1 chapter 7 transport networks: technology examples m. pickavet and c. develder
TRANSCRIPT
Transport networks:Technology Examples 2
Outline
1. Transport network examples1.1 Belgacom1.2 Telenet1.3 Deutsche Telekom1.4 International network
2. SDH3. WDM
Transport networks:
Technology Examples 3
• Unique telephony operator in Belgium for a long time• Basic services: telephony, leased lines, public data network, etc.
• Since 1998, also competition possible on last monopoly: the telephone service
• Basic fixed telephone services expanded to new services (e.g. mobile telephony, fast Internet, digTV)
• Increase bandwidth down to the customer (xDSL techniques)
Belgacom Network
Transport networks:
Technology Examples 4
TEX
TEX
TEX
TEX
DXCDXC
DXCDXC
DXCDXC
DXCDXC
ADMADM
ADMADM
AD
MA
DM
ADMADM
ADMADM
AD
MA
DM
LEX
LEX LEX
LEX
core transport networkregional transport network regional transport network
LEX
LEX LEX
TEX
TEX
LEX
TEX TEX
Belgacom: switching and transport network
Technology: mainly SDH (+PDH & WDM)
Transport networks:
Technology Examples 5
level 1: COREnetwork
level 2: REGIONALnetwork
ZTCZTC: ZonalTransmissionCenter
LTC
LTC: LocalTransmissionCenter
RING + MESH
RING
Belgacom: transport network architecture
Transport networks:
Technology Examples 6
TEX
core
reg
ion
al
DXCDXC ......mesh
ADMADMring
...
...
ADMADM ADMADM
ring
...
...
Belgacom: Zonal Transmission Center (ZTC)
Transport networks:
Technology Examples 7
ZTC: ZonalTransmissionCenter
international links
Belgacom: CORE network topology
Transport networks:Technology Examples 8
Outline
1. Transport network examples1.1 Belgacom1.2 Telenet1.3 Deutsche Telekom1.4 International network
2. SDH3. WDM
Transport networks:
Technology Examples 9
• origin: reuse of existing coax cable (used for TV distribution by CATV operators)
• now: offer also interactive services (telephony, Internet access, digTV)
upgrade access network construct a backbone network
(switching and transmission)
Telenet Network
Transport networks:
Technology Examples 10
HFCloop
Node
Tree and branch 2-waycoaxial network
Subscriberpremise
Secondary ring
Primary ring
head-end
Switch
Telenet: Topology Concept
Transport networks:
Technology Examples 11
21
3
4
8
5
7
6
MIDDELKERKEROKSEM
KOEKELAREVEURNE
IEPER
ROESELARE
SINT-ELOOIS-WINKEL
WAREGEM
OUDENAARDE
ZOTTEGEM
MELLE
EEKLO
LOKEREN
AALST
SINT-NIKLAAS
DENDERMONDE
BRUSSEGEM
MECHELEN
HOVE
SCHOTEN
STABROEK
PERK
LEUVEN
HERENTHOUT
ZOERSEL BEERSE
OUD-TURNHOUT
GEEL
OVERPELT
MAASEIK
GENK
BERINGEN
TESTELT
SINT-JORIS-WINGE
BILZEN
SINT-TRUIDENWOMMERSOM
DUISBURG
DWORPHERFELINGEN
LENNIKMENEN
BRUGGE
GENT
KORTRIJK
ASSE
HOBOKEN
HASSELT
NOC
Primary ring
Secondary ringHeadend
SwitchNOC
Telenet: Physical Topology
Zie ook www.telenet.be, “Bedrijfsinfo”, “Het Netwerk”
Transport networks:
Technology Examples 12
accessmultiplexerin head-end
switch
SDH network connections(not the physical topology)
Telenet: Basic Architecture
Transport networks:Technology Examples 13
Outline
1. Transport network examples1.1 Belgacom1.2 Telenet1.3 Deutsche Telekom1.4 International network
2. SDH3. WDM
Transport networks:
Technology Examples 14
• Unique telephony operator in Germany for a long timecf. Belgacom in Belgium
• For mobile solutions: T-mobilecf. Proximus
• Largest European network operator• Presence in countries: Germany, but also US, UK, eastern Europe
• Some numbers (2006-2007): • Total traffic volume: 2250 Gbit/s• Number of lines:
• broadband: 12 million• narrowband: 39 million
Deutsche Telekom
Transport networks:Technology Examples 15
Deutsche Telekom: physical topology
• 50 core nodes
• Technology: WDM
Transport networks:Technology Examples 16
Deutsche Telekom: logical IP topology
• 63 PoPs
