1IEEE 802.3ba – Jan 2008

802.3ba Cu specifications

Chris Di Minico MC Communicationscdiminico@ieee.org

2IEEE 802.3ba – Jan 2008

Contributors •Galen Fromm, Jim McGrath - Molex•Jens Aumann, Leoni High Speed Cables•Vivek Telang, Broadcom

3IEEE 802.3ba – Jan 2008

Supporters •Dan Dove, ProCurve Networking by HP•Shimon Muller, Sun Microsystems

4IEEE 802.3ba – Jan 2008

Presentation objectives •Considerations for 802.3ba Cu specifications for baseline proposal.

•Measurement models and simulation models in development to evaluate usage of 10GBASE-KR (Clause 72) for 10 Gb/s lane options for both 40GBASE-CR4 and 100GBASE-CR10 cable assemblies.

•QSFP cable connector and 10 meters of twinaxial cable considered for 40GBASE-CR4 cable assemblies.

5IEEE 802.3ba – Jan 2008

• Support full-duplex operation only• Preserve the 802.3 / Ethernet frame format utilizing the 802.3 MAC• Preserve minimum and maximum FrameSize of current 802.3 standard• Support a BER better than or equal to 10-12 at the MAC/PLS service

interface• Provide appropriate support for OTN

• Support a MAC data rate of 40 Gb/s• Provide Physical Layer specifications which support 40 Gb/s operation

over:– at least 100m on OM3 MMF– at least 10m over a copper cable assembly– at least 1m over a backplane

• Support a MAC data rate of 100 Gb/s• Provide Physical Layer specifications which support 100 Gb/s operation

over:– at least 40km on SMF– at least 10km on SMF– at least 100m on OM3 MMF– at least 10m over a copper cable assembly

802.3ba objectives

6IEEE 802.3ba – Jan 2008

40GBASE-CR4 and 100GBASE-CRn link

Cable assembly

MDIMDI

100GBASE-CRn or

40GBASE-CR4

TransmitFunction

Signal shield

Signal<p>

Signal<n>

Link shield

Lane n

100GBASE-CRn or

40GBASE-CR4

ReceiveFunction

7IEEE 802.3ba – Jan 2008

• Evaluate usage of 10GBASE-KR (Clause 72) and 10GBASE-CX4 to specify 40GBASE-CR4 and 100GBASE-CR10

– For commonality with 40 Gb/s backplane proposal:• 64b/66b PCS• Signaling speed 10.3125 Gbd (per lane)• Optional FEC sublayer (TBD)

• Evaluate usage CX4 for commonality with twinaxial cable assembly usage and specifications (plug-and-play over all specified distances)

• S-parameters (+ additional parameters i.e., group delay, etc..)

• QSFP MSA – 10 Gb/s lane operation demonstrated up to 10 meters of twinaxial cable

• Group delay differences between backplane and twinaxial cable assemblies (64b/66b spectra versus 8b/10b)

Cu cable assembly baseline proposal

8IEEE 802.3ba – Jan 2008

• Support a MAC data rate of 100 Gb/s• Provide Physical Layer specifications which support

100 Gb/s operation over:– at least 10m over a copper cable assembly– 10 x 10 Gb/s lane– 4 x 25 Gb/s lane (TBD)– 5 x 20 Gb/s lane (TBD)

• Support a MAC data rate of 40 Gb/s• Provide Physical Layer specifications which support

40 Gb/s operation over:– at least 10m over a copper cable assembly– 4 x 10 Gb/s lane

Copper cable assembly: PHY lane options discussed

9IEEE 802.3ba – Jan 2008

•S-parameters are sufficient to specify interconnect-induced signal impairments e.g.,•Measured:

-Insertion loss -Return loss-Crosstalk

-NEXT -FEXT

•Computed:-PSNEXT-PSELFEXT

•Limits: -Measurement based-InfiniBand

S-parameter interconnect specifications

For 10GBASE-CX4 - All cable assembly measurements are to be made between TP1 and TP4 as shown in the Figure illustrated above.

