DEPARTEMENT SIGNAL ET TELECOMMUNICATION
Réseaux Hauts Débits
Réseaux Optiques
5ème Année B IRT
2008-2009 Stephan ROULLOT
1
All Rights Reserved © Alcatel-Lucent 2006, #####
Cours Réseaux Optiques
Partie I - PDH, SDH,
Carrier Ethernet, FTTx
Stéphan RoullotAlcatel-LucentOptical Networking [email protected]
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Agenda
1. Introduction Alcatel-Lucent2. Transport Protocols in Public Networks
3. Multiplexing techniques
4. PDH Overview5. SDH Overview & Advantages of SDH
6. Basic SDH Frame Structure and Transmission Principles7. SDH Multiplexing Structure
8. SDH Pointer Function9. Overheads
10. Synchronization11. Protection Mechanisms : MSP, MS-SPRING, SNCP, DNI, hardware
12. Classification of optical interfaces & Transmission Range
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Agenda
13. Functional Equipment Specification14. Typical Equipment Types & Network Applications
15. OAM&P
16. ASTN / GMPLS17. Standardization
18. Conclusion on SDH, evolution to Next-Generation SDH, MSPP19. Native Ethernet
20. Example of prolonging SDH life: Ethernet over SDH, 21. Recent developments around Carrier Ethernet Technologies
22. Transport Network Evolution23. FTTx
24. Overview Optical Market & Competition
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IntroductionAlcatel-Lucent
2
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Lucent Technologies History
Lucent Technologies spun-off from AT&T in 1996
§ Acquired PKI, TRT, etc in Europe§ Manufactures equipment for telecommunication networks§ Transmission, Switching, Wireless, Data, Access, IMS
§ Bell Laboratories§ ~35.000 employees world-wide
France (300 employees): Le Plessis-Robinson, Lannion§ Formerly TRT
§ Activities: Wireless R&D, Marketing & Sales, Support ServicesOptical Networking Group (~600 employees in R&D):
§ R&D centers in the USA (Holmdel, Westford, Whippany) for SONET, DWDM equipments, and Germany (Nürnberg) for SDH, OXC equipments
§ Manufacturing outsourced in China
Merge with Alcatel effective December 1st 2006
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IP/MPLS/IP/MPLS/Optical CoreOptical Core
PSTN, ISPs, Peer IP Networks
A Portfolio of Wireline Solutions at the Forefront of IP Network Transformation
PON
DSL
Service Service AggregationAggregation
Service EdgeService Edge
Intelligent Transport
Gateways,Mobility HA
UMTS/LTE
CDMA
WiMAX
Residential Broadband
Next Generation Wireless
Enterprise
Converged NetworkScalable service delivery across resilient,
IP-rich Infrastructure
Distributed per-subscriberand per-service control
Integrated network, element, service and subscriber management
Federated Control
IPTV IMS Web
NG IP BaseStation
Policy-Driven Subscriber and Resource Management
Universal Universal AccessAccess
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Alcatel-Lucent Optics Division: More Value for Our Customers
1 • We can serve customers better everywhere
2• We can deliver richer optical networking solutions3• We can better help customers transform their networks for the future
the widest optical presence worldwide
the most comprehensive optical portfolio
the best of innovation and research in optics
Industry’s strongest and most diversified customer baseThe partner of choice of converged global service providers
Alcatel-Lucent brings together
All Rights Reserved © Alcatel-Lucent 2006, #####8 | Cours Réseaux Optiques – Partie I | March 2008
390,000 ADMs80,000 MSPPs
20,000 WDM Sys/Nodes8,200 Cross-Connects
Alcatel-Lucent in Optical NetworkingGlobal Expertise, Widespread Local Presence
150,000 ADMs138,000 MSPPs14,300 WDM Systems11,200 Cross-Connects461,500 Km Submarine Networks
Alcatel -Lucent25%
Fujitsu 10%
Huawei 10%
Cisco 7%
Ericsson 5%
NEC 6%
Nortel 12%
Siemens 7%
Tellabs 7%
Others 10%
# 1# 1
Alcatel-Lucent is a leader in every growing segment of the optical networking market
OpticalOpticalNetworkingNetworking
Source: OvumSource: Ovum--RHKRHK
#1 worldwide§ WDM - 21%§ OXC - 50.8%(source Dell‘Oro, 3Q06)
#1 worldwide§ Submarine§ MSPP - 28.5%(source Dell‘Oro, 3Q06)
Best technology à Massive customer references à Best market share More than 700 customers in 150 countries
3
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Paris, CalaisParis, Calais
Stuttgart, Nuremberg Stuttgart,
Nuremberg
Vimercate,Trieste,Genoa
Vimercate,Trieste,GenoaWestfordWestford
Murray Hill, HolmdelMurray Hill, Holmdel
ChengduChengdu
PlanoPlano
GreenwichGreenwich
Shanghai Shanghai
Optics: Locations
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Transport Protocols in Public Networks
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Transport Networks (wire-line)
Transport networks are the means to transport end-user services
§ Access networks: Transport from the end-user premises (CP = Customer Premises) to a "service node"
§ Metro or Core networks: Transport between two "service nodes"Examples of service nodes
§ Digital Switch for voice services§ IP router for IP services
CP
Access
Metro
Core
CPE
X X
CP
Access
Metro
CPE
XX
Service Nodes
Public Network
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Protocols for Transport Networks
Various protocols are in use for transport of information over (wire-line) public networks
§ DWDM (OTN) - Layer 1
§ SDH / SONET - Layer 1
§ ISDN - Layer 1
§ Ethernet (CSMA/CD) - Layer 1 and Layer 2
§ ATM - Layer 2
§ MPLS - Layer 2~3
§ IP - Layer 3
Multiple protocols need to be "stacked" to get the desired capabilities
§ IP -> ATM -> SDH
§ IP -> Ethernet -> DWDM
§ IP -> MPLS -> Ethernet -> MPLS -> SDH
§ etc (any meaningful combination)
4
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X.86
Data (IP, IPX, MPLS, etc.)
SONET/SDH
Fibr
e C
hann
el*
ES
CO
N*
FIC
ON
*
GFP
S A N s
Fiber
HDLC*
Ethernet*
POS
ATM
WDM/OTN
F R
Video
DV
I*
PrivateLines
Voice
RPR
(Under Study)
Protocol Stacking
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Technical Factors distinguishing protocols (1)
Bandwidth Efficiency
§ The ability to transport any traffic volume from the end-users and keep the public network well filled
§ Statistical multiplexing gain is inherently present in datagram protocols§ High protocol stacks decrease efficiency (e.g. ATM "cell-tax")
§ In case of congestion, delay sensitive traffic should be favored
Scalability
§ Scalability of speed: the bandwidth of links can be increased without adding hardware or by adding minimal hardware
§ Scalability of size: network elements can be added to an existing network without loss of performance
e.g. impact of network diameter on convergence time of routing protocols
Delay, delay variation§ This is predominantly an issue for continuous bit-rate services (voice, video)
§ TDM (SDH, ISDN) is optimized for these services§ Connection-oriented datagram protocols (ATM) are "good-enough"
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Technical Factors distinguishing protocols (2)
Complexity
§ Complexity covers the operational aspects of a network. The more effort is required to add/change network paths/parameters or to isolate faults, the costlier it is for a service provider
§ The advantage of IP & Ethernet is that routing is taken care of automatically.
However, this is not a principal difference. ASTN/GMPLS is a new development, which provides SDH with capabilities comparable to OSPF and IS-IS.
Robustness
§ The network must be fault-tolerant: failed nodes may not bring down a network; traffic is automatically rerouted after link or node failures
§ There is some resilience against human error
Security
§ Keep traffic streams of different end-users separated. Much more difficult in case no dedicated "layer" is available for the service provider (e.g. IP)
§ Prevent customers from using more bandwidth or higher priority than their contract allows
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Non-technical factors to favor protocols
Cost (at the network level)
§ The number one selection criteria
Installed Base
§ The installed base often limits the choices for a service provider when it comes to buying new equipment
§ Changing means building a separate network (overlay), train the staff, maintain new sets of spares, solve inter-working issues with old network
Management Systems
§ The availability of a good network management system saves a lot of operational costs in the day-to-day running of the network: adding nodes, adding customers/bandwidth, troubleshooting, collecting network statistics
Standards Compliance
§ Necessary to get inter-working with other service providers
§ Necessary for inter-working between equipment vendors; allows a service provider to buy systems from multiple vendors: keeps prices down
5
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Difficulties in changing protocols
Companies are often strongly bound to certain protocols. Only big companies can afford to support multiple protocols§ Cisco -- IP
§ Lucent ONG -- DWDM, SDHEquipment Vendors
§ Protocol choice is coupled to Technology§ Product Range is built around certain protocols
Service Providers§ Installed Equipment base
§ Existing Customer baseIn practice it is impossible for a company to change protocol quickly§ Adapt evolutionary (preferred, but takes time)
§ Buy other company (costly, but quick)
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Multiplexing Technologies
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Multiplexing Techniques
Multiplexing is a method to aggregate low speed traffic onto a high speed communication link.
Multiplexing techniques:
Each analog channel is modulated using a different carrier
frequency
Frequency Domain Multiplexing (FDM)
Each digital channel is given its own time
slot. Examples: PDH, SDH
and SONET
Time Domain Multiplexing (TDM)
Each channel is given its own optical
wavelength (color)
Wavelength Division Multiplexing (WDM)
PDH = Plesiochronous Digital Hierarchy, SDH= Synchronous Digital Hierarchy, SONET= Synchronous Optical Network)
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Multiplexing Techniques - TDM
Bits or bytes successively retrieved from the different channels to build asingle bit stream
Flexible traffic management; fixed bandwidth
Mux/demux feature required
6
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Multiplexing Techniques - WDM
DWDM = Dense WDM
CWDM = Coarse WDMMerging of optical traffic on a single fiber
Expansible bandwidth
Cost reduction (reuse of existing optical signals)
Independence of bit rates and frame formats
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Multiplexing Techniques - Capacities
8 16
1000
0,01
0,1
1
10
100
Gbit/s
24
32 80128
128
40
NxSTM64
NxSTM16
STM-N
STM1
STM4
STM16
STM64
STM256
Data
1985 1990 1995 2000 2005
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Before SDH: PDH
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PCM (Pulse Code Modulation)
Voice codec according Shannon/Nyquist theorem:
§ Phone analog signal band = 3.4 kHz (rounded up to 4 kHz)
§ Required sampling rate : 8000Hz (i.e. 1 sample every 125 µs)No gain above since higher harmonics are cut by the low-pass filter
§ All Time Intervals in digital transport networks are multiple of 125 µs
PCM (MIC (Modulation par Impulsion et Codage) is the basis of digital transmission in PSTN:
§ Codec delivers data blocks of 8 bits ð 64 kbit/s per channel
§ All timeslots in digital transport networks are multiple of 64 kbit/s
7
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E1 Frame Structure (MIC 2G)
Basic E1 frame at 2.048Mbit/s (T1 at 1.544Mbit/s in the US) contains 30 TS, 1 framing byte (TS0), 1 signaling channel (TS16) synchronously multiplexed
1 2 3 4 5 6 7 8
32 x 8 = 256 bits (125 µs)
TS0 TS16
Voice sample 8bits
TS1
Frame Alignment Out-of-band Signaling
TS15 TS17 TS314 signaling bits per channel
Need 15 frames for signaling of the 30 voice channels. These 15 frames + 16th constitute a multiframe (G.704)
Digital channel:8 bits x 8000 Hz = 64 kbit/s
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PDH (Plesiochronous Digital Hierarchy)
Old TDM technique (G.702) of E1 channels (“tributaries”)
Multiplexing of 4 tributary channels into the next multiplex
Nodes have their own clock; E1 channels are plesiochronous(2.048.000 Hz ± 102 Hz)
Rate adaptation during multiplexing steps:
§ Addition of stuffing bits to each plesiochronous tributary to make them synchronous and in phase (process called “positive justification”)
§ Synchronization and signaling bits added (stuffing bits must be signaled for the remote end to eliminate them)
§ Bitrate of Multiplex N+1 > 4 x bitrate of Multiplex N
§ No direct access to tributary signals, requirement for complete demultiplexing
No (or little) standard for optical signals at PDH speeds
Still used for the lower multiplexing stages
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PDH Multiplexing
Add and drop of low bit rates is very difficult as all channels must be de-multiplexed and then multiplexed again
140 Mbit/s
34 Mbit/s
8 Mbit/s2 Mbit/s
34 Mbit/s
8 Mbit/s2 Mbit/s
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PDH Transmission Rates
64 kbit/s
Europe & rest of the world
North AmericaJapan
J5 397 200 kbit/s
x4
564 992 kbit/s
x4
E5
274 176 kbit/s
x6
DS4
DS0, E0, J0
J3
x5
32 064 kbit/s
G.752
J4 97 728 kbit/s
x3 G.752
DS3
x7
44 736 kbit/s
G.752
x4
E4139 264 kbit/s
G.753
34 368 kbit/s
x4
E3
G.751
6 312 kbit/s
x4
DS2, J2
G.743
G.755x4
G.747x3
8 448 kbit/s
x4
E2
G.742
Interworking (G.802)
xN: Multiplexing factor
2 048 kbit/sx30
E1
x24
DS1, J1 1 544 kbit/s
8
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SDH Overview & Advantages
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SDH Historical Background
1984: Difficulties encountered with the interconnection of high-bitrate systems
1985: Solution by Bellcore SONET
§ Introduction of synchronous multiplexing bases
§ Frame at 49.920 Mbit/s adapted for T1
1986: Investigations on synchronous transmission within CCITT
§ Objective: interface at about 150 Mbit/s
1987: First CCITT Task force on the subject
§ USA proposition based on SONET solution and taking into account of the European hierarchy
1988: Definition of the SDH principles
1989: Publication of first Recommendations - G.707, G.708, G.709 - which form the basis of SDH
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SDH (Synchronous Digital Hierarchy)
Derived from North American SONET standard in 1988
State of the art synchronous TDM technology for backbone communication over optical fibers
Synchronous means that
§ multiplexing is synchronous, direct access/visibility to tributaries
§ transmission is synchronous: reception clock is extracted incoming signal
§ the whole network is synchronized to a single master clock which is distributed to all network elements
In order for this clock not to become a single point of failure, most networks have several backup clocks
International technology (except US with SONET)
§ SDH is based on international standards from ITU -T (former CCITT) and ETSI
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High transmission rates
§ Payload > 150 Mbit/s for STM-1
§ Currently up to 40 Gbit/s, above DWDM is used
§ Future proof platform (STM-256, STM-1024)
Optical fiber support
§ High transmission quality
§ Standardized physical interfaces with confined optical parameters
Simplified add & drop function
§ Direct access to tributary signal (2 Mbit/s for example) in STM-1 aggregate signal
§ Mixing of signals of different hierarchies/technologies in a single STM-1
Advantages of SDH (1)
9
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Flexibility
§ Network able to transport different signals (Ethernet, Video, PABX, PDH, SDH, ATM, IP, etc)
§ Guarantees services down to PDHHigh availability and reliability
§ Provides various transmission protection schemes§ Highly reliable System Design with redundant hardware
Built-in Operation, Administration, Maintenance and Provisioning (OAM&P) functions
§ Associated with strong Network Management supportInternational standardization in ITU -T
§ Guarantee Multi-vendor Interoperability
§ Compatibility of transmission equipments and networks worldwide
Advantages of SDH (2)
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Network Layering, Data Transparency
Voice, Data, Video, Multimedia...
