1. Optical Networking CS 294-3 2/5/2002
John Strand
AT&T Optical Networks Research Dept.
I hope that you will ask questions freely at any time during these lectures. This will help me to adjust my presentations to best help you. It also will make the lectures more interesting for me.
If you have additional questions, please feel free to contact me after November 5 at AT&T:
My address is:
My postal address is: John Strand AT&T, Room Schulz Drive Red Bank, N.J U. S. A.
U. of California - Berkeley - EECS Dept.
The Views Expressed In This Talk Are The Author’s. They Do Not Necessarily Represent
The Views Of AT&T Or Any Other Corporation Or Individual.

2. Outline Transport - Traditional TDM Networks Optical Networking
Optical Networking & IP
There will be 5 lectures, as shown on this Viewgraph. Each lecture will be about 3 hours long, with a 15 minute break in the middle.
These lectures are based primarily on my experience as architect of AT&T’s domestic transport network and designer of the algorithms which AT&T uses to engineer this network. I will try to highlight the issues which AT&T and our U.S. competitors are wrestling with today.
The lectures were initially developed to train AT&T network planners and researchers. The version you will be seeing has been modified to make it more appropriate for university seminars and industry meetings.
I hope you will forgive the focus on the U.S. telecommunications industry. This is primarily due to my limited understanding of the situation in China.
Through your questions I may be able to help you relate our experience to the problems your country will be facing.
Concentrate On Intercity Networks
Time Constraint
Metro, Access Optical Networks More Complex, Less Mature

3. Layering IP Layers Transport Layers Prototype Apps Context Awareness
Services
Adaptation
Wide-Area
PM &
Monitoring
Possible Service
Architecture Layers
Transport
Layers
DS1
DS3
SONET- Path
Line
Section
Conduit
Wavelength
Fiber
Cable
ROW IP
Layers
"Service"
Application
Tranport
Network
Link
Physical

4. Basic DS-1 Signal Format
193 Bits
Time
Slot 2
Time
Slot 3
Time
Slot 1
Time
Slot 23
Time
Slot 24 F
Bit
o o o o o o o o o o o
1 bit
8 bits
8 bits
8 bits
8 bits
8 bits
Designed To Carry 24 Full Duplex 64 Kilobit/sec Voice Circuits (“DS-0’s”)
Transmission Rate = 1.55 Megabits/Second (8000 frames/sec * 193 bits/frame)
DS-1 Is A Protocol; T-1 Is A Specific AT&T Implementation Of This Protocol For Local Networks
This Is The Traditional Building Block For Transmission Networks In U.S.
The Slowest Inter-Office Signal Is The DS-1.
It was defined in the 1960’s to carry kb/sec full duplex voice channels. Many variations have since been defined.
It is built on 193-bit frames, with 8000 frames/second.
Frequently A DS-1 formatted signal is mis-named a “T-1”. The DS-1 is the protocol, T-1 is a specific physical implementation of the protocol. The same confusion exists at higher rates - T-3 and DS-3, for example.

5. 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 Operations, Administration, Maintenance, & Provisioning (OAM&P)
SONET Interface
SONET
Network
Element
SONET
Network
Element
Digital
Tributaries
Digital
Tributaries
SONET defines all aspects of the interface between SONET-compatible network elements.
SONET is the North American standard.
In most other parts of the world, the standard is "Synchronous Digital Hierarchy" (SDH).
SONET and SDH are "almost" identical. If you understand one you should have no problem learning about the other.
Because all of VG's were prepared for SONET-oriented audiences I will describe SONET.

6. SONET Structure Byte-Interleaved Multiplexing PRS: Primary Source
Network Of
Synchronized
Clocks
PRS: Primary Source
ST2: Stratum 2
ST3: Stratum 3
Must Be
Synchronized
Byte-Interleaved Multiplexing

7. Digital Signal Hierarchies
Most Common Rates
DS-1
(1.544 Mb/s)
Asynchronous
("Plesiochronous")
[Non-Standardized]
DS-3
(45 Mb/s)
VT1.5
(1.7 Mb/s)
SONET
STS-3
(156 Mb/s)
STS-12
(622 Mb/s)
STS-48
(2500 Mb/s)
STS-192
(10000 Mb/s)
STS-1
(52 Mb/s)
Capacity
(DS-1 Equiv) 1 28 84
336
1344
5376
VC-11
SDH
STM-4
STM-16
VC-3
STM-1
STM-64
For high capacity transport, lower bit-rate signals like a DS-1 are combined together into successively larger signals.
The older, asynchronous hierarchy combined up to 28 DS-1’s together in a single 45 Megabit/sec (Mb/sec) signal. A number of non-standardized higher rates were also used. (AT&T combined 36 DS-3’s together into a 1700 Mb/sec signal, for example.
During the last decade, a new set of synchronous standards have emerged. In the U.S., this is the “Synchronous Optical NETwork” (SONET) standard. Outside of the U.S. a very similar “Synchronous Digital Network” (SDH) standard has been adopted.
SONET is based on a 52 Mb/sec format called the “STS-1”. (STS = “Synchronous Transfer Signal”). These can be combined together using a byte-interleaving technique. An STS-n signal consists of n STS-1 signals combined together in this fashion.
In most established networks, such as AT&T’s, it would be too expensive to replace all the existing DS-1 and DS-3 based equipment. Instead each DS-3 is encapsulated in an STS-1 for SONET transport.
SDH is based on the 155 Mb/sec STM-1. This is “almost” identical to the SONET STS-3.
DS: Digital Signal
SONET: Synchronous Optical NETwork (US)
SDH: Synchronous Digital Hierarchy (ITU)
STS: Synchronous Transport Signal
STM: Synchronous Transfer Mode
VC: Virtual Container
VT: Virtual Tributary

