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1
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?