New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 1
CSCI-370/EENG-480
Computer Networks
Khurram Kazi
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 2
Examining the Optical Transport Networks Standards and Their Impact on Next Generation Networks
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 3
Vision Of Optical Transport Networking
GOAL: To provide a flexible, scalable, and robust Optical Transport Network, catering to an expanding variety of client signals with equally varied service requirements (flexibility, scalability, and survivability coupled with bit-rate and protocol independence).
Optical Transport Network (OTN)
SONET/SDH
PDHATM
IP, “Next Big Thing”
1/10/100 Gigabit Ethernet
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 4
“Idealized” Optical Network
Attributes:• Channels start anywhere, end
anywhere (i.e. no per-wavelength engineering rules due to noise accumulation effects, vendor-specific wavelength plans)
• Channels are format and bit-rate independent
• Wavelength conversion (interchange) to minimize stranded capacity
• Access to optical layer for embedded base
• Support for multi-vendor environment
• Easy upgrade (add bandwidth on demand)
But, How to manage this network ?
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 5
There are Issues with idealized vision! Expectation for Transparency of the Optical Layer -
Support for legacy and Emerging Formats in the network - PDH, SONET/SDH, ATM, GbE, IP, GFP ….
To Network Optical Channels requires an ability to Manage Optical Channels
Optical layer OAM&P (Operations, Administration, Maintenance & Provisioning) information will be needed to support Optical Networking applications
OAM is supported in form of Optical Layer “overhead”
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 6
There are Issues with idealized vision! Expectation for Transparency of the Optical Layer -
Support for legacy and Emerging Formats in the network - PDH, SONET/SDH, ATM, GbE, IP, GFP ….
To Network Optical Channels requires an ability to Manage Optical Channels
Optical layer OAM&P (Operations, Administration, Maintenance & Provisioning) information will be needed to support Optical Networking applications
OAM is supported in form of Optical Layer “overhead”
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 7
How Did We Get to This Point:Some SONET/SDH Basics
In SONET/SDH the networking levels are STS/HOVC and VT/LOVC path layers
The Section+Line/RS+MS levels are neither intended nor designed to support networking Only to support monitoring of, and fault localization within, a repeatered
line. SONET/SDH signals are defined in a period in which most operators were
governmental like organizations One per country
SONET/SDH signals are defined initially under the assumption that the path endpoints are owned by the operator
Services supported by SONET/SDH networks were considered to be PDH services DS1, E1, E3, DS3, E4
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 8
Marketplace Evolved
After some years the customers wanted to own the SONET/SDH path endpoints To benefit from the more extensive quality of service (i.e.
monitoring) capabilities As an "afterthought", one level of TCM was added to the
SONET/SDH path signal specifications
Operator organizations got privatised, and many new operator organizations entered the marketplace Bandwidth is leased from each other in an extensive way Two levels of of overhead per path signal is now rather
limited
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 9
Technology Evolved
WDM technology became available, and is deployed to get around fiber shortage The initial WDM line systems were offering essentially "virtual fibers" to
the SONET/SDH network Optical fabric technology became available recently, and will be added to the
networks to provide flexible interconnect between WDM line systems, SONET/SDH terminals and Data equipment (IP Routers, Ethernet Switches, ATM Switches). The signals routed around are SONET/SDH and GbE signals, with a strong
claim of being fully transparent transported. These SONET/SDH and GbE section level signals are not designed to
support path layer characteristics, as is now required. They (unsolicited) "upgraded" to path level signals, due to the addition of optical fabric equipment to the network.
From day one, the endpoints of these signals can be owned by the customer, leaving the operator without any overhead to verify the performance of its transport.
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 10
Technology Evolved More and more customers own the endpoints of
SONET/SDH signals and require transparent transport of all bits in the signal.
This makes it impossible to "steal" some bits in the frame for the operators business for OAMP.
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 11
Do we have all Optical Networks?