8. SONET Rates Optical Designation Bit Rate (Mb/s) Level
STS-1 OC
STS-3 OC
STS-12 OC
STS-48 OC ,
STS-192 OC ,
STS-768 OC ,
A Summary of the SONET rates.
"STS" refers to the protocol - the frame structure. When an STS-N is transported optically it is frequently called an "OC-N" (for "Optical Carrier"); when transported electrically it can be called an "EC-N".
STS = SYNCHRONOUS TRANSPORT SIGNAL
OC = OPTICAL CARRIER (“..result of a direct optical converions of the STS after synchronous scrambling” - ANSI)
EC (Not Shown) = ELECTRICAL CARRIER

9. SONET STS-1 Frame Structure87
Bytes 3 t T O H
87 Columns
Ptr P O H P O H
SPE F I x e d S t u f F I x e d S t u f
Synchronous
Payload
Envelope
(SPE) t 9
Rows
The STS-1 has an 810 byte frame, usually shown as 90 columns and 9 rows. This frame is transmitted 8000 times a second - the same rate as a DS1 or DS3, for a total of Mbit/sec.
There are 3 overhead columns (described later). These contain a pointer showing where the "Synchronous Payload Envelope" (SPE) containing the information being transmitted starts.
There is a significant amount of overhead, which is detailed in the "Efficiencies" table in the lower right. For example, if an STS-1 is used to transport a DS3, only 86.3% of the Mb/sec STS-1 signal is carrying content. 87
Bytes 3

10. STS-N And STS-Nc (N = 3, 12, 48, 192) STS-N
Formed By Byte-Interleaving N STS-1 Signals
3N Columns of Transport Overhead
Frame Aligned
Redundant Fields Not Used - eg APS, Datacomm
N Distinct Payloads (87N Bytes)
NOT Frame Aligned
N Columns Of Path Overhead - All Used
2N Columns Of Fixed Stuff Bytes
84N Columns Of Information
STS-Nc
Single Payload
1 Column Of Path Overhead
3N - 1 Columns Of Fixed Stuff Bytes
87N - N/3 Columns Of Information
Higher rate signals are created by byte-interleaving STS-1. This puts 3N columns of OH in an STS-N, even though only 3 of these columns are normally used.
STS-N and STS-Nc differ in the structure of their payloads:
STS-N has N separate 87-column SPE's, each with a Path OH column.
STS-Nc has one large N * 87 column SPE, and has only 1 Path OH column.
The STS-Nc is of particular value for data communications. It allows the use of a single queue at the transmit end of the circuit.

11. Virtual Container (VC) Multiplex Section (MS)
SONET/SDH Layering
Multiplexer
Or Other
PTE
Cross-
Connect
Regenerator
(derived clock)
SONET
Path
Line
Section
SDH
Virtual Container (VC)
Multiplex Section (MS)
Regenerator Section
(RS)
Key Feature: Basis Of
Fault Management & Restoration
Maintenance

12. Service Survivability Objectives Typical Commercial Networks
1000
100 10
Restoration Time
Objectives (secs) 1
0.1
0.01
Standard
Voice
Leased
Lines
Frame
Relay IP
Services
New trends in IP services: supporting real-time application, e.g. voice and video, & mission critical data
=> Require much faster restoration than traditional IP rerouting

13. Network Outage Analysis
Voice Services
Equipment
Failure
Route Failure
Backhoe, Flood, Train Wreck
~1/1000 km/year

14. Survivability 101 Survivability Requires: Fault Detection
Switch Fabrics To Put Failed Facility On This Capacity
Spare Inter-Office Capacity X A B Y
Protection: Pre-Allocated
Restoration: Dynamically Allocated
Survivability Requires:
Each line in this example represents a fiber route.
Suppose there is a facility routed X-A-B-Y.
If there is a failure between A and B, this circuit could be rerouted onto X-A-C-D-B-Y.
This requires spare capacity on A-C, C-D, and D-A.
It also requires a switching capacity at A, C, D, and B to reroute the failed circuits.
Fault Detection
Control Logic To Identify Fault & Reroute Failed Circuits

