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
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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
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Agenda
10Gigabit Ethernet
What are we testing ?
Testing Models and Connectivity
Significance of the test plug
Accuracy
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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
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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
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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:[email protected]
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