SDH/SONET
WDM
ATM
Ethernet
IP
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Basic SDH Frame Structure and Transmission Principles
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Bit Ordering conventions
The order of transmission of information in all the diagrams is first from left to right and then from top to bottom.
Within each byte the most significant bit (MSB) is transmitted first. The most significant bit (bit 1) is illustrated at the left in all the diagrams.
1 2 3
MSB
4 5 6 7 8
LSB
Transmission order
10
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SDH is transmitted in frames. Each frame is exactly 125 µs in time.
The basic SDH frame is called STM-1 and is often represented as a block of 9 rows with 270 bytes
Basic STM-1 Frame Structure (rectangular form)
Payload (VC-4)
150, 336 Mbit/sMSOH
SOH = Section OverHead
RSOH270 bytes
261 columns (payload)9 columns (OH)
9 rows
5
3
AU Pointer
125 µs
STM-1 =RSOH =MSOH =AU =
Synchronous Transport Module Level 1Regenerator Section OverheadMultiplex Section OverheadAdministrative Unit
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SDH Transmission Principle
The transmission of STM-N frames is made serially row by row starting from the left with row 1 column 1 through column 270, then row 2 column 1…
Frame period = 125 µs
The frame rate is always 8 000 frames per second, which is equivalent to a frame period/length of 125 µs
270 x 9 = 2430 bytes per frame x 8 bits/byte = 19 440 bits/frame
19 440 bits/frame x 8 000 frames/sec = 155.520 Mbit/s = STM-1
Row 3Row 2Row 1 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9
RSOH Pointer (9 bytes)
tMSOH
payload payload payload payload payload payload payload payload payload
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Scrambling
The STM-N (N=0, 1, 4, 16, 64, 256) signal must have sufficient bit timing content for clock recovery. A suitable bit pattern, which prevents a long sequence of "1"s or "0"s is provided by scrambling the STM-N signal with a frame synchronous scrambler of sequence length 127 operating at the line rate and with generating polynomial = 1 + X6 + X7. The scrambler runs continuously throughout the complete STM-N frame, except the first row of the STM-N (N = 64) SOH (9 × N bytes, including the A1 and A2 framing bytes) which is not scrambled.
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A B C D A B C D A
STM-N Multiplexing/Interleaving Principle
A higher order signal is created by byte interleaving the payload from the lower order signals. De-multiplexing is done in the opposite way.The bit rates of the higher order hierarchy levels are integer multiples of the STM-1 transmission rate.
Frame rate of higher order hierarchy signals as well as lower order signals are the same: 8000 frames per second (125 µs)The overhead bytes are not carried forward. The multiplexer adds new overhead bytes in both directions
STM-4
4 x STM-1STM-1
A
STM-1B
STM-1C
STM-1D
Bytes
11
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SONET and SDH Transmission Rates
SONET signals Bit rates Equivalent SDH signalselectrical optical Mbit/s electrical opticalSTS-1 OC-1 51,84 STM-0 STM-0oSTS-3 OC-3 155,52 STM-1 STM-1oSTS-9 OC-9 466,56STS-12 OC-12 622,08 STM-4 STM-4oSTS-18 OC-18 933,12STS-36 OC-36 1244,16STS-48 OC-48 2488,32 STM-16 STM-16oSTS-192 OC-192 9953,28 STM-64 STM-64oSTS-768 OC-768 39813,12 STM-256 STM-256o
These hierarchy levels are not existing and are shown only for the sake of completeness
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SDH Multiplexing Structure
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Synchronous Multiplexing
C4 139264 kbit/sATM
C3
POH
VC-3
POH
PTR
44736 kbit/s34368 kbit/s
x1TUG3
TU-3
C2
POH
VC-2
6312 kbit/sX1TUG2
TU-2
x3
x7
C12
POH
VC-12=140 octets
POH
PTR
2048 kbit/s
TU-12
C11
POH
VC-11
1544 kbit/s
x3
POH
VC-4
AUG
AU4
x1
x64
x16x4
(K)
(L)
(M)
POH
PTR
POH
PTR
Cn
POH
SOH
VCn
AUG
PTR
POH
x1
Container
VirtualContainer
Synchronous Transport
Module
Tributary Unit Group or Administrative Unit Group
--> TUG : Tributary Unit Group -->AUG : Administrative Unit
Group
Tributary Unit orAdministrative Unit
-->TU= Tributary Unit-->AU = Administrative Unit
SOH
STM-64 : 9,953 Gbit/s
STM-16 : 2,488 Gbit/s
SOH
STM-4 : 622 Mbit/s
SOH
SOH
STM-1 : 155 Mbit/s
STM-256 : 39,808 Gbit/s
SOHx256
Tributary Unit Group
TributaryUnit
VirtualContainer
ContainerAdministrative
Unit GroupAdministrative
Unit Synchronous
Transport Module Tributaries
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Definitions
C-n (Container):§ Information structure which forms the network synchronous information payload for
a virtual container. Size of C-n matches PDH, ATM, etc tributary bit-rates.
VC-n (Virtual Container):§ LO VC consists of a single container i (i=11, 12,2,3) and associated POH (Path
OverHead).
§ HO VC consists either of a single container i (i=4) or of an assembly of Tributary Unit Groups, together with Virtual Container POH appropriate to the level.
TU-n (Tributary Unit): Consists of a VC-n and its associated pointer.TUG-n (Tributary Unit Group): not a physical entity, virtual structure grouping different sized TU to increase flexibility of the transport network.AU-n (Administrative Unit): Consists of an information payload (higher order virtual container) and associated pointer.
AUG-n (Administrative Unit Group): Consists of a homogeneous group of AU -3s or AU-4s.STM-N (Synchronous Transport Module): Contains N AUGs together with SOH.
12
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x1
x4x16
x1x4
x3
x1
x1
x4
x64
x1
x1x3
x7 x7
x1
x3
x4Multiplexing/Interleavingx1
Aligning (adding pointer)
Synchronous Multiplexing Processes
STM-16
STM-4
STM-1
STM-0
AUG
AU-4-16c
AU-4
AU-3
AU-4-4c
VC-4-16c
VC-4
VC-3
VC-4-4c
C4-16c
C-4
C4-4c
TUG- 3 TU-3 VC-3
TU-2
TU-12
TU-11
VC-2
VC-11
VC-12
TUG- 2
Pointer processing
Note : Concatenation (Rec. G707, G803) =A procedure whereby a multiplicity of Virtual Containers is associated onewith another with the result that their combined capacity can be used as a single container across which bit sequence integrity is maintained.There is two types of concatenation : contiguous or virtual
contiguous concatenation
STM-64 AU-4-16c VC-4-16c C4-64c
contiguous concatenation
Mapping + Justification + POH addition
(adding SOH)
C-3
C-2
C-11
C-12
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Synchronous MultiplexingTU-12, klm numbering
010203040506070809101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263
123123123123123123123123123123123123123123123123123123123123123
1
23
4
5
6
71
2
3
4
5
6
7
1
2
34
5
6
7
1
2
3
VC 12TU 12TUG 2TUG 3VC 4 2 PI
AU 4
AUG
STM-1
K L M
TU12 N°1 is marked with KLM address = 111.TU12 N°32 is marked with KLM address = 242.TU12 N°63 is marked with KLM address = 373
KLM address of TU-12 defines its row in the VC4 :- K indicates TUG-3 rank used (1 to 3)- L indicates TUG-2 rank used (1 to 7)- M indicates TU-12 rank used (1 to 3)
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Multiplexing StructuresDifferent Regional Options
LOWER ORDERMULTIPLEXING
HIGHER ORDERMULTIPLEXING
European Structure of Multiplexing
STM-N AU-4 VC-4 C-4
C-3
TU-3
TU-2 VC-2 C-2
TU-12 VC-12 C-12
139264 Kbi t /sATM
44736 Kbit/s34368 Kbi t /s
6312 Kbit/s
2048 Kbi t /s
TU-11 VC-11 C-11 1544 Kbit/s
X 1
X 1
X 3
X 7
X 3
AUG
TUG-3 VC-3
TUG-2
STM-N AU-4 VC-4 C-4
AU-3 VC-3 C-3
TU-3 VC-3
VC-2
VC-12
139264 Kbit/sATM
44736 Kbi t /s34368 Kbit/s
6312 Kbi t /s
2048 Kbit/s
VC-11 1544 Kbi t /s
X 3
X 7 X
1
X 3
X 4
TUG-3
TUG-2
AUG
C-2
C-12
C-11
TU-2
TU-12
TU-11
AU-3 VC-3
LOWER ORDERMULTIPLEXING
HIGHER ORDERMULTIPLEXING
North America and Japan Structure of Multiplexing
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Steps of Multiplexing (1)140Mbit/s – VC-4 – STM-1
STM-1 AU-4 C-4
TU-3
TU-2 VC-2 C-2
TU-12 VC-12 C-12
139264 Kbit/sATM
44736 Kbit/s34368 Kbit/s
6312 Kbit/s
2048 Kbit/s
TU-11 VC-11 C-11 1544 Kbit/s
X 1
X 1
X 3
X 7
X 3
AUG
SOH
SOH
POH C-4
VC-4
AU- 4 Pointer
TUG-3
VC-4
TUG-2
VC-3
C-3AU-3 VC-3
HIGHER ORDERMULTIPLEXING
LOWER ORDERMULTIPLEXING
13
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Asynchronous Mapping of 140 Mbit/s Signal into a VC-4
W 96 I X 96 I 96 I 96 I 96 IY Y Y
X 96 I Y 96 I 96 I 96 I 96 IY Y X
Y 96 I Y 96 I 96 I 96 I 96 IY X Y
Y 96 I Y 96 I 96 I 96 I 96 IX Y Z
Information BitFixed Stuff BitOverhead BitJustification Opportunity BitJustification Control Bit
I :R:O:S:C:
1 12 Bytes1
Y
X
W
Z
: I I I I I I I I
: CRRRRROO
: RRRRRRRR
: I I I I I IS R
: Path Overhead
One of nine rows in a VC-4
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Steps of Multiplexing (2)34/45Mbit/s – VC-3 – TU-3 – VC-4 – STM-1
SOH
SOH
PO
HVC-3
TU-3
POH
POINTER
C-3
VC-4
STM-1 AU-4 C-4
AU-3 VC-3 C-3
TU-3 VC-3
TU-2 VC-2 C-2
TU-12 C-12
139264 Kbit/sATM
44736 Kbit/s34368 Kbit/s
6312 Kbit/s
2048 Kbit/s
C-11 1544 Kbit/s
X 1
X 1
X 3
X 7
X 3
AUG VC-4
TUG-3
TUG-2
VC-12
TU-11 VC-11AU Pointer
HIGHER ORDERMULTIPLEXING
LOWER ORDERMULTIPLEXING
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Asynchronous Mapping of a 45 Mbit/s Signalin a VC-3
One of nine rows in a VC3
Information Bitfixed Stuff BitOverhead Bitstuff opportunitystuff control bit
I :R:O:S:C:
85 Bytes
C C R R R R R R
8R 8R 200 I 8R 200 I8 I 8R 200 I8 IPOH
R R C I I I I I C C R R O O R S
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Asynchronous Mapping of a 34 Mbit/s Signalin a VC-3
average (bits / STM frame) = 4296 bits / STM frame = 34368 kbit/s
84 Bytes
J1
B3
C2
informationbits
8
8
8
8 8
8
fixed stuff
fixed stuff
C1 C2
fixed stuff
fixed stuff
3ro
ws
of9
8
8
8
8
8
8 8
information bitsfixed stuff
S1 S2
= stuff opportunities
2424 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24
2424 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24
24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24
1/3
PO
H
14
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Steps of Multiplexing (3)2Mbit/s – VC-12 – TU-12 – VC-4 – STM-1
AUGSTM-1 AU-4 VC-4
C-3
TU-3 VC-3
TU-2 VC-2 C-2
TU-12 VC-12
139264 Kbit/sATM
44736 Kbit/s34368 Kbit/s
6312 Kbit/s
2048 Kbit/s
TU-11 VC-11 C-11 1544 Kbit/s
X 1
X 1
X 3
X 7
X 3
RSOH
MSOH
pointer AU- 4 J1
TUG-3
TUG-2
C-12
C-4
TU- 12
C12
PTR
VC- 12
POH
STM-1 : 270 columns * 9 rows
VC-4 : 261 columns * 9 rows
TUG-3 86 columns
TUG-212 columns Note : To decrease the relative size of the path over-
head with regard to the payload, the C12 duration is 500us (and not 125us), it means four 2 Mbits/s frames. The 2 Mbits/s signal is then inserted in a C12 container of 139 bytes.
