-5 Information technology – Generic cabling systems – Part 5: Data centres

- 3 - EN 50173-5:2007
Contents
Introduction . 5
1 Scope and conformance . 8
1.1 Scope . 8
1.2 Conformance . 8
2 Normative references . 9
3 Definitions and abbreviations . 9
3.1 Definitions. 9
3.2 Abbreviations . 10
4 Structure of the generic cabling system in data centres . 11
4.1 General. 11
4.2 Functional elements. 11
4.3 General structure and hierarchy. 11
4.4 Cabling subsystems. 12
4.5 Accommodation of functional elements.13
4.6 Interfaces. 14
4.7 Dimensioning and configuring. 14
5 Channel performance in data centres . 17
5.1 General. 17
5.2 Environmental performance . 18
5.3 Transmission performance. 19
6 Reference implementations in data centres. 20
6.1 General. 20
6.2 Balanced cabling. 20
6.3 Optical fibre cabling . 26
7 Cable requirements in data centres.27
7.1 General. 27
7.2 Balanced cables . 27
7.3 Optical fibre cables . 28
8 Connecting hardware requirements in data centres . 28
8.1 General requirements . 28
8.2 Connecting hardware for balanced cabling . 28
8.3 Connecting hardware for optical fibre cabling.29
9 Requirements for cords and jumpers in data centres. 29
9.1 Jumpers. 29
9.2 Balanced cords . 29

9.3 Optical fibre cords. 29
Annex A (normative) Link performance limits . 30
Annex B (normative) Channel insertion loss models for high bit rate, multimode, optical fibre
applications . 31
Bibliography . 32
Figures
Figure 1 - Schematic relationship between the EN 50173 series and other relevant standards .6
Figure 2 - Structure of generic cabling.12
Figure 3 - Hierarchical structure of generic cabling.12
Figure 4 - Example of accommodation of functional elements .14
Figure 5 - Test and equipment interfaces .15
Figure 6 - Connection of functional elements providing redundancy .16
Figure 7 - The External Network Interface .16
Figure 8 - Example of a channel.18
Figure 9 - Example of a system showing the location of cabling interfaces.18
Figure 10 - Zone distribution cabling models .22
Figure 11 – Main distribution cabling model.23
Figure 12 - Network access cabling model .25
Figure A.1 - Link options.30
Tables
Table 1 - Contextual relationship between EN 50173 series and other standards relevant for information
technology cabling systems.7
Table 2 - Zone distribution channel equations .21
Table 3 - Main distribution channel equations.24
Table 4 - Network access cabling channel equations .26
Table 5 - Optical fibre channel parameters .27
Table B.1 – Maximum channel attenuation allocated to connecting hardware .31
Table B.2 - Maximum connecting hardware attenuation .32

- 5 - EN 50173-5:2007
Introduction
The importance of the information technology cabling infrastructure is similar to that of other utilities such as
heating, lighting and electricity supplies. As with other utilities, interruptions to service can have serious
impact. Poor quality of service due to lack of planning, use of inappropriate components, incorrect installation,
poor administration or inadequate support can threaten an organisation's effectiveness.
Cabling within data centres comprises both application-specific and multipurpose networks that are mission-
critical to the enterprise. Generic cabling designs in accordance with the EN 50173 series have supported the
development of high data rate applications based upon a defined cabling model. This European standard
recognizes the benefit of generic cabling to provision multiple services and to connect large quantities of
equipment within the limited space of data centre premises, and is to be used in conjunction with
EN 50173-1.
This European Standard, EN 50173-5, provides:
a) users with an application independent generic cabling system and an open market for cabling
components;
b) requirements for infrastructures that support critical applications within data centres;
c) a flexible cabling scheme such that modifications are both easy and economical;
d) a scaleable structure to support expansion with minimum operational disruption;
e) building professionals (for example, architects) with guidance allowing the accommodation of cabling
before specific requirements are known; i.e. in the initial planning either for construction or refurbishment;
f) industry and standardisation bodies with a cabling system which supports current products and provides
a basis for future product development and applications standardisation.
This European Standard specifies multi-vendor cabling, and is related to:
- the associated standard covering general requirements for generic cabling within premises (EN 50173-1);
- standards for cabling components developed by Technical Committees of CENELEC and/or IEC;
- standards for the quality assurance and installation of information technology cabling (series EN 50174)
and testing of installed cabling (EN 50346);
- applications developed by the technical committees of IEC (including the subcommittees of ISO/IEC
JTC 1) and study groups of ITU-T.
It is anticipated that the generic cabling system meeting the requirements of this European Standard will have
a life expectancy in excess of ten years.

