National Communications System NCS Fiber Optic Networks

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National Communications System (NCS)Fiber Optic
Networks

• Dave Hotz
• Director of Systems Installation and Transmission
  Support
• Jim Chaney
• Director of Field Operations Central and West
• Global Crossing

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Fiber Cable
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Fiber Has More Capacity

• This single fiber can carry more communications
  than the giant copper cable!

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Fiber Optic Cable

• Protects the fibers wherever they are installed
• May have 1 to over 1000 fibers

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Fiber Optic Connectors

• Terminates the fibers
• Connects to other fibers or transmission
  equipment

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Fiber Optic Communications

• Applications include
• Telephones
• Internet
• LANs - local area networks
• CATV - for video, voice and Internet connections
• Utilities - management of power grid
• Security - closed-circuit TV and intrusion
  sensors
• Military - everywhere!

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What Is Fiber Optics ?

• Transmitting communications signals over hair
  thin strands of glass or plastic
• Not a "new" technology
• Concept a century old
• Used commercially for last 25 years

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Why Use Fiber Optics?

• Economics
• Speed
• Distance
• Weight/size
• Freedom from interference
• Electrical isolation
• Security

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Fiber Optic Applications

• Fiber is already used in
• gt 90 of all long distance telephony
• gt 50 of all local telephony
• Most CATV networks
• Most LAN (computer network) backbones
• Many video surveillance links

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Fiber Optic Applications

• Fiber is the least expensive, most reliable
  method for high speed and/or long distance
  communications
• While we already transmit signals at Gigabits per
  second speeds, we have only started to utilize
  the potential bandwidth of fiber

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Fiber Technology
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Fiber Technology
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Fiber Optic Data Links
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Light Used In Fiber Optics

• Fiber optic systems transmit using infrared
  light, invisible to the human eye, because it
  goes further in the optical fiber at those
  wavelengths

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Wavelength-Division Multiplexing
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Fiber Optic Applications

• Outside Plant vs. Premises Installations

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Fiber Optic Installation - Outside Plant
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Fiber Optic Installation -Premises
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SONET
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What is SONET?

• Synchronous Optical Network standard
• Defines a digital hierarchy of synchronous
  signals
• Maps asynchronous signals (DS1, DS3) to
  synchronous format
• Defines electrical and optical connections
  between equipment
• Allows for interconnection of different vendors
  equipment
• Provides overhead channels for interoffice OAMP

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Digital Signal HierarchiesMost Common Rates
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SONET Rates
Optical Designation
Bit Rate (Mb/s)
Level
STS-1 OC-1 51.840 STS-3 OC-3 155.520 STS-12 OC-1
2 622.080 STS-48 OC-48 2,488.320 STS-192
OC-192 9,953.280
STS SYNCHRONOUS TRANSPORT SIGNAL OC OPTICAL
CARRIER (..result of a direct
optical conversions of the STS after
synchronous scrambling - ANSI)
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SONET Network Layers
Services DS3, DS1, etc
Path
Line
Line
Section
Section
Section
Section
Physical (Photonic)

• E/O Conversion
• Line Code
• Physical Signal
• No additional overhead

DS3 etc
MUX
LTE
Regen
MUX
LTE
LTE
Regen
SONET ADM
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Functional Description of SONET Layers
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SONET Configurations
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Generic SONET Network Elements
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Key SONET Configurations
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Key SONET ConfigurationsLinear Office Sequences
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Key SONET Configurations
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Explanation of Wavelength Division Multiplexing
(WDM)
WDM System Multiple Signal Wavelengths
Conventional System Only 1 signal Wavelength
Transmission capacity per fiber is multiplied by
the number of Signal Wavelengths Technological
Difficulties - Signal multiplex/demultiplex -
Optical amplifier bandwidth limitation -
Inter-channel interaction due to optical fiber
non-linearity (four wave mixing and cross-phase
modulation)
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To get more information on a single fiber Use
more wavelengths (DWDM)
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(No Transcript)
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SONET Network Management
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Definition of a Ring

• A Ring is a collection of nodes (NE1, NE2, .)
• forming a closed loop.
• Each node is connected to two adjacent nodes
• via
• a duplex communications facility.
• A SONET Ring will provide
• Redundant Bandwidth
• Redundant Network Equipment
• or both

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SONET Ring APS(Automatic Protection Switching)

• Uni-directional Vs. Bi-directional Rings
• Two-Fiber Vs. Four Fiber Rings
• Ring Switching Vs. Span Switching

• Applications of
• Bi-directional Line Switched Ring (BLSR)
• Uni-directional Path Switched Ring (UPSR)

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Ring Classification

• A Unidirectional Line Switched Ring (ULSR)
• A Bidirectional Line Switched Ring (BLSR)
• A Unidirectional Path Switched Ring (UPSR)
• A Bidirectional Path Switched Ring (BPSR)

Any of the above type can be a two-fiber or a
four fiber ring. Therefore, for all practical
applications, SONET/SDH standards provide eight
types of ring for network node interconnections
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2 FiberUnidirectional Vs. Bidirectional Rings
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Two-Fiber Vs. Four-Fiber Rings
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Ring Switching 2-Fiber Ring
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Ring Switching 4-Fiber Ring
B Ring Switching Four-fiber ring
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Span Switching - 4-fiber Rings Only
Route before PS
Route before PS
A
B
A
B
Route after PS
C
D
B Ring Switching Four-fiber ring
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Bi-directional Line Switched RingNo Failures
w
C
B
A
A
W
P
w
P
P
A
D
B
B
P
P
w
w
P
F
E
C
C
w
Bidirectional Traffic
Unidirectional Traffic
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Bi-directional Line Switched RingSpan Switch
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Bi-directional Line Switched RingRing Switch
X
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Bi-directional Line Switched RingRing Switch -
Node Failure
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Bi-directional Line Switched RingNo Failures
W
C
B
W
P
W
P
P
A
D
P
P
W
W
P
F
E
W
Original Circuits (Both Slot 2)
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Bi-directional Line Switched RingNeed For
Squelching
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Bi-directional Line Switched RingDouble Ring
Failure (No Recovery)
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SONET Rings will fail -- The question is When?

• Initial estimates of DWDM hardware show that it
  is 8 times more reliable than WDM equipment
• POEs not included
• Ring reliability is dependent upon ring mileage
• Ring sizes vary from 200 miles to 2800 miles
• Ring Failures
• Given 100, 1000-mile perimeter rings
• Current optimistic estimation is 1 network ring
  failure every 5 yrs
• PCIs not included
• Most probable cause of a complete ring failure is
  an equipment failure and a fiber cut
• Physical diversity violations in some rings
  (single-pt-of-failure)

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Ring InterworkingInterconnect Problem (No
Recovery)
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Dual Ring Interworking(Unidirectional A gt Z
Circuit)No Failure
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Dual Ring Interworking(Unidirectional A gt Z
Circuit)ADM Failure
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Dual Ring Interworking(Unidirectional A gt Z
Circuit)Office Or Double ADM Failure
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Other Types Of SONET Self-Healing Rings(2-Fiber
Unidirectional Line-Switched Ring)
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Other Types Of SONET Self-Healing Rings(2-Fiber
Unidirectional Line-Switched Ring)
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Other Types Of SONET Self-Healing Rings(2-Fiber
Bi-directional Line-Switched Ring)
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BITS
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(No Transcript)
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Clock Accuracy Levels
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Sync Status Message
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SS Messages
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(No Transcript)