ISO/IEC TR 11801-9905:2018

Information technology — Generic cabling systems for customer premises — Part 9905: Guidelines for the use of installed cabling to support 25GBASE-T application

ISO/IEC TR 11801-9905:2018(E) This technical report provides guidance on whether installed Class D and Class E channels specified in ISO/IEC 11801:2002 will support 2,5GBASE-T and 5GBASE-T. It also provides mitigation procedures to improve the performance of Class D and Class E channels to the point where these applications are supported. Higher classes according to ISO/IEC 11801:2002 will support 2,5GBASE-T and 5GBASE-T without mitigation up to 100 m.

Technologies de l'information — Câblage générique des locaux d'utilisateurs — Partie 9905: Titre manque

General Information

• Status: Published
• Publication Date: 11-Feb-2018
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Drafting Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Current Stage: 6060 - International Standard published
• Completion Date: 12-Feb-2018

Standards Content (Sample)

ISO/IEC TR 11801-9905
Edition 1.0 2018-02
TECHNICAL
REPORT

Information technology – Generic cabling for customer premises –
Part 9905: Guidelines for the use of installed cabling to support 25GBASE-T
application

ISO/IEC TR 11801-9905:2018-02(en)

---------------------- Page: 1 ----------------------
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ISO/IEC TR 11801-9905


Edition 1.0 2018-02




TECHNICAL



REPORT



















Information technology – Generic cabling for customer premises –

Part 9905: Guidelines for the use of installed cabling to support 25GBASE-T

application

























INTERNATIONAL

ELECTROTECHNICAL

COMMISSION






ICS 35.200 ISBN978-2-8322-5373-1



  Warning! Make sure that you obtained this publication from an authorized distributor.

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– 2 – ISO/IEC TR 11801-9905:2018
© ISO/IEC 2018
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviations . 8
4 Cabling channel specifications for 25 GBASE-T . 9
4.1 General . 9
4.2 25GBASE-T application specifications . 9
4.2.1 Return loss . 9
4.2.2 Insertion loss/attenuation . 10
4.2.3 NEXT . 11
4.2.4 Attenuation to crosstalk ratio at the near-end (ACR-N) . 13
4.2.5 Attenuation to crosstalk ratio at the far-end (ACR-F). . 13
4.2.6 Propagation delay . 15
4.2.7 Delay skew . 15
4.2.8 Unbalance attenuation and coupling attenuation . 15
4.2.9 Alien crosstalk . 16
4.3 Associated risk of 25GBASE-T operation over installed cabling . 17
4.4 Characterization of balanced channels using Category 7 components . 17
A
4.4.1 General . 17
4.4.2 Selection of channels for qualification . 18
4.4.3 Return loss . 18
4.4.4 Insertion loss . 19
4.4.5 Near-end crosstalk loss (NEXT) . 19
4.4.6 Attenuation to crosstalk loss ratio near-end (ACR-N) . 21
4.4.7 Attenuation to crosstalk ratio far-end (ACR-F) . 22
4.4.8 Alien (exogenous) crosstalk . 24
4.4.9 Propagation delay . 25
4.4.10 Delay skew . 25
4.4.11 Coupling attenuation . 25
4.4.12 Alien crosstalk and coupling attenuation . 26
4.5 Characterization of balanced channels using Category 7 components . 26
4.5.1 General . 26
4.5.2 Selection of channels for qualification . 27
4.5.3 Return loss . 27
4.5.4 Insertion loss . 28
4.5.5 Near-end crosstalk loss (NEXT) . 28
4.5.6 Attenuation to crosstalk loss ratio near-end (ACR-N) . 30
4.5.7 Attenuation to crosstalk ratio far-end (ACR-F) . 31
4.5.8 Alien (exogenous) crosstalk . 33
4.5.9 Propagation delay . 34
4.5.10 Delay skew . 34
4.5.11 Coupling attenuation . 34
4.5.12 Alien crosstalk and coupling attenuation . 35
4.6 Characterization of balanced channels using Category 6 components . 35
A
4.6.1 General . 35
4.6.2 Selection of channels for qualification . 36

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ISO/IEC TR 11801-9905:2018 – 3 –
© ISO/IEC 2018
4.6.3 Test specifications for channels made out of Category 6 components . 36
A
5 Guidance for mitigation procedures to improve the cabling of existing installations . 36
5.1 General . 36
5.2 Mitigation procedures related to internal noise . 36
5.3 Mitigation procedures related to exogenous noise (alien crosstalk) . 36
6 Guidance for cabling for new installations . 37
Bibliography . 38

