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Optical Transport Network

Tri Phung

How is it deployed?

March 19, 2002

Topics

� ADM (Add / Drop Multiplexer) Overview

� Network and Network Facilities

� Network Deployment Process

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March 19, 2002

ADM - Classic vs New Generation

� Chassis– Rack, Shelves, Slots, Fiber management

� Typical Circuit Packs– Supportive/auxiliary: Control, NetSync,

Orderwire, Network Interface Card (NIC, e.g. Ethernet), Async, I/O, Circuit breakers, Fan, Air duct

– Network related: Switch, Tributary

� General Engineering Rules– Limitation: slot, protection, capacity– Timing source, signal

March 19, 2002

ADM Rack� A rack houses shelves

� Two common types of racks– ANSI (American Standard) - mostly– ETSI (European Standard)

ETSI 7.22’x19”x12”ANSI 7’x23”x12”

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March 19, 2002

ADM - Shelves, Slots

� Typically each NE is subdivided to shelves

� Each shelf has slots where circuit packs can be installed.

� Sometimes slots are specific, other times not

� Normally there are 3 types of slots holding:– Auxiliary circuit packs– High speed circuit packs– Tributary (low speed) circuit packs

March 19, 2002

ADM Example (OC-192 ADM)

Control Shelf

Fiber trays

Main shelf

Tributary (trib) shelves

FansVent

Fans

Craft Access Terminal (CAT)

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March 19, 2002

Tributaries (OC-12)

March 19, 2002

Fiber Tray

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March 19, 2002

General Engineering Rules• Working and Protection Slots usually are specific (e.g.

the odd slot protects the even one)

• Loses capacity if using slower speed cards (e.g. an OC-48 has 4 slots that can accommodate 4 OC-12 cards/circuit packs/tribs. If using OC-3 tribs lost 3/4 of the capacity of the NE

• Newer tribs come in the form of “quad”, “octa”, or “hex”, which is referred to the number of ports on the card; (e.g. 4, 8, or 16 OC-x per trib). What is the drawback?

• Another flavor of the newer trib is the half height card/trib, as seen in the next example

March 19, 2002

Another ADM (OC-48 ADM)

1 NE has 2 shelves, which occupies only 1/2 of a rack

Orderwire, NIC, Control, NetSync (ESI) cards

High Speed (OC-48 Working)

High Speed (OC-48 Protection)

Fibers are normally dressed toward and along the sides of the rack.

Uses a “Coke Can” rule to avoid micro-bend

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March 19, 2002

Timing Sources� Two type of common timing signals:

– North America: DS1 (1.4 Mbps)– Europe: E1 (2.0 Mbps)

� Two ways of Timing:

– External : receives the timing reference from external clock

called BITS timing (Building Integrated Timing Source), which will require the External Timing Interface (ETI)

– Line timing : receives from the optical trunk

– Why not always use Line timing?

March 19, 2002

New Generation ADM - DACS

LineModules

Switch Modules

Power Unit, Cooling Unit

OpticalModules Processor

Module

ProcessorModule

TimingModule

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March 19, 2002

General Engineering Rules• Working and Protection Slots Rule is more flexible

• Still loses capacity if not using the next-lower-speed circuit pack

• Does have multi-port circuit pack. (Normally, very expensive and have the same drawback)

• Timing Rule as before - Timing can be external or line timing (e.g. receive the timing source from external clock, which will require the External Timing Interface (ETI) or from the optical trunk - line timing)

March 19, 2002

Equipment Rack / NE

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March 19, 2002

Full Rack Properly Dressed

March 19, 2002

Cable guide along the side of the rack

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March 19, 2002

Network & Network Sites

� Outside plan– Cable, Splice, Cable Vault, Pig Tail, Tier Cable,

Fiber Distribution Panel

� Facility type/design– TI, POP, Co-location, Hut, Shelter– Cable ladder, duct

March 19, 2002

Outside Plant

� Outside plant refers to everything outside the building

� Fiber cable reels come from manufacturers in 2, 4, 6 Km

� Spliced together to connects facilities, which are normally 80 to 100 Km apart

� Cables from outside that enter into the building are terminated at the Cable Vault

� PVC and other protected sleeves are stripped off to “pig tails”

� Spliced to the Fiber Distribution Panel (FDP), which is then cross connected to the “Tier” cable to different floors of the building

� Tier cable is terminated at another FDP before heading to the equipment

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March 19, 2002

Cabling

Tier C

ableOutside Plant

FD

P

Fiber D

istribution Panel (F

DP

)

From the street

Pig Tail

Cable Vault

March 19, 2002

Fiber Distribution Panel

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March 19, 2002

Facility Types• TI: Tenant Improvement. Lease and upgrade the building

to house network equipment

• POP: Point of Presence.

