Standards compliant testing of Cat.6A permanent

links is a true foundation for an in interoperable

and trouble free performing channel

Christian SchillabProduct Manager InfrastructureSuperVision

Fluke Networks EuropeMember British Standards Institute Working Group TCT 7/-/1

& CENELEC TC215 WG1 PTH und PTT

christian.schillab@flukenetworks.com

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The Goal Of This Presentation

Update on the relevant testing standards and

introduction to the feature set to look for in a

field tester, which is capable to test a system for

10GABSE-T readiness or Cat.6A compliance

3

Agenda

10Gigabit Ethernet

What are we testing ?

Testing Models and Connectivity

Significance of the test plug

Accuracy

4

Development of 10GBase-T

• IEEE (Institute of Electrical and Electronics Engineers) 802.3an task force

• Develop 10 Gb/s Ethernet application over twisted pair copper medium

(10GBASE-T)

• Define signal encoding and requirements for “electronic devices” and used

bandwidth up to 500MHz

• IEEE is focused on the „Channel‟ requirements for 10 Gb/s transmission

• Study and develop the detailed specifications of the physical medium

(twisted-pair copper cabling) in cooperation with ISO/IEC and TIA

workgroups

5

Twisted-Pair Cabling Expected to Support 10GBASE-T

Currently Installed Cabling Channel

Length

(m)

Comments

ISO Class F 100 Supported (IEEE objective)

ISO Class E/

TIA Cat 6 UTP

55 (33?) Supported (IEEE objective)

ISO Class E ScTP 100 Expected to meet requirements

ISO Class E /

TIA Cat 6

55 to 100 Requires additional (field) test of PS AXTalk

parameters

New Cabling

TIA: Augmented Cat.6 (Cat.6A)

ISO: Class EA

100 Some standards still in progress –

Only channel requirements are final in all

ISO/IEC, TIA and CENELEC

6

Twisted-Pair Cabling supporting 10GBASE-TThe role for field testing !

Currently Installed

Cabling

Channel

Length (m)

Comments

ISO Class F 100 Supported (IEEE objective)

ISO Class E/

TIA Cat 6 UTP

55 (33) Supported (IEEE objective) (*)

ISO Class E ScTP 100 Expected to meet requirements

ISO Class E /

TIA Cat 6

55 to 100 Requires additional (field) test of PS AXTalk

parameters (*)

New Cabling

TIA: Augmented Cat 6

ISO: Class EA

100 Some standards still in progress –

Only channel requirements are final in all

ISO/IEC, TIA and CENELEC

Expected !?!?

How to make sure?

TEST per

TSB-155 or ISO-TR24750

1.AXT parameters

are not depending on

workmanship and met

“By Design”

2.Pair to Pair (“In

Channel”) parameters

continue to depend

on workmanship

… needs testing

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PATCH

CORD

Cross-

connect

Panel

HORIZONTAL CABLE

TO

PATCH

CORD

WORKSTATION

TELECOMMUNICATIONS

ROOM

WORK AREA

Testing The “CHANNEL”

CP *

* Consolidation Point

(Optional)

excluded from

the measurement

excluded from the

measurement

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Test

Leads HORIZONTAL CABLE TO

Test

Leads

WORK AREA

Testing the “Permanent Link”

CP *

* Consolidation Point (Optional)

Measurement does not

include contributions by the

test leads but does include

the mated NEXT and RL of

test plug and jack

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Definition for a PATCH CORD Test Head

How the standards establish limits…..

Definition of requirements and limits for the CHANNEL: Length,

Crosstalk, Reflections, Attenuation

Requirements for the Permanent LINK

Requirements for components: Plugs & Jacks (CHW),

Cables

Definition of the component test procedure

Range of

TEST Plugs

Certification of compliant jacks in

laboratories

The way to INTEROPERABILITY !Permanent Link = True “foundation” for a building’s cabling infrastructure

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Example: „System Solution“ vs. „Mix & Match“• Manufactuere „A“ and „B“ belong to the top 10

• Both offer Cat.6A products since 2006

5.7 4.3

0.1

0.0

System Solution

Mix &

Match

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Background on test plugs

QUESTIONS:

• Why is the test plug so

important ?

• Who defines the

properties of a test plug ?

• What could it be compared

with ?

ANSWERS:

• All modular jacks (RJ45) use

compensation to achieve

Cat.5e/Cat.6/Cat.6a performance

• Experts in the standards bodies

define procedures for the selection of

test plugs

• It could be compared with the meter

prototype established by the

Académie Des Sciences in Paris in

the 17th century

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NEXT Compensation ?What if the test plug is different or wrong ?

Case A B C

Test plug properties Compliant & “centered” “Better” &

non-compliant

“Worse” &

non-compliant

…NEXT at 100 MHz - 37dB - 39dB - 35dB

… mV/V 14 11 18

Mated NEXT Compliant =

better -54db (2mV)

Non-compliant Non-compliant

Comment The jack is over

compensating

The jack is under

compensating

jackplug

mated

jackplug

matedjack

plug

mated

Conclusion:

Wrong Test Plug = Wrong Test Result !!!