Figure 1 and Table 1 show the schematic and contextual relationships between the standards produced by
TC 215 for information technology cabling, namely
1) this and other parts of the EN 50173 series;
2) application dependent cabling design (e.g. EN 50098 series);
3) installation (EN 50174 series);
4) testing of installed cabling (EN 50346);
5) equipotential bonding requirements (EN 50310).
ENEN 500 50098-98-1:1: CCuuststomomerer pr prememiisseses EENN 50173-50173-2:2: I Innffoorrmmatatiion ton teecchnolhnology -ogy -
cablcabliing fng foorr i innffoorrmmatatiion on tteecchhnnoollogy -ogy - GGenereneriicc c cablabliing ng -- OOffffiicce pre prememiisseses
IISSDDNN basi basicc accesaccesss
ENEN 50173-50173-3:3: I Innffoorrmmatatiion ton teechnolchnologyogy - -
EENN 50098-50098-2:2: C Cuuststomomerer pr prememiisses es GGenereneriicc cabl cabliing ng -- IIndustndustrriiaall prprememiisseses
ENEN 50173- 50173-1:1: I Innffoorrmmatatiion on tteechnolchnologyogy --
cablcabliing fng foorr i innffoorrmmatatiion on tteechnolchnology -ogy -
ENEN 50173- 50173-4:4: IInnffoorrmmatatiion ton teechnolchnology ogy -- GGenereneriicc cabl cabliing ng -- GGenereneralal r requiequirreemmententss
2048 2048 kbikbitt//ss I ISSDDNN pr priimmararyy ac access and cess and
GGenereneriicc c cablabliing -ng - HHomomeses
lleaseased led liine netne netwwoorrkk i inntteerrffacacee
ENEN 50173- 50173-5:5: IInnffoorrmmatatiion ton teechnolchnology ogy --
GGenereneriicc cabl cabliing -ng - DDatata a centcentrreess
ENEN 50174- 50174-1:1: IInnffoorrmmaattiion ton teechchnolnology ogy --
CCablabliing ing innssttalalllaattiion on -- SSpecpeciiffiiccatatiion and on and
qualqualiittyy assur assuranceance
EENN 50174-50174-2:2: I Innffoorrmmatatiion ton teecchnolhnology -ogy - ENEN 50310: 50310: Appl Appliiccatatiion ofon of eqequiuipotpotententiiaall
CCablabliing ing innssttalalllaattiion on -- IInstnstaallllatatiion on bondibonding and ng and eareartthhiinngg iin buin buillddiings wngs wiitthh
plplannianning anng and prd practactiicesces iinnsiside de buibuillddiingsngs iinnffoorrmmatatiion ton teechnolchnology ogy equiequipmpmentent
EENN 50174-50174-3:3: I Innffoorrmmatatiion ton teecchnolhnology -ogy -
CCablabliing ing innssttalalllaattiion on -- IInstnstaallllatatiion on
plplannianning anng and prd practactiicesces outoutsiside de buibuillddiingsngs
ENEN 50346:50346: I Innffoorrmmatatiion ton teechnolchnologyogy - -
CCablabliing ing innssttalalllaattiion on --
TestTestiing ofng of i innststalallled ed cablcabliinngg

NOTE For the purposes of the standards in the EN 50173 and EN 50174 series the term “information technology” includes ICT, BCT
and CCCB applications.
Figure 1 - Schematic relationship between the EN 50173 series and other relevant standards