Network is all not optical Optical implies, analogue impairments are back in town Every X hundred/thousand kilometers signals must be regenerated
The network looks more optical than before, while the regenerator spacing increased significantly Since the mid-80's regenerator spacing has increased from
about 1.5 km (565 Mbit/s coax) via 40/80/120 km (SONET/SDH) to 500/1000/4000 km ((ultra) long haul terrestrial WDM)
Optical amplifiers are deployed at intermediate points in these spans, instead of electrical regenerators
Strong forward error correction codes are added to the original SONET/SDH signal in the regenerators to get the long regenerator spacing
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 12
Do we have all Optical Networks? Regenerators in a WDM network will also appear
At the edges of administrative domainsProviding well defined hand-off points to the next operator or
customer Around Optical Fabrics
Compensating for the incurred loss when going through the fabric (connectors, bridge & selector, MEMs)
The SONET/SDH signal is wrapped into this strong FEC signal
Bit rate of the signal is increased
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 13
Alternative "OTN"
If one ignores the transparency requirement of some customers for a moment, the minimum processing in a regenerator can be defined to be: termination of FEC frame and error correction termination of SONET/SDH Section/RS overhead termination of SONET/SDH Line/MS overhead forwarding of STS/AUG bitstream insertion of new SONET/SDH Line/MS overhead insertion of new SONET/SDH Section/RS overhead insertion of new FEC frame and FEC code
If needed, also STS/HOVC tandem connection overhead can be processed (either terminated, or terminated and re-inserted, or inserted). If single instance is available and not owned by somebody else
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 14
Alternative "OTN"
The regenerator circuits around optical fabric equipment may add to the above set of processes: the TDM muxing process to create higher rate aggregate
SONET/SDH signals or, the inverse process in which a higher rate service signal
is "de-aggregated" to be transported via multiple lower rate SONET/SDH signals
and vice versa in the other direction
If SONET/SDH cross connect equipment is extended with multi wavelength interfaces, it would function as electrical fabric equipment.
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 15
Alternative "OTN"
The above processing would result in a SONET/SDH network extended with Additional SONET/SDH "path level repeater" equipment
(two LTEs back to back)" Multi wavelength interfaces (OC-N, STM-N)
Providing virtual fibers An Optical Section Connection (OS_C) function,
Management of the virtual fiber group signal transport can be implemented by means of the addition of a supervisory signal like defined in G.709
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 16
"BUT..."
But the transparent transport of SONET/SDH signals is one of the key requirements so far We can not ignore it... So, the SONET/SDH processing described in the above
regenerator circuit is not an acceptable level of processing… Unless the transparent transport requirement is dropped… And thus the new applications behind it are dropped...
Wouldn't this cause a status quo then? I.e. No enhancements in transport networking any longer, Fiber leasing only, instead of virtual fiber leasing
to other operators and customers building their own networks ...
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 17
OTN Characteristics:" New transport networking layer (carrier grade solution)
Next step (after SDH/SONET) to support ever growing data driven needs for bandwidth and emergence of new broadband servicesTerrabit/second per fiber via DWDM lines (transport level)Gigabit/second paths at 2.5 Gb/s, 10 Gb/s, 40 Gb/s (networking
level) Service transparency for SDH/SONET, ETHERNET, ATM, IP,
MPLS No change of SDH/SONET!One exception; interpretation of STM-LOF alarm + STM-AIS
due to OTN fail Enhanced OAM & networking functionality for all services Shortest physical layer stack for data services (IP OTN Fiber)
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 18
OTN Characteristics Gigabit level bandwidth granularity required to
scale and manage multi-Terabit networksWavelength level switching maximizes nodal
switching capacity, the gating factor for reconfigurable network capacity
Avoids very large numbers of fine granularity pipes that stress network planning, administration, survivability, and management
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 19
OTN Specifications: Where are They Being Developed? ITU Study Groups involved:
SG13 ‘General Network Aspects’: WP3WP4
SG15 ‘Transport networks, systems and equipment’WP3WP4
SG4 “Network Management” Optical Inter-networking Forum; OIF Internet Engineering Task Force; IETF Regional standards - ANSI and ETSI
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 20
OTN Architecture
Rec. G.872 “Architecture of optical transport network” (approved in Feb ‘99 and is currently being revised)
It describes the functional architecture of optical transport network using the methodology of ITU-T Rec.G.805.
It also defines : Definition of generic requirements for management of OTN A phased approach for interworking to ensure smooth
transition
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 21
OTN Sub-network
Optical Optical ClientClient
NE NE
OChOAM
OChOAM
OTN Sub-network
Optical Optical ClientClient
NENENE
m
n
OChOAM
OChOAM
OTN Client Connections, Wavelengths & Optical Channels
OTN Client Connection:OTN Client Connection: An “end-to-end” Optical Transport Network service between optical clients, which may cross multiple OTN sub-networks, may traverse multiple Optical Channels, and may reside within multiple successive wavelengths
Wavelength:Wavelength: A particular frequency (1..n) within multiplexed optical signal
Optical Channel (OCh):Optical Channel (OCh): A network engineering and administration construct, supplying a portion of an OTN client connection. The OCh creates an “optical path” out of one or more concatenated wavelengths, with associated OAM.
