DEPARTEMENT SIGNAL E T TELECOMMUNICATION …sudriaesme.free.fr/Arthur 3ème Année/Réseaux haut...

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]

All Rights Reserved © Alcatel-Lucent 2006, #####2 | Cours Réseaux Optiques – Partie I | March 2008

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


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


IntroductionAlcatel-Lucent

2


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


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


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


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


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


Transport Protocols in Public Networks


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


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


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


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"


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


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


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)


Multiplexing Technologies


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)


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


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


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


Before SDH: PDH


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


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


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


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


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


SDH Overview & Advantages


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


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


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


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)


Network Layering, Data Transparency

Voice, Data, Video, Multimedia...

SDH/SONET

WDM

ATM

Ethernet

IP


Basic SDH Frame Structure and Transmission Principles


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


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


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


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.


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


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


SDH Multiplexing Structure


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


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


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


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)


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



North America and Japan Structure of Multiplexing


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



13


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


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


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




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


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


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


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.


SDH Pointer Function


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


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


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”)


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


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


Overheads


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


Tasks of the SOH

Data Channels

QualitySupervision

LineProtection

FrameAlignment

MaintenanceFunctions

VoiceConnection

SOH


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


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{


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


Tasks of the POH

Connectivity Check

VC QualitySupervision

Alarm Information

User Channel

Mapping Identification

MaintenanceFunctions

POH


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


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


Synchronization


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


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


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


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)


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



SSMs applied in SDH ring network: restoration in progress


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


ReferencePriority

PRC

DUS

20



SSMs applied in SDH ring network: restoration completed


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


ReferencePriority

DUS


Protection Mechanisms


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


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


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


SDH Network Configurations

Point-to-point Configuration

SDH TerminalMultiplexer


Linear Configuration



Repeaters

SDH Add/DropMultiplexer

Ring implementation choices:§ 2-fiber or 4-fiber§ unidirectional or bidirectional§ line switched or path switched§ STM rate

Ring configuration


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


• 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


• 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)


Head End BridgeNon-Intrusive MonitorsTail End Switch

Server Layer

SSF

SF,SD

SF,SD

SNCP Non Intrusively Monitored: SNC/N


• Signals are terminated in front of the switch • APS protocol necessary (K3) in Bidirectional mode• Not implemented today


Head End Bridge Non-Intrusive MonitorsTail End Switch

Server Layer

Trail

VC Trail Protection


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)


(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


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)


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


A

B

C

DProtection (9-16)

#1

#1

#1 #1

#9

Working (1-8)Switching nodes

Bridge

Protected traffic + APS signalling

MS-SPRingSingle failure


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


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)


A

B

C

DProtection (9-16)

Bridge

Switch

#1

#1

#1 #1

#9

#9

Working (1-8)

MS-SPRingRing Segmentation


A

B

C

DProtection (9-16)

Bridge

Switch

#1

#1

#1 #1

Misconnections !

#9

#9

Working (1-8)

MS-SPRingRing Segmentation (2)


A

B

C

DProtection (9-16)

Bridge

Switch

AISAIS

AIS

AIS

AIS

#1

#1

#1 #1

#9

#9

Working (1-8)

MS-SPRingSquelching

25


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


DNI between two MS-SPRing rings

SecundaryNode

Stand-by VC -4 Connection

STM-16 or STM-64MS-SPRING


PrimaryNode

ServiceSelector

Drop & Continue

Active VC -4 Connection


DNI – Interconnect Failures



SecundaryNode

PrimaryNode

ServiceSelector

Drop & Continue




DNI – Node Failure



SecundaryNode

PrimaryNode

ServiceSelector

Drop & Continue



26


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


Classification of Optical Interfaces & Transmission wavelengths


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:


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


Transmission Ranges

Wavelength

WDMWDM ::

1300 1500 1600

ITU G.692 comb

SDHSDH :: 1310 nm 1550 nm

80 traffic channels

Supervisory channel

50 GHz

Loss


Functional Equipment Specification


Functional Block Diagram Representation ITU-T G.783 (1) - PI, RS, MS layers


Functional Block Diagram Representation ITU-T G.783 (2) - HO-VC, LO-VC layers

28


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


Typical Network Element Types & Network Applications


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


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


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


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


OAM&P


CircuitSwitch

CircuitSwitch



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


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)


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



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



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


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


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


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


ASTN / GMPLS

32


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


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


Standardization


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


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.


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)


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


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


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


Conclusion and Future of SDH


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


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


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”)


Native Ethernet


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


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

36


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


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


Next-Generation SDH:Ethernet over SDH


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


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


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


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


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


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


Ethernet Multi-point Transport

CP CP

PublicNetwork

CPE

CP

CPCPE

LANWAN

CPE

CPE

SDH

SDH

SDH

SDH


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


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


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


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


Ethernet Shared Transport

CP CP

LAN Network

CP

LANWAN

CPE

SDH

CPE

SDH

CPE

SDH

CPE

SDH PublicNetwork

Single VCn-Xv pipe, multiplecustomers


PublicNetwork

Ethernet Trunking

CPCP

CP CP

LANWAN

CPE

SDH

CPE

SDH

CPE

SDH

CPE

SDH

SDH

Internet

Router PoPTrunking LANinterface

40


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


Overview of Carrier Ethernet TechnologiesRecent Developments


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 ?


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


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)


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


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


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


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


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


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)


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


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


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


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


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


HVPLS

VPLS

Inter -domain VPLS

VPLS Scalability: H-VPLS


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)


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


MPLS Evolutions: T-MPLS

T-MPLS = "Transport MPLS“§ 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


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


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


SERVICE PROVIDERS

EQUIPMENT MANUFACTURERS

TM

ContentsContents Carrier EthernetCarrier Ethernet TechnicalTechnical Future WorkFuture Work CertificationCertification MembershipMembershipMarketingMarketing

MEF Certified Companies January 2007


Transport network evolution

46


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


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


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


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


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


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


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)


FTTx

48


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)


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


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


Comparison of DSL, Cable and FTTH Technology Bandwidth

49


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


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


Central Office

Access/ Distribution

End-user

Fiber to the curb

Copper Drop


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


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


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


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


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


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


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


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


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

51


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


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


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


Overview of the Optical Market and Competition

52


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


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


Optical Market Revenue Comparison (2005) by Product Group (post-merge)




• 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


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


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DEPARTEMENT SIGNAL E T TELECOMMUNICATION …sudriaesme.free.fr/Arthur 3ème Année/Réseaux haut...

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