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The significance of the test plug when testing… the Permanent Link in an installation or

… components for compliance in a laboratory

This is TRUE

The standards define the properties of a test plug

In the laboratory a set of test plugs – low / “centered” / high - is used to certify the compliance of a component

Testing with a compliant and “centered” test plug is a true foundation for a compliant link and channel without a test of the channel

A non compliant test plug could show “optimistic” results with a non-compliant jack. The odds are 50/50

This is NOT TRUE

A regular patch cord has a “centered” plug

A patch cord can be used to achieve reproducible results

A normalization process can be used to compensate for “non-centered” or “undefined” test plugs

A non-compliant cord represents a worst case scenario.

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Cat.6A = an other Cat.6 “Déjà Vu” ?

Definition of requirements and limits for the CHANNEL: Length,

Crosstalk, Reflections, Attenuation

Requirements for the Permanent LINK

Requirements for components: Plugs & Jacks (CHW),

Cables

Definition of the component test procedure

Range of

TEST PlugsCertification of compliant jacks

Definition for a PATCH CORD Test Head

TIA finished Feb.8, 2008 TIA-568B.2 Addendum 10

wich is based on Draft 10

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ISO/IEC Class EA = Cat.6 “Déjà Vu” ?

Definition of requirements and limits for the CHANNEL: Length,

Crosstalk, Reflections, Attenuation

Requirements for the Permanent LINK … DRAFT

Requirements for components: Plugs & Jacks (CHW),

Cables …DRAFT

Definition of the component test procedure

Range of

TEST PlugsCertification of compliant jacks

Definition for a PATCH CORD Test Head

Component Test Procedure: First DRAFT

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In the field:

• A PCB based test plug has proven to

provide reproducible results

• First version in 2001

• NEW version in 2007: DTX-PLA002

with a replaceable tip

In the laboratory:• The setup is very complex

• Typically many test plugs had to be sampled to

find the max. of 12 needed (Cat.6 / 250MHz)

• PCB based test plugs are a convenient and

reliable alternative

• The standards recognizes the benefit

of a PCB based test plug

If a test plug looks different from a patch cord

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Benefits of a rugged test plug with replaceable tips ?

1. The cost of ownership (COO) is

reduced significantly if only the

contact block needs replacing

2. A solid metal case will wear little.

…example shows a test plug

after 17780 insertions

3. There is no tab which might

break off

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Cat.6A and Class EA

what it is important to keep in mind ?

• Component specification were either finalized only recently or they are still in draft. TIA-568B Add.10 was finished only recently Feb.8”

The manufacturers warranty program will determine whether the Channel or Permanent Link is tested

• Certification of the CHANNEL could be important for “System Solutions” (single source)

• Performance margins will be significantly smaller than with Cat.6

• Alien Crosstalk is a parameter of large significance.

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0 100 200 300 400 500 600

TIA Cat.6a

10GBASE-T

Cat.6 CH

Cat.5e CH

1000BASE-T

MHz

dB

NEXT Anforderungen

Slim performance margins of early Cat.6A systems demand high accuracy from the field tester !

Better then Level-IIIe ?

• 1000BASE-T works with

Class.D/Cat.5e !

• 1000BASE-T allowed

„Room for Error“

or „…Optimism“

• 10GBASE-T gives little

room for error

• First 10G NICS are

expected for 2008 !

NEXT Requirement

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ISO/IEC 61935-1 defines requirements for field testers and laboratory equipment

Level Class Status

IIe D published

III E published

IV F published (June 2004)

IIIe “New” Class

EA

Requirements are nearly identical

with TIA-568B.2 Add.10.

Final Draft was voted “yes” in May

2007

Includes details about Alien Crosstalk

Testing

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Does a Level IV compliant tester automatically comply with Leve-IIIe requirements ?

NO !

• For Modular (RJ-45) connecting hardware Level-IIIe

compliance needs to be demonstrated independently

– Algorithms to compensate for the mated NEXT

Patch cord Tester

are more complex for modular/RJ-45 connecting hardware

– The standard clearly spells it out

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Is it justifiable to rely on test results if standards were published only recently or if parts of it still in a draft stage and typical performance margins very slim ?

• YES IF the Level-IIIe requirements are satisfied with plentiful of margin

– Level IIIe allows uncertainties of > 5dB !!!

• YES IF the accuracy requirements are exceeded for the Permanent Link as well as the CHANNEL Configuration

• YES IF detailed test and not just a statement of compliance from a reputable source is available

• YES IF a solid solution for the Permanent Link with “Centered” test plugs is available

Level IIIe requirement

Accuracy Margin

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Conclusion

1. Testing the permanent link should be the configuration

of choice if supported by the warranty program

2. The permanent link is a true foundation for a compliant

channel

3. The result from testing a permanent link can only be

relevant if the test plug is truly centered

4. Agreement on the test plug –between planner and

installer - will prevent debates in the case of failing link

5. A test plug with little variation from plug to plug will

provide consistent results

6. Requirements for the test plug can be considered stable

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THANK YOU FOR YOUR ATTENTION !

….. If you got any questions please do not hesitate to let us know

mailto:christian.schillab@flukenetworks.com

And remember….

Centered Test Pug

+ Better then Level-IIIe accuracy---------------------------------------------------------------------------------------------

= Reliable PASS/FAIL

information

PASSing Permanent Link

+ Compliant Patch Cords-----------------------------------------------------------------------

= Compliant Channel

= 10GBASE-T working

seamless

Random Test Plug = Random Test Result