15. Effect Of Restoration Topology
Restoration Overbuild
(Protection Capacity/Service Capacity)
Degree 2
Nodes
"Ring"
"Mesh"
100%
50%
Degree 3
Nodes
The topology of a network puts a lower bound on the amount of additional capacity required for complete restoration.
Suppose the load on each link is constant.
If there are N diverse paths between each pair of nodes, then the extra capacity required to restore a single path failure can be spread over the remaining N-1 paths.
When rings are used, in essence the network is decomposed into a set of "Degree 2" subnetworks. Thus 100% "Overbuild" is required.
If a restoration method allowing more sharing of restoration capacity is used, it is normally possible to come close to needing only 1/(D - 1) additional capacity, where D is the average nodal degree.
However, it is difficult to restore as rapidly as a ring if a more complex rerouting algorithm is used, because of the time required to determine the state of the network after a failure and to determine which reroutes to apply.
1/(N-1)
Degree N
Nodes
Degree = # Of Physically Diverse Routes

16. Ring Example
SONET: Bi-Directional Line-Switched Ring (BLSR)
SDH: Multiplex Section Shared Protection Ring (MS-SPRING) S
S: Service B C P
P: Protection
Different
Fibers But
Same Cable A D
Original Circuit
Now suppose that the Service OC-48 between E and F fails.
The switch fabrics in the 2 ADM's reroute the traffic over the protection OC48. F E
Protection Switch

17. X Ring Example S B C P A D F E
SONET: Bi-Directional Line-Switched Ring (BLSR)
SDH: Multiplex Section Shared Protection Ring (MS-SPRING) S
S: Service
Standardization:
Physical Layer & Signaling Standardized
Client State Information Not Standardized
OAM Not Standardized B C P
P: Protection
Different
Fibers But
Same Cable A D
Original Circuit
Now suppose that the Service OC-48 between E and F fails.
The switch fabrics in the 2 ADM's reroute the traffic over the protection OC48. X F E
Protection Switch

18. Public Switched Telephone Network
(PSTN)
Central
Office
Toll Network
Toll Connect Trunks
Inter-Toll Trunks
Switches: Terminate Trunks Switch Individual Calls
64 Kb/sec FDX Circuits
Central
Office CO
Customer
Premises
Equipment
(CPE)

19. Basic Service Types CPE Central Office PSTN Transport Network Switch
~ 100 Intercity Switches*
Switch
"POTS"
PBX
Transport Network
Shared By Many Services
~10x As Many Offices*
Private Line (PL)
POTS: Plain Old Telephone Service
* ATT Network

20. Entering The Transport Network
64 kb/s
1.5 Mb/s
Mb/s
Gb/s
POTS 1 1 o 28 O
1.5 Mb/s PL
Mb/s PL
1Gb Ethernet
Gb/s PL,
10 Gb WAN Ethernet
&
VG PL O D S 1 W D M
Backbone
Fiber
Network 24 D S 3 O C
192
10 Gb WAN Ethernet
SONET Framed Gb/s
Asynchronous *
POTS: "Plain Old Telephone Service"
VG: Voice Grade
PL: Private Line

21. Service Routing
Transport Layer
Service Layer
(e.g., POTS or PL)

22. Outline Transport - Traditional TDM Networks Optical Networks
Optical Networking & IP
There will be 5 lectures, as shown on this Viewgraph. Each lecture will be about 3 hours long, with a 15 minute break in the middle.
These lectures are based primarily on my experience as architect of AT&T’s domestic transport network and designer of the algorithms which AT&T uses to engineer this network. I will try to highlight the issues which AT&T and our U.S. competitors are wrestling with today.
The lectures were initially developed to train AT&T network planners and researchers. The version you will be seeing has been modified to make it more appropriate for university seminars and industry meetings.
I hope you will forgive the focus on the U.S. telecommunications industry. This is primarily due to my limited understanding of the situation in China.
Through your questions I may be able to help you relate our experience to the problems your country will be facing.

23. Fiber Structure Lightpack Cable Design Typical Loss: 0.2 – 0.25 dB/km
Protection Layers
Pure Glass Core
8.3 micron*
Glass Cladding
Protects “core”
Serves as a “Light guide”
125 micron
Inner Polymer Coating
Outer Polymer Coating
250 micron
Typical Loss: 0.2 – 0.25 dB/km
Plus Connector Loss
Single Fiber
* Single Mode Fiber; Multi-Mode Has A 50 Micron Core

24. Intercity Fiber Network
About 50,00 Route Miles Of Fiber Cable

25. All-Optical Amplification Of Multi-Wavelength Signal!!!
Optical Amplifier/WDM Revolution
Frequency-registered
transmitters
Receivers R l1
All-Optical Amplification
Of Multi-Wavelength Signal!!! R l2 OA OA
WDM
Mux
WDM
DeMux l3 R km
(80 km typically) lN R
Up to 10,000 km
(600 km in 2001 basic commercial products)
WDM: Wavelength Division Multiplex
OA: Optical Amplifier