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 22
Building a New Transport Networking Tech
What does Optical Networking (really)? Transport Networking at a new level of granularity:
the Optical Channel (OCh) LevelManage frequency-slots (OCh’s, single or multiple
s) instead of time-slots (e.g., VC-3/4’s) Ability to Manage Optical Channels Include Optical layer OAM&P (Operations,
Administration, Maintenance & Provisioning) information needed to support Optical Transport Networking applications
OAM&P is supported in form of Optical Layer overheads
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 23
Building OTN Tech with O/E/O Objectives
Minimise O/E/O processing in OTN O/E/O processing at edges of administrative/vendor (sub)domains
Span engineering O/E/O processing at edges of protected or switched domain
Span engineering (short/long route effects)Signal Fail & Signal Degrade condition determination
If more than 1 optical transparent subnetwork is included
O/E/O processing at intermediate pointsSpan engineering (long line sections)Losses in optical fabrics
O/E & E/O processing around electrical fabric
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 24
G.709 - Interfaces for the OTN G.709 specifies two sets of OTM-n interfaces:
OTM interfaces to be used when interconnecting equipment of two different operators, of an operator and a user, or of two different vendors
OTM interfaces to be used when interconnecting equipment of the same vendor
These interfaces support the: Performance needs of future optical networks Development of cost effective optical networks Ability to interconnect optical network equipment of different vendors
and/or operators Ability to forward the service signal (i.e. ODUk or client)
Furthermore: G.709 supports fault management and performance monitoring as needed in
the current competitive marketplace with many operators and high quality demanding customers
G.709 is the basis of the new "managed wavelength services"
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 25
In Depth Coverage of G.709
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 26
OTN Containment Relationships
Optical Transport Module
OPSn
OCh Optical Channel
Optical Channel CarrierOCC OCC OCC
Client
OTUk FECOH OCh Transport Unit
ODUkOH OCh Data Unit
OPUkOH OCh Payload Unit
Wra
pp
er
Ass
ocia
ted
over
hea
d
OPS0
Optical Physical Section
OTM Overhead Signal
Optical Supervisory ChannelOSCOOS
OSC
OH
OH
OH
Non
-ass
ocia
ted
ove
rhea
d
OMSn
OTSn
Optical Multiplex Section
Optical Transmission Section
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 27
OTN Layer Network Trails
Example of OTSn, OMSn, OCh, OTUk, ODUk, OPS0 trails Transport of STM-N signal via OTM-0, OTM-n and STM-N lines
DXC 3R3R
3R
OTSn OTSn OTSn OTSn OTSnOMSn OMSn OMSn
STM-NODUk
Client
Client
3R
DXC
OPS0 OSn
OT
M-0
OT
M-n
ST
M-N
OCXC
OCADMLT R R LT
LT Line Terminal w/ optical channel multiplexingOCADM Optical Channel Add/Drop MultiplexerOCXC Optical Channel Cross-Connect3R O/E/O w/ Reamplification, Reshaping & Retiming and monitoringR Repeater
OCh, OTUk OCh, OTUkOCh, OTUk
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 28
OTN: Network Management Issues
Carrier CCarrier BCarrier A
OTN ClientConnection
ClientClient
OCh-TC OCh-TC OCh-TC
OCh-P
OCh-S OCh-S
Interface Interface Interface Interface
•Integrity of client signal across interfaces•Autonomous management within a domain (at all layers)•Standardized management structure across interfaces
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 29
Client Signal and Wrapper Frame Structure
Client Signal
STM, ATM, IP GbEClient Signal
STM, ATM, IP GbE
OCh Layer
OMS Layer
OTS Layer
OCh Layer
OMS Layer
OTS Layer
OChOAM
OCh Payload(client signal)
FECData
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 30
Digitally Wrapped OCh Frame Structure
OChOAM
OCh Payload(client signal)
FECData
4080 columns
4rows
Frame size: 4 rows (bytes) x 4080 columns (bytes)
Frame structure includes OPU, ODU, and OTU. Frame transmission: from left to right Overheads used for path, tandem connection (TC) and section management FEC helps extend the reach length.