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SDH Pointer Function
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AU/TU-n Pointer Function
Pointer
Pointer
- AU pointer
- TU pointer
J1
VC4
SOH
SOH
SOH
SOH
FRAME N
FRAME N+1FRAME N+1
FRAME N
Position Determination (addressing):– The pointer indicates where the VC-n path overhead begins in higher order frame
Bit Rate Adaptation:– The pointer provides a method of allowing flexible and dynamic alignment of the
VC-n within the AU/TU-n frame: the VC-n is allowed to "float" within the AU/TU-n frame. Thus, the pointer is able to accommodate differences, not only in the phases between VC-n and the higher order frame, but also in the frame rates
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AU/TU-n Pointer
J1
H1 H2 H3H3H3 O O OY 1Y 1
t
NegativeJustification
(3 Bytes)
PositiveJustification
(3 Bytes)
SOH SOH SOH SOH SOH SOH J1 SOH SOH SOHPointer
Pointer addressing only every 3 bytes
15
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J
J
J
PT
PT
PT-1
PT-1
J
J
J
PT
PT
PT+1
PT+1
J S
J1
J1
J1
J1 J1
J1
J1
J1FRAME N
FRAME N+1
FRAME N+2
FRAME N+3
AU/TU-n Pointer Justification
Pointer use is associated to a justification process
Positive Justification:• bit-rate of the container < bit-rate of
the frame• there are less data received than can
be transmitted in the frame
Negative Justification:• bit-rate of the container > bit-rate of
the frame• there are more data received than can
be transmitted in the frameAll Rights Reserved © Alcatel-Lucent 2006, #####58 | Cours Réseaux Optiques – Partie I | March 2008
Positive Justification/Stuffing
Step 1: Pointer value n before stuffing
Step 2: The pointer value is inverted in the I-bits. The three bytes following the H3-bytes contain stuffing bits
Step 3: The pointer has the pointervalue n+1“VC-4 is slowed down”
H2 H31H1 1 H3H3YY
empty
n+1
H31 1 H3H3YYH1 H2
n
empty
H31 1 H3H3YYH1 H2
empty
n
... J1- Byte (1. Byte of VC -4)
... Stuff bytes ( “1,1,1”)
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Negative Justification/Stuffing
... J1- Byte (1. Byte of VC -4)
... Stuff bytes ( “1,1,1”)
Step 1: Pointer value n before stuffing
Step 2: The pointer value is inverted in the D-bits. Missing payload bytes are transmitted using H3 bytes which contains valid information
Step 3: The pointer has the pointervalue n-1 “VC-4 is accelerated”
H2 H31H1 1 H3H3YY
empty
n-1
H31 1 H3H3YYH1 H2
n
data
H31 1 H3H3YYH1 H2
empty
n
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AU-n/TU-3 Pointer Coding
N N N N S S I D I D I D I D I D
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
H1 H2 H3
T1518180-95IDN
IncrementDecrementNew data flag
Negativejustificationopportunity
Positivejustificationopportunity
Negative justification• Invert 5 D-bits • Accept majority vote
SS bits (bit 5-6 of H1):•Composition of the AU-n /TU-n frame (AU/TU type) Concatenation Indication• 1001SS1111111111 (SS bits are unspecified)
NOTE – The pointer is set to all "1"s when AIS occurs.
10 bit pointer value
New Data Flag (bit 1-4 of H1):• Notification of a new pointer value• Set/Enabled when at least 3 out of 4 bits match "1001“ • Reset/Disabled when at least 3 out of 4 bits match "0110“ (normal operation)• Invalid with other codes
Pointer value (bit 7-8 of H1 + bit 1-8 of H2):Normal range is:for AMU-4, AU-3: 0-782 decimalfor TU-3: 0-764 decimal
Note : The TU12 pointer is elaborated by associating in the 500us period, 4 bytes named V1, V2, V3, V4
V1, V2 = pointer which position V5
V3 = positive/negative justification opportunity
V4 = reserve
Positive justification• Invert 5 I-bits • Accept majority vote
H3: Pointer action byte (Used for information bytes in case of negative stuffing)
16
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Overheads
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SDH Frame Structure - Overheads
Virtual Container 4
RSOH
AUPointer
MSOH
Section Overhead bytes
9 COLUMNS
J1
B3
C2
G1
F2
H4
F3
K3
N1
260 COLUMNS
Path overhead bytesPayload data bytes
1
G-703
VC-i
VC-i
VC-4
VC-4
STM-N STM-N
VC-4
VC-4
VC-i
VC-i
G 703
POH VC-i
POH VC-4
MSOH
RSOH
Regenerators
RSOH: Regenerator Section OverheadMSOH: Multiplex Section OverheadPOH: Path Overhead
Note: Bytes B1, D1-D12, E1, E2, F1, K1 and K2 are only defined for the first STM-1
These three path and line sections are associated with Equipment Layers
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Tasks of the SOH
Data Channels
QualitySupervision
LineProtection
FrameAlignment
MaintenanceFunctions
VoiceConnection
SOH
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Overheads Bytes – RSOH
AU Pointer
MultiplexSection
OverHead
RegeneratorSection
OverHead
B2
H1 Y Y H2 1* 1* H3 H3 H3
B2
NU NU
NU NU
A1 A1 A1 A2 A2 A2 J0
B1 E1 F1
D1 D2 D3
B2 K1 K2
D4 D5 D6
D7 D8 D9
D10 D11 D12
E2Z1 Z1 Z2 Z2S1 M1
A1-A2: Frame Alignment pattern, A1= 11110110 (F6) A2=00101000 (28) - not scrambledThe FAW word of an STM-N frame is composed of 3×N A1 bytes followed by 3×N A2 bytes (6xN bytes).J0: Regenerator section trace identifier, 16 bytes frame (First byte = CRC-7)B1: Regenerator section error monitoring function, BIP-8 : Bit Interleaved Parity 8 codeE1: Orderwire channel for voice communication, accessed at regeneratorsF1: User channel allocated for user specific purposesD1-D2-D3: Data Communication Channel (DCCr = 192kbit/s)NU : Bytes reserved for national use
: Bytes reserved for future international standardisation
17
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Bit Interleaved Parity n (BIP-n) code
1 2 3 ….. n 1 2 3 ….. n 1 2 3 ….. n
Even Parity Check #1
Even Parity Check #2
1 …..
n bit sequence n bit n bit
Entire block for the BIP-n check
Even Parity Check #n
P1 P2 P3 ….. Pnn bit
BIP-n codeword: computed over relevant part of frame of frame X after scrambling and is placed in byte B1/B2 of the frame X+1 before scrambling
…….
all bits of STM-N frame for B1 all bits minus RSOH for B2{
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Overhead Bytes – MSOH
E1
D2
B2
H1 Y Y H2 1* 1* H3 H3 H3
B2
NU NU
NU NU
A1 A1 A1 A2 A2 A2 J0
B1 F1
D1 D3
B2 K1 K2
D4 D5 D6
D7 D8 D9
D10 D11 D12
E2Z1 Z1 Z2 Z2S1 M1
B2: Multiplex Section error monitoring function, BIP-N x 24 : Bit Interleaved Parity N x 24K1-K2 (b1 -b5): Automatic Protection Switching (APS) channelK2 (b6 -b8): MS-RDI (Multiplex Section Remote Defect Indication) or AIS IndicationD4 to D12: Data Communication Channel (DCCm = 576kbit/s)S1 (b5 -b8): Synchronization Status Messages (SSM), timing marker for clock traceabilityM1: MS-REI, Multiplex Section Remote Error Indication detected by B2Z1-Z2: Spare bytes, not yet definedE2: Orderwire channel for voice communication between multiplexers
AU Pointer
MultiplexSection
OverHead
RegeneratorSection
OverHead
: Bytes reserved for national useNU
: Bytes reserved for future international standardisation
NU NU
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Tasks of the POH
Connectivity Check
VC QualitySupervision
Alarm Information
User Channel
Mapping Identification
MaintenanceFunctions
POH
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Overhead Bytes – VC-4/3 POH
J1
B3
C2
G1
F2
H4
F3
K3
N1
J1: Path Trace/Trail Trace Identifier (TTI): this byte is used to transmit repetitively a Path Access Point Identifier so that a path receiving terminal can verify its continued connection to the intended transmitter, 16 bytes string (first byte = CRC-7)B3: Path error monitoring function for VC-4-Xc/VC-4/VC-3, BIP-8C2: Trail Signal Label = Composition of the VC-4-Xc/VC-4/VC-3 (00 = Unequipped, 01= Equipped - non-specific, 02 = TUG structure, 04 = Async. mapping of 34 or 45 Mbits/s into the C-3, 12 = Async. mapping of 140 Mbits/s into the C-4, 13 = ATM mapping, 16= PPP/HDLC, 1B = GFP, FF= VC-AIS)G1 : Remote path status (REI (bit 1-4), RDI (bit 5)) detected at remote end by B3F2/F3: user data channel reserved for user communication purposes between path elements and payload dependent.H4 : Position indicator (e.g. used as a multiframe position indicator for the TU-12)K3 (b1-b4): Automatic Protection Switching (APS) channel for VC Trail Protection at VC-4/3 path levels (not used today)N1: Network operator byte, allocated for Tandem Connection Monitoring (TCM)
The POH provides for integrity of communication between the point of assembly of a Virtual Container (VC) and its point of disassembly.
18
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Overhead Bytes – VC-12 POH
V5:
BIP-2 = VC-12 error monitoring REI = Remote Error Indication, detected by BIP-2RFI = Remote Failure Indication
L1, L2, L3 = VC-12 signal label
RDI = Remote Defect Indication: Alarms on the remote VC-12, after protection
J2: VC-12 Path Trace / Trail Trace Identifier , same as J1 for the VC-4/3
N2: Network operator byte allocated to provide a Tandem Connection Monitoring (TCM) function
K4: - bits 1 - 4 : Automatic Protection Switching (APS) channel- bits 5 - 7 : Reserved for optional use - bit 8 : Spare for future use
000 ---> unequipped001 ---> equipped -non-specific010 ---> asynchronous011 ---> bit synchronous100 ---> byte synchronous
BIP2 REI RFI L1 L2 L3 RDI
1 2 3 4 5 6 7 8V5
J2N2
K4
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Synchronization
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Why Synchronization?
Phase differences cause frame slips§ Frame slips cause data loss
Two signals to be synchronous must have:§ The same frequency (bit rate)§ The same phase
The variation in position of bits on the time axis (Phase) relative to the ideal position (UI) is called jitter§ Jitter & wander tolerance specified by ITU standards
time
time
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Synchronization Rules in SDH
2 Mbit/s (VC-12) not usable for synchronization (pointer jitter)
Single “master clock” is used for synchronization (G.811)
§ Primary Reference Clock (PRC)
§ Global Positioning System (GPS)
All transmission nodes have to be synchronized
§ The synchronization network is a network that reliably distributes synchronization information from a common reference source (master-clock) to those network elements that need to be synchronized.
§ The synchronization network uses the STM-N links of the SDH transport network as “physical layer” for inter-office distribution.
§ Intra-office distribution is build up with dedicated cabling.
2 MHz or dedicated 2 Mbit/s
19
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Synchronization Protection
Failures in the synchronization distribution network can be overcome
§ By duplication of equipment and/or
§ By duplication of routing in combination with some selection mechanism at the receiving end (SDH nodes have several timing references)
Reference selection mechanisms can be:
§ Manual restoration
§ Automatic restoration based on Network Management
§ Automatic restoration based on Priority assignments
§ Automatic restoration based on the Synchronization Status Messages (SSM) algorithm (ITU -T G.781) using the S1 byte of the STM-N overhead
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Rec. G811, PRC Quality (Primary Reference Clock): 10-11
Rec. G813, Synchronous Equipment Timing Source SEC Quality (SDH Equipment Clock)
S1 bits (b5-b8)
SDH synchronization Quality Level description
Do not use for synchronization, DUS (Don’t Use) or DNU (Do Not Use)
Incr
easi
ng
Clo
ck q
ualit
y
S1 byte (b5-b8), Synchronization Status Message
Rec. G812 Transit SSU-T Quality (Synchronization Supply Unit Transit): 1,5x10-9
Rec. G812 Local SSU-L Quality (Synchronization Supply Unit Transit): 3x10-8
Quality unknown0000 (00)
0010 (02)
0100 (04)
1000 (08)
1011 (11)
1111 (15)
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SDH Network Synchronization Example
SSMs applied in SDH ring network: normal situation
Active synchronizationStand-by synchronization
A
B
PRC
DUS
SEC
1
2
SEC
1
2
E
SECSEC1
2
F
SEC2
1
D
SEC2
1
C DUS
DUS
DUSDUS
PRC
PRC
PRC
PRC
PRC
PRC
21
PRC
PRC
2
SynchronizationStatus Message
ReferencePriority
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SDH Network Synchronization Example
SSMs applied in SDH ring network: restoration in progress
Active synchronizationStand-by synchronization
A
B
PRC
DUS
SEC
1
2
SEC
1
2
E
SECSEC1
2
F
SEC2
1
D
SEC2
1
CSEC
DUS
DUSDUS
PRC
SEC
SEC
SEC
PRC
PRC
21
PRC
PRC
2
SynchronizationStatus Message
ReferencePriority
PRC
DUS
20
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SDH Network Synchronization Example
SSMs applied in SDH ring network: restoration completed
Active synchronizationStand-by synchronization
A
B
PRC
DUS
SEC
1
2
SEC
1
2
E
SECSEC1
2
F
SEC2
1
D
SEC2
1
CPRC
PRC
PRCPRC
DUS
DUS
DUS
PRC
PRC
21
PRC
PRC
2
SynchronizationStatus Message
ReferencePriority
DUS
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Protection Mechanisms
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Terminology
Network Configurations
Network Protection Schemes:
§ Sub-Network Connection Protection (a.k.a Path Protection)SNC/NSNC/I
Trail Protection
§ Multiplex Section ProtectionMultiplex Section Protection (MSP)Multiplex Section Shared Protection Ring (MS-SPRing)
§ Dual Node Interworking (DNI)
Equipment Protection:§ 1:N equipment protection for electrical tributaries
Protection Mechanisms
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SDH networks are high capacity systems
STM-64 = 129,000 voice telephone calls!