26. A. Willner

27. Optical Amplifier/WDM Revolution
Conventional Transmission - 20 Gb/s
1310
RPTR
LTE
40km
DS3
120 km OA
OC-48
DS3
OC3/12
12 fibers 1 fiber; 36 regenerators 1 optical amplifier
In Each Direction:
12 Fibers
36 Regenerators
Economic Advantage Is Distance Dependent
Intercity: Compelling
Metro: Depends On Dark Fiber Availability
WDM: Wavelength Division Multiplex
OA: Optical Amplifier

28. * Single Fiber Capacity Bandwidth (Bits / l) Capacity = (Bandwidth/ l)
Moore's
Law
Bandwidth
(Bandwidth/ l)
(Bits / l) *
Capacity =
Source: K. Coffman & A. Odlyzko, “Internet Growth: Is There A Moore’s Law For Data Traffic?” (research.att.com/~amo)

29. Single Fiber Capacity Bandwidth
Fiber loss
1300
1525
1565
1600
1400

30. Single Fiber Capacity Bandwidth/l - C Band x2 4 THz ~ 125 GHz/nm
199.0
196.0
195.0
194.0
193.0
192.0
¦(THz)
l (nm)
1505
1510
1530
1535
1540
1545
1550
1555
1560
1565
~ 125 GHz/nm
C-Band
50 GHz Spacing
(For OC48)
(80 l) x (2.5 GHz/l) = 200 GHz
(40 l) x (10 GHz/l) = 400 GHz x2
100 GHz Spacing
(For OC192)

31. Transport Layer Model LA CHCG LA CHCG PHNX SONET ADM Layer Hard- Wired
“Packet”
“Packet”
1/0 DCS 4E
Service
Layers LA
CHCG
“Packet”
“Packet” LA
CHCG
DS1
(1.5 Mb/s)
3/1 DCS
Layer
ATM/IP
DS3
(45 Mb/s)
3/1 DCS
Core ATM/IP Layers
DACS III
3/3 DCS
Layer (DACS III)
DS3
(45 Mb/s)
PHNX
SONET ADM
Layer
ADM
ADM
ADM
ADM
ADM
ADM
ADM
OC48+
(2.5+ Gb/s)
Hard-
Wired
Wavelength Path
Crossconnect
Wavelength Mux Section
Proprietary
( Gb/s)
OTS
(OTS: Optical Transport
System)
Media
Layer
Fiber Conduit/
Sheath

32. Optical Cross-Connect (OXC) Alternatives
Line Rate
(Proprietary)
Line Rate
(Proprietary)
OC48
OC192
OC48
OC192
Wavelength
Path
Cross-
Connect
ADM’s
SDCS
Other
Service
Equipment
D W D M
Wavelength
Multiplex
Section
(WMS)
Cross-
Connect
D W D M
D W D M
Fewer Bits Per Port
Compatible With Opaque Architecture
Better For Restoration
More Bits Per Port
Multivendor & Restoration Issues
WIXC
Would Go Here
Could Have Either Optical Or Electrical Fabric

33. Office Architecture Impact
Optical Cross-Connect (Wavelength Path Cross-Connect)
Service Layers
Service Layers
OXC
Adds An Additional Cost
Operationally Essential In Larger Offices & Offices With High Churn
Allows Software Controlled Provisioning

34. Opaque Wavelength Path Crossconnect
Standard
cross-office optics
(1.3 mm)
Optical transport system
(1.55 mm)
Optical transport system
(1.55 mm)
l-Mux
...
...
Wavelength Path
Crossconnect
(Optical or
Electronic
Interior)
...
...
Fibers In
Fibers
Out
...
...
Transparency
= node-bypass
...
...
...
...
Add ports
Drop ports

35. Opaque Wavelength Path Crossconnect
(Electrical Fabric)
640 Gbps,
To 48 Tbps
Power,
Cooling
Optical
Modules
Processor
Module
Line
Modules
Timing
Module
Transparent
Switch Modules
(STS-1 Granularity)
Processor
Module

36. Fixed l Lasers in Optical Switches
MUX
DWDM
Today’s
switches are surrounded
with OEO –>
70% of system
cost
Fixed Wavelength T x R LR SR LR SR SR LR T x R M U X T x R D E M U X
DWDM
DWDM
Fixed wavelength transponders are required for each input and output fiber T x R SR LR T x R
MUX
DWDM

37. An Early MEMS Device Free-Space Micromachined Optical Switch (FS-MOS)
Switch Time < 1 ms
8x8 is 1 cm x 1 cm
Opportunities To Extend To
Significantly Larger Arrays
On A Single Substrate
Measured Switching Times
Under 1 ms (500ms)
3-D MEMS (2 degrees of
Freedom) seems to be the
Currently preferred architecture
Output fibers
Micro
lens
Free-rotating
switch-mirror array
Silicon
substrate
Si substrate
Input fibers
Switch reconfigured by actuating selected micromirrors

