How will Cat 8 redefine the limits of copper? - Ravi Doddavaram Psiber Data
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How will Cat 8 redefine the
limits of copper?
Ravi Doddavaram
Psiber Data
rdoddavaram@psiber-data.com
Traditional Datacenter Topology
Still Not Interesting
40 Gbps (LOM) or LAG
10 Gbps(LOM) Romely for instance
Virtual NICs push bandwidth
requirements on Servers/Access
LAN/SAN Convergence
SAN is the biggest driver
for bandwidth
Most of the adoption for
40GBase Technologies are
driven from here
FCoE will enable a unified
network architecture if Media
supports, and no cost penalty
LAN/SAN Convergence
SAN is the biggest driver
for bandwidth
Most of the adoption for
40GBase Technologies are
driven from here
FCoE will enable a unified
network architecture if Media
supports, and no cost penalty
Virtualization will make the
figure on the right look like a
big cloud!
“Datacenter Networks are in my way!”
What is driving 40G on Copper/Fiber?
Change in Data Center Topology
Moving away from traditional 3 Tier to 2 Tier
(more virtualization)
LAN/SAN convergence (Storage Speeds far
exceed Network speeds)
Growth of 10G Base-T
LOM Integration of 10G
Cost of Base-T solution is significantly cheaper
than SR solution when possible
New on board 10G servers (like the Intel
“Romley” based servers with 10G MACs)
28nm Technology driving power down
(1.5W/10GBase-T port)
Why Base-T even today? Source of pricing: Aquantia
Why Base-T even today? Source of pricing: Aquantia
What we learnt from 10GBase-T
40G Pit Falls
Adoption will depend on three criteria
Power Consumption
With 28nm Technology, power ratio is about 2:1 as fiber
IEEE has taken this into consideration hence higher
bandwidth of cabling (Next slide)
Reach objective
Not a 90m link, but should support longer length than DAC
Advantage of 40GBase-T for supporting 30m reach (EoR, MoR)
configuration
Cost per Gb and utilization efficiency
DAC supports up to 7m but utilization efficiency is poor
Active links are expensive
LOM of 10G will drive cost per Gb down
Power Consumption Issue: Addressed with
higher bandwidth
40G Base-T Class I, 1.6 GHz 40G Base-T Class II, 1.6 GHz
Source: ISO11801-99-1Current status of Standards
• IEEE 802.3 NGBASE-T Study Group has become the IEEE P802.3bq 40GBASE-T Task
Force. The task force has commenced their work in the creation of a draft standard
for 40GBASE-T. Expected by Feb’2016. Work has begun in defining the PHY
specification
• IEEE is influencing alignment between TIA TR-42.7 and ISO/IEC JTC 1/SC 25/WG 3 on
specifications for cabling systems being developed for use with 40GBASE-T
• Current draft of TIA 568 C.2 for CAT 8 is 0.9. Defined most parameters for cabling
including Frequency, Channel performance
• Liaison from IEC TC46/WG9 to IEC SC25/WG3 for 2GHz Field Testing to be sent soon,
draft is agreed upon
• Field Tester standard, Level 2G task group has been establishedTIA Category 8
1 MHz to 2000 MHz
Support for 40GBASE-T (IEEE P802.3bq)
Insertion Loss (IL) is critical parameter
30m Channel Length, 26m Permanent Link Length
Approx. 55% of ChannelsTIA Cabling for IEEE 802.3 40GBASE-T (draft)
Class I Class II
2000 MHz 2000 MHz
New & New &
Improved Cat6A Improved Cat7A
Components Components
30m 30m
2 Connectors 2 ConnectorsTIA Insertion Loss Limit
0 200 400 600 800 1000 1200 1400 1600 1800 2000
0.00
5.00
10.00
15.00
Cat 8*
20.00
25.00
30.00
35.00
40.00
45.00
50.00
55.00
Cat 5e Cat 6 Cat 6A
60.00
*CAT8 limits are
TIA Cat 8 CH IL TIA Cat 6A CH IL TIA Cat 6 CH IL TIA Cat5e CH IL
based on early draftISO Cabling for IEEE 802.3 40GBASE-T (draft)
Cat7A Cat7A Class I Class II
1000 MHz 1600 MHz 2000 MHz 2000 MHz
Standardized New & New &
Standardized