Failure requires instant restoration
SDH has Automatic Protection Switching (APS)
§ Perhaps the most critical aspect of the technology, what distinguishes it most from IP
§ Linear networks use duplicate fiber(s) and sometimes duplicate piece of equipment for protection
§ Ring/Mesh networks use diverse routing
Golden rule: 50 ms restoration time
Importance of Automatic Protection Switching
21
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Revertive§ After the failed state has
stopped to exist all protection switches automatically revert back to their original non-failed state
§ Configurable Wait-to-Restore (WtR) Timer
Non-Revertive§ After the failed state has
stopped to exist all protection switches remain in their current position thus becoming the normal non-failed state
Shared§ Each protection channel can be shared by more than one working
channel, e.g. 1:N. Otherwise 1+1
§ The shared protection channel may be used for Extra-Traffic, e.g. 1:N
Terminology
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SDH Network Configurations
Point-to-point Configuration
SDH TerminalMultiplexer
SDH TerminalMultiplexer
Linear Configuration
SDH TerminalMultiplexer
SDH TerminalMultiplexer
Repeaters
SDH Add/DropMultiplexer
Ring implementation choices:§ 2-fiber or 4-fiber§ unidirectional or bidirectional§ line switched or path switched§ STM rate
Ring configuration
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Sub-Network Connection Protection (SNCP)(a.k.a. “Path Protection”)
Path-level protection: SNCP protects a portion of a path (Subnetwork Connection) for VC-12, VC-3, VC-4, VC-4-4/16/64c
§ SNCP is based on transmitting the signals to be protected overboth a working and a protection path through the network.The SNC endpoint selects the best signal out of the two
§ SNCP can be configured in any mix of topologies (e.g. ring, mesh, unprotected, MSP and MS-SPRING)
Switch Criteria: transmission failure or external request
Always Unidirectional (No APS signaling possible)
Either Revertive or Non-Revertive
No Extra Traffic : permanently bridged
Different types of SNCP :
§ SNC-I (Inherent)
§ SNC-N (Non intrusive)
SDHNetwork
ITU-T Rec. G.841
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• Signals are not terminated in front of the switch• No monitoring is done on the protected signal itself,
only the Server Layer defects (SSF) generate switch: Switching criteria at TU or AU level (TU -LOP & TU -AIS)
Subnetwork Connection
Head End Bridge
Tail End Switch
Server Layer
SSF
SNCP Inherently Monitored: SNC/I
22
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• Signals are not terminated in front of the switch• Non intrusively Monitored (SNC/N):
Switching criteria at TU/AU level and at VC level (VC-12 UNEQ, VC-12 TIM, VC-12 SD non-intrusively monitored)
Subnetwork Connection
Head End BridgeNon-Intrusive MonitorsTail End Switch
Server Layer
SSF
SF,SD
SF,SD
SNCP Non Intrusively Monitored: SNC/N
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• Signals are terminated in front of the switch • APS protocol necessary (K3) in Bidirectional mode• Not implemented today
Subnetwork Connection
Head End Bridge Non-Intrusive MonitorsTail End Switch
Server Layer
Trail
VC Trail Protection
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Protects whole frame except RSOH
Point-to-point protection
Need the duplication of the STM-N interface board and the transmission support
Switch Mode: either Revertive or Non Revertive
1+1 MSP has no Extra Traffic: permanently bridged
§ 1:1 also defined, allowing extra traffic but less common
Communication/switching mode: unidirectional or bidirectional
1+1 protection protocol using K1 and K2 (b1-b5) bytes of MSOH following ITU-T Rec. G.841
Switch criteria: transmission failures (Server layer defects: LOS, LOF, MS-AIS, MS DEG (B2 errors) or external requests
Also implemented on POS interfaces of routers (called APS)
ITU-T Rec. G.841
RSOH
MSOH
HO PTR HO-VC
Multiplex Section Protection (MSP)
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(P)
(W)
Head End Bridge
Tail End Switch
Worker channel
Protection channel (Standby)
W
P
W
P
STM-N port
STM-N port
STM-N port
STM-N port
Network Element BNetwork Element A
Unidirectional Switching:• Both directions are independent:
switch is performed in the tail end (failure detecting end) only
• No APS protocol required (although reporting is possible)
Bidirectional Switching:• Both directions switch
simultaneously• APS protocol using K1/K2 byte
(carried on the protection line) to signal switch coordination
1+1 Multiplex Section Protection (MSP)
23
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Principles:
§ MS-SPRING works in ring-type network with maximum 16 nodes. Protection is implemented by utilizing redundant bandwidth (capacity)
§ For STM-64 MS-SPRING, each bi-directional line carries 32 working channels and 32 protection channels of STM-1 equivalent capacity in each direction. For STM-16, the system utilizes 8 working and 8 protection channels in each direction.
§ Traffic is rerouted around a faulty segment using the redundant protection channels in case of a line-card or fiber failure
Always bidirectional, requires APS signaling (K1,K2)
Always Revertive (Shared Protection!)
Possibility of Extra Traffic: use of protection capacity
Optimal bandwidth use for meshed traffic
ITU-T Rec. G.841
Multiplex Section Shared Protection Ring (MS-SPRing)
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A
B
C
DWorking (1-8)
Protection (9-16)
#1
#1
#1 #1
Protected channels : STM16 --> AU4 1 to 8, STM64 --> AU4 1 to 32Protection channels : STM16 --> AU4 9 to 16, STM64 --> AU4 33 to 64
MS-SPRing Basic configuration – no failure
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A
B
C
DProtection (9-16)
#1
#1
#1 #1
#9
Working (1-8)Switching nodes
Bridge
Protected traffic + APS signalling
MS-SPRingSingle failure
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A
B
C
DProtection (9-16)
BridgeIntermediate Nodes(APS + Protection Pass-Through)
#1
#1
#1 #1
#9
#9
Working (1-8)
Protected traffic + APS signalling
MS-SPRingSingle failure (2)
24
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A
B
C
DProtection (9-16)
BridgeIntermediate(APS + Protection Pass-Through)
#1
#1
#1 #1
#9
#1
#9
Working (1-8)
SwitchRestored traffic + APS signalling
APS
MS-SPRingSingle failure (3)
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A
B
C
DProtection (9-16)
Bridge
Switch
#1
#1
#1 #1
#9
#9
Working (1-8)
MS-SPRingRing Segmentation
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A
B
C
DProtection (9-16)
Bridge
Switch
#1
#1
#1 #1
Misconnections !
#9
#9
Working (1-8)
MS-SPRingRing Segmentation (2)
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A
B
C
DProtection (9-16)
Bridge
Switch
AISAIS
AIS
AIS
AIS
#1
#1
#1 #1
#9
#9
Working (1-8)
MS-SPRingSquelching
25
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Dual Node Interworking (DNI)
The DNI protection scheme protects the interconnection between two subnetworks within which the traffic is already protected by another network protection like MS-SPRING or SNCP
§ Different combination possible:
DNI between 2 MS-SPRing rings
DNI between 2 SNCP rings
DNI between a MS-SPRing and a SNCP ring
§ Connection between the two ring networks is made using 2 or 4 nodes
DNI offers
§ Protection against node failures and failures in the interconnection between the rings
§ Independence of protection actions in both rings
§ Better reliability than end-to-end path protection, especially for very long paths
ITU-T Rec. G.842
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DNI between two MS-SPRing rings
SecundaryNode
Stand-by VC -4 Connection
STM-16 or STM-64MS-SPRING
STM-16 or STM-64MS-SPRING
PrimaryNode
ServiceSelector
Drop & Continue
Active VC -4 Connection
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DNI – Interconnect Failures
STM-16 or STM-64MS-SPRING
STM-16 or STM-64MS-SPRING
SecundaryNode
PrimaryNode
ServiceSelector
Drop & Continue
Stand-by VC -4 Connection
Active VC -4 Connection
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DNI – Node Failure
STM-16 or STM-64MS-SPRING
STM-16 or STM-64MS-SPRING
SecundaryNode
PrimaryNode
ServiceSelector
Drop & Continue
Stand-by VC -4 Connection
Active VC -4 Connection
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DNI between a MS-SPRing and a LO-SNCP Ring
Sub- Network AMS-SPRING
Sub- Network BSNCP
Sub- Network CMS-SPRING
Vc12/3Termination VC4
A
MS-SPRINGHO SNCP Connection HO DROP Connection
B C
LO Connection Group(DNI - W Connection)
LO Connection Group(DNI - P Connection)
Vc12/3
D
LO-SNCP
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Classification of Optical Interfaces & Transmission wavelengths
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Classification of Optical Interfaces
Inter-office Application Intra-
office Short-haul Long-haul
Source nominal wavelength (nm)
1310 1310 1550 1310 1550
Type of fibre Rec. G.652 Rec. G.652 Rec. G.652 Rec. G.652 Rec. G.652 Rec. G.654
Rec. G.653
Distance (km) a) ≤ 2 ∼ 15 ∼ 40 ∼ 80
STM-1 I-1 S-1.1 S-1.2 L-1.1 L-1.2 L-1.3
STM-4 I-4 S-4.1 S-4.2 L-4.1 L-4.2 L-4.3 STM level
STM-16 I-16 S-16.1 S-16.2 L-16.1 L-16.2 L-16.3 a) These are target distances to be used for classification and not for specification. The possibility of
applying the set of optical parameters in this Recommendation to single-channel systems on G.655 fibre is not to be precluded by the designation of the fibre types in the application codes.
ITU-T G.957 for STM-1, 4, 16 systemsITU-T G.691 for STM-64, 256 or STM-16 with OA systems
ITU-T G.957:
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Classification of Optical Interfaces - Legend
G.652 (SSMF) : Characteristics of a standard single-mode optical fiber cableG.653 (DSF) : Characteristics of a dispersion-shifted optical fiber cableG.654 (CSF) : Characteristics of a cut-off shifted optical fiber cable G.655 (NZDSF) : Characteristics of a non-zero dispersion shifted optical fiber cable
L-16.2Letter:Intra-office (I), Short-Reach (S), Long-Reach (L)Very-Long-Reach (V)Ultra-Long-Reach (U)
STM-n level
(blank) or 1 = nominal 1310 nm wavelength sources on G.652 fibre;
2 = nominal 1550 nm wavelength sources on G.652 fibre for short-haul applications and either G.652 or G.654 fibre for long-haul applications;
3 = nominal 1550 nm wavelength sources on G.653 fibre.
27
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Transmission Ranges
Wavelength
WDMWDM ::
1300 1500 1600
ITU G.692 comb
SDHSDH :: 1310 nm 1550 nm
80 traffic channels
Supervisory channel
50 GHz
Loss
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Functional Equipment Specification
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Functional Block Diagram Representation ITU-T G.783 (1) - PI, RS, MS layers
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Functional Block Diagram Representation ITU-T G.783 (2) - HO-VC, LO-VC layers
28
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L K J H G F E D C B AM
STM-nAU4/AUGVC4VC4TUG3VCnVCnCnSynchronous
Frame
LOI HOA TTFC4
PPI
Physical Interface
LPA
CnCreation
LPT
VCnCreation
LPC
VCnCross -
connect
HPA
TU& TUG 3Creation
HPT
VC4Creation
HPC
VC4Croos -
connect
MSA
AU 4AUG
Creation
MSP
Protection
MST
MSOHCreation
RST
RSOHCreation
SPI
PhysicalInterface
PDHTributary
n PPI: Plésiochronous Physical Interface n LPA: Low order Path Adaptationn LPT: Low order Path Terminaison
n LPC: Low order Path Connection
n HPA: High order Path Adaptationn HPT: High order Path Terminaison
n HPC: High order Path Connection
n MSA: Multiplex Section Adaptation n MSP: Multiplex Section Protectionn MST: Multiplex Section Terminaitionn RST: Regeneration Section Terminaitionn SPI: Synchronous Physical interface
L.O.I: Lower Order Interface
H.O.A:High Order Assembler
T.T.F: Transport Terminal Function
Old G.783 Functional Block Diagram Representation
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Typical Network Element Types & Network Applications
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STM-NG. 703STM-M
STM-N
STM-NSTM-N
G. 703
STM-NSTM-N
STM-N
STM-M STM-MSTM-N STM-N
VC-i
VC-i
VC-4
VC-4
VC-4
Terminal
Multiplexer Multiplexer Multiplexer
Type I.1, I.2
Type III.1
Type II
Type I
Type III.2
Type II.1, II.2
M > N
VC-i processing VC-4 processing
Add & Drop
Multiplexer
Regenerator
STM-N
STM-N
A Terminal Multiplexer (TM) is used to connect lower speed PDH or synchronous signals to a high speed communication link.
An Add/Drop Multiplexer (ADM) is used to to add or drop PDH or SDH signals to a high speed communication link. Has always at least two high speed connections.A Digital Cross-Connect can do everything the other network elements can and has even greater flexibility.
A Regenerator has the same speed on both input and output. It is used to retime and amplify the line signal.
VC-i
G. 703 G. 703
SDH Network Element Types
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Aggregate signals
STM-N frame STM-N frame
Aggregate signals
Tributary Signals
1 n
EastWest
Notation: ADM–N/MN: Line/Aggregate STM-levelM: Tributary STM-level
Add & Drop Multiplexer
29
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Bus structure
2 / 8 / 34 / 140 Mbit/s
2 / 8 / 34 / 140 Mbit/s
Ring structure
STM-1(155 Mbit/s)
ATMswitch
LAN
ATMswitchSTM-1
(155 Mbit/s)
LAN
2 / 8 / 34 / 140 Mbit/s
Point to point
2 / 8 / 34 / 140 Mbit/s
Typical SDH Network Designs
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Bac
kbon
e/C
ore
Metro-Access
Metro-Core
LO-SNCP RingSTM-16
Metro - Edge
STM-16LO-SNCP Ring
Hub Office
STM-1/4LO-SNCP
Ring
E/FEGbE
STM-1 .. 641/10 GbE
POP/CO
P B X
End Office
IPSvcs
Switch
HO-SNC/ MS-SPRing
STM-64
P B X
STM-16GbE
E1, E3DS1, DS3STM-1E/FES(H)DSL
End Office
Ring or Meshscalable from
STM-16 to STM-256
Managed DWDMPassive DWDM
E1, E3 DS1, DS3STM-1/4E/FE/GbE
P B X
E1, E3DS1, DS3STM-1E/FES(H)DSL
E1, E3DS3STM-1/4E/FE/GbE
D/OXCL2
D/OXCL2
ADM 16/1L2D/OXC
L2
D/OXCL2
ADM 1/1
L2
ADM 1/1
L2
ADM 16/1 L2
ADM 64/1L2
ADM 16/1
L2
ADM 16/1
L2ADM 64
DCS4/4/1
DWDM DWDM
ADM 1/1
L2
Metropolitan Network Applications of SDH
STM-16GbE
ADM 1/1
L2ADM 16/1
L2
Ethernet / MPLS switch
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OAM&P
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CircuitSwitch
CircuitSwitch
SDH TerminalMultiplexer
SDH TerminalMultiplexer
SDH Add/DropMultiplexerRepeaters Repeaters
Regenerator Sections Regenerator Sections
Multiplex Section Multiplex Section
Path
SDH Layering: Path Layer
Multiplex Layer
RegeneratorLayer
Photonic Layer
Construction of AU-n
Construction of STM-n
Management of STM-n Transmission
Electro -Optical Conversion
SDH Communication Layers
30
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High order path
Multiplex section
Regenerator section
STM-N Alarm Scheme
LOS/ LOF
MS-RDI MS-RDI
MS-AIS AIS AIS
HP-RDI
HP-BIP
MS-BIPBIP Err.