38. An 8 x 8 Switch
Chip size: 1 cm x 1 cm
Source: L-Y. Lin

39. Contained Domain of Transparency
TDRs
TDRs
Optical Domain Circuit Switch
TDRs
Issues:
Transmission Engineering Concerns Especially For Non-Tree Topologies
Fault Detection & Localization
Without Wavelength Conversion Becomes Separate Single-l Networks

40. Optical Transport System (OTS)
OTS System Length
Optical Transport System (OTS)
ADM o
D W D M
ADM o
D W D M
80 km
80 km
80 km
80 km
80 km
80 km
80 km OA OA OA OA OA OA
560 Km
“7 x 25 dB Spacing”
Key Variables:
Distance Between OA's
Number of Spans

41. Domains Of Transparency Transponder Costs In Traditional Systems

42. Domains Of Transparency
Ultra Long-Haul (ULH) Economics 1 3 5 7 9
No. Of Standard OTS Systems (5 span) In Series
1.25
1.5
1.75 2
Utilization (%)
100
ULH/Standard
Cost Ratio
ULH
Wins
Standard
Transponder
OA/OADM
DWDM
~500 km
OTS Type
Standard . .
A B C D
Typical ULH Technology Enhancements:
Strong Forward Error Correction
Raman Amplification
Dynamic Power Management
More Expensive Terminals & OA’s
Fewer Transponders At Intermediate Locations
~5000 km
Ultra-Long Haul (ULH)

43. Contained Domain of Transparency
TDRs
TDRs
Optical Domain Circuit Switch
TDRs
Issues:
Transmission Engineering Concerns Especially For Non-Tree Topologies
Fault Detection & Localization
Without Wavelength Conversion Becomes Separate Single-l Networks
Single-Vendor For The Forseeable Future

44. Distance Before OEO Regen
Limiting Factors
PMD Constraint
~ (B * DPMD)-2
Nonlinearities
Launch
Power
(PL)
Operating Region
ASE Constraint
~ PL/SNRmin
In Large All-Optical Domains
Each Vendor Trades Off The Design Parameters Differently
This Makes Routing In Multi-Vendor Networks Difficult To Standardize
Other
System
Parameters
Length Of All-Optical Path
PL Launch Power
SNRmin Min SNR
PMD Polarization Mode Dispersion
B Bandwidth of l
DPMD PMD Parameter (fiber dependent)
ASE Amplified Spontaneous
Emission
Refs: A. Chiu, J. Strand, R. Tkach, "Issues for Routing In The Optical Layer", IEEE Communications (2001)
J. Strand (ed.), IETF I-D "Impairments And Other Constraints On Optical Layer Routing", draft-ietf-ipo-impairments-01.txt

45. Outline Transport - Traditional TDM Networks Optical Networking
Optical Networking & IP
There will be 5 lectures, as shown on this Viewgraph. Each lecture will be about 3 hours long, with a 15 minute break in the middle.
These lectures are based primarily on my experience as architect of AT&T’s domestic transport network and designer of the algorithms which AT&T uses to engineer this network. I will try to highlight the issues which AT&T and our U.S. competitors are wrestling with today.
The lectures were initially developed to train AT&T network planners and researchers. The version you will be seeing has been modified to make it more appropriate for university seminars and industry meetings.
I hope you will forgive the focus on the U.S. telecommunications industry. This is primarily due to my limited understanding of the situation in China.
Through your questions I may be able to help you relate our experience to the problems your country will be facing.
Concentrate On Intercity Networks
Time Constraint
Metro, Access Optical Networks More Complex, Less Mature

46. IP Transport Transport For IP - IP For Transport - Data Services
(Mostly IP-Based)
Voice & Other
TDM-Based Services
DS1 (1.5 Mb/Sec)
Transport For IP -
Defining Functionality
Of These Interfaces
Wideband & Broadband
DCS Layers
DS3 (45 Mb/Sec) -
STM-4 (622 Mb/Sec)
Digital Transmission
Layer
IP For Transport -
Introducing IP Functionality
Into The Optical Layer
STM-16c (2.5 Gb/Sec) -
STM-64c (10 Gb/Sec)
Optical Layer
Proprietary
(20 Gb/Sec Gb/Sec)
Media Layer

47. IP Transport Transport For IP - IP For Transport - Data Services
(Mostly IP-Based)
Voice & Other
TDM-Based Services
DS1 (1.5 Mb/Sec)
Transport For IP -
Defining Functionality
Of These Interfaces
Wideband & Broadband
DCS Layers
DS3 (45 Mb/Sec) -
STM-4 (622 Mb/Sec)
Digital Transmission
Layer
IP For Transport -
Introducing IP Functionality
Into The Optical Layer
STM-16c (2.5 Gb/Sec) -
STM-64c (10 Gb/Sec)
Optical Layer
Proprietary
(20 Gb/Sec Gb/Sec)
Media Layer

