the shunted ring fault tolerant network physical … · the shunted ring fault tolerant network...

Drew GlistaNaval Air Systems [email protected]

THE SHUNTED RINGFAULT TOLERANT NETWORK

PHYSICAL LAYER

• BEST SUITED TO OPTICS

• LARGE NUMBER OF TERMINALS POSSIBLE

• COMFORTABLE POWER BUDGET

• LOW SENSITIVITY AND DYNAMIC RANGE RECEIVERS

• LOW COST

ADVANTAGES

ISSUES

• NODE AND CABLE FAILURES

• REQUIRES BYPASS MECHANISM

• POWER BUDGET FOR SUCCESSIVE BYPASSES

• DUAL COUNTER ROTATING TOPOLOGY LIMITATIONS

• DATA LOSS AND RESTORATION TIME

• WDM “ALL OPTICAL” IMPLEMENTATION

FIBER OPTIC RING TOPOLOGY

1 MILISECOND = 1,000 BITS @ 1MBPS1 MILISECOND = 1,000,000 BITS @ 1GBPS1 MILISECOND = 10,000,000 BITS @ 10GBPS

1 MICROSECOND = 1 BIT @ 1 MBPS1 MICROSECOND = 1000 BITS @ 1GBPS1 MICROSECEND = 10000 BITS @ 10GBPS

1 NANOSECOND = 1 BITS @ 1GBPS1 NANOSECOND = 10 BITS @ 10GBPS

As Network Speeds Increase, Slow Bypass SwitchesCan Cause Significant Loss of Data During Reconfiguration

Speed and long Term Reliability of Electro-Mechanical Bypass Switches Can Adversely Impact Network Data Availability

BYPASS SWITCH SPEED = LOST DATA

• The Shunted Ring Topology uses Passive Optical Fiber to Bypass Terminal Faults and high Speed Electronic or Optical Switching to Reconfigure the Network.

• Shunted Ring Networks can Eliminate or Minimize Data Loss without Disruption of Service With ReducedReconfiguration Time

• Shunted Ring Networks Provide Fault Prediction,Detection, Isolation and Circumvention with EnormousLife Cycle Cost Savings.

• Shunted Ring Networks can Reduce Latency and EnhancePerformance through Feedforward Options.

SHUNTED RINGTOPOLOGY

DATA FROMTERMINAL

N-1

DATA FROMTERMINAL

N-2

DATA TOTERMINAL

N+1

PRIMARY PHOTODIODE

SWITCHED PHOTODIODE TRANSCEIVER

PRIMARY FIBER

BYPASS FIBER

DATA TOTERMINAL

N+1

PRIMARY FIBER

BYPASS FIBER

PASSIVE BYPASSFIBER PATH

THROUGH NODE

1X2COUPLER

THRESHOLDCOMPARATOR/

SWITCH

BYPASS

PHOTODIODE

LASER

DATABUFFER

AND MEMORYLOGICDECODE/ENCODE

• DATA ARRIVES AT N+1 NODE VIA BYPASS NODEPRIOR TO ARRIVAL ON PRIMARY FIBER DUE TO REPEATER DELAY AT NTH NODE

• THIS DATA CAN BE STORED IN A BUFFER (OR OPTICAL DELAY LINE) AT THE N+1 NODE

• IF THE NTH NODE FAILS, THE BUFFERED DATA STREAM IS SWITCHED INTO THE N+1 ACTIVE CIRCUIT FOR TERMINAL USE OR REPEATEREDTRANSMISSION

• THE FAULT DETECTION OCCURS DOWNSTREAM FROM THE ACTUAL FAULT

• PROVIDES A BUILT-IN- TEST MECHANISM AT THEPHYSICAL LAYER BASED ON DESIRED CRITERIA

SHUNTED RING NETWORK TOPOLOGYBypasses Node Failure - Including Power Loss At Node