MS-REIHP-REI
HP-RDI
SDH regenerator
SDH multiplexerSDH multiplexer
K2
M1
B1
K2
B2
G1
G1
B3
Fault Management (1)
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SDH alarms Description OH Byte LOS Loss of signal NES Non expected signal AIS Alarm indication signal
Regenerator Section OOF Out of frame A1, A2 LOF Loss of frame A1, A2
RS DEG RS Degraded Signal B1 RS TIM RS trace identifier mismatch J0
Multiplex Section MS-AIS Multiplex section AIS K2 MS-RDI MS remote defect indication K2 MS-REI MS remote error indication M1 MS-DEG MS Degraded Signal B2
Administrative Unit AU-LOP Loss of AU pointer H1, H2 AU-AIS AU alarm indication signal AU incl. H1, H2 AU-PJE AU pointer justification event H1, H2
High order path VC-4 UNEQ HO path unequipped C2 VC-4 RDI HO path remote defect indication G1 VC-4 REI HO path remote error indication G1 VC-4 TIM HO path trace identifier mismatch J1 VC-4 PLM HO path payload label mismatch C2 VC-4 DEG HO path error monitoring B3
Fault Management (2)
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SDH alarms Description OH Byte Tributary unit
TU-LOP Loss of TU pointer V1, V2 TU-AIS TU alarm indication signal TU incl, V1 to V4 TU-LOM TU loss of multiframe H4
Low order path VC-12/3 UNEQ LO path unequipped V5 / C2
VC-12/3 RDI LO path remote defect indication V5 / G1 VC-12/3 REI LO path remote error indication V5 / G1 VC-12/3 TIM LO path trace identifier mismatch J2 / J1 VC-12/3 PLM LO path payload label mismatch V5 / C2 VC-12/3 DEG LO path Degraded Signal V5 / B3
Fault Management (3)
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Performance Monitoring
Bit error monitoring
§ Locally via BIP parity check on B1, B2, B3, V5 Overhead bytes
§ Far-End using REI
Definitions according ITU -T Rec. G.826 :
§ Errored Block (EB): A block in which one or more bits are in error.§ Errored Second (ES): A one-second period with one or more errored blocks
or at least one defect.
§ Severely Errored Second (SES): A one-second period which contains ≥30% errored blocks or at least one defect. SES is a subset of ES.
§ Unavailable Second (UAS) : if more than 10 consecutives SES.§ Background Block Error (BBE): An errored block not occurring as part of an
SES
31
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Performance Monitoring - Examples
VC-4 :
§ 1 VC-4 block = 18792 bit/s§ VC-4 rate : 150336 kbit/s (18792 bits/125 µs)
---> 8000 blocks/s§ SES if > 30% false blocks ---> SES if more than 2400 false blocks
VC-12 :
§ 1 VC-12 block : 1120 bits (140 bytes x 8 bits)§ VC-12 rate : 2240 kbit/s (1120 bits/125 µs/4)
---> 2000 blocks/s§ SES if > 30% false blocks ---> SES if more than 600 false blocks
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TCP/IP Network
ECCECC
- ECC or DCC : Embedded Control Channel, Data Communication Channel = D1 -D3 (DCCr) or D4 -D12 (DCCm)- GNE = Gateway Network Element
SDH Network
- Configuration Management- Fault management- Performance Management- Security Management
GNE
NE
NE
NE
ECCECC
Server
PC, Workstation
Network Management Architecture
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Service Subscription
Network Circuit Design
NE Provisioning Commands Raw AlarmsConfiguration Data
Filtered AlarmsConfiguration Information
Service Impact
Service Management
Network Management
Element Management
Network Element SDH & DWDMTechnologies
Local Management (craft terminal)
Network Management Architecture
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ASTN / GMPLS
32
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Today the SONET/SDH and DWDM layers of the network are quasi-static, and connection management is prone to human operator via the management plane
Introduction of a ASTN/GMPLS control plane allow:§ Reduced Network Costs (CapEx) - Equipment and Fiber Infrastructure:§ Controlled network resource sharing§ Improved Network Utilization in meshed networks
§ Reduced Operation Costs (OpEx) - Maintenance & Network Design Flexibility:§ Less design effort, easy enhancement and local elimination of bottlenecks as needed§ Cheaper and more accurate inventory (via automatic self-awareness, topology discovery,
verification of physical neighbor) and “plug-and-use” operations§ Automatic connection set-up: reduce the operational burden of manual circuit provisioning
§ Enhanced Services:§ Support multiple Quality of Service (QoS) for differentiated services with multiple grade of
protection/restoration§ Support opportunities for operators to develop sustainable revenues through new services
opportunities such as Optical Virtual Private Networks (VPN) with dynamic bandwidth§ Automatic path setup via O-UNI: create end-to-end connections with only the start and end-
point specified by the User or external equipment (router)
Market Drivers for Optical Mesh Networking
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ONNS™ Signaling Control Plane
OpticalTransport
Plane
We can calculate best routes for
connections and restoration
We can set-up, tear down, and restore
connectionsWe can auto -discover topology and resource
availability Via Link State Advertisements (LSA) based
on OSPF
I can manage revenue producing services, bridge connection domains, and
optimize network performance
I can request connections and change
QoS
Management Plane
O-UNI / E-NNIO-UNI / E-NNI
CentralizedIntelligence:
DistributedIntelligence:
I-NNI
I-NNI Signaling based on IETF CR-LDP
I have a flexible software architecture that supports module
replacements
NMI
ASTN/GMPLS: Distributed Control Plane
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Standardization
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The Role of Standards
Standardization is extremely important
§ To ensure inter-operability
§ To defend/promote certain protocols (and their underlying technologies)Once a standards battle is lost, investments may have become worthless
Standards bodies become part of the "battleground"
§ Only technical argumentation is accepted
Different standards bodies have each there "jurisdiction"
§ ITU-T (Int'l, UN mandate), T1 (USA): DWDM, SDH, ATM, Ethernet
§ IEEE (US dominated): Ethernet
§ IETF (US dominated): IP, MPLS
§ This creates some competition between these standards bodies
In addition numerous industry fora are rallied around certain protocols
§ IP/MPLS (MFA) Forum, Metro Ethernet Forum, RPR Alliance, 10 GbE Alliance
33
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Standard Bodies
International Europe USA Focus
ITU-T X Transport, Switching
ETSI X
ISO/IEC X
Telcordia X Management
ANSI X Transport
IEEE X Ethernet
IETF X IP
EEC X EMC, Envir.
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SDH Standardization Linkage between Recommendations
G.707(SDH Frame)
G.810, G.811, G.812, G.813(Synchronization)
G.821, G.826(Errors)
G.784(Management)G.781/783
(Multiplexer) G.957(Line System)
Equipment
TransmissionHierarchy Performance
TMN(Management)
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ITU-T Recommendations SDH technology
G.703: Physical/electrical characteristics of hierarchical digital interfacesG.704: Synchronous frame structures used at 1544, 6312, 2048, 8488 and 44 736 kbit/s hierarchical
levelsG.705: Characteristics of plesiochronous digital hierarchy (PDH) equipment functional blocksG.707: Network node interface for the synchronous digital hierarchy (SDH)G.781: Synchronization Layer FunctionsG.783: Characteristics of synchronous digital hierarchy (SDH) equipment functional blocksG.812: Timing requirements at the outputs of slave clocks suitable for plesiochronous operation of
international digital linksG.813: Timing characteristics of SDH equipment slave clocks (SEC)G.823: The control of jitter and wander within digital networks which are based on PDHG.825: The control of jitter and wander within digital networks which are based on SDHG.841: Types and characteristics of SDH network protection architectureG.842: Interworking of SDH network protection architecturesG.957: Optical interfaces for equipments and systems relating to the synchronous digital hierarchyG.691: Optical Interfaces for SDH Systems with Optical Amplifiers, and STM-64/256 systemsG.7041/Y.1303: Generic framing procedure (GFP)G.7042/Y.1305: Link capacity adjustment scheme (LCAS) for virtual concatenated signals
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ITU-T Recommendations Management of SDH - Architecture
G.784: Synchronous Digital Hierarchy (SDH) managementG.803: Architecture of transport networks based on the synchronous digital hierarchy (SDH)G.807/Y.1302: Requirements for automatic switched transport networks (ASTN)G.826: Error performance parameters and objectives for international constant bit rate digital
paths at or above the primary rateG.7712/Y.1703: Architecture and Specification of Data Communication NetworkM.2100: Performance limits for bringing-into-service and maintenance of international digital
paths, sections and transmission systemsM.2101.1: Performance limits for bringing-into-service and maintenance of international SDH paths
and multiplex sectionsQ.811: Lower Layer Protocol Profiles For the Q3 InterfaceQ.812: Upper Layer Protocol Profiles For the Q3 Interface
34
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ITU-T Recommendations Fibers
G.650: Definition and test methods for the relevant parameters of single-mode fibersG.652: Characteristics of a single-mode optical fibre cableG.653: Characteristics of a dispersion-shifted single-mode optical fibre cableG.654: Characteristics of a cut-off shifted single-mode optical fibre cableG.655: Characteristics of a non-zero dispersion shifted single-mode optical fibre cableG.664: General automatic power shut-down procedures for optical transport systemsG.911: Parameters and calculation methodologies for reliability and availability of fiberopticsystems
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Conclusion and Future of SDH
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High-capacity, granular bandwidthPowerful bandwidth management capabilitiesInteroperability between different vendor equipments§ International standard§ Compatible with PDH Network
Multi-service transport (protocol opaque)§ Network able to carry different services (ATM, Ethernet, IP, SAN, etc)
Robustness:§ Carrier-class design, high availability components§ APS supports millisecond fault tolerance
Sophisticated OAM&P and network management capabilitiesWithout theoretical limitation for high bit rates§ Limitation by electronics and PMD to STM-256 (40G) today§ Not enough bandwidth: optical backbones need multi-Tbit/s…DWDM….
Perceived as legacy technology§ Investments shift away to Ethernet/IP technology but the latter are not
“transport” oriented…
Conclusion – Multiple Benefits of SDH
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The Evolution of SDH
Second Generation SDH:– Ring subnetworks
– SNCP, MS-SPRing and DNI protection
– Flexible connectivity
– Automated provisioning– 4/4/3/1 cross-connection in muxes
– PDH + packet (ATM, POS)
– SDH and SONET with SDH ó SONET conversion
– Network Synchronisation (G.812,813) Protection (G.841,842)
– STM-64 line interfaces, colored optics– Some consolidation of central
functions
1996 1998 2000 2002
Transport Architecture
Network Operating Model
InterfaceServices
Standardizationfocus
Misc.
First Generation SDH:– Point-to-point optical line systems
– Basic path protection over mesh
– Fixed mapping
– Static circuit, manual provisioning– 4/1 or 4/4 cross-connection in DXC
and later ADM
– PDH (TDM PL)– SDH or SONET only
– G.707,783,803 Managed transport
– Mux mountains– Physically Large, multiple circuit
packs for central functions
CCITT ITU-T, ETSI, ANSI
199419921990
35
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Miniaturisation and consolidation
§ Narrowband and broadband grooming and aggregation in single platform
§ E1 to STM-64 in one platform§ Focus on Metro (= regional in Europe)
Flexibility§ Optimised for STM-16 or STM-64
function§ E1 through to STM-16 interfaces
§ High capacity, non-blocking 4/4/3/1 local cross connect
§ Simple engineering rules: “any card, any slot”
§ Circuit packs used in several NE type
Multi-layer mesh network architecture(G.807 ASTN)
Dynamic networking, On-demand resources, efficiency, granularity
§ “trio” GFP, VCAT, LCAS
Multiple protocol support
§ PDH, SDH
§ legacy packet (ATM, POS)
§ Ethernet w/ L2 support, SAN
Cost savings
§ CapexPrice reduction of optics
Installation requirements
§ OpexPower savings
Floorspace
Inherent reliability
Characteristics of Third Generation SDH (“MSPP”)
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Native Ethernet
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Why so much fuss about Ethernet?