- 7 - EN 50173-5:2007
Table 1 - Contextual relationship between EN 50173 series and other standards relevant for information
technology cabling systems
Specification phase Installation phase Operation phase
Building design Generic cabling
phase design phase
EN 50310 EN 50173 series EN 50174-1 EN 50174-1
except
EN 50173-4
5.2: Common bonding 4: Structure 4: Requirements for 5: Requirements for
network (CBN) within installers premises owners
5: Channel
a building
performance 5: Requirements for
6.3: AC distribution premises owners
7: Cable requirements
system and bonding
of the protective
8: Connecting
conductor (TN-S)
hardware
requirements
9: Requirements for
cords and jumpers
A: Link performance
limits
Planning phase
and
EN 50173-4 EN 50174-2 EN 50174-2
4 and 5: Structure 5: Requirements for 4: Requirements for
planning installations installers of
6: Channel
of information information
performance
technology cabling technology cabling
8: Cable requirements
6: Segregation of 6: Segregation of
metallic information metallic information
9: Connecting
technology and mains technology and mains
hardware
power cabling power cabling
requirements
7: Additional
10: Requirements for
considerations
cords and jumpers
A: Link performance
limits
and and
EN 50174-3 EN 50174-3
and and
(for equipotential (for equipotential
bonding) bonding)
EN 50310 EN 50310
5.2: Common bonding 5.2: Common bonding
network (CBN) within network (CBN) within
a building a building
6.3: AC distribution 6.3: AC distribution
system and bonding system and bonding
of the protective of the protective
conductor (TN-S) conductor (TN-S)
and
EN 50346
4: General
requirements
5: Test parameters for
balanced cabling
6: Test parameters for
optical fibre cabling
1 Scope and conformance
1.1 Scope
This European Standard specifies generic cabling that supports a wide range of communications services for
use within a data centre. It covers balanced cabling and optical fibre cabling.
This European Standard is based upon and references the requirements of EN 50173-1. This European
Standard contains additional requirements that are appropriate to data centres in which the distance over
which communications services have to be distributed is the maximum defined for backbone cabling
implementations within EN 50173-1. The principles of this European Standard may also be applied to
installations that do not fall within this range.
In addition to the requirements of EN 50173-1, this European Standard specifies:
a) a modified structure and configuration for generic cabling within data centres used to support existing and
emerging applications;
b) implementation options to reflect the quantity of connections required in data centre infrastructures;
c) requirements that reflect the range of operating environments within data centres.
Safety (electrical safety and protection, fire, optical power etc.) and electromagnetic compatibility (EMC)
requirements are outside the scope of this European Standard and are covered by other standards and
regulations. However, information given in this European Standard may be of assistance in meeting these
standards and regulations.
1.2 Conformance
For a cabling system to conform to this European Standard:
a) the structure and configuration shall conform to the requirements of Clause 4;
b) connecting hardware in the cabling structure shall conform to the requirements of Clause 8.
c) the performance of channels shall conform to the transmission performance and environmental
requirements of Clause 5. This shall be achieved by one of the following:
- a channel design and implementation ensuring that the prescribed channel performance Class is met;
- attachment of appropriate components to a link design meeting the prescribed performance Class of
Annex A. Channel performance shall be assured where a channel is created by adding more than one
cord to either end of a link meeting the requirements of Annex A;
- using the reference implementations of Clause 6 and compatible cabling components conforming to the
requirements of Clauses 7, 8 and 9, based upon a statistical approach of performance modelling.
d) local regulations concerning safety shall be met.
In addition the following requirements of the EN 50174 series of standards shall be met:
e) installation specification and quality planning to address:
- the test parameters to be measured;
- the sampling levels to be applied;
- the treatment of channels or links which fail to meet requirements or for which test results lie within
the relevant measurement accuracy;