1 16 17 3824 3825 4080
SONET/SDHSONET/SDH ATMATM PDHPDH IPIP GbEGbE GFPGFP
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Engineering and Computer Sciences
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Features of Digitally Encapsulated OCh Frames Digital encapsulation of frames enable “virtual
transparency” (service transparency) Releases the Optical Network from SONET/SDH
dependency Allows for end-to-end Optical Transport Networking
solutions
Forward Error Correction for increased distance Performance Monitoring: ideal for native data services and
lease of wavelengths applications Signaling for optical channel routing and optical layer
protection and restoration
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 32
Building Blocks of Wrapped Frame:OPU, ODU and OTU Information Structures
ODU: OCh Data Unit OCC: Optical Channel Carrier (a tributary slot in OTM-n)
OPU: Optical channel Payload Unit OMS: Optical Multiplex Section
OTM: Optical Transport Module OTS: Optical TransmissionOTU: OCh Transport Unit OCG: Optical Carrier Group n: represents number of wavelengths, m : represents bit rate
OTM-n.m
OPUOPU ODUODU OTUOTU
Wrapper
ADAPTER MUX
n
OMU-n.mOTSOH
OTSOH
ClientClient1
.
.
....SONET/SDH, IP
ATM, GbE, . . .
Client
OChOCh OCCOCC
OCC
.
.
.OCG-n.m
+OMSOH
OCG-n.m
+OMSOH
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 33
Optical Channel Payload Unit:OPU Frame Structure
Client signal is mapped into OPU payload area at fixed rate * in floating mode (no pointer)
OPU overheads: payload and mapping specific* recommended rate: 2.48832 Gb/s (OPU1), 9.95328 Gb/s (OPU2), 39.81312 Gb/s (OPU3)
1
2
3
4
2 3Row
Column
OPU Payload Area(4 x 3808 bytes)
1
Client SignalSTM, IP, ATM, GbE, . . .
OPUOH
3810
Client SignalSTM, IP, ATM, GbE
OCh Payload(client signal)
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 34
Optical Channel Data Unit:ODU Frame Structure
ODU Frame size: 4 rows x 3824 columns (bytes) ODU overhead are used for path and TC OAM&P OPU is mapped within ODU payload in a locked mode 1st Row of ODU overhead is for Frame alignment & OTU Overhead
1
2
3
4
2 14Row
Column
ODU Payload Area(4 x 3824 bytes)
1
Client SignalSTM, IP, ATM, GbE, . . .
ODU Overhead Area
3824
OPU (4 x 3810)
15…..
ODU Payload
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 35
Optical Channel Transport Unit:OTU Frame Structure
OTU Frame size: 4 rows x 4080 columns (bytes) Forward Error Correction (FEC): RS(255, 239) code and 14 bytes of overhead (bytes 1 - 7 are for frame alignment)
ODU is mapped within OTU payload in a locked mode OTU overheads are used for OCh section management
1
2
3
4
14Row
Column
ODU Payload Area(4 x 3824 bytes)
1 3824
ODU (4 x 3824)
15
Optical Transport Unit Payload
Mode Locked
OUT FECRS(255,239)4 x 256 bytes
3825 4080
FA OH OTUk OH
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 36
OPU/ODU/OTU Bit Rates:
Signal Type Nominal Bit Rate (Kb/s)
Bit Rate Tolerance Approx. Period
OPU1 2 488 320 +/- 20 ppm 48.971 s
OPU2 238/237 * 9 953 280 +/- 20 ppm 12.191 s
OPU3 238/236 * 39 813 120 +/- 20 ppm s
ODU1 239/238 * 2 488 320 +/- 20 ppm 48.971 s
ODU2 239/237 * 9 953 280 +/- 20 ppm 12.191 s
ODU3 239/236 * 39 813 120 +/- 20 ppm s
OTU1 255/238 * 2 488 320 +/- 20 ppm 48.971 s
OTU2 255/237 * 9 953 280 +/- 20 ppm 12.191 s
OTU2 255/236 * 39 813 120 +/- 20 ppm s
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 37
ODU/OTU Frame Alignment
1 2 3 4 5 6 7 8
FAS OH Byte 1
1 2 3 4 5 6 7 8
FAS OH Byte 2
1 2 3 4 5 6 7 8
FAS OH Byte 3