Ethernet is one of the Hot Topics in the market today:
§ Cheap and ubiquitous technology
§ End customers are familiar with it, and perceive Ethernet Services as the solution to get a better bandwidth / price ratio since no protocol conversion
§ Service Providers like its flexibility
In scaling bandwidth of services easier than with existing data services (ATM, FR, TDM) or
Topology, service connectivity
§ Service Providers look at Ethernet as an enabler for Data transport in the network
§ Industry is developing new technologies to improve Ethernet for Service Providers environments
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Native Ethernet in the Metro
Based on carrier-class Ethernet Switches (L2/3)* performing Ethernet bridging, inter-connected using dark fibre or even WDM§ Protection via STP or LAG or proprietary schemes
§ Security and service isolation with VLANs§ Security (IEEE 802.1x, L2 ACL)
§ Vendor proprietary L2 enhancements§ Administration via SNMP
Topologies: P2P, Hub & Spoke, Dual Homing§ Inefficient support of rings in terms of protection, bandwidth usage and
fairness: this translates in higher fibre usage (Dual Homing architectures)
Advantages:§ Cheap (very good price/GbE port or per bit ratio), robust§ Great scalability in bandwidth
High port density: 1GbE, 10GbEHuge Switching capacity
§ Feature richness (“IP-aware”, enhanced statistics, etc)* Assuming non-MPLS
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Scalability
§ MAC Address Learning in Core (MAC Address Table explosion) Problems only in large, flat L2 networks. Mitigated by splitting MAC-domains by e.g. using a router (will be used by large corporate accounts anyway)
§ Broadcast flooding
§ VLAN label space limited to 4k
§ Upper limit on Network Diameter due to Spanning Tree (IEEE: 7)
Lack of Fairness § Partially solved by policing and shaping, issue remains for “best effort”
traffic
Protection and Spanning Tree
§ Layer 2 protection relies on IEEE 802.1D STP with typically ~30 s convergence time
§ Now improved to less than 1s (with PHY fault monitors) with IEEE Std. 802.1w-2001 RSTP, but still not 50ms
§ Bandwidth efficiency can be less than optimum with STP (unless MSTP)
Scalability Limits of Ethernet switching in the Public Network
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Assessment of the Optical (plain) Ethernet approach
Seems the more straightforward way to introduce Ethernet in SP network and corresponds to what was deployed during the Hype years Drawbacks:§ Despite several innovative enhancements (IEEE, IETF or proprietary),
still not considered carrier-grade solutionLimited fast protection mechanisms (> 50 ms)Lack of fault isolation and poor OAM for network-level service management
§ Impossibility to address cost-effectively Private Services (only EoSDH can dedicate L1 resources)§ Bad QoS perception, DiffServ QoS complex to engineer
§ Not multi-service (TDM services require CEM), need overlay networksEconomic Studies available to show that Ethernet over SDH is more competitive for Ethernet + TDM scenario
§ Maximum link distances are shorter than 70km (w/ 1000BASE -ZX)§ Difficulty to link MANs with end-end redundancy and protection
§ Ethernet scalability limits are applicable for the whole network
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Next-Generation SDH:Ethernet over SDH
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Ethernet over SDH
One way to promote a protocol is to enhance it
§ Make it cover more applications, especially those covered by competing protocols
§ "Ethernet in the Metro"§ "Voice over IP"
Enhance the economic life-time of SDH based on the following ideas§ Service Providers use largely SDH networks
§ End-users use largely EthernetEthernet interfaces are very cheapEthernet is relatively simple
Mapping Ethernet in SDH as payload§ Bandwidth adaptation is needed to gain efficiency
Ethernet -- variable with upper-bounds at 10, 100 and 1000 Mbit/sSDH -- fixed at 2, 45, 150, 600, 2400 and 9600 Mbit/s
37
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Encapsulation
Encapsulation with GFP (Generic Framing Procedure) acc. ITU -T G.7041:
§ Adaptation to synchronous transport layer
§ Add GFP-header (8 bytes) to each Ethernet frame to indicate frame length and payload type, used for delineation
§ Fill idle time with GFP idle-frames (4 bytes)
IDLE L / T Ethernet frame IDLEIDLE L / T
Ethernet frame L / T Ethernet frame IDLEIDLE
GFP Header indicatespayload length and type
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Virtual Concatenation (1)
To overcome the fixed payload sizes of SDH an inverse multiplexing scheme known as "virtual concatenation" is defined§ Possibility to make connections of which the bandwidth can be
incremented in steps of a single VC-12, VC-3 or VC-4
§ VC-12-Xv: X = 1 - 63 (one VC-12 ≈ 2 Mbit/s)§ VC-3-Xv: X = 1 - 255 (one VC-3 ≈ 50 Mbit/s)
§ VC-4-Xv: X = 1 - 255 (one VC-4 ≈ 150 Mbit/s)
SDHNetwork
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Virtual Concatenation (2)
The implementation of virtual concatenation only affects the source and sink nodes. All intermediate SDH network elements remain unaware of virtual concatenation§ For this reason virtual concatenation is easier to introduce in existing SDH
networks
The differential network delay of the VC's is compensated in the sink node§ No routing constraints for the VC's in the concatenated group
Inherent protection against failure
§ If a VC in the concatenated group fails the rest of the group continues operating, but at less capacity - "load-sharing"
Possibility to increase and decrease the end-to-end channel capacity "in-service". No bit errors in the transported payload§ LCAS (Link Capacity Adjustment Scheme) Protocol, ITU -T G.7042
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Ethernet Bridging in SDH
To gain more efficiency, the statistical properties of Ethernet traffic can be used by including a IEEE 802.1D bridge function in an SDH box
§ Traffic of multiple end-users can be combined
§ Since traffic peaks are unlikely to coincide a certain over-subscription of the bandwidth is possible
§ Use VLAN tags to distinguish frames from different end-users; the tags are removed when the traffic is returning
In addition the bridge function can be used to support MAC Address learning, which makes multi-point connections possible
Spanning Tree Protocol is used to keep the network "loop-free" and to provide restoration in case of link or node failures
38
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Public
Network
Ethernet interface on SDH box
1
PHY
Virt. Concat.
EthernetBridge
GFPEncap-sulation
VC
2
3
XFEGbE
CP CP
Ethernetover SDH
Ethernet
LAN port
CPE
CPE
SDH
SDH
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Ethernet Multi-point Transport
CP CP
PublicNetwork
CPE
CP
CPCPE
LANWAN
CPE
CPE
SDH
SDH
SDH
SDH
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Ethernet Frame
Prea
mbl
e
SFD
Dest
inat
ion
Addr
ess
Sour
ceAd
dres
s
Leng
th/T
ype
Data
FCS
VLAN
-tag
(opt
iona
l)
SFD = Start of Frame DelimiterFCS = Frame Check Sequence
6 6 46-1500 44 217
MAC frame (64-1522)PHY
dependent
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Ethernet Protocols
Automatic Address learning (IEEE 802.1D)
§ Forward traffic to a certain port, based on destination address§ Fill MAC address table automatically, based on source addresses of
incoming frames§ Age out learned addresses after 5 minutes, but timer is reset each time
a learned address is confirmed by another frame
§ Unknown addresses and Broadcast traffic is "flooded" (forwarded on all ports)
Spanning Tree Protocol (STP) (IEEE 802.1D)§ Remove loops in WAN network by blocking some links
§ Special BPDUs (Bridge PDUs) are transmitted by bridgesOne bridge is declared the "root"Other bridges determine which port offers "least cost path" to root, based on bandwidth
39
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Automatic Address Learning
X
X
X
A
1
2
3
B
C
12
2
3
1
D
BA
A 1
MAC
A 1
MAC
A 3MAC
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Bridge#20
Bridge#25
Bridge#32
Bridge#96
Bridge#70
Link Cost ≈1000 / Capacity [Mbit/s]
10
20
50
1001010
10
1. Initial Situation
Bridge#20
Bridge#25
Bridge#32
Bridge#96
Bridge#70
10
20
50
1001010
10
Root ID
2. All bridges assumethey're the root
Cost Own IDBPDU:
96 0 96
20 0 20
70 0 70
32 0 32
25 0 25
Bridge#20
Bridge#25
Bridge#32
Bridge#96
Bridge#70
10
20
50
1001010
10
8
3. Lowest BPDU "wins"
96 0 96
20 0 20
70 0 70
20 10 32
20 10 25
Bridge#20
Bridge#25
Bridge#32
Bridge#96
Bridge#70
10
20
50
1001010
10
4. Spanning Tree formed
XX
20 20 96
20 0 20
20 40 70
20 10 32
20 10 25
X
Spanning Tree Protocol
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Ethernet Shared Transport
CP CP
LAN Network
CP
LANWAN
CPE
SDH
CPE
SDH
CPE
SDH
CPE
SDH PublicNetwork
Single VCn-Xv pipe, multiplecustomers
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PublicNetwork
Ethernet Trunking
CPCP
CP CP
LANWAN
CPE
SDH
CPE
SDH
CPE
SDH
CPE
SDH
SDH
Internet
Router PoPTrunking LANinterface
40
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Packet Processing capabilities in SDH MSPP
Source: RHK Inc.MS-ADM= Multi-service ADM; MSTN= Multi-service Transport Node; ETP=Ethernet Transport Device; CE = Circuit emulation
“Pure packet”
No packet features Packet-aware L2 features
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Overview of Carrier Ethernet TechnologiesRecent Developments
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Broadband Access (Residential + Business) Network Architecture
Edge/CoreAggregationAccess
IP-DSLAM
N x GE
FTTx GE
DSL
Voice
Video
Data
ServiceDelivery
Platforms
SoftswitchVoice Gateway
PSTN
High SpeedInternet
Headend
VoD
VoIP
IPTV
Residential
Ethernet/SDH/WDM
Metro Transport Core Transport
IP/MPLS
2G/3G Mobile,WiMAX
FEE1/DS1
FE/GE
E1/DS3STM/OC/λ
Business
Wireless
SGSN
GGSNService Router
3G Core Networ
kEthernet/MPLS/VPLS
ScalableCircuit
& Packet Transport
ATMDSLAM STM/OC
Ethernet/SDH/WDM (ROADM)
10GE
10GE
Video Servers
IP/MPLSSome form of enhanced Ethernet ?
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Carrier Ethernet Technology Landscape
“Metro Ethernet” encompasses all public Ethernet networking methods: § Native Ethernet Switching IEEE 802.1Q§ IEEE 802.1ad PB§ IEEE 802.1ah PBB § PBT (PBB-TE)§ IEEE 802.17 RPR§ MPLS L2 VPN: VPWS, VPLS, H -VPLS (using carrier IP/MPLS backbone)§ T-MPLS
Each Ethernet multiplexing layer option can run over any physical layers:§ SDH/SONET/OTN with GFP/VCAT/LCAS Optical Transport§ CWDM/DWDM Optical Transport§ IEEE 802.3 Ethernet PHY directly over fiber§ IEEE 802.3ah EFM (Ethernet/xDSL, E-PON)§ MPLS§ ATM
The MEF has carefully defined Carrier Ethernet in terms of services attributes and functions, not technology
Competing and complementary at the same time
41
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Limitations of today’s Ethernet solutions
Mature and widely deployed technology but…Service Provider devices switch based on customer addresses (C-MAC)§ C-MAC address table scalability§ Vulnerable to Denial of Service attacks
Limited network scalability § VID space § STP bridge diameter
Very limited Traffic Engineering capabilities § Inefficient usage of network resources because of Spanning Tree requirement
Slow Protection switching§ Inherently slow because STP is a distance-vector protocol
Weak security because of self-learning networkAnd (but not inherently linked with the technology itself)§ Limited OA&M (being worked in IEEE/ITU -T/MEF)§ Limited control plane tools§ Limited OSS tools (being worked by ITU -T/TMF/MEF)
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Evolution Objectives
Change as little to existing data plane technology as possible
§ Maintain low prices
§ Backward compatibility with existing bridges
Increase or Improve:
§ Scalability§ Network utilization
Enable traffic engineering
§ QoS
§ Fast protection switching
§ Security
Support a wide variety of services efficiently
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Ethernet Evolutions:IEEE 802.1ad Provider Bridges ( PB)
Previously known as Q-in-Q, Now Approved Standard§ Enables segregation of customers and
transparency for customer traffic§ Specifies dual VLAN stacking
C-VLAN: Customer VLAN, S-VLAN: Provider VLAN: same tag format, but different Ethertype in TPID field, supports encoding of Drop Eligibility in DEI bit)
Most common customer interfaceUnique Service ID per Service (S-VID)§ 4K Services (12-bits)
Forwarding is basic L2 with flooding/learning based on MAC DA/SA at the S-VID level and xSTP for loop preventionScalability§ Limited to 4K instances§ Still relies on (M)STP
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Ethernet Evolutions: IEEE 802.1ah Provider Backbone Bridges ( PBB)
MAC-in-MAC encapsulation§ Virtualization: Isolates customer
network from service provider network§ Hierarchical scaling
4K Interconnect Flood DomainsUnique Service ID per Service using the I-Tag (I-SID)Forwarding is basic L2 with flooding/learning based on MAC DA/SA at the B-VID level and xSTP for loop prevention§ Still uses (M)STP and does not address
all scalability issues of EthernetScalability§ Massive service scale (24-bit)§ No need to burn an I-SID at every node
for every service to build a P2P mesh§ C-MACs learned and associated per B-
VID/I-SID
42
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Ethernet Evolutions: IEEE 802.1Qay Provider Backbone Transport ( PBT) or PBB-TE
PBT defines p2p Ethernet transport tunnels § Combines PBB with provisioned forwarding tables§ Turning off flooding, broadcasting, learning, Spanning Tree Protocol
Instead, end-to-end paths are explicitly configured § 60-bit label <B-DA + B-VID> used as a global connection identifier
New VID semantic: VLANs are not used to limit broadcast domains. B-VIDs are used a “path selector” to B-DA, to establish two paths to destination DMAC ANo translation/swappingIVL forwarding mode
§ B-SA used to track source nodeResiliency§ Primary and backup tunnels monitored by IEEE 802.1ag CFM
Unique Service ID per Service (I-SID)Scalability§ Tunnel scale (58-bit space)§ Service scale (24-bit space)§ I-SID per P2P service
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Ethernet Encapsulations
IEEE 802.3 Basic Ethernet Frame
IEEE 802.1Q VLAN Frame
IEEE 802.1ad Provider Bridge Frame
IEEE 802.1ah Provider Backbone Bridge Frame
MPLS Frame
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RPR is a packet-based transport technology
RPR is a new MAC, different from the standard Ethernet MAC (IEEE 802.3 CSMA/CD) leveraging
§ Resiliency of fibre rings
§ Bandwidth efficiency of packet-switching technologies
RPR applies strictly to Layer 2 (logical) ring topologies§ Compare with Token Ring (IEEE 802.5) or FDDI,
but bi-directional
§ It does not need to be a physical ring, e.g. when RPR is transported over SDH, it is possible to have a logical ring over a physical network consisting of a mesh or multiple rings, but requires constant bandwidth over whole ring perimeter