- 9 - EN 50173-5:2007
f) administration;
g) installation.
Test methods to verify conformance with the channel and link requirements of Clause 5 and Annex A
respectively are specified in EN 50346. Neither this standard nor EN 50174-1 specifies the test and sampling
levels to be adopted.
Specifications marked "ffs" (for further study) in EN 50173-1 are preliminary and are not required for
conformance to this European Standard.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 50173-1:2007, Information technology – Generic cabling systems – Part 1: General requirements
EN 50174-1, Information technology – Cabling installation – Part 1: Specification and quality assurance
EN 50174-2, Information technology – Cabling installation – Part 2: Installation planning and practices inside
buildings
EN 50174-3, Information technology – Cabling installation – Part 3: Installation planning and practices outside
buildings
EN 50377-7-1, Connector sets and interconnect components to be used in optical fibre communication
systems – Product specifications – Part 7-1: Type LC-PC duplex terminated on IEC 60793-2 category A1a
and A1b multimode fibre
EN 50377-7-2, Connector sets and interconnect components to be used in optical fibre communication
systems – Product specifications – Part 7-2: LC-PC duplex terminated on IEC 60793-2 category B1.1
singlemode fibre
EN 50377-7-3, Connector sets and interconnect components to be used in optical fibre communication
systems – Product specifications – Part 7-3: Type LC-APC duplex terminated on IEC 60793-2 category B1.1
singlemode fibre
EN 50377-7-4, Connector sets and interconnect components to be used in optical fibre communication
systems – Product specifications – Part 7-4: LC-PC simplex terminated on IEC 60793-2 category B1.1
singlemode fibre
EN 61076-3-106:2006, Connectors for electronic equipment - Product requirements - Part 3-106: Rectangular
connectors - Detail specification for protective housings for use with 8-way shielded and unshielded con-
nectors for industrial environments incorporating the IEC 60603-7 series interface (IEC 61076-3-106:2006)
EN 61754-7, Fibre optic connector interfaces – Part 7: Type MPO connector family (IEC 61754-7:2004)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this European Standard the following definitions apply in addition to those of EN 50173-1.
3.1.1
equipment outlet
fixed connecting device where the zone distribution cabling terminates. The equipment outlet provides the
interface to the equipment cabling

3.1.2
local distribution point
connection point in the zone distribution cabling subsystem between a zone distributor and one or more
equipment outlets
3.1.3
local distribution point cable
LDP cable
cable connecting a local distribution point to an equipment outlet
3.1.4
local distribution point link
LDP link
transmission path between a local distribution point and the interface at the other end of the zone distribution
cable including the connecting hardware at each end
3.1.5
main distribution cable
cable connecting the main distributor to the zone distributor
3.1.6
main distributor
distributor used to make connections between the main distribution cabling subsystem, network access
cabling subsystem and cabling subsystems specified in EN 50173-1 and active equipment
3.1.7
network access cable
cable connecting the external network interface to the main distributor or zone distributor
3.1.8
zone distribution cable
cable connecting the zone distributor to the equipment outlet(s) or local distribution point(s)
3.1.9
zone distributor
distributor used to make connections between the main distribution cabling subsystem, zone distribution
cabling subsystem, network access cabling subsystem, cabling subsystems specified in EN 50173-1 series
and active equipment
3.2 Abbreviations
For the purposes of this European Standard the following abbreviations apply in addition to those of
EN 50173-1.
BEF Building entrance facility
ENI External network interface
EO Equipment outlet
LDP Local distribution point
MD Main distributor
OE EQP Opto-electronic equipment
ZD Zone distributor
- 11 - EN 50173-5:2007
4 Structure of the generic cabling system in data centres
4.1 General
This Clause identifies the functional elements of generic cabling, describes how they are connected together
to form subsystems and identifies the interfaces at which application-specific components are connected.
Channels, created by connecting application-specific cabling components to the generic cabling, are used to
support applications. Applications listed in EN 50173-1:2007, Annex F, are supported by connecting active
equipment at the external network interfaces, equipment outlets and the distributors.
In general, all functional elements, subsystems and interfaces from the campus distributor to the floor
distributor as described in EN 50173-1 are applicable.
4.2 Functional elements
In addition to the distributors specified in EN 50173-1 this standard specifies the following functional elements
and interfaces of generic cabling:
a) external network interface (ENI);
b) network access cable;
c) main distributor (MD);
d) main distribution cable;
e) zone distributor (ZD);
f) zone distribution cable;
g) local distribution point (LDP);
h) local distribution point cable (LDP cable);
i) equipment outlet (EO).
Groups of these functional elements are connected together to form cabling subsystems (see 4.3).
4.3 General structure and hierarchy
Generic cabling systems contain up to three types of cabling subsystems: network access, main distribution and
zone distribution. Where present within the premises, a distributor in accordance with EN 50173-1 is connected to
the generic cabling using the network access cabling.
The cabling subsystems are connected together to create a generic cabling system with a structure as shown in
Figure 2. The composition of the cabling subsystems is described in 4.4.1, 4.4.2 and 4.4.3. The functional
elements of the cabling subsystems are interconnected to form a basic hierarchical topology as shown in Figure 3.
Where the functions of distributors are combined (see 4.7.1) the cabling subsystems linking them are not
required.
Connections between cabling subsystems are either active, requiring application-specific equipment, or
passive. Connection to application-specific equipment at an MD and ZD adopts an interconnect or a cross-
connect approach (see EN 50173-1). Connection to application-specific equipment at an ENI and EO adopts
an interconnect approach (see EN 50173-1). Passive connections between cabling subsystems adopt either
a cross-connect approach, by way of either patch cords or jumpers, or an interconnect approach.