1 2 3 4 5 6 7 8
FAS OH Byte 4
1 2 3 4 5 6 7 8
FAS OH Byte 5
1 2 3 4 5 6 7 8
FAS OH Byte 6
OA1 OA1 OA1 OA2 OA2 OA2
OA1: 11110110 OA2: 00101000 => 0xF6F6F6 282828
MultiFrame Alignment Signal (MFAS) may be used for 2-frame, 4-frame, …. 256-
frame MultiFrame structures
1 2 3 4 5 6 7 8
MFAS OH Byte
:0000 00000000 00010000 00100000 00110000 0100
::
1111 11101111 11110000 00000000 0001
:
MF
AS
sequence
76
ODUk OH
1
4080
FA MFAS OTUk OH
OPUkOH
Payload (client Signal) FEC
15 16 3824
4
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 38
OPUk Overheads Used for Client Mapping1
4080
15 16 3824
4
PSI: payload Structure Identifier JC (bits 7 & 8): Justification Control, 2/3
majority vote in justification decision in demapping
NJO: Negative justification Opportunity PJO: Positive Justification Opportunity
Hex Code Payload Type 01 Exp. Mapping 02 Async. STM-N mapping 03 Bit Sync STM-n mapping 04 ATM mapping 05 GFP mapping 10 Bit stream with octet timing mapping 11 Bit stream w/o octet timing mapping ….. FD NULL test signal mapping FE PRBS test signal mapping
ODUk OH
FA MFAS OTUk OH RES
RES
RES
PSI
JC
JC
JC
NJO PJO
Payload (client Signal)FEC
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 39
Asynchronous and Bit Synchronous Mapping
Using additional byte for payload
ODUk OH
FA MFAS
OTUk OH RES
RESRES
PSI
JC
JCJC
NJO PJO
Payload (client Signal)slightly slow! FEC
PJO;Byte Stuffing
ODUk OH
FA MFAS
OTUk OH RES
RESRES
PSI
JC
JCJC
NJO
Payload (client Signal)exact match! FEC
Exact rate
ODUk OH
FA MFAS
OTUk OH RES
RESRES
PSI
JCJC
Payload (client Signal)slightly faster! FECJC
JC
Once per frame, it is possible to perform +ve or -ve justification
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 40
Mapping of CBR 2.5 Gb/s Signal Into OPU1
ODUk OH
FA MFAS OTUk OH RES
RES
RES
PSI
JC
JC
JC
NJO PJO
Payload (client Signal)FEC
15 16
Client SignalSTM, IP, ATM, GbE, . . .
3824
Client Signal
17
OPU1
2.48832 Gb/s 20 ppm
Groups of 8 successive bits (not necessarily being a byte) of CBR2G5 signal are mapped into Payload of the OPU1
Once per OPU1 frame, it is possible to perform either a positive or a negative justification action
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Engineering and Computer Sciences
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Mapping of CBR 10 Gb/s Signal into OPU2
ODUk OH
FA MFAS OTUk OH RES
RES
RES
PSI
JC
JC
JC
NJO PJO
15 16
Client SignalSTM, IP, ATM, GbE, . . .
3824
Client Signal
17
OPU2
9.95328 Gb/s 20 ppm
Groups of 8 successive bits (not necessarily being a byte) of the 10 Gb/s signal are mapped into Payload of the OPU2
64 Fixed Stuff (FS) bytes are added in columns 1905 to 1920
Once per OPU2 frame, it is possible to perform either a positive or a negative justification action
16FS FEC
1905
1920
Payload Payload
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Mapping of CBR40 Gb/s Signal into OPU3
ODUk OH
FA MFAS OTUk OH RES
RES
RES
PSI
JC
JC
JC
NJO PJO
15 16
Client SignalSTM, IP, ATM, GbE, . . .
3824
Client Signal
17
OPU3
39.81312 Gb/s 20 ppm
Groups of 8 successive bits (not necessarily being a byte) of the 40 Gb/s signal are mapped into Payload of the OPU3
128 Fixed Stuff (FS) bytes are added in columns 1265 to 1280 & 2545 to 2560
Once per OPU3 frame, it is possible to perform either a positive or a negative justification action
16FS
1265
1280
Payload Payload 16FS FECPayload
2544
2560
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 43
Mapping of ATM Cells into OPUk
ODUk OH
FA MFAS OTUk OH
15 16 3824 17
OPUk…..