Spatial Reuse*: bandwidth efficiency by using “destination stripping” and routing via shortest leg of ring from source to destination
Shared bandwidth, ring-level aggregation
Supports a “fairness” protocol at node level
*: in theory, does not apply for bridged Ethernet services
Ethernet Evolutions:IEEE 802.17 Resilient Packet Rings (RPR)
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Fast restoration (50 ms) by using either traffic§ Wrapping (compare with MS-SPRing/BLSR)§ Steering
Transport flexibility: RPR is Layer 2 protocol and independent of Layer 1 and 3Supports multiple QoS classesPlug&Play
§ node hot-insertion, >100 per ring (large ring diameter but limited by latency)§ topology discovery/awareness, no master/slave node§ minimum provisioning/engineering
Not very successful§ Requires special (costly) hardware§ Only useful in specific topologies
E.g. limited ability to interconnect rings§ Benefits are local and don’t extend network-wide
Limited interworking with native Ethernet and Provider bridges§ Amendment to avoid flooding of L2 bridged traffic
§ RPR has some application space but will remain isolated to certain metro regions
Ethernet Evolutions:IEEE 802.17 Resilient Packet Rings (RPR)
43
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MPLS Evolutions: VPWS - Basic Concepts
PWE3 (PseudoWire Emulation End to End)
§ Virtual Private Wire Services
§ Martini
A PW is an Virtual Connection that emulates a physical link (such as an Ethernet, ATM, Frame Relay)
The payload of packets traveling over a pseudowire are L2 frames (Ethernet, ATM, FR) rather than IP datagrams (L3 frames)
Similar to ATM / FR services, uses tunnels and connections
Carrier equipment does not peer with customer equipment
§ Increases scalability and securityProvides true multi-protocol support through transparency
§ Upper Layer Protocol agnostic
§ Most applications may be IP but many customers want FR/ATM like services from their provider rather than IP-based services
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Martini (PW) Circuits
VPN A
VPN B
VPN A
VPN Tunneling ProtocolsLDP
MPLS
VPN B
SP Tunnels
VPN Tunnels (inside SP Tunnels)VPN AVPN B
Layer2 link
Header 1 Header 2 L2 Data Packet
Header 1 Header 2 L2 Data Packet
P
PE
P
PE
PE
CE
CE
CE
CE
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MPLS Evolutions: VPLS - Adds L2 Bridging Functions to PWE
Provides Ethernet Private LAN (E-LAN)Builds on PWE signalingAdds switching intelligence to PE nodes§ Full mesh of VC LSPs and Tunnels
No forwarding between MPLS tunnels and VC LSP§ Bundled Martini pseudo wires§ Requires a full mesh of VC LSPs
VPLS Forwarding§ Learns MAC addresses per pseudo-wire (VC LSP)§ Forwarding based on MAC addresses§ Replicates multicast & broadcast frames§ Floods unknown frames§ Split-horizon for loop prevention drives full mesh requirement
Standard IEEE 802.1D code§ Used to interface with customer facing ports§ Provides local switching
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VPN-A
Defines an Ethernet (IEEE 802.1D) learning bridge model over carrier IP/MPLS § Full mesh of Tunnel LSPs is established between VPLS-aware PEs (via RSVP-TE)§ Layer-2 VC LSPs are set up in Tunnel LSPs (via e.g. LDP)§ PEs do MAC learning/bridging on a per LSP basis and map C-VLANs into VC LSP§ Emulates a single distributed IEEE 802.1Q switch§ VPLS topology can be point-to-multipoint, any-to-any (full / partial mesh)§ Benefit from all other MPLS advantages: Traffic Engineering, Fast Re-Route, QoS
Defines an Ethernet (IEEE 802.1D) learning bridge model over carrier IP/MPLS § Full mesh of Tunnel LSPs is established between VPLS-aware PEs (via RSVP-TE)§ Layer-2 VC LSPs are set up in Tunnel LSPs (via e.g. LDP)§ PEs do MAC learning/bridging on a per LSP basis and map C-VLANs into VC LSP§ Emulates a single distributed IEEE 802.1Q switch§ VPLS topology can be point-to-multipoint, any-to-any (full / partial mesh)§ Benefit from all other MPLS advantages: Traffic Engineering, Fast Re-Route, QoS
VPN-B
PEPE PEPEVPN-A
PEPE
VPLS-A
CECE
CECE
CECE
MTU-sMTU-s
VPN-B
CECE
VPN-BCECE
MTU-sMTU-s
L2 aggregation Ethernet NetworkL2 aggregation
Ethernet Network
CECETunnel LSPTunnel LSP
VC VC
BB
B
PP
VPLS (bridge) instanceVPLS (bridge) instance
Attachment circuitAttachment circuit
VPLS Reference Model
44
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HVPLS
VPLS
Inter -domain VPLS
VPLS Scalability: H-VPLS
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VPLS
§ Tunnels tied to physical infrastructure
§ Dedicated P2P pseudowire mesh with split-horizon forwarding within the core between PEs for every service instance
§ Scalability
PW sessions signaled via MPLS control plane
Tunnels scale as PEs are added
At a minimum for n PEs there are n tunnels (20 bits)
Pseudowires scale n!/2(n-2)! * service count (20 bits)
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H-VPLS
§ Introduced to offload PW mesh scaling issues as service count grows
§ MTU-s introduction requires fewer PEs and smaller PW mesh
Implementations often seek to increase service count, which in turn drives larger MAC table size requirements
§ ScalabilityPW sessions signaled via MPLS control planeHub and spoke PW architecture reduces PW mesh issue
As service count grows, trade off MAC table size vs. PW mesh
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MPLS Evolutions: T-MPLS
T-MPLS = "Transport MPLSҤ Attempt by ITU (SG13&SG15) to formalize a profile of MPLS for L2 transport
network applicationsFunctional modeling, strict decoupling fwd/ctl/mgmt, compliance with ITU -T's transport network principles
Defined as:§ A co-ps transport network technology§ Reusing MPLS principles and fwd-plane design
MPLS PDU format, MPLS processes (TTL, …)
§ With some options fixed to suit ITU -style transport:No PHP, ECMPNo uniform modelStrictly connection-oriented (-> no merging)
§ Strong Transport OAM based on G.8114 (vs. IETF LSP Ping)§ Strong Resilience mechanisms based on G.8131/G.8132 (vs. IETF FRR)
Currently no defined control nor management plane§ Plan to use GMPLS/ASTN control plane
45
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ITU-T Primary SDO where most large carriers
and equipment vendors participate and where the expertise in transport
networks resides. Ethernet over Transport architecture and equipment
standardization is in SG15, other functions such as OA&M are in SG13.
IEEE 802 Primary organization historically
responsible for Ethernet specification. Recently engaged
in specifications to carry Ethernet over carrier transport networks, including hierarchical forwarding
and OA&M.
Metro Ethernet ForumPrimary organization responsible for definition of Ethernet services, User-Network/Network-Network Interfaces and Implementation Agreements to
foment the quick adoption of Ethernet transport services
(Technical + Marketing committees).
IETFPrimary organization responsible for
definition of Virtual Private LAN Service (VPLS) in the L2VPN WG
(Internet area), Ethernet tunneling on IP/MPLS network with pseudo-
wires (VPWS) in the pwe3 WG (Transport area), and MPLS.
Main Ethernet Standardization Organizations
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Metro Ethernet Forum
• Carrier Ethernet is a ubiquitous, standardized, carrier-class SERVICE defined by five attributes that distinguish Carrier Ethernet from familiar LAN based Ethernet
• It brings the compelling business benefit of the Ethernet cost model to achieve significant savings
Carrier Ethernet
• Scalability
• Standardized Services
• Service Management
• Quality of Service
• Reliability
Carrier Ethernet Attributes
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SERVICE PROVIDERS
EQUIPMENT MANUFACTURERS
TM
ContentsContents Carrier EthernetCarrier Ethernet TechnicalTechnical Future WorkFuture Work CertificationCertification MembershipMembershipMarketingMarketing
MEF Certified Companies January 2007
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Transport network evolution
46
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Application drivers: Service Transformation
§ Triple Play à VoIP, HSI and IPTV (unicast & multicast)
§ Mobile à Multimedia services, visiophony, video streaming
§ Ethernet Services à Managed Ethernet Services including Virtual leased line (E-Line) and Virtual private LAN service (E-LAN), IP-VPN
§ SAN interconnectà Business continuity, disaster recovery
§ Video transport à Production and contribution networks
New residential and business services drive the transport network transformation
All Rights Reserved © Alcatel-Lucent 2006, #####182 | Cours Réseaux Optiques – Partie I | March 2008
Application drivers: Impact for the Network
Growth in metro and core, but with important service diversity
BandwidthFactor 6 traffic increaseBetween 2004 and 2008
2004
2008Source: Alcatel Study 2005
6x50%
10%3%
7%
24%
6%
25%
4%
27%
11%
31%
2%Private Lines (Enterprise DIA, Retail, Wholesale)
Voice (Fixed +Mobile)
Video Distribution
Broadband Internet Access, SMEs
Broadband InternetAccess, Residential
Data Services (ATM/FR, L2-VPN, L3-VPN)
Diversity An unpredictable mix of technologies and protocols
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Transport Network – Definition and Requirements
Scalability
Reliable aggregation and transport of any client traffic type, in any scale, at the lowest cost per bit
Transport Network
Quality Cost-EfficiencyMulti-service
Ability to support any number of client traffic
instances whatever network size, from
access to core
Ability to ensure that client traffic is reliably delivered at monitored
performance e2e
Ability to deliver any type of client traffic (transparency to
service)
Acting as server layer for all the rest by keeping processing complexity low and
operations easy
Transport values have evolved through long TDM evolutionThey hold through transition to packets
All Rights Reserved © Alcatel-Lucent 2006, #####184 | Cours Réseaux Optiques – Partie I | March 2008
Meeting Operator Rationales: focus on scalability and operational simplification
WDM
SONET/SDH
SAN, PDH,IP/MPLS
ATM, FR, Ethernet
Squ
eeze
(st
ack)
Grow (BW)
Map at Edge
Map & Switch
L0
L1
ClientPacket
Networking
To increase scalability, bring networking into layer-0 and packet into layer-1Layer-1: universal matrix and transport-optimized MPLS
Layer-0: Range from ROADM to tunable multi-degree switching
SONET/SDH
SAN, PDH, ATM, FR, Ethernet, IP/MPLS, Clear Channel
Map at Edge
Packet ODU
Photonic SwitchingL0
L1
Lot of sub 2.5G TDM clients are there and grow due to mobile
More efficient transport for L2 and L3 services
T-MPLS
Aggregation
Core
Clear channel for Carriers’ Carrier and large enterpriseMulti-vendor capable lambda networksDistributed regeneration and recoloring
47
All Rights Reserved © Alcatel-Lucent 2006, #####185 | Cours Réseaux Optiques – Partie I | March 2008
Technology Enabler: Universal Switch matrix for smooth transition from TDM to packet
Today / 100% Circuit
Start with SDH only, introduce packets gradually
Start with packets only, introduce SDH gradually
Current practice - MSPP migration New practice - Transport Switch
TDM card Packet card
Photonic card
Universal Switch
Universal Switch
Universal Switch
STM-1E1
STM-64 STM-64 10GE GE FE10GE
Vision / 100% Packet
Deploy SDH networks with full scalability to packet transportDeploy packet-centric network with true TDM capability
All Rights Reserved © Alcatel-Lucent 2006, #####186 | Cours Réseaux Optiques – Partie I | March 2008
Technology Enabler:Transport MPLS (T-MPLS)
Carrier-grade packet networkingStrong market adoption
MPLS
New ITU-T standardProfile of MPLS improved and cost optimized
T-MPLS
Linked to IPAllows connection-less networking
OAM below transport standardsNo separation of data & ctrl plane
BUT transport unfriendly
T-MPLS = MPLS – IP + OAM (+ GMPLS in option)
Client-Server independenceStrictly connection-orientedTransport-grade OAM & survivabilityNMS or GMPLS control plane
Purpose-designed for packet transport
All Rights Reserved © Alcatel-Lucent 2006, #####187 | Cours Réseaux Optiques – Partie I | March 2008
T-MPLS becomes MPLS-TP with IETF/ITU -T Joint Working Team
IETF and ITU -T formed a Joint Working Team to find a way to bring the two technologies together
Undertook a technical feasibility study, and identified NO show-stoppers
MPLS “Transport Profile” (MPLS-TP) definition
Integration of MPLS-TP into transport network
Alignment of current T-MPLS Recommendations with MPLS-TP
Convergent solution termed “MPLS Transport Profile” (MPLS-TP)
All Rights Reserved © Alcatel-Lucent 2006, #####188 | Cours Réseaux Optiques – Partie I | March 2008
FTTx
48
All Rights Reserved © Alcatel-Lucent 2006, #####189 | Cours Réseaux Optiques – Partie I | March 2008
FTTP Market & DriversBroadband Access Market - Current Status
Broadband access market is mature now:
§ Broadband access penetration in Europe 30% today, 40% by 2008
§ Full-blown (bandwidth) competition: DSL, Cable
§ Line prices have dropped (far) below $40
§ Average Revenue per User (ARPU) is also decreasing
§ Limitations in bandwidth and coverage
Careful introduction of:
§ New value-added services & bundles (triple play)Internet Services (Peer to peer, gaming, hosting)TV Entertainment Services (Video broadcast, VoD, PVR (SDTV), HDTV)Conversational Services (VoIP, Video conferencing)Business and Public Services (File sharing, Telemedicine, Distance learning)From a single provider (bundled services)!
§ New technologies (ADSL2+, VDSL, FTTN, FTTP)
All Rights Reserved © Alcatel-Lucent 2006, #####190 | Cours Réseaux Optiques – Partie I | March 2008
FTTP Market & Drivers Major Drivers for Broadband Access migration
Political Pressure§ Worldwide access revolution taking place§ Europe must keep up with Asia and US§ Regulators and governments are actively stimulating new access technologies
Competition§ Increasing competition in Europe (on bandwidth and triple play services)§ In some countries from CATV (NL, Belgium, Swiss)§ In many counties from competitive carriers using ULL
FT is losing 60% of new DSL connections to the competitionOther examples: UK, Spain, and starting in Germany and Italy – all planning to provide triple play
Reduce Cost§ Single integrated network for voice, video, data§ Easier installation, operation & maintenance
Increase ARPUIncrease bandwidth and coverageOvercome copper limitationsCustomer demand Retain and grow customer baseNetwork renewal/replacement
All Rights Reserved © Alcatel-Lucent 2006, #####191 | Cours Réseaux Optiques – Partie I | March 2008
FTTP Market & Drivers Bandwidth Needs
Basic Triple is OK for approx 50-60% of households in Europe using ADSL§ 1 video channel (4Mbit/s MPEG2), 1Mbit/s Internet and VoIP = 5Mbit/s§ Commercial services: Telefonica, France Telecom, FastWeb, Free Telecom
Many Service Providers target 20 Mbit/s§ HDTV with MPEG4, multi video channels, 5-10Mbit/s for Internet services § Telemedicine, VPNs, video conferencing for business customers§ Also require at least 3Mbit/s upstream (peer to peer traffic)§ Coverage should be >80%
Which technologies can accommodate this bandwidth need ?