Table 1 – Return loss for a channel . 9
Table 2 –Return loss values for a channel at key frequencies . 10
Table 3 – Insertion loss for a channel . 10
Table 4 – Insertion loss values for a channel at key frequencies . 11
Table 5 – NEXT for a channel . 11
Table 6 – NEXT values for a channel at key frequencies . 12
Table 7 – PS NEXT for a channel . 12
Table 8 – PS NEXT values for a channel at key frequencies . 13
Table 9 – ACR-F for a channel . 13
Table 10 – ACR-F values for a channel at key frequencies . 14
Table 11 – PS ACR -F for a channel . 14
Table 12 – PS ACR-F values for a channel at key frequencies . 14
Table 13 – Propagation delay for a channel . 15
Table 14 – Propagation delay values for a channel at key frequencies . 15
Table 15 – Delay skew for a channel . 15
Table 16 – PS ANEXT for a channel . 16
Table 17 – PS ANEXT values for a channel at key frequencies . 16
Table 18 – PS AACR-F for a channel . 17
Table 19 – PS AACR-F values for a channel at key frequencies . 17
Table 20 – Risk of 25GBASE-T operation over installed cabling channels . 17
Table 21 – Formulae for return loss limits for a channel . 18
Table 22 – Return loss limits for a channel at key frequencies . 18
Table 23 – Formula for insertion loss limits for a channel . 19
Table 24 – Insertion loss limits for a channel at key frequencies . 19
Table 25 – Formulae for pair-to-pair NEXT limits for a channel . 19
Table 26 – Pair-to-pair NEXT limits for a channel at key frequencies . 20
Table 27 – Formulae for PS NEXT limits for a channel . 20
Table 28 –PS NEXT limits for a channel at key frequencies . 20
Table 29 – ACR-N limits for a channel at key frequencies . 21
Table 30 – PS ACR-N limits for a channel at key frequencies . 22
Table 31 – Formulae for ACR-F limits for a channel . 22
Table 32 – ACR-F limits for a channel at key frequencies . 23
Table 33 – Formulae for PS ACR-F limits for a channel . 23
Table 34 – PS ACR-F limits for a channel at key frequencies . 23
Table 35 – Formulae for PS ANEXT limits for a channel . 24
Table 36 – PS ANEXT limits for a channel at key frequencies . 24

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– 4 – ISO/IEC TR 11801-9905:2018
© ISO/IEC 2018
Table 37 – Formula for PS AACR-F limits for a channel . 24
Table 38 – PS AACR-F limits for a channel at key frequencies . 25
Table 39 – Formula for propagation delay limits for a channel . 25
Table 40 – Propagation delay limits for a channel at key frequencies . 25
Table 41 – Formula for coupling attenuation limits for a channel . 26
Table 42 – Coupling attenuation limits for a channel at key frequencies . 26
Table 43 – Alien crosstalk and coupling attenuation . 26
Table 44 – Formulae for return loss limits for a channel . 27
Table 45 – Return loss limits for a channel at key frequencies . 27
Table 46 – Formula for insertion loss limits for a channel . 28
Table 47 – Insertion loss limits for a channel at key frequencies . 28
Table 48 – Formulae for pair-to-pair NEXT limits for a channel . 28
Table 49 – Pair-to-pair NEXT limits for a channel at key frequencies . 29
Table 50 – Formulae for PS NEXT limits for a channel . 29
Table 51 – PS NEXT limits for a channel at key frequencies . 29
Table 52 – ACR-N limits for a channel at key frequencies . 30
Table 53- PS ACR-N limits for a channel at key frequencies . 31
Table 54 – Formulae for ACR-F limits for a channel . 31
Table 55 – ACR-F limits for a channel at key frequencies . 32
Table 56 – Formulae for PS ACR-F limits for a channel . 32
Table 57 – PS ACR-F limits for a channel at key frequencies . 32
Table 58 – Formulae for PS ANEXT limits for a channel . 33
Table 59 – PS ANEXT limits for a channel at key frequencies . 33
Table 60 – Formula for PS AACR-F limits for a channel . 33
Table 61 – PS AACR-F limits for a channel at key frequencies . 34
Table 62 – Formula for propagation delay limits for a channel . 34
Table 63 – Propagation delay limits for a channel at key frequencies . 34
Table 64 – Formula for coupling attenuation limits for a channel . 35
Table 65 – Coupling attenuation limits for a channel at key frequencies . 35
Table 66 – Alien crosstalk and coupling attenuation for shielded channels . 35