DATA OUT DATA IN

SWITCHEDPHOTODIODE

TRANSCEIVER

1 X NCOUPLER

PRIMARY FIBER

BYPASSFIBER

LASER

NODESNODES

VCSEL ARRAY

ALTERNATE “SKIP-A-NODE” IMPLEMENTATIONVCSEL Array Replaces Coupler

COUNTER-ROTATING SKIP-A-NODE RINGS

REDUNDANTCABLES FC1 FC2 FC3EC1 EC2 EC1

FC = FLIGHT CONTROL COMPUTEREC =ENGINE CONTROL COMPUTER

SINGLECABLE

Bi-Directional Ring “Skip-A-Node” Ring

CLOCKWISE DATA FLOW

COUNTER-CLOCKWISEDATA FLOW

CROSS CHANNELDATA LINK

MICROCHIPCOUPLER SMART PIXEL

ARRAY

A SINGLE “SMART PIXEL” CHIP PROVIDES NETWORK RECONFIGURATION AND BYPASS CONTROL

FROM TERMINALN-1

FROM TERMINALN-2

FROM TERMINALN-3

PRIMARYFIBER

TO TERMINALN+1

BYPASSFIBER

SECONDARYBYPASS

TO TERMINALN+1

TO TERMINALN+2

I/O

A DUAL BYPASS NODE

SWITCHED TRANSCEIVER

1 X 3COUPLER

D1

PASSIVE FIBER BYPASSPATH THROUGH 2 NODES

D2

D3

D1

D2

D3

D1

D2

D3

D1

D2

DUAL BYPASS RING TOPOLOGYWorse Case Loss Budget ˜ 1XN Star Topology Budget• Provides a Circuit-switched Subnet in a Packet Ring• Provides a Switch Selectable Broadcast Option