EO
ENI MD ZD LDP
EQP
Distributor
in accordance
with EN 50173-1 Network Zone distribution Equipment
Main distribution
access cabling subsystem cabling
cabling
cabling
subsystem
subsystem
Generic cabling system
Figure 2 - Structure of generic cabling

DDiissttrriibutbutoorr
ENENII ENENII
iinn ac accorcorddaanncece
wiwitthh E ENN 501 50173-73-11
NNeettwworork ak acccceessss
cabcablliinng sg suubbsyssystteemm
NNeettwwoorrkk ac accecessss
MDMD
cacablbliing sng suubbsyssystteemm
MMaaiinn di diststrriibubuttiioonn
ccablabliinngg su subsbsystysteemm
ZDZD ZDZD
ZoZonene di dissttrriibubuttiionon ZoZone dine dissttrriibutbutiioonn
cacablbliing subng subsyssystteemm cacablbliing sng suubbsyssystteemm
LDPLDP LDPLDP LDPLDP LDPLDP
EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO
optoptiionaonall c caablbleses

NOTE Network access cabling is also used to connect ENI to ZD.
Figure 3 - Hierarchical structure of generic cabling
4.4 Cabling subsystems
4.4.1 Network access cabling subsystem
The network access cabling subsystem extends from an MD (or ZD) to the ENIs and/or other distributors in
accordance with EN 50173-1 connected to it. The subsystem includes:
a) the network access cables;
b) the mechanical termination of the network access cables at the ENI;

- 13 - EN 50173-5:2007
c) the mechanical termination of the network access cables at the MD, ZD or other distributors in
accordance with EN 50173-1.
Although equipment cords are used to connect the transmission equipment to the cabling subsystem, they
are not considered part of the network access cabling subsystem because they are application-specific.
4.4.2 Main distribution cabling subsystem
The main distribution cabling subsystem extends from an MD to the ZDs connected to it. The subsystem
includes:
a) the main distribution cables;
b) the mechanical termination of the main distribution cables at the MD together with associated patch cords
and/or jumpers at the MD;
c) the mechanical termination of the main distribution cables at the ZD.
Although equipment cords are used to connect the transmission equipment to the cabling subsystem, they
are not considered part of the main distribution cabling subsystem because they are application-specific.
4.4.3 Zone distribution cabling subsystem
The zone distribution cabling subsystem extends from a ZD to the EOs connected to it. The subsystem
includes:
a) the zone distribution cables;
b) the mechanical termination of the zone distribution cables at the EO and the ZD together with associated
patch cords and/or jumpers at the ZD;
c) LDPs (optional);
d) LDP cables (optional);
e) the EOs.
Although equipment cords are used to connect the transmission equipment to the cabling subsystem, they
are not considered part of the cabling subsystem because they are application-specific. Zone distribution
cables shall be continuous from the ZD to the EOs unless an LDP is installed (see 4.7.7).
4.4.4 Design objectives
In order to provide longest operational life while minimising the disruption and cost associated with re-cabling,
the fixed installed cabling should be designed to:
a) support the broadest set of existing and emerging applications;
b) accommodate the anticipated growth in volume of supported applications throughout the predicted
lifetime of the installation.
4.5 Accommodation of functional elements
Figure 4 shows an example of how the functional elements are accommodated in a building (only a single
floor of the building is shown for simplicity).