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ISO/IEC TR 11801-9905:2018 – 5 –
© ISO/IEC 2018
INFORMATION TECHNOLOGY –
GENERIC CABLING FOR CUSTOMER PREMISES –

Part 9905: Guidelines for the use of installed cabling
to support 25GBASE-T application
FOREWORD
1) ISO (International Organization for Standardization) and IEC (International Electrotechnical Commission) form the
specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in
the development of International Standards. Their preparation is entrusted to technical committees; any ISO and
IEC member body interested in the subject dealt with may participate in this preparatory work. International
governmental and non-governmental organizations liaising with ISO and IEC also participate in this preparation.
2) In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.
3) The formal decisions or agreements of IEC and ISO on technical matters express, as nearly as possible, an
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The main task of the joint technical committee is to prepare International Standards. However,
the joint technical committee may propose the publication of a Technical Report when it has
collected data of a different kind from that which is normally published as an International
Standard, for example "state of the art".
ISO/IEC TR 11801-9905, which is a Technical Report, was prepared by subcommittee 25:
Interconnection of information technology equipment, of ISO/IEC joint technical committee 1:
Information technology.
The list of all currently available parts of the ISO/IEC 11801 series, under the general title
Information technology — Generic cabling for customer premises, can be found on the IEC
website.

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– 6 – ISO/IEC TR 11801-9905:2018
© ISO/IEC 2018
This Technical Report has been approved by vote of the member bodies, and the voting
results may be obtained from the address given on the second title page.
This Technical Report is to be read in conjunction with ISO/IEC/IEEE 8802.3:2017/AMD3.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

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ISO/IEC TR 11801-9905:2018 – 7 –
© ISO/IEC 2018
INTRODUCTION
This document provides guidance to determine whether and which installed channels will
support 25GBASE-T. It takes into account the design goals for 25GBASE-T equipment such
as:
a) the frequency signal range up to 1 250 MHz;
b) the support of two-connector channels up to 30 m in length.
The requirements of 25GBASE-T are fully defined in ISO/IEC/IEEE 8802-3:2017/AMD3.
Installed two-connector channels which are characterized up to 1 250 MHz and support all the
requirements of the ISO/IEC/IEEE 8802-3:2017/AMD3 link segment are expected to support
the 25GBASE-T application.
Characterization of channels using Category 7 components is described in 4.4.
A
Characterization of channels using Category 7 components is described in 4.5.
Characterization of channels using Category 6 components is described in 4.6.
A
This document also provides mitigation procedures to improve the performance of installed
channels to the point where the 25GBASE-T application is supported. Additionally, this
document recommends the use of Class I and Class II channels to support 25GBASE-T in
new installations.
Class I and Class II channels according to ISO/IEC 11801-1 will support 25GBASE-T without
mitigation.
Component requirements are not provided in this document and should not be inferred from
the channel limits provided.

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© ISO/IEC 2018
INFORMATION TECHNOLOGY –
GENERIC CABLING FOR CUSTOMER PREMISES –

Part 9905: Guidelines for the use of installed cabling
to support 25GBASE-T application



1 Scope
This part of ISO/IEC 11801, which is a Technical Report,
a) provides guidance on how to select and assess installed channels which conform to
ISO/IEC 11801-1, and clarify if they also support ISO/IEC/IEEE 8802-3:2017/AMD3 for
25GBASE-T;
b) specifies the methods to assess whether installed channels constructed with Category 7 ,
A
7, or 6 components meet the 25GBASE-T requirements;
A
c) provides guidance to identify which channels are likely to meet the 25GBASE-T
requirements to avoid unnecessary testing;
d) provides mitigation techniques to improve the performance of installed channels to meet
the 25GBASE-T requirements;
e) provides cabling recommendations for new installations.
NOTE 1 The channel transmission performance specified in this document is derived from the 25GBASE-T
requirements in ISO/IEC/IEEE 8802-3:2017/AMD3.
NOTE 2 This document does not re-specify component or channel definitions of ISO/IEC 11801-1.
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.
ISO/IEC 11801-1, Information technology – Generic cabling systems – Part 1: General
requirements
ISO/IEC/IEEE 8802-3:2017/AMD3, Information technology – Telecommunications and
information exchange between systems – Local and metropolitan area networks – Specific
requirements – Part 3: Standard for Ethernet – Amendment 3: Physical layers and
management parameters for 25 Gb/s and 40 Gb/s operation, types 25GBASE-T and
40GBASE-T
3 Terms, definitions and abbreviations
For the purposes of this document, the terms, definitions and abbreviations given in
ISO/IEC 11801-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