Source: Belgacom Presentation at IIR Conference in Barcelona, 2004
All Rights Reserved © Alcatel-Lucent 2006, #####192 | Cours Réseaux Optiques – Partie I | March 2008
Comparison of DSL, Cable and FTTH Technology Bandwidth
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All Rights Reserved © Alcatel-Lucent 2006, #####193 | Cours Réseaux Optiques – Partie I | March 2008
Why Fiber Now?
Worldwide acceptance, standardization & mass market for:§ IP-based services § IP/Ethernet based networks§ SFP-based optical Ethernet technologies (IEEE 802)§ Standard Single Mode Fiber (SMF - G.652)§ Passive Optical Network (PON) standards
Technical improvements have driven down the costs of all FTTx components§ QoS and reliability of (optical) Ethernet networks§ Processor power & link speed§ Signal processing§ Cable installation
FTTx economics§ Need case-by-case business case to compare CAPEX of all FTTx technologies and
bandwidth optionsDensity, housing, cabling, trenching, CO and access equipment, CPE, CPE installation
§ For greenfield or renewal FTTx already serious alternative (the cost of laying fiber is the same as that of laying copper)
§ Re-use of existing copper makes a big cost difference and remains strong argument for DSL
All Rights Reserved © Alcatel-Lucent 2006, #####194 | Cours Réseaux Optiques – Partie I | March 2008
Option 1: Enhance CO-based DSL§ Increase DSL speed and/or reach (ADSL2+, VDSL, …)§ Increase DSLAM capacity & performance
The Broadband Access Network Evolution - Migration options
Deep Fiber NodeDLC & VDSL
Copper Drop
Fiber Drop -Retrofit
Fiber-fed DLC & ADSL
Copper Drop
Fiber Drop -Retrofit
Central Office
Access/ Distribution
End-user
Fiber to the curb
Copper Drop
Fiber Drop -Retrofit
Fiber to thePremises
Fiber Drop
Fiber to the MDU
Fiber or copper Drop
FTTP
FTTN
End-to-end copperCopper
Drop
CO-DSL
Option 2: Extend fiber to the user§ Fiber-to-the-Node (FTTN) –
shorten copper loop§ Fiber-to-the-Premises (FTTP) –
no copper loop
All Rights Reserved © Alcatel-Lucent 2006, #####195 | Cours Réseaux Optiques – Partie I | March 2008
FTTP Basics
FTT-Premises means home, office, MDU, building, etc.§ Typically within 100m of end-user§ Fiber or cat5 copper drops (native Ethernet, no DSL)
FTTP brings huge benefits of fiber to access network, e.g.:§ Future proof investment§ Zero interference§ Virtually unlimited bandwidth, response to 3 play (HDTV, VoIP, IA)§ Large distances
Various FTTP technologies in the market:§ Active or Passive§ P2P or PMP (PON)§ GPON or EPON (or BPON)§ Video digital in-band vs analog overlay
Common characteristics:§ Native Ethernet based (in EMEA)§ Average bit-rate per user at least 20Mbps (up & down)§ Access line speed 100-2400Mbps
All Rights Reserved © Alcatel-Lucent 2006, #####196 | Cours Réseaux Optiques – Partie I | March 2008
FTTP Options
Ethernet P2P – Direct Fiber (DF)Passive Outside plant
Ethernet-only transportIn-band video
Standardized form available today
Ethernet P2P – DF
100 Mbsper sub
IEEE 802.3ah
EPON
EthernetSwitch
OLT
Optical power splitter
t128.5 Mbps
per sub1 GbpsEPON = Ethernet-PON
Ethernet/IP -only transportIn-band video
Standardized in 2004tn
Ethernet Switch
100Bx
AON = Active Optical NetworkActive Outside plant
Ethernet-only transportIn-band video
Standardized form available today
Ethernet P2P -AON
Active Switch/MuxN x 1 Gbpsor 10 Gbps
100 Mbsper sub
Ethernet Switch
ITU G.984 GPON
Multi-serviceswitch OLT
Optical power splitter
t1 33.4-66.8 Mbps/sub1.2 or 2.5 Gbps down,155M –1.25Gbps up
GPON = Gigabit -PONNative protocol transport using ATM,
GFP/SDH, EthernetStandardized in 2004tn 3.8-60.4 Mbps/sub
ITU G.983 BPON
ATM switch
Optical power splitter
t1 15.7-31.6 Mbps/sub1.2 G or 622 Mb/s down BPON = Broadband-PON
ATM-only transportStandardized form available today,
introduced in the 1990stn 3.9-15.6 Mbps/sub155/622Mb/s up
25.7 Mbps/sub
50
All Rights Reserved © Alcatel-Lucent 2006, #####197 | Cours Réseaux Optiques – Partie I | March 2008
Basics of PON Architecture
Downstream:§ Uses either ATM, TDM or Ethernet
Framing and Line Coding§ QoS / Multicast support provided by
Edge Router
Upstream:§ TDMA protocol
ONU sends packets in timeslotsMust avoid timeslot collisionsBurstmode Optics
§ BW allocation easily mapped to timeslots (MPCP)
1 2 3 21
2 2
3
1
2 2
3
3
3
3
1 2 3 21
2 2
3
1 2 3 2
1 2 3 2
1 2 3 2
1:N optical splitters(N dependent on PON technology)
Shared network, Tree topology with passive optical splitters§ No active electronics, lower costs and simplifies operations
PHY specification dictates reach/bandwidthOLT: Optical Line Terminal, at Central OfficeONU: Optical Network Unit, in CPEs
1490nm
1310nm
OLT
OLT
ONU
ONU
All Rights Reserved © Alcatel-Lucent 2006, #####198 | Cours Réseaux Optiques – Partie I | March 2008
EPON vs GPON
ITU (GPON) vs IEEE (EPON)
Hot debate in the market, vendors taking position (whitepapers etc.)
GPON benefits:
§ Higher bitrates (up to 2.5Gbps)
§ Higher efficiency (more advanced MAC, less overhead)
§ Supports native TDM, ATM, packet
§ Operator Driven (FSAN): protection, security, long reach
§ Mature – Relies on B-PON foundations
EPON benefits:
§ Cheaper (control electronics)
§ Uses regular Ethernet optics
§ Claims “TDM over Ethernet” support
Packet-only GPON compares to EPON
§ Somewhat more expensive but offers more bandwidth and efficiency
All Rights Reserved © Alcatel-Lucent 2006, #####199 | Cours Réseaux Optiques – Partie I | March 2008
PON vs E-P2P / Active vs. Passive Solutions Comparison
CPE
CO CPE
CPE
CPE
CO CPE
CPE
SW
CPE
CO CPE
CPE
PONEthernet Point to Point
AON Direct Fibre
Passive Active Passive
Less fibre
N+1 transceivers
Less fibre
2N+2 transceivers
More fibre
2N transceiversShared medium Dedicated links Dedicated links
Expensive shared PON interface (optics and electrical)
Cheap interfaces (standard Ethernet)
Cheap interfaces (standard Ethernet)
Medium/Low CAPEX Low CAPEX Medium CAPEX
Low OPEX Medium OPEX Low OPEX
Low upgradability Medium upgradability Maximum upgradability
All Rights Reserved © Alcatel-Lucent 2006, #####200 | Cours Réseaux Optiques – Partie I | March 2008
PON vs E-P2P: application areas
Both technologies are being explored and deployed throughout the worldBoth technologies have their merits and application areas
§ Access networks are too varied for a single solutionPON application examples:
§ Long loop length§ Congested ducts
P2P application examples:§ Shared indoor access applications (MTU/Building/Business)§ When dedicated, upgradeable & secure bandwidth is required§ Shorter loop length, no congested ducts§ VDSL evolution towards AON
Migration to direct fiber solutions§ Combines best of both worlds (passive and dedicated bandwidth)§ Fiber prices and installation techniques keep improving§ Maximum future proof
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All Rights Reserved © Alcatel-Lucent 2006, #####201 | Cours Réseaux Optiques – Partie I | March 2008
Parameter BPON EPON GPON WDMPON
Linerates 155, 622 Mbps, 1.2 Gbps ↓155 Mbps or 622 Mbps ↑
1.25 Gbps ↓1.25 Gbps ↑
1.2 Gbps or 2.4 Gbps ↓155, 622 Mbps,1.2, 2.4 Gbps ↑
Any
Wavelengths 1480 – 1500 nm ↓1260-1360 nm ↑1550-1560 (video-option)
1480 – 1500 nm ↓1260-1360 nm ↑1550-1560 (video-option)
1480 - 1500 nm ↓ (1 fiber)1260 - 1360 nm ↓ (2 fiber)1260 - 1360 nm ↑
Not yet standardized –could use DWDM, CWDM or G.983.3 compatible λ plan
Security Rudimentary (Churning) Not within 802.3ah scope Secure (AES) Secure (λ)
Physical reach Max. 20 kmSplits: 1:32 – 1:128
Max. 20 km (10 km is option) Splits: 1:32 – 1:64
Max. 20 km (10 km is option) Splits: 1:32 – 1:128
Depends on laser technology used and channel spacing
Typical useable bandwidth per subscriber (32 split)
15.9 Mbps + 870 Mhz RF ↓3 Mbps ↑
25 Mbps ↓25 Mbps ↑
30 Mbps ↓20 Mbps ↑
>100 Mbps ↓>100 Mbps ↑
Dynamic BW Allocation
Yes. ATM UNI signalling for PVCs supported
Yes. Mandated but no signaling protocol
Yes. Same as BPON for ATM mode. GEM mode TBD
MAC layer dependent
TDM support Yes Partial – vendor specific Yes MAC layer dependent
Multicast support No Yes TBD No
QoS ATM 4.1 Classes of Service 802.1p priority queuing ATM 4.1 Classes of Service802.1 p, Diffserv TBD
Depends on MAC layer protocol
Management (OAM) Extensive message and MIB defintion
Still evolving Still evolving with BPON baseline definitions
λ OAM undefined, MAC layer dependent
Standards ITU-T G.983.1 IEEE 802.3ah EFM ITU-T G.984.1,2 CWDM ITU…DWDM ITU…
PON Technology Comparison
All Rights Reserved © Alcatel-Lucent 2006, #####202 | Cours Réseaux Optiques – Partie I | March 2008
IEEE 802.3ah EFM Three Technologies in one Architecture
EFMA and IEEE 802.3ah
CPE
Access Node
Copper 10Mbps
EMF-CEFM over point-to-point Copper: over existing copper wire (Cat1-5) at speeds of 10 Mbps up to at least 750m, or 2 Mbps up to 2700m
CPE
Access Node
Fiber 1Gbps
Fiber 100Mbps
EFM-FEFM over point-to-point Fiber: over SMF at speeds of 100 and 1000 Mbps up to at least 10 km
Access Node
Fiber 1Gbps
Fiber 1Gbps Shared
Optical Splitter
CPE
EFM-PEFM over point-to-multipoint Fiber: EPON over SMF at a speed of up to 1Gbps, up to 20 km
EFM-Hmix of the above (e.g. FTTC)
Associated Ethernet OAM functions
All Rights Reserved © Alcatel-Lucent 2006, #####203 | Cours Réseaux Optiques – Partie I | March 2008
EFM Standards Scopevs. existing IEEE 802.3 standards
10GbE
1000BASE-LX (SMF)1000BASE-SX (MMF)
10BASE-T (Cat5)
100BASE-T (Cat5)
100BASE-FX (MMF)
10PASS-TS (VDSL)
2BASE-TL (SHDSL)
Existing IEEE 802.3 standards
Maximum Bandwidth (Symmetric)
10Gbps
1Gbps
100Mbps
10Mbps
2Mbps
100m 500m 750m 2000m 2700m 5km 10km 20km
Minimum
Reach
100BASE-L/BX10(SMF)
1000BASE-B/L/PX10
1000BASE-PX20(SMF)
EFMC IEEE 802.3 ah
EFMF IEEE 802.3 ah
EFMP IEEE 802.3 ah
All Rights Reserved © Alcatel-Lucent 2006, #####204 | Cours Réseaux Optiques – Partie I | March 2008
Overview of the Optical Market and Competition
52
All Rights Reserved © Alcatel-Lucent 2006, #####205 | Cours Réseaux Optiques – Partie I | March 2008
ADVAADTRANAlcatel-LucentCalientCienaCiscoCorrigent DatangECI Ericsson (Marconi)
FiberHomeFujitsuHitachi HuaweiInfineraLantern LuminousMahiMeritonNEC
Nokia SiemensNortelOkiPacketLightPhotonixnetPolarisRBNSagemSamsungSorrento/Zhone
SycamoreTelco SystemsTellabsTransmodeTropicTurin NetworksUTStarcomXteraZTE
The top ten Optical Networking vendors control 85% of the market
Optical Networking Companies
All Rights Reserved © Alcatel-Lucent 2006, #####206 | Cours Réseaux Optiques – Partie I | March 2008
Total Optical Market Share 2006 (pre-merge)
Source: Dell’Oro Group
• Large equipment vendors generally have complete portfolio
• Smaller vendors target specific applications
• Market Share per product segment (ADM, OXC, DWDM) can look very different
All Rights Reserved © Alcatel-Lucent 2006, #####207 | Cours Réseaux Optiques – Partie I | March 2008
Optical Market Revenue Comparison (2005) by Product Group (post-merge)
Source: Dell’Oro Group
All Rights Reserved © Alcatel-Lucent 2006, #####208 | Cours Réseaux Optiques – Partie I | March 2008
Source: Dell’Oro Group
• EMEA remains the largest region• NAR is now approximately 1/3 of the pie• AP is now about 30% larger than China • CALA is 4% of the total TAM
• EMEA remains the largest region• NAR is now approximately 1/3 of the pie• AP is now about 30% larger than China • CALA is 4% of the total TAM
Spending by Region
53
All Rights Reserved © Alcatel-Lucent 2006, #####209 | Cours Réseaux Optiques – Partie I | March 2008
2006 Optical Total Addressable Market Revenue Split by Segment
• The TAM estimate for 2006 was approximately $9B• The Traditional ADM and MSPP segments combined continue to
represent about 2/3 of the market in 2006.• The contribution of each segment remains unchanged
• The TAM estimate for 2006 was approximately $9B• The Traditional ADM and MSPP segments combined continue to
represent about 2/3 of the market in 2006.• The contribution of each segment remains unchanged
Note: Carrier Ethernet not included
All Rights Reserved © Alcatel-Lucent 2006, #####210 | Cours Réseaux Optiques – Partie I | March 2008
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