The MD, ZD and LDP shall be housed in permanent and accessible locations within the data centre.
The ENI shall be housed in permanent and accessible locations either internal or external to the data centre.
Equipment/telecommunications room
in accordance
with EN 50173-1
Distributor
Data centre
BEF in accordance
with EN 50173-1
ENI MD ZD EO
LDP
Figure 4 - Example of accommodation of functional elements
4.6 Interfaces
4.6.1 Equipment interfaces and test interfaces
Potential equipment interfaces for data centres are located at the ends of the cabling subsystems (as shown
in Figure 5). An LDP does not provide an equipment interface to the generic cabling system.
Potential test interfaces for data centres are located at the ends of the cabling subsystems and at the LDP, if
present (as shown in Figure 5).
4.6.2 Channels and links
The transmission performance of generic cabling between specific test interfaces is detailed in Clause 5 in
terms of the channel and Annex A for links.
The channel is the transmission path between telecommunications equipment (EQP in Figure 5) such as
servers and switches. A typical channel would consist of the cabling subsystem together with equipment
cords. For longer reach services the channel would be formed by the connection of two or more subsystems
(including equipment cords). It is important that the generic cabling channel is designed to meet the required
Class of performance for the applications that are to be run. For the purposes of testing, the channel excludes
the connections at the application-specific equipment.
Links may be tested either during commissioning or for the detection of faults that are suspected in the
cabling. For the purposes of testing the link includes the connections at the ends of the cabling link under
test.
4.7 Dimensioning and configuring
4.7.1 Distributors
The number and type of subsystems that are included in a generic cabling implementation depends upon the
layout and size of the data centre and upon the strategy of the user.
The design of distributors should ensure that the lengths of patch cords, jumpers and equipment cords are
minimised. The design lengths of the cords should be maintained during operation. Distributors should be
located such that the resulting cable lengths are consistent with the channel performance requirements of
Clause 5.
Where the components of Clauses 7, 8 and 9 are used the distributors shall be located in accordance with
the reference implementations of Clause 6. Where other components are used, distributors shall be located
so that the desired performance Class of Clause 5 is delivered.

- 15 - EN 50173-5:2007
a) Zone distribution cabling
EI EI EI
ZD
EO
EQP C C C C C C EQP
LDP
TI TI TI TI TI
b) Main distribution cabling
EI EI EI EI
ZD
MD
EQP C C C C C C EQP
TI TI TI TI
c) Network access cabling from MD to distributor in accordance with EN 50173-1
EI EI EI EI
Distributor in accordance
with EN 50173-1
MD
EQP C C C C C C EQP
TI TI TI TI
d) Network access cabling from MD to ENI
EI EI EI
MD
ENI
EQP C C C C C EQP
TI TI TI TI
See NOTE
NOTE Where the EQP connected to the ENI lies outside the premises containing the data centres, the interconnecting cord will typically
comprise a combination of fixed cabling and cords that are outside the scope of this standard. In such cases the connection to the EQP
may not provide a TI.
Figure 5 - Test and equipment interfaces
The functions of multiple distributors may be combined.
In certain circumstances, for example for security or reliability reasons, redundancy may be built into a cab-
ling design. Figure 6 shows one of many possible examples of the connection of functional elements within
the structured framework to provide such protection against failure in one or more parts of the cabling
infrastructure. This might form the basis for the design of generic cabling for a data centre providing some
protection against such hazards as fire damage or the failure of the external network feeder cable.

ENENII ENIENI
DiDissttrriibubuttoorr
iinn acc accoorrdandancece
wiwitthh E ENN 50150173-73-11
MDMD MDMD
ZDZD ZDZD
LDLDPP LDLDPP
EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO EOEO