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ISO/IEC TR 11801-9905:2018 – 9 –
© ISO/IEC 2018
4 Cabling channel specifications for 25 GBASE-T
4.1 General
This document provides guidelines for the assessment of installed cabling channels for the
additional requirements of ISO/IEC/IEEE 8802-3:2017/AMD3 for 25GBASE-T. It is assumed
that each installed channel does fulfil the requirements of its appropriate cabling class defined
in ISO/IEC 11801-1.
The requirements defined in Clause 4 are a combination of the original class requirements of
the installed cabling and the requirements in support of 25GBASE-T.
For a balanced cabling installation covered by this document:
a) the channel performance is specified according to ISO/IEC 11801-1 and additionally
according to Clause 4 (or appropriate subclause);
b) the interfaces to the cabling are specified according to ISO/IEC 11801-1:2017, Clause 10,
with respect to mating interfaces;
c) local regulations concerning safety and EMC apply.
The test procedures for balanced cabling installations are specified in IEC 61935-1 in
accordance with ISO/IEC 11801-1 and ISO/IEC 14763-2.
4.2 25GBASE-T application specifications
NOTE 1 These specifications are consistent with the link segment specifications of
ISO/IEC/IEEE 8802-3:2017/AMD3.
NOTE 2 All specifications are based on a channel length of 30 m with 2 connections.
4.2.1 Return loss
The return loss (RL) of each pair of a channel is specified in Table 1. The limits shown in
Table 2 are derived from the formulae at key frequencies.
The return loss requirement is specified for both ends of the cabling. Return loss (RL) values
at frequencies where the insertion loss (IL) is below 3,0 dB are for information only.
Table 1 – Return loss for a channel
Class Frequency Minimum return loss
MHz dB
1 ≤ f < 10
19,0
10 ≤ f < 40
24− 5 lg( f )

40 ≤ f < 130 16,0
I
130 ≤ f < 1  000 35− 9 lg( f )
1  000 ≤ f ≤ 1 250
8,0

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– 10 – ISO/IEC TR 11801-9905:2018
© ISO/IEC 2018
Table 2 –Return loss values for
a channel at key frequencies
Frequency Minimum return loss
MHz dB
Class
I
1 19,0
16 18,0
100 16,0
250 13,4
500 10,7
600 10,0
1  000 8,0
1  250 8,0

4.2.2 Insertion loss/attenuation
The insertion loss (IL) of each pair of a channel is specified in Table 3. The limits shown in
Table 4 are derived from the formulae at key frequencies.
Table 3 – Insertion loss for a channel
a
Frequency Maximum insertion loss
Class
MHz dB
0,078
b
1 < f ≤ 500
0,634 ff+0,00156×+

f

I
0,078
c

500 < f ≤ 1 250 0,60698 ff+0,00277×+

f

a
Insertion loss (IL) at frequencies that correspond to calculated values of less than 4,0 dB revert to a
maximum requirement of 4,0 dB.
 
0,25
b
 
This formula is derived using:
0,312× 1,8 f + 0,005× f+ + 2×(0,02× f )+ 0,032 4× f


f
 
c
This formula is derived using:
 
0,25
 

0,312× 1,8 f + 0,005× f+ + 2×(0,006 49× f + 0,000 605× f)+ 0,032 4× f
 
f
 

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ISO/IEC TR 11801-9905:2018 – 11 –
© ISO/IEC 2018
Table 4 – Insertion loss values for
a channel at key frequencies
Maximum insertion loss
Frequency
dB
MHz
Class
I
1 4,0
16 4,0
100 6,5
250 10,4
500 15,0
600 16,5
1  000 22,0
1  250 24,9

4.2.3 NEXT
4.2.3.1 Pair-to-pair NEXT
The NEXT between each pair combination of a channel is specified in Table 5. The limits
shown in Table 6 are derived from the formulae at key frequencies.
The NEXT requirement is specified for both ends of the cabling. NEXT values at frequencies
where the insertion loss (IL) is below 4,0 dB are for information only.
Table 5 – NEXT for a channel
a
Frequency Minimum NEXT
Class
MHz dB
75,3− 15 lg ( f ) 94− 20 lg ( f )
 
 
− 20 − 20
1 ≤ f ≤ 500 - 20 lg 10 + 2× 10
 
...