10GBASE-CX4 Cable assembly

10IEEE 802.3ba – Jan 2008

•Channel measurement reference: TP1 to TP4. 802.3ap Channel Parameters

•MeasuredInsertion Loss NEXTFEXTReturn Loss

•ComputedInsertion loss deviation Insertion loss to crosstalk ratioPSNEXT, PSFEXT, PSXT

•LimitsTo support existing platforms (ATCA)

11IEEE 802.3ba – Jan 2008

•Infiniband Copper

•Annex A5: Pluggable Interfaces: CATx, Copper and Optical-Pluggable QSFP FOR 4x, 8x and 12x -Multiple 4x QSFP pluggables used for 8x or 12x links

Cable board connector – QSFP - 38 ckt

QSFP Connector: 38-contact, right angle surface mount connector

QSFP Module SFF-8436

32 - QSFP Ports1U rack space

Source: Molex

12IEEE 802.3ba – Jan 2008

Tx R2

TxRx

4 near-end crosstalk Disturbers

multi-disturber NEXT

Insertion loss,

Tx3 far-end crosstalkdisturbers

multi-disturber FEXTRx

+

802.3ap – channel parameter comparisons•Insertion loss to crosstalk ratio (ICR) computed from S-parameter measurements and models of QSFP 10 meter copper cable assembly (24 AWG).

13IEEE 802.3ba – Jan 2008

802.3ap IL limits vs 10 m QSFP cable assembly 24 AWG including test fixtures

0

5

10

15

20

25

30

0 1000 2000 3000 4000 5000 6000

GHzdB

Tx1_IL-cable assembly+ pcb test fixture loss

A(f)-Least Squares Fit

Amax(f)-802.3ap

ILmax(f)

10GBASE-KRfmin=0.05 GHzfmax=15.00 GHzf1=1.00 GHzf2=6.00 GHzfa=0.100 GHzfb=5.15625 GHz

A(f) fitted attenuation limitf1=1.00 GHzf2=6.00 GHz

Amax(f) max attenuation limit f1=1.00 GHzf2=6.00 GHz

ILmax(f) limitfmin=0.05 GHz≤ f2=6.00 GHz

802.3ap recommends that A(f) ≤ Amax(f) f1=1 GHz to f2=6 GHz

802.3ap recommends that IL(f) ≤ ILmax(f) fmin=0.05 to f2=6 GHz

14IEEE 802.3ba – Jan 2008

802.3ap ICR limits versus 10 m QSFP cable assembly 24 AWG including test fixture

0

20

40

60

80

100

120

0 1000 2000 3000 4000 5000 6000

GHz

dB

ICRmin(f)

ICRfit(f)

ICR(f)

Tx1_IL-cable assembly+ pcb test fixture loss

PSNEXT(f)

PSFEXT_scaled

PSXT(f)

SDD12_NEXT_Tx1Rx1

SDD12_NEXT_Tx2Rx1

SDD12_NEXT_Tx3Rx1

SDD12_NEXT_Tx4Rx1

SDD12_FEXT_Tx1Rx2

10GBASE-KRfmin=0.05 GHzfmax=15.00 GHzf1=1.00 GHzf2=6.00 GHzfa=0.100 GHzfb=5.15625 GHz

A(f) max attenuationf1=1.00 GHzf2=6.00 GHz

PSNEXT(f) - 4 disturbers

ICRmin(f) fa=.100 GHzfb= 5.15625 GHz

ICRfit(f) fa=.100 GHzfb= 5.15625 GHz

PSFEXT(f) - 3 disturbers

PSXT(f) - 4 NEXT + 3 FEXT

802.3ap recommends that ICRfit(f)≥ ICRmin(f) fa=0.100 to f2=5.15625 GHz

15IEEE 802.3ba – Jan 2008

802.3ap RL limits vs 10 m QSFP cable assembly 24 AWG including test fixture

0

5

10

15

20

25

30

35

40

45

50

10 100 1000 10000

GHz

dB

SDD11-Tx2_RL

SDD11-Tx2_RL

RL(f)

16IEEE 802.3ba – Jan 2008

802.3ap ILD vs 10 m QSFP cable assembly 24 AWG including test fixtures

-5

-4

-3

-2

-1

0

1

2

3

4

5

0 1000 2000 3000 4000 5000 6000 7000

GHz

dB

ILD(f)

ILDmin(f)

ILDmax(f)f100.51.0(f)ILDILD(f) 9

min−×−−=≥

f100.51.0(f)ILDILD(f) 9max

−×−=≤

17IEEE 802.3ba – Jan 2008

Simulation Setup• Insertion Loss, Return Loss, Crosstalk per data from Chris

DiMinico• Package models based on measured data• Receiver architecture same as that used in KR group (802.3ap)• MATLAB simulations

– Pulse Response “Frequency-domain” Analysis, with MMSE optimization

• Performance evaluation based on detailed, worst-case error probabilities (not simple Gaussian assumption)