FEC
… ……………………………...
ATM Cells
OP
Uk
OH
A constant bit rate ATM cell stream with a capacity that is identical to OPUk payload area is created by multiplexing ATM cells from a set of ATM VP signals
Rate adaptation is performed as a part of this cell stream creation process by either idle cells or by discarding cells
ATM Cell boundaries are aligned with OPUk payload byte boundaries
HEC framing is used on the recovering of the ATM cells
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 44
Mapping of IP or Ethernet Into OPUk using GFP
ODUk OH
FA MFAS OTUk OH
15 16 3824 17
OPUk…..
Variable Length GFP Frames
OP
Uk
OH
…...………………………
… .…...
FEC
GFP Idle
A new protocol is being defined: Generic Framing Procedure (GFP)
Encapsulation for packet based client signals (e.g, IP or Ethernet)
no need for SDH or 10 G Ethernet to encapsulate IP
Mapping of GFP frames is performed by aligning the byte structure of every GFP frame with the byte structure of the OPUk payload.
A GFP frame consists of a GFP header and a GFP payload area; frame size varies from 4 to 65535 bytes
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Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 45
Generic Framing Procedure
Frame Multiplexing:On a frame-by-frame basis. When no frames are waiting, idle frames are inserted.
Frame Delineation Algorithm:Based on detection of correct cHEC. PLI is used to find the start of the next frame
Frame Multiplexing:On a frame-by-frame basis. When no frames are waiting, idle frames are inserted.
Frame Delineation Algorithm:Based on detection of correct cHEC. PLI is used to find the start of the next frame
PLIPLI
cHECcHEC
Payload Area
FCS(optional)
0000
cHECcHEC
GFP Frame
Idle Frame
Up to 65535bytes
PLI: PDU Length Indicator
cHEC: Core - Header Error Control
FSC: Frame Check Sequence
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Engineering and Computer Sciences
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ASTN/ASON ArchitectureASTN/ASON Architecture
Key concepts: Logical separation of transport and control, 3 types of logical interfaces
RA
RARA
View in slide show modeMANAGEMENT PLANE
TRANSPORT PLANE
CONTROL PLANEUNI
MS MS
OXC
OXC
OXC
OXC
OXC
OXC
OXC
OXC
CCCC
CC
CC
CC
CC
CC
I-NNI E-NNI
RequestAgent
ConnectionController
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Distributed Control Plane Protocols Key Elements
MPLS-based signaling protocols for distributed connection management RSVP-TE based for UNI, CR-LDP based for I/E-NNI
Routing protocols for topology and resource update OSPF-TE for intra-domain, O-BGP for inter-domain
Protocol Interaction Examples Switched Connections
Request Agent (RA) initiates connection setup via UNI (RSVP-TE based) signaling
Routing takes place via OSPF-TE and O-BGP Connection Controllers (CC) communicate via NNI (CR-LDP based) signaling
Soft Permanent Connections Management Plane initiates connection setup Routing takes place via OSPF and BGP CC communicate via NNI (CR-LDP based) signaling
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Kazi Fall 2007 CSCI 370/EENG 480 48
An Animation is worth a million words...An Animation is worth a million words...
UNI
RA
RARA
OXC
OXC
OXC
OXC
OXC
OXC
OXC
OXC
CCCC
CC
CC
CC
CC
CC
I-NNI E-NNI
Switched Connections
Soft Permanent Connections
RSVP-TE
User Initiates Connection Setup
OSPF-TE O-BGP OSPF-TERouting functions (OSPF-TE + O-BGP) find path
CR-LDP
NNI Signaling for cross-connect setup
RSVP-TE
End-user notified
Connection Controllers signal to complete cross connects
End-to-end Connection Established
MS MS
Management System Initiates Connection SetupOSPF-TE O-BGP OSPF-TE
Routing functions (OSPF-TE + O-BGP) find path
CR-LDP
NNI Signaling for cross-connect setupConnection Controllers signal to complete cross connects
End-to-end Connection Established
View in slide show mode
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 49
End-End Intelligent Transport Networking Solution
•Multi-operator interoperability provided via open UNI and E-NNI interfaces. •Will enable the service provider to accept requests for bandwidth on demand from its customers connected to the metro access and/or metro core, connecting with transport backbone network providers to make true end-to-end bandwidth on demand a reality all the way to the access node.