48. Replacing The OLXC With A Router
IP For Transport
Replacing The OLXC With A Router IP
Services
Non-IP
Services
Non-IP
Services
IP Router
OXC
OLXC
Office Architecture
“Big Fat Router”
Office Architecture

49. Comparing The Architectures
IP For Transport
Comparing The Architectures
Ports & Assumed Costs
OLXC $x Per OC48
IP Router $y Per OC48
IP Router
Through (a)
Terminating (1 – a)
IP Router
“Big Fat Router”
Office Architecture
OLXC
OLXC
Office Architecture
OLXC Architecture Less Expensive If:
OLXC Cost x
Typical Values:
a = 0.8
x/y << 0.2
Router Cost
< a y

50. MPLS Transport HierarchyIP X s
LSP s
LSP X
Physical Transmission System
SONET (STS-N)
OCh
Etc.
LSP t
LSP u
LSP Y
LSP a
LSP s
LSP t
Label Switched Path's (LSP's) Are LOGICAL, NOT PHYSICAL
Need Not Occupy Bandwidth
Specific LSP’s Change At Each MPLS Node: z End-to-end connection defined at set-up

51. MPLS Tunneling "Virtual" Muxing - No Utilization Penalty
POP 3
PUSH 7
SWAP 7=>11
PUSH 42 11 42
SWAP 42 => 88 11 88
POP 88
SWAP 11=>3 3
LSP 3
LSP 7
LSP 11
LSP 42
LSP 88
"Virtual" Muxing - No Utilization Penalty
This Is A Key Driver For Replacing TDM

52. TDM Multiplexing DS1 DS3 STS-48 STS-48 DS3 DS3
Tunneling Using MPLS LSP's Is Analogous To TDM Multiplexing
DS1
DS3
STS-48
STS-48
DS3
DS3

53. From MPLS To GMPLS GMPLS: Generalized MPLS Implicit Label (1) (2)
POP 3
PUSH 7
SWAP 7=>11
PUSH 42 11 42
SWAP 42 => 88 11 88
POP 88
SWAP 11=>3 3
LSP 3
LSP 7
STS-192 (1)
STS-192 (2)
LSP 11
LSP 42
LSP 88
GMPLS: Generalized MPLS

54. GMPLS In An OXC Network Vision:
1. Select source, destination, and service
2. OSPF determines optimal route
3. RSVP-TE/CR-LDP establishes circuit
Label Request Message
Label Mapping Message
Vision:
Provisioning Time: Weeks To Milliseconds
Greatly Simplify Process
ISSUE: Standards Lagging Need - Proprietary Control Planes Are Being Deployed Rapidly
Source: Sycamore OFC2000

55. Many Technologies - One Network
GMPLS Vision
Many Technologies - One Network
FS: Fiber Switched
LS: Lambda Switched
PS: Packet Switched
FA: Forwarding Adjacency

56. GMPLS Overlay Network Model~
Router
Connection
Requests, etc.
Optical
Network
UNI
Overlay Network
Optical Network (OXC) computes the path
Network Level Abstraction For IP Control Plane

57. GMPLS Peer Network Model
Router ~
Topology &
Capacity Information
Optical
Network
Network
Signalling
Peer Network
Router computes the path (Routers have enough information about the characteristics of the optical devices/network)
Link-level abstraction For IP Layer Control Plane

58. Canarie OBGP Current View of Optical Internets
ISP
AS 4
AS 1
Customers buy managed service at the edge
Optical VLAN
AS 1
Customer
AS 3
BGP Peering is done at the edge
Big Carrier Optical Cloud using MPLS and IGP for management of wavelengths for provisioning, restoral and protection
AS 2
B. St. Arnaud

59. BGP Routing + OXC = OBGP Canarie OBGP BGP Routing + OXC = OBGP
Virtual BGP Routing process runs on Router B CPU which controls optical switch
AS 200
BGP Neighbor
BGP Neighbor
Router B
Metric 100
Metric 100
Router A
Metric 200
Metric 200
Router C
AS 100
AS 300
B. St. Arnaud

60. Dark Fiber Mapped to Dim Wavelength
Canarie OBGP Vision
School
Aggregating Router
ISP Controlled
Optical Switch
ISP A
Dark Fiber
OiBGP
IGP
BGP
Multi Home Router
IGP
Dark Fiber Mapped to Dim Wavelength
Customer Controlled
Optical Switch
ISP Controlled
Optical Switch
BGP neighbors
University X
IGP
IGP
OBGP
OBGP
Customer Owned
Dark Fiber
ISP B
OBGP
University Y
B. St. Arnaud

61. Optical Interworking Forum Services Concept
ISP
AS 4
AS 1
Customers buy managed service at the edge
Optical VLAN
AS 1
Customer
AS 3
BGP Peering is done at the edge
Bandwidth On Demand - Connection Request Over UNI Specifying QoS Desired - Overlay Model
OVPN - Dedicated Subnet Configured By Customer - Peer Model
AS 2

