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Wide Area Networks (WAN) -Synchronous Digital Hierarchy (SDH)

AAU

Jens H. Sørensenjhaus@tdc.dk20 Oktober 2005

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Table of Contents

• Objectives• Introduction to WANs• Typical WAN Technologies• SDH Protocol• SDH Equipment• SDH Networks• SDH Network Management• SDH Services (partly 2nd part)• WDM/OTN (2nd part)• Network availability, restoration and automatic protection

(2nd part)• Next/new Generation SDH and relations to IP, ATM, WDM,

Ethernet … (2nd part)• Network Synchronisation (2nd part)

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Objectives

Discussion of

• LAN versus WAN, scaleability issues• WAN technologies, overview• Typical WANs, examples, SDH• Relations to networks based on

Ethernet/IP/ATM/DSL …• Upcoming WAN networks

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What is a WAN?

• Definition of "WAN" according to Webopedia:• A computer network that spans a relatively large

geographical area.• Typically, a WAN consists of two or more

local-area networks (LANs).• Computers connected to a wide-area network are

often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites.

• The largest WAN in existence is the Internet.

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Introduction to WANs

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Introductionto WANs

ExampleHigh CapacityLinks

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Introductionto WANs

ExamplePhysical andlogical Links

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Introduction to WANs - scaleability

• Can Ethernet based LANs be connected nationwide supporting millions of users?

• Scaleability issues (Ethernet)– no. of MAC addresses, VLANs, broadcast domains (ARP), STP

convergence, performance of MAC and CSMA/CD under high load, QoS etc..

– Creation of hierarchical networks– Long distance optical systems

• Scaleability issues (IP)– routing tables/IP-address aggregation, rearrangement of fixed

IP-addresses, QoS

• Other technologies are currently used…

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Introduction to WANs

802.3 Ethernet: MAC, LLC

TCP, UDP

IP

SDH, PDH, DXC 1/0

radio links, satellite,

fiber, copper, WLAN ….

ATMMPLS

10/100/1000 BASET, TX, SX, LX, FX…

1010

Typical WAN Technologies

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WAN Technologies

• WAN capacity levels:– 0: 64 kbit/s– 1: 2 Mbit/s (PDH)– 2: 8 Mbit/s (PDH)– 3: 34 Mbit/s/ 45Mbit/s (PDH)– 4: 140/155 Mbit/s (PDH/SDH STM-1, SONET OC-3)– 5: 622 Mbit/s (SDH STM-4, SONET OC-12)– 6: 2,5 Gbit/s (SDH STM-16, SONET OC-48)– …….

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WAN Technologies

• DXC 1/0• Plesiochronous Digital Hierarchy (PDH)• Synchronous Digital Hierarchy (SDH, SONET)• ATM, Frame Relay• PSTN, ISDN• Radio Links• Satellite• +• IP• Ethernet• …..

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WAN Technologies

• Why not only concentrate on IP/ethernet networks?– Scaleability issues– SDH, PDH … are essential parts of all incumbent

operators WAN networks including many new service providers

– 2M and STM-N is widely used as leased lines including ATM/IP/DSL backbone networks

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SDH Protocol

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SDH Protocol - Multiplexing

• Multiplexing PDH signals– Plesiochronous multiplexing using bit stuffing

• Multiplexing SDH signals– Synchronous Multiplexing using Pointer Processing

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SDH ramme, hastigheder og funktionalitetSOH Payload

Section OverHead POH = Path OverHead1 2 3 4 5 6 7 8 9 10 11 - 270

1 J12 RSOH B33 Regenerator Section OverHead C24 AU pointers G15 F26 MSOH H47 Multiplex Section OverHead F38 K39 N1

Path payload (C4)Payload (VC-4)