VV

12

VV

12

VV

12

THRESHOLD COMPARATOR

PLANARSILICA ON SILICON

COUPLER

RIBBONCABLE

BITCKTS

LOGICSWITCH

I/O

LASER

MEMORY

LOGICTHRESHOLD

BITTHRESHOLD

MARGIN

V2=

V1=

NOTIONAL “SMART” TRANSCEIVER

ARRAYCONNECTOR

TO NODE N+1

TO NODE N+2

TO NODE N+3

BUFFER

DT

TTT

D D

N

N-1

N+1

N+2

1 2 3

LOW

LOW

LOW

LASER DEGRADING N-1 LASER FAILED

DT

TT

T

D D

N

N-1

N+1

N+2

1 2 3

LOW

NORMAL

NORMAL

PRIMARY LINK N-1 to N DEGRADING

DT

TT

T

D D

N

N-1

N+1

N+2

1 2 3

NORMAL

NORMAL

OFF

BROKENPRIMARY FIBER

N-1 TO N

DT

TT

T

D D

N

N-1

N+1

N+2

1 2 3

OFF

OFF

OFF

DT

TT

T

D D

N

N-1

N+1

N+2

1 2 3

NORMAL

OFF

OFF

BROKENPRIMARY FIBER

N-2 TO N-1

DT

TT

T

D D

N

N-1

N+1

N+2

1 2 3

NORMAL LOW

NORMAL

SECONDARYLINK DEGRADING

N-1 TO N

FAULT DETECTION AND PREDICTION

SIGNAL LEVEL

TER

MIN

AL

SIGNAL LEVEL SIGNAL LEVEL

SIGNAL LEVEL SIGNAL LEVEL SIGNAL LEVEL

TER

MIN

AL

TER

MIN

AL

TER

MIN

AL

TER

MIN

AL

TER

MIN

AL

VV

12

VV

12

VV

12

THRESHOLD COMPARATOR

RIBBONCABLE

BITCKTS

LOGICSWITCH

I/OMEMORY

LOGICTHRESHOLD

BITTHRESHOLD

MARGIN

V2=

V1=

NOTIONAL “SMART” TRANSCEIVER

VCSEL ARRAY

ARRAY CONNECTOR

TO NODE N+1

TO NODE N+2

TO NODE N+3

BUFFERREGISTERS

COUNTER-ROTATING RINGSSingle Bypass - One Source

Bi-Directional Single Bypass Ring

Bi-Directional “Skip-a-Node”Ring

CLOCKWISE DATA FLOW


ELECTRICALCROSS CHANNEL

DATA LINK

MICROCHIPCOUPLER

SMART PIXELARRAY


N+1

N+2

BYPASSTO N+1

N-1

NODE FAILURES AUTO-SWITCH TO BYPASS FIBER

BROKEN CABLEAUTO-LOOPBACK

TWO BROKEN CABLESTWO SEPARATED RINGS

TWO SUCCESSIVE FAILURESAUTO-LOOPBACK

COUNTER-ROTATING RINGSSingle Bypass - Two Sources

Bi-Directional Dual Bypass Ring

ELECTRICALCROSS CHANNEL

DATA LINK


CLOCKWISE DATA FLOW


MICROCHIPCOUPLER

SMART PIXELARRAY

OPTICALAMPLIFIER

OPTICALSWITCH

OPTIONAL DELAY

SIGNALIN

SIGNALOUT

“ALL OPTICAL” TERMINAL

LASER

SIGNAL FROMTERMINAL N-1

PRIMARY SIGNAL TO TERMINAL N+1

BYPASS SIGNAL TO TERMINAL N+2


1 X 2COUPLER

THRESHOLDCOMPARATOR

OPTICALSIGNAL FROMTERMINAL N-2

LASER

PHOTODIODES

SIGNAL TOTERMINAL

SIGNAL FROMTERMINAL

OPTICALSIGNAL FROMTERMINAL N-1

INTEGRATED OPTICSWITCH

SIGNAL TOOPTICAL AMPLIFIER

ALL OPTICAL TERMINAL DUAL BYPASS

OPTICALAMPLIFIER

OPTICALSELECTLOGIC

1 X 3COUPLER

PRIMARY SIGNALTO TERMINAL N+1

BYPASS TOTERMINAL N+1

BYPASS TOTERMINAL N+2




RING 1

RING 2

RING N

RING 3

MULTI-RINGCONNECTIVITY

• Bypass Multiple Node or Cable Failures

• Detect, Isolate, and Circumvent Faults in Real Time

• Eliminate or Minimize Data Loss During Reconfiguration

• Circumvent Power Failure at a Terminal via the Passive Bypass Fiber

• Detect/Remove Babbling or "stuck-on" Terminals

• Built-in Failure Prediction of Active and PassiveComponents

• Diagnostics at the Physical Layer of the Network

• Auto - Loopback For Cable Cuts

• Reconfiguration Initiated Up or Down Stream from Failure

RELIABILITY BENEFITS

• Inherent Built-in-Test

• Preventive Maintenance ThroughFailure Prediction

• Hot Swap of Failed Terminal Modules

• Built-In Spare Fibers

• Minimal Loss of Service

MAINTAINABILITY BENEFITS

• Topology Permits Distributed Bandwidth

• High Speed Recovery

• Single Mode or Multi-Mode

• Scalable to “All Optical” and WDM Implementation

• Accelerates Message Passing by Bypassing Intermediate Repeaters

• Uni-directional or Bi-Directional Transmission

• Analog or Digital Implementation

• In-line Bit Error Detection and Correction

PERFORMANCE BENEFITS

• Rapid Reconfiguration with Available Electricalor Optical Switch Technology

• Redundant Fiber Paths to Overcome Fiber Damage

• Feedforward/Feedback Paths for Congestion Control

• Anticipatory Decoding of Header Fields to RapidlyConfigure Virtual Circuits

• Compatibility with Most Network Protocols

• Comfortable Power Budget for LAN Applications

PERFORMANCE BENEFITS

A B C D

E

F

G

H

F

G

H

E

A B C D

0 1 2 3

4 5 6 7

8 9 10 11

12 13 14 15

01

2

3

4

5

6

789

10

11

12

13

14

15

EQUIVALENT CONNECTIVITYA RING CAN IMPLEMENT A MESH TOPOLOGY OR ANY SUBSET THEREOF

GENERATION II PHOTONIC HARDWARE IS THE AFFORDABLE ENABLER

GENERATION II HARDWARELOW COST ENABLERS

VERTICAL CAVITY/TUNABLE LASERS

3.0

Guide Pins

8.0

2.0

6.4

2.5

0.7

7.0

0.250

Fiber Ribbon

SMALL FORM FACTOR ARRAY CONNECTORS

RIBBON CABLES

AIR BLOWN FIBER

Silicon Substrate

Silicon Waveguide

Single opticalmode

Thermal silicacladding

Buried oxide

PLANAR WAVEGUIDES

FunctionalElements

OpticalBackplane

ElectricalBackplane

OPTICAL BACKPLANES820n

m

895n

m

1550

nm

1574

nm

COARSE WDM DENSE WDM

REFERENCES

Glista, A.S. "Fault Tolerant Topologies for Fiber Optic Networks and Computer Interconnects Operating in the Severe Avionics Environment", IEEE Journal of Lightwave Communications Systems, February, 1991.

Glista, A.S.“A Shunted Ring Fiber Optic Network Topology Providing Fault Detection, Isolation and Circumvention”, IEEE NAECON, May 1993

Glista, A.S., “Optical Interconnects:Topology and Protocol issues”, SPIE OE/Lase ‘94, Jan,1994

Fault Tolerant Fiber Optic Coupler/Repeater for Use in High Speed Data Transmission and the Like (Grants Number 4,837,856 and 5,229,875.)

the shunted ring fault tolerant network physical … · the shunted ring fault tolerant network...

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