Improved Improved
Cat7A Cat7A Cat6A Cat7A
Components Components Components Components
25m 30m 30m 50m
2 Connectors 2 Connectors 2 Connectors 2 ConnectorsISO Class I / Class II : Insertion Loss Limit
0 200 400 600 800 1000 1200 1400 1600 1800 2000
0
5
10
FA 40G* Class I*
15
20
25
30
35
40
45
50 FA
55
60
65
D E EA F Class II*
70
ISO Class I CH IL ISO Class II CH IL ISO 40G CH IL ISO FA CH IL
*limits are based on
ISO F CH IL ISO EA CH IL ISO E CH IL ISO D CH IL
early draftTypical CAT 8 Measurements The next few slides present an experiment done in Singapore with a prototype cable that qualifies for the draft ISO specifications in National Metrology Center (NMC) The experiment correlates the measurements done on the cable using a laboratory Network Analyzer in NMC and a field tester Results were published in TIA, ISO and IEEE meetings and extremely well received
Test Setup
Test Adapters & Calibration Artifacts
THRU / OPEN / SHORT / LOADMeasurement Setup with Network Analyzer
Measurement Setup with Field Tester
SeminartitelReturn Loss 17.08.2007 Seite 22
Near End Crosstalk
Insertion Loss
Known Issues with high frequency cable designs Insertion Loss suck outs • Typically seen in screened systems above 1300 MHz. • Usually the cause is the improper shield termination to connectors, or shield lay-lengths.
Alien Crosstalk Field Measurements
Alien Crosstalk Measurements
UTP Cable ANEXT
-40 0 200 400 600 800 1000 1200 1400 1600 1800 2000
-60
"12-12-NA"
-80 Pair_12-12-WX
-100
-120
F/UTP Cable ANEXT
-50
0 200 400 600 800 1000 1200 1400 1600 1800 2000
-60
-70
-80 "36-12 -NA"
-90 Pair_36-12-WX
-100
-110
-120Alien Crosstalk: Is it still the white Elephant?
Still a very key measurement for 10G Base-T installations. Several installation
issues go un-noticed
Field testing doesn’t have to be complex anymore
One of the few measurements that directly correlates to BER (application
bandwidth). TCL, ELCTCL are secondary effects which show up as Alien
Crosstalk or Near End Crosstalk
Perhaps not so important in the shielded world (Realm of CAT 8) but work still
in progressAdditional Measurements?
ELTCL, LCTCL, Coupling Attenuation
• Measure of balance of the twist of cabling and noise rejection of the cable
• Not very meaningful in the field because it is a inherent property of the cable
or connector, not much can be done in the field to rectify it
• Will be interesting to see how repeatable the measurements are with different
common mode impedances of different cables in the field
• A fault in ELTCL, Coupling Attenuation will always result in a NEXT, Alien
Crosstalk failure. Instead of tightening limit for a new measurement might as
well look at the NEXT performance
• ISO/IEC liaison letter to TC46 requests the committee the need to evaluate
suitability of this measurement in the field along with Coupling attenuation
measurementEnd to End testing: Concept
Existing configuration Additional Test Configuration
Channel under
Test
Field Tester Field Tester
Comparison with network analyzer is a problem due to soft de-embedding in
channel testing
Issue typically seen at higher frequencies
Proposal to include “Patch cord” type test configuration for CAT 8 cables
Widely supported but no additional effort required as Field testers already
support “Patch Cord configuration”The End
Psiber Data is an active member on both TIA & ISO Cabling committees.
Level V Field Tester Standard expected soon
(All of us field test manufacturers claim compliance, but the standard
is still in draft state)
Discussion on Level 2G has started (Please note the difference in the name
no more level IV, V)
Thank you
Please email your questions & comments to rdoddavaram@Psiber-data.comYou can also read