125 msec

STM = Synchronous Transport ModuleBitrate 9 x 270 x 8 / 0,125 155.520 kb/s

LO Path overhead (V5, J2, N2, K4)1 2 3 4 5 6 7 8 9 10 11 12

1 J1 J1 J12 RSOH B3 B3 B33 C2 C2 C24 AU pointers G1 G1 G15 F2 F2 F26 MSOH H4 H4 H47 F3 F3 F38 K3 K3 K39 N1 N1 N1

Payload (3 x VC-3) 125 msec

STM-1

STM-1

PDH HastighedE1 2 Mb/sE3 34 Mb/sE4 140 Mb/s

SDH Hastighedvc-12 2,2 Mb/svc-3 48 Mb/svc-4 150 Mb/sSTM-1 155 Mb/sSTM-4 622 Mb/sSTM-16 2488 Mb/sSTM-64 9953 Mb/s

Time Division Multiplexing (TDM)

SDH på 5 min

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SDH Protocol - Multiplexing

• Multiplexing PDH signals– Plesiochronous multiplexing using bit stuffing

• Multiplexing SDH signals– Synchronous Multiplexing using Pointer Processing

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2020

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SDH Protocol

AU-4 PointerAdjustment

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SDH Protocol - Multiplexing

• Multiplexing PDH signals– Plesiochronous multiplexing using bit stuffing

• Multiplexing SDH signals– Synchronous Multiplexing using Pointer Processing

• Multiplexing Structure– Adaptation of PDH and other signals

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SDH protocol - Multiplexing Structure

STM-N AUG AU-4 VC-4

Pointer processing

Multiplexing

Aligning

Mapping

Container-nC-n

TUG-3x 1x 3

x 1x N

x 3

x 4

x 1

TU-3 VC-3

C-4

C-3

TUG-2 TU-2 VC-2

TU-12 VC-12 C-12

VC-11 C-11

(note 2)

139 264 kbit/s

44 736 kbit/s34 368 kbit/s

2 048 kbit/s

1 544 kbit/s

(note 1)

(note 1)

(note 1)

(note 1)

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SDH mapping schemeInitial mappingMore MultiplexingContiguous Concatenation

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C-4-64c

C-4-256c

C-4-16c

C-4-4cAU-4-4c VC-4-4c

AU-4-16c VC-4-16c

AU-4-64c VC-4-64c

AU-4-256c VC-4-256c

x 1

x 1

x 1

x 1

AUG-64

AUG-256

AUG-16

AUG-4

STM-256

STM-64

STM-16

STM-4

x 1

x 1

x 1

x 1

x 4

x 4

x 4

x 4

C-4

C-3

C-2

C-12

C-11VC-11

VC-12

VC-2

VC-3

TUG-2 TU-2

STM-0

AUG-1

VC-3

TUG-3

VC-4

AU-3

TU-11

TU-3

AU-4STM-1

x 1

x 1 x 1

x 1

x 1

x4

x 3

x 3

x 7

x 7

pointer processing

multiplexing

aligning

mapping

x 3

TU-12

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SDH Equipment

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SDH Equipment

DXC4/1

Interfaces: 2M, 34M, 45M, 140M, STM-1, (STM-4/16)

XC matrix scaleable up to 32/128/256 STM-1 equivalent, non-blocking

ADM 4/1Aggregate

Tributary

Aggr. Interfaces: STM-1/4/(16)

Trib. interfaces: 2M, 34M, 45M, 140M, STM-1/(4)

ADM 4/4Aggregate

Tributary

Aggr. Interfaces: STM-4/16/64

Trib. interfaces: STM-1/4/16

No access to lower order signals

SDH på 5 min

Regenerator functionREG

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ADM 4/1 STM-4 example

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ADM 4/4STM-64 example

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SDH Networks

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SDH NetworksHierarchical example

Level 1

Level 2

Level 3

AP1 BJSK figure 09a

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Network Structures - Pros and Cons

Structure Pros Cons

Chain Fiber effectiveSimple nodesLow start cost

Low connectivityNo redundancyP2P upgrade costly

Ring Fiber effectiveSimple nodesRedundancy

Low connectivityP2P upgrade very costly

Mesh High connectivityRedundancyCost efficient P2P upgrade

Fiber consumingComplex nodes

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SDH Networks - example , Routing in a hierarchical Network