62. Examples of network views
View from domain A via a distance-vector or path-vector protocol
Domain 2
Reachable
Address list
Domain 1
Reachable
Address list
Domain 4
Reachable
Address list
Domain 3
Reachable
Address list
Domain 5
Reachable
Address list

63. Examples of Network views
View from any domain of the rest of the network via a link state protocol
Protection 1:N, N=3
Available BW = …
SRLG = …
Domain 2
Reachable
Address list
Domain 1
Reachable
Address list
Protection 1+1
Available BW = …
SRLG = …
Protection 1+1
Available BW = …
SRLG = …
Protection 1+1
Available BW = …
SRLG = …
Domain 4
Reachable
Address list
Protection 1:N, N=7
Available BW = …
SRLG = …
Protection 1+1
Available BW = …
SRLG = …
Domain 3
Reachable
Address list
Domain 5
Reachable
Address list
Protection 1:N, N=10
Available BW = …
SRLG = …

64. Initial OIF NNI Target Single carrier’s network
User control
Domain
Control Domain A C
UNI
NNI B
firewall
L2/L3
Load
Balancer
Single carrier’s network
NNI
Why Single Carrier Multi-Domain First?
Standards Lag Deployment - Vendor Proprietary Control Planes
Rapid & Unpredictable Technological Change Makes It Unlikely That Standards Will Keep Up
Uncertain Business Model
Initial Multi-Carrier NNI Likely To Be LEC/IXC (JLS Opinion)

65. Metro/Core Characteristics
oif Application-Driven Assumptions And Requirements
Metro/Core Characteristics
1. Significant Differences In Technology, Economic Trade-Offs, & Services Supported
2. Likely To Be Multi-Vendor
3. Proprietary Or Customized IGP's Are Likely
4. Significant Operational Autonomy
Information Trust, Not Always Policy Trust
Domains Likely To Require Control Of The Use Of Their Resources
5. Routing
Carrier-Specific
NMS May Be Involved
High Unit Costs, Long Connection Times Make Economics An Important Consideration
6. Conduit & Fiber Cable Sharing Make SRG Information Across Domains Complex - Will Frequently Not Be Available
Metro
Metro A X
Metro Y J K

66. Metro/Core Characteristics
oif Application-Driven Assumptions And Requirements
Metro/Core Characteristics
1. Significant Differences In Technology, Economic Trade-Offs, & Services Supported
2. Likely To Be Multi-Vendor
3. Proprietary Or Customized IGP's Are Likely
4. Significant Operational Autonomy
Information Trust, Not Always Policy Trust
Domains Likely To Require Control Of The Use Of Their Resources
5. Routing
Carrier-Specific
NMS May Be Involved
High Unit Costs, Long Connection Times Make Economics An Important Consideration
6. Conduit & Fiber Cable Sharing Make SRG Information Across Domains Complex - Will Frequently Not Be Available Y
Metro
Metro
Metro A Y J K

67. Multi-Vendors In Backbone - Characteristics
oif Application-Driven Assumptions And Requirements
Multi-Vendors In Backbone - Characteristics
1. Proprietary Or Customized IGP's Are Likely
2. Information & Policy Trust Not Likely To Be An Issue
3. Vendor-Specific Technologies & Constraints Not Captured In Standards Are Likely
(E.g., All-Optical, Tunable Lasers, Adaptive Wavebands) J K L A Z N P Q S T U M R B Y
Routing Costs: A(nodes) + B(distance)
Large A Small B
Small A Large B
Opaque
Network
(Vendor A)
Express
Domain of
Transparency
(Vendor B) J K L N P Q S T U M R Z A J K L N P Q S T U M R B Y

68. IP Transport Transport For IP - IP For Transport - Data Services
(Mostly IP-Based)
Voice & Other
TDM-Based Services
DS1 (1.5 Mb/Sec)
Transport For IP -
Defining Functionality
Of These Interfaces
Wideband & Broadband
DCS Layers
DS3 (45 Mb/Sec) -
STM-4 (622 Mb/Sec)
Digital Transmission
Layer
IP For Transport -
Introducing IP Functionality
Into The Optical Layer
STM-16c (2.5 Gb/Sec) -
STM-64c (10 Gb/Sec)
Optical Layer
Proprietary
(20 Gb/Sec Gb/Sec)
Media Layer

69. Traffic On U.S. Long Distance Network
1997 – 1999
Source: K. Coffman & A. Odlyzko

70. Entering The Transport Network
64 kb/s
1.5 Mb/s
Mb/s
Gb/s
POTS
&
VG PL 1 24 O 1 o 28 BW
Growth
Rates
1.5 Mb/s PL
Mb/s PL
Backbone
Fiber
Network
Gb/s PL
POTS: "Plain Old Telephone Service"
VG: Voice Grade
PL: Private Line