• On-chip impairments included– Clock jitter, Offsets, Front-end noise, Detailed analog circuit

models, Detailed equalizer implementation penalties• Worst-casing of ISI data patterns and crosstalk phase

Source: Vivek Telang, Broadcom

18IEEE 802.3ba – Jan 2008

Channel models

Source: Vivek Telang, Broadcom

19IEEE 802.3ba – Jan 2008

18.5SNR (dB)

Slicer SNR & BER

1.4x10-17

BER

Simulation results

Source: Vivek Telang, Broadcom

20IEEE 802.3ba – Jan 2008

dB

dB

dB

dB

dB

dBUnit

TBD

TBD

TBD

TBD

TBD

TBDValueDescription

40GBASE-CR4 and 100GBASE-CR10 cable assembly•Cable assembly differential parameters

f

TBDfTBDfTBDfLossInsertion +×+≤)(

TBDfReturnLoss ≥)(

×−≥TBDfTBDTBDfNextLoss log)(

×−≥

TBDfTBDTBDfMDNextLoss log)(

×−≥TBDfTBDTBDfELFEXT log)(

×−≥TBDfTBDTBDfMDELFEXT log)(

21IEEE 802.3ba – Jan 2008

Source: ganga_02_1107.pdf

Possible 40 Gb/s Layer Diagram

22IEEE 802.3ba – Jan 2008

Possible 100 Gb/s Layer Diagram

Source: ganga_02_1107.pdf

23IEEE 802.3ba – Jan 2008

Cu link diagrams

MDI

n pair Twinaxial cable

n=4,10,…

TP1 TP2 TP3 TP4

CRntransmit function

cable assembly

MDI

CRnReceive FunctionIncluding

AC –coupling

PMDPMD

PMDService Interface

PMDService Interface

Tx_bit<> Rx_bit<>

backplane connector

x4 backplane

TP1TP4

KR4transmit function

Backplane channel

KR4Receive FunctionIncluding

AC –coupling

PMDPMD

PMDService Interface

PMDService Interface

Tx_bit<> Rx_bit<>

24IEEE 802.3ba – Jan 2008

40GBASE-?Rn optical link diagram – OM3 Fiber

MDI

TP2 TP3

?RnOptical

transmit function

optical fiber cable

?RnOptical Receive Function

PMDService Interface

PMDService Interface

Tx_bit<> Rx_bit<>

MDI

patch cord

25IEEE 802.3ba – Jan 2008

Conclusions•Measurements of 10 meter QSFP cable assembly compared to 10GBASE-KR (Clause 72) channel parameter limits used to validate 10 Gb/s lane operation over 10 meter QSFP cable assembly for 40GBASE-CR4.

•CX4 twinaxial cable assembly differential parameters proposed as basis for 40GBASE-CR4 and 100GBASE-CR10 link specification (i.e., S-parameters).

26IEEE 802.3ba – Jan 2008

Backup

27IEEE 802.3ba – Jan 2008

Test points

MDI

Twinaxial cable

TP1 TP2 TP3 TP4

Tx package pcb

Txdriver

Rxslicer

Rx packagepcb

Rx attributes e.g.,

equalization,AC coupling

backplane

TP1

backplane connector

backplane channel

TP4

Txpackage pcb

Txdriver

Rxslicer

pcbTx attributes

e.g., pre-emphasis

Rx attributes e.g.,

equalization,AC coupling

Rx package

cable assembly

MDI

Tx attributes e.g.,

Pre-emphasis

28IEEE 802.3ba – Jan 2008

Cu cable assembly channel model

cable

TP1

MDI

Cable assembly

TP4

Txpackage pcb

Txdriver

Rxslicer

pcbTx attributes

e.g., pre-emphasis

Rx attributes e.g.,

equalization,AC coupling

Rx package

-Cable board connector – QSFP-10 meters - 24 AWG – twinaxial cable

4_7nf.s4p – 10nf.s4p

http://www.ieee802.org/3/ap/public/channel_model/index.html#Package%20Models

Worst-case Package Model (*.zip) Richard Mellitz

Spec_RL_pkg_802_3.s4pSpec_RL_pkg_802_3.s4p

Spec_RL_pkg_802_3.s4p

29IEEE 802.3ba – Jan 2008

Cable – 24 AWG twinaxial

Source: Leoni High Speed Cables

Insertion Loss-10 m-24 AWG

0

20

40

60

80

100

120

140

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

MHz

dB

SDD12-PR1

SDD12-PR2

SDD12-PR3

SDD12-PR4

SDD12-PR5

SDD12-PR6

SDD12-PR7

SDD12-PR8