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SDH Networks add on

N iveau 1

N iveau 3

N iveau 2

N iveau 0

BJSK

SDH netstruktur

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Inte

rnati

on

al N

etw

ork

st

ruct

ure

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SDH networks - fiber infrastructure

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SDH networks- WDM

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SDH networks- STM-64

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SDH networks- STM-16

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SDH networks - VC-4

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SDH Network node example

MSH-41cTM/ADM

DXC1DXC1

AC-4 TM AC-4 TM AC-4 TM

MSH64ADM

MSH64ADM

AC-4ADM

AC-4TM

AC-4 TMMSH-41cTM/ADM

lag 1 kanter (maskenet)

lag 3 kanter/strukturer

lag

1 o

g 2

kan

ter (rin

gn

et)

lag

2 k

an

ter

(ma

ske

ne

t)STM-16

STM-16

STM-64

STM-16STM-4STM-1

STM-1/4/16

STM-1/4

STM-1/4

STM-1

STM-1

STM-1

STM-1

SDH netstruktur

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SDH networkOptical cards and application codes

• STM16:– S16.1 (short haul, 1300 nm, 10 km)– L16.1 (long haul, 1300 nm, 20 km)– L16.2 (long haul, 1550 nm, 80 km)– V16.2 (very long haul, 1550 nm, 120 km)– U16.2 (ultra long haul, 1550 nm, 160 km)– L16.2 colered interface til WDM rel 1.0– L16.2 colered interface til WDM rel. 3.0

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Standards

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• Concatenation, Protocols etc.

• Link Capacity Adjustment Scheme (LCAS)• Generic Framing Procedure (GFP)• Equipment• Equipment• Equipment Management Function

G.707 (10/2000)corr 1, corr 2*, add 1*

G.7042/Y.1305 (11/2001)* G.7041/Y.1303 (11/2001)*G.783 (02/2001)*G.709 (02/2001)G.798 (11/2001)

ITU-T

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SDH Network Management

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En netteknologi f.eks. SDH

Network ManagerNetwork Manager

SDH Network ManagementNetwork & Service Management View

Network ManagerNetwork Manager

NetworkElements

ElementManagerElementManager

SM funktion #1SM funktion #1

Technicaladministrativesystems (inventory)

• planning• modelling• registration

Element Level Management

Network Level Management

Service Level Management

Subnetwork Manager

Subnetwork Manager

Bussines Level Management

NetworkElements

ElementManagerElementManager

Subnetwork Manager

Subnetwork Manager

SM funktion #2SM funktion #2

Costumer administrative systemsCustomer acces/ applikationer

Funktions:• Provisionering• Performance• Assurance• Alarmmanager

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SDH Network ManagementElement Manager

– Matrix: 48 ports 4/4 non-blocking, dubleret

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pvc

Frame Relay

pvc

WAN

Site 1

System 2 serversystem1

4700

cat5005

cat5005

System 3

Site 2

System 2 serverSystem1

cat5005

cat5005

System 3

4700

2500

Bay hub

Site M

2500Site S

Coax

2600Site L

cat1924

vlan

SDH Network Management

DCN, Data Communications Network is needed

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Sub-NetworkLevel:

NEs Level:

NE GUI

Double click

SDH Network ManagementNetwork Manager

Point and click management

6 levels subnetwork nesting

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Fault Management /Service ManagementFilter via tree view

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SDH Services

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SDH Services

• Leased line Services (fixed dedicated bandwidth):– 2 Mbit/s, n x 2 Mbit/s– VC-12, n x VC-12– 34 Mbit/s, 45 M Mbit/s– VC-3, n x VC-3– 140 Mbit/s– VC-4– VC-4-4c, VC-4-16c– Grey fibres / WDM channels

• add-on services– Alternative routing, Specific routing, automatic protection,

various Service Level Agreements (SLAs)