71. US Domestic Backbone (Mid-’99)
268,794 OC-12 Miles

72. X X Transport Layering Functionality & Value Added Data Services
(Mostly IP-Based)
Voice & Other
TDM-Based Services X X
Functionality
& Value Added
DS1 (1.5 Mb/Sec)
Wideband & Broadband
DCS Layers
DS3 (45 Mb/Sec) -
OC-12 (622 Mb/Sec)
Digital Transmission Layer
ADM's
Rings
OC-48c (2.5 Gb/Sec) -
OC-192c (10 Gb/Sec)
Optical Layer
Optical Transport Systems (DWDM, OA,OADM)
"Optical Cross-Connects"
Proprietary
(20 Gb/Sec Gb/Sec)
Media Layer
Fiber
Conduit

73. Possible Solution Elements
Transport For IP
Customer Drivers
Possible Solution Elements
Price - $/OC48/month
Availability
How Quickly
Where
Displacement Of Internal ISP Costs
Interfaces
Cost Of Reliability
Buffer Capacity
Peak Loads
Traffic Shifts
Traffic Growth
Network Management
Differentiators
QoS
Rapid Provisioning
Optical Network Interworking
Heterogeneous Technologies
Metro/Core
Other Backbone Providers
Flexible Bandwidth
Asymmetric Circuits
Concatenated Links
Virtual Concatenation
Inverse Multiplexing
Additional Customer Restoration Options
Re-Provisioning
Customer Control
Speed Options
Sub-OC48 Functionality
Layer 1 Interface Enhancements

74. Restoration Refresher Key Trade-Off
Restoration Granularity
Unit Capacity Cost
Optical
Layer
Services
Layers
Digital
Transmission
DCS Layers
Connection
STS-1 => STS-12
STS-48+
l or Fiber
Services Layer (IP) Can Restore Exactly The Right Connections
Optical Layer More Economical If Large Bundles Of Connections Need To Be Restored

75. ISP Peering Relationships
Customer
Provider
EXPENSIVE
Peer
(Frequently) No $$

76. Reducing The BGP Hop Count
Transport For IP
Reducing The BGP Hop Count A Z R C X B Y
Toll Switching Hierarchy
Internet ISP Hierarchy
Local ISP
Regional ISP
Tier 1 ISP
Hi-Usage
Trunks
Optical
Direct Connects
Typical Transit Cost (Telia): $1K - 10K / Mbps /Year

77. References
T. E. Stern & K. Bala, Multiwavelength Optical Networks, Addison-Wesley, 1999
J. L. Strand, “Optical Network Architecture Evolution”, chapter in I. Kaminow and T. Li (eds.), Optical Fiber Telecommunications IV, Academic Press, to appear March 2002
R. Ramaswami and K. N. Sivarajan, Optical Networks: A Practical Perspective, San Francisco: Morgan Kaufmann, 1998.
B. Mukherjee, Optical Communications Networks, New York: McGraw Hill, 1997.
R. H. Cardwell, O. J. Wasem, H. Kobrinski, “WDM Architectures and Economics in Metropolitan Areas", Optical Networks, vol. 1 no.3, pp
O. Gerstel and R. Ramaswami, "Optical Layer Survivability: A Services Perspective", IEEE Communications Magazine, vol. 38 no. 3, March 2000, pp
   R. D. Doverspike, S. Phillips, and Jeffery R. Westbrook, "Future Transport Network Architectures", IEEE Communications Magazine, vol. 37 no. 8, August 1999, pp
R. Doverspike and J. Yates, "Challenges for MPLS in Optical Network Restoration", IEEE Communications Magazine, vol. 39 no. 2, Feb. 2001, pp
M. W. Maeda, "Management and Control of Transparent Optical Networks", IEEE J. on Selected Areas In Communications, vol. 16, no. 7, Sept. 1998, pp
J. L. Strand, J.; A. L. Chiu, , R. Tkach,. “Issues For Routing In The Optical Layer”, IEEE Communications Magazine, 2/2001, vol. 39, no. 2, pp. 81 –87
John Strand, Robert Doverspike, Guangzhi Li, “Importance of Wavelength Conversion In An Optical Network”, Optical Networks Magazine, vol. 2 No. 3 (May/June 2001), pp
R. W. Tkach, E. L. Goldstein, J. A. Nagel, J. L. Strand, “Fundamental limits of optical transparency”, OFC '98, pp

78. Some Relevant U.S. Web Sites
“Tier 1” Inter City Service Providers
AT&T
MCI Worldcom
Sprint
New Entrants
Qwest
Level3
Frontier
Williams
Major Equipment Providers
Lucent
Alcatel
Nortel
Cisco
NEC
New Equipment Vendors
Ciena & Lightera
Cisco & Monterey
Avici
Juniper
Sycamore
Standards Organizations
ITU T1
OIF
IETF
ATM Forum
New Business Models
Band-X
Arbinet
Government Sites:
FCC
NTIA