Figure 6 - Connection of functional elements providing redundancy
Redundancy may be provided by utilising multiple cables between distributors with cables following different
routes. In addition, consideration should be given to using multiple service providers to provide service
redundancy. The multiple service providers should have diverse routes to each of the multiple ENIs.
4.7.2 External network interface
The External Network Interface (ENI) is a termination of the network access cabling that allows connection of
external services to the network access cabling as shown in Figure 7.
The ENI interface presented shall be in accordance with Clause 8.
Where the components of Clauses 7, 8 and 9 are used the ENIs shall be located in accordance with the
reference implementations of Clause 6.
EExxtteerrnnal sal seerrvviceice cab cablingling NNeettwwoorrkk a acccceess ss cacabblinlingg
((bbeyeyondond the the s sccoope ope off t thhisis s sttandandarard)d)
InInterterccoonnecnnectiontion
ENENII
CCrroosssscconneonneccttioion n
CC
ENENII
CC EQEQPP CC
ENENII
PPaassssivive ore or a acctitivvee eq equipmeuipmenntt
enenabliabling cng connonnecectiotionn of of
nenetwtwororkk ac accceessss c caablingbling
toto ex externaternall s seerrvviicce ce caablbliinngg

Figure 7 - The External Network Interface

- 17 - EN 50173-5:2007
4.7.3 Cables
Cable types used in the reference implementations of Clause 6 are given in Clause 7. Hardware for
connecting cables shall only provide direct onward attachment for each conductor and shall not provide any
contact between more than one incoming or outgoing conductor (e.g. bridge taps shall not be used).
4.7.4 Equipment cords
Equipment cords connect application-specific equipment to the generic cabling at the ENIs, EOs and
distributors. Equipment cords are non-permanent and can be application-specific. The performance
contribution of these cords shall be taken into account in the design of the channel. Clause 6 provides guidance on
cord lengths for reference implementations of generic cabling.
4.7.5 Patch cords and jumpers
Patch cords and jumpers are used within cross-connect implementations at distributors. The performance
contribution of these cords shall be taken into account in the design of the channel. Clause 6 provides guidance
on cord/jumper lengths for reference implementations of generic cabling.
4.7.6 Equipment outlets
The design of generic cabling should provide for EOs to be installed with a high density and located in close
proximity to the application-specific equipment to which they are to be connected. The number of cable
elements presented at the EO is not restricted by this standard.
A group of EOs can be served by more than one LDP.
The EO interface presented shall be in accordance with Clause 8.
4.7.7 LDP
The installation of an LDP in the zone distribution cabling between the ZD and the EO may be useful where
frequent additions or movements of equipment are required. One LDP is permitted between a ZD and any
EO. The connection at the LDP shall adopt an interconnect approach (see EN 50173-1).
Where an LDP is used, it shall have sufficient capacity to support the area of the data centre which it is
designed to serve during its intended operational life. The area served may be defined in terms of number of
frames/cabinets/closures to be supported and may include allowance for growth.
It is possible to locate LDPs in ceiling voids and under floors provided that those locations meet the
requirements of 4.5.
For balanced cabling, the effect of multiple connections in close proximity on transmission performance
should be taken into consideration when planning the cable lengths between the ZD and the LDP.
5 Channel performance in data centres
5.1 General
This Clause specifies the minimum channel performance of balanced and optical fibre cabling in terms of the
Classes as specified in 5.3. The transmission performance of channels is specified at and between the
connections to active equipment as shown in Figure 8. The channel comprises only passive sections of cable,
connections, equipment cords, patch cords and jumpers.
Where applications listed in EN 50173-1:2007, Annex F, are to be supported, the transmission and
environmental performance of the connections at the active equipment are the responsibility of the equipment
supplier.
Channel
EQP C C C C C C EQP
Patch cord/ Equipment
Equipment Patch cord/
Jumper cord
cord Jumper
Figure 8 - Example of a channel
Application support depends on channel transmission performance only, which in turn depends on cable
length, number of connections and performance of the components within the environments to which the
channel is subjected.
Channels are implemented using:
- network access cabling only;
- main distribution cabling only;
- zone distribution cabling only;
- combinations of the above.
Figure 9 shows an example of equipment at the MD connected to transmission equipment at the EO using
two channels, an optical fibre channel and a balanced cabling channel. The optical fibre and balanced cabling
channels are connected together using an optical fibre to balanced copper cable converter. There are four
channel interfaces; one at each end of the balanced channel, and one at each end of the optical fibre
channel.
MD ZD
C C C C C EQP
EO
C C C
Optical fibre channel Balanced cabling
channel
C C C
EQP OE EQP
= optional connection
C
Figure 9 - Example of a system showing the location of cabling interfaces
5.2 Environmental performance
See EN 50173-1.
...