• Co-location: Carrier’s facilities that allow customer’s equipment be installed

• Hut/Shelter: Small structures along railroads, utility pipe lines (usually is in the middle of “nowhere”) - often are on the property of the company that has the right-of-way.

March 19, 2002

Concrete Shelter

Complete Build out Shelter for a REGEN Site. This shelter has an interior floor to ceiling height of 10.5 Feet

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March 19, 2002

Interior of the shelter. Picture taken from the doorway. Note the floor cutouts for the fiber cable and telco lines.

There are two HVAC units mounted on the end wall. The HVAC vent covers on the side walls are for a third HVAC unit required for the future full build out.

Station GND

March 19, 2002

The shelter is complete and ready for shipment to Field.

The interior is completely installed and consists of:•Fiber Bay, All cable ladder (zone 4 bracing), Fiber Guide, Batteries, Rectifiers, Fire Suppression

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March 19, 2002

Loaded and ready for transport to the Plant

March 19, 2002

Network Deployment Process� Choosing equipment

– GA (General Availability) vs CA (Control Availability), features, documentation, bugs list, training

� Lab evaluation– Interoperability, bugs severity– Standards compliance, Safety

� Deployment– Data Communication Channel (DCC), power,

space, floor loading, cable ladder clearance, wall/access, fiber management

– Site construction/design, site access– Sparing

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March 19, 2002

SONET Protection Scheme

� Why 1+1, 1:1, 1:N? When to use which?

� Why UPSR, BLSR/2, and BLSR/4?

March 19, 2002

1+1, 1:1, 1:N� There is another protection scheme usually

referred to as 1:0 !? What is it?

� 1+1 & 1:1 are usually used to protect high speed trunk (more bandwidth, more critical, potentially affects more customer traffic)

� 1+1 & 1:1 are also used if required by the Service Level Agreement (SLA)

� 1:N is used (when possible) to protect low speed side (trib side); less critical / best effort traffic, e.g., IP

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March 19, 2002

UPSR vs BLSR

� UPSR traffic flows only in one direction (e.g., clockwise or counter clockwise).Note: Traffic is still bidirectional

� BLSR traffic flows in both directions

UPSR BLSR

March 19, 2002

UPSR and BLSR Protection

A B C

H D

G F E

Ring Swap - Source and Destination handle protection

UPSR

Why ring swap is undesirable?

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March 19, 2002

Backbone Rings

Washington D.C.

New York CitySan

Francisco

San Jose

Denver

Los Angeles

Kansas City Indianapolis

Cleveland

Boston

Chicago

Seattle

Philadelphia

Albany

Topeka

El Paso

Houston

Atlanta

Minneapolis

Sacramento

Miami

Tampa

Orlando

Charlotte

Salt Lake City

Detroit

Cincinnati

Portland

Bay Ring

Ring

Ring

Ring

Ring

Ring

Ring

Ring

Ring

Ring

Ring

Take a very long time if a ring swap occurs (hundreds of milliseconds)

March 19, 2002

UPSR and BLSR Protection

A B C

H D

G F E

No Ring Swap

BLSR/4

Span switch (not source-destination switch)

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March 19, 2002

Typical Current-Day Network

IP Router

Modem

Modem

OC-48

DS3

IP Router

IP Router

OC-48

ATM/Frame Relay Switch

OC-3/12/48

OC-12/48

ATM/Frame Relay Switch

OC-192 BLSR/4 Systems

OC-12/48

OC-3/12/48

OC-12/48

March 19, 2002

ATM / SONETLayer

Service/IPLayerRouter

TransmissionFiber

Q.Link

λ1 λ1MOA

DWDM Interface

Data Services over Wavelengths

Today Network Architecture

SONET RING OC-192 BLSR/4OC-192 BLSR/4

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March 19, 2002

Any Questions?