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 50
NN Distributed Routing Control Nodes
Keep Local Routing Tables Exchange Routing
Information Via Routing Protocols
Keep Network Capacity Inventory
Perform Topology Discovery Perform Routing Algorithms
Restoration Schemes Use Embedded Network
Intelligence to Offer Mesh Based Restoration
LocalRoutingTable
LocalRoutingTable
LocalRoutingTable
LocalRoutingTable
LocalRoutingTable
NN: Network Navigator
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 51
OSM requests Optical Channel from ONN
ONN establishes end-to-end Och Connection
OSM configures client devices
True End-to-End Service is Established
WavelengthServiceProvisioning
Optical NetworkNavigator
Operator Selects:•End Points for Optical Channel•Service Level Agreement (SLA) Parameters•Optical Path Characteristics•Restoration Type•Billing Options– etc.
Optical Network Topology View
Optical Services Manager
(OSM)
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 52
NN Real-Time Provisioning
Fast Provisioning of High Capacity Services
Eliminates Order Backlog
Automatic Resource Management Optimal Topology Transport Traffic
Engineering
ProvisioningSystem
Router
Router
CompanyLocation B
CompanyLocation A
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 53
Dynamic Trunking
When utilization threshold is reached, or traffic patterns change client devices request a new trunk
In response to request OSM provisions a new Optical Path
AA
BB
CC
Router B is bogged down with
A C traffic!
All trunks are OK.
Optical Network Topology View
Optical Services Manager
(OSM)
Provision new, direct trunk between Routers A
& C
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 54
Router
Router
Router
CompanyLocation A
CompanyLocation B
CompanyLocation C
MeshProtection
1+1 NetworkProtection
Un-ProtectedTraffic
Survivability tailored for each application 0x1 (for traffic protected at the
service layer) 1+1 Mesh
QoS as a Protection Option Choose your option; e.g., unprotected,
1+1, mesh, etc. Mesh Restoration - “The New Trend in Optical
Network Restoration” Effective use of network resources Minimizes wasted capacity needed for
protection Flexible Versatile
Network Survivability
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 55
Optical VPNEach customer gets their own Optical “Virtual Private Network” through a web GUI
Customer can: • View own network • Create connections• Monitor their status• Request new end-points• Request more capacity
Network provider can: • Create VPN• Add/delete end-points• Modify allocated connections• Monitor VPN status• Bill
Optical Network Topology View
Optical Services Manager (OSM)
Optical Network Topology View
Customer WS
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 56
External Fora - Control Plane Specifications
ITU-T
ITU-T SG 13 & 15
Q10/13, Q12/15,Q14/15
ASTN/ASON requirements,architecture, and control planespecifications (discovery, signaling,data comm network)
ANSIT1X1 Establishment of recommendations
and positions into internationalstandards
IETF MPLS,CCAMP, IPOWGs
Extensions to IP-based routing andsignaling protocol specifications forASTN, including architecture andrequirementsIETF
IETF TE WG Traffic engineering approaches for IPlayer networks, includingsurvivability
OIFOIF Architecture,Signaling, OAMWGs
Control plane architecture andsignaling specifications for signalingUNI
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 57
Automatically Switched Transport Network (ASTN)
Refers to set of draft Recs. related to distributed control of transport networks G.807, Architecture of the Automatically Switched Transport
Network G.ason, Architecture of the Automatically Switched Optical
Network G.dcm, Distributed Connection Management G.disc, Automatic Neighbor and Service Discovery
Targeted at any type of circuit-switched network; initial focus: SDH/SONET OTN
Addresses single-provider, multi-provider, and user-provider application domains
New York Institute of Technology
Engineering and Computer Sciences
Kazi Fall 2007 CSCI 370/EENG 480 58
Generalized MPLS (GMPLS) Refers to set of drafts related to “IP-based Optical Control”
GMPLS (extension of MPLS-TE) Signaling Functional Spec. for CR-LDP and RSVP-TE
G-MPLS Architecture Link Management Protocol (LMP) Link Bundling in MPLS Traffic Engineering OSPF/ISIS Extensions to GMPLS Extension of MPLS-TE model
Targeted at different types of “Label Switch Routers” PSC (Packet Switch Capable) interface SONET/SDH-based (w/wo DWDM) LSC (Lambda Switch Capable) interface FSC (Fiber/Lambda Group Switch Capable) interface
Currently focused upon single provider application domain