• Hierarchical topology:
•Core:•3 innercore nodes (fully meshed)•6 outercore nodes (dual homed with innercore nodes)
•Regio/metro
Transport networks:Technology Examples 17
Outline
1. Transport network examples1.1 Belgacom1.2 Telenet1.3 Deutsche Telekom1.4 International network
2. SDH3. WDM
Transport networks:Technology Examples 18
International networksM
ap
of
Euro
pean
Netw
ork
Con
nect
ivit
y
Transport networks:Technology Examples 19
International network: Level3
Zie ook www.level3.comTechnology: WDM, SONET, …
Transport networks:Technology Examples 20
Outline
1. Transport network examples2. Synchronous Digital Hierarchy (SDH)
2.1 Introduction2.2 Main layer structure2.3 Detailed layer structure2.4 Frame structure and synchronisation2.5 Network elements2.6 Network architectures
3. WDM
Transport networks:
Technology Examples 21
• bi-directional transport network technology• multiplexing: TDM (Time Division Multiplexing)
• historically: mainly replacing PDH- based on direct synchronous multiplexing- about 5% of signal structure for ‘overhead’- can accommodate both existing and future signals- can interconnect equipment from multiple vendors
• high bandwidth links (capacities: 155 Mbit/s, 622 Mbit/s, 2.5 Gbit/s and 10 Gbit/s)
• semi-permanent network connections (bitrates: 150 Mbit/s, 49.5 Mbit/s, 6.9 Mbit/s, 2.3 Mbit/s)
• central management (TMN) or distributed control (GMPLS)
• network elements: Digital Cross-Connect (DXC)Add-Drop Multiplexer (ADM)Terminal Multiplexer (TM)
Main features of SDH
Transport networks:
Technology Examples 22
• physical layer: Synchronous Transport Module (STM-N)
• link capacity: STM-1: 155 Mbit/sSTM-4: 622 Mbit/sSTM-16: 2.5 Gbit/sSTM-64: 10 Gbit/s
Physical Layer
Transport networks:
Technology Examples 23
Signals that can be transported by SDH:• PDH: 2, (8,), 34, 140 Mbit/s (Europe)• IP: Internet packets• ATM: Asynchronous Transfer Mode• FDDI: Fiber Distributed Data Interface• etc…
Several network connection types(virtual containers):
• VC-4 (150 Mbit/s)• VC-3 (49.5 Mbit/s)• VC-2 (6.9 Mbit/s)• VC-12 (2.3 Mbit/s)
SDH transport capabilities
STM-N
VC-12
3x
OR
1x
VC-2
OR
1x
7x
VC-3
OR
1x
3x
VC-4
Nx
Transport networks:
Technology Examples 24
SynchronousTransport
Module(SDH)
Line RateMbit/s
SynchronousTransport
Signal(SONET)
-
STM - 1
STM - 4
STM - 16
STM - 64
51.84
155.52
622.08
2488.32
9953.28
STS - 1
STS - 3
STS - 12
STS - 48
STS - 192
SONET: - Synchronous Optical Network- introduced 1985 (USA, Japan)
SDH:- CCITT 1988: SDH and SONET linked- ETSI 1990: SONET part of SDH
SDH versus SONET
Transport networks:Technology Examples 25
Outline
1. Transport network examples2. Synchronous Digital Hierarchy (SDH)
2.1 Introduction2.2 Main layer structure2.3 Detailed layer structure2.4 Frame structure and synchronisation2.5 Network elements2.6 Network architectures
3. WDM
Transport networks:
Technology Examples 26
• VC-4 or Virtual Container-4 link connection • VC-4 link connection capacity: 150 Mbit/s• link capacity in # link connections:
STM-1 ==> 1 x VC-4STM-4 ==> 4 x VC-4STM-16 ==> 16 x VC-4STM-64 ==> 64 x VC-4
4
TDM1 N=4 1 4N=4
fiber (622 Mbit/s)
STM-4 network connection
VC-4 link connection
VC-4 link
Higher Order Path Layer
Transport networks:
Technology Examples 27
VC-4 link
fiber (622 Mbit/s)
1 4N=4 1 4N=4
fiber (622 Mbit/s)
1 4N=4 1 4N=4VC-4 link
networkconnection
VC-4matrix
VC-4 link connection VC-4 link connection
matrixconnection
HOP Network Connection
Transport networks:
Technology Examples 28
63
VC-12
21
VC-2
3
VC-3
VC-12VC-2VC-3 LOP layer
1 4N=4
HOP layer
Physical layer
VC-4 = 63 VC-12VC-4 = 21 VC-2VC-4 = 3 VC-3VC-4 = combination of VC-3, VC-2 and VC-12
Lower Order Path Layer
Transport networks:
Technology Examples 29
VC-12 link
VC-12 networkconnection
VC-12 link connection
VC-12 link
VC-12 link connection
fiber (622 Mbit/s)
N=4 N=4
fiber (622 Mbit/s)
N=4 N=4
VC-4 link connection
VC-4 link connection
VC-4 matrixconnection
fiber (622 Mbit/s)
N=4 N=4
fiber (622 Mbit/s)
N=4 N=4
VC-4 link connection
VC-4 link connection
VC-4 matrixconnection
VC-12 matrixconnection
LOP Network Connection
Transport networks:
Technology Examples 30
• full interconnection of switches with VC-3 network connections• ring topology interconnection of VC-3 ADMs with VC-4 network connections• use physical star topology
VC-3ADM
VC-3ADM
VC-3ADM
VC-3ADM
VC-4DXC
switch switch
switch switch
STM-4links
Exercise
Transport networks:
Technology Examples 35
DXC
HOPor
LOP matrix
tributary ports (to higher layer)
aggregate ports(to lower layer)
ADM
LOP/HOP
HOP/Physical
MUX
Network Elements: MUX / ADM / DXC
Transport networks:Technology Examples 36
Outline
1. Transport network examples2. Synchronous Digital Hierarchy (SDH)
2.1 Introduction2.2 Main layer structure2.3 Detailed layer structure2.4 Frame structure and synchronisation2.5 Network elements2.6 Network architectures
3. WDM
Transport networks:
Technology Examples 37
physical layer
regenerator section layer
multiplex section layer
higher order path layerSDH
transportlayers
Overview
lower order path layer
circuit layer
Transport networks:
Technology Examples 38
• optical fiber• coaxial cable• radio link
electrical
fiber linkphysical la
yer
tcp tcp
optical
Physical Layer
Transport networks:
Technology Examples 39
transfer of bits between two physical points
bitrates: 155 Mbit/s, 622 Mbit/s, 2.5 Gbit/s, 10 Gbit/s
laser transmitter
photodetector receiver
optical fiber
Physical Layer
Transport networks:
Technology Examples 40
regenera
tor
secti
on layer
RS link connection =RS network connection
fiber link connectionphysical la
yer
RS trail
Regenerator Section (RS) Layer
Transport networks:
Technology Examples 41
regeneratorfiber fiber
• signal regeneration• signal monitoring• signaling
Regenerator Section (RS) Layer
Transport networks:
Technology Examples 42
MS link connection MS link connection
MS network connection
MS trail
multiplex
sect
ion layer
cptcp tcp
fiber fiber
RS network connection RS network connectionregenera
tor
sect
ion layer
physical la
yer
Multiplexing Section (MS) Layer
Transport networks:
Technology Examples 43
multiplex
sect
ion layer
fiber fiber
regenera
tor
sect
ion layer
physical la
yer
.... ..
.... ..
HOP link
HOP link connection HOP link connection
HOP link
higher o
rder
path la
yer HOP network connection
matrixconnection
HOP trail
Higher Order Path (HOP) Layer
Transport networks:
Technology Examples 44
higher layer
HOP la
yer
lower layers
fiber
Higher Order Path (HOP) Layer
Transport networks:
Technology Examples 45
matrixconnection
fiber fiber
multiplex
section la
yer
regenerator
section la
yer
physical la
yer
... ...
higher ord
er
path la
yer.....
....... ..
LOP link connection
LOP link
LOP link connection
LOP link
.. ..
LOP trail
LOP network connection
lower ord
er
path la
yer
Lower Order Path (LOP) Layer
Transport networks:Technology Examples 46
Outline
1. Transport network examples2. Synchronous Digital Hierarchy (SDH)
2.1 Introduction2.2 Main layer structure2.3 Detailed layer structure2.4 Frame structure and synchronisation2.5 Network elements2.6 Network architectures
3. WDM
Transport networks:
Technology Examples 47
1 2 3 4 5 6 7 8 910111213141516 270
271
540
272
273
21
61
24
30
21
62
21
63
...frame 1 270 columns
2430 bytes/frame x 8 bits/byte x 8000 frames/sec = 155.52 Mbit/s
1 2 3 4 5 6 7 8 910111213141516 ... 270
271
540
272
273
21
61
24
30
21
62
21
63
...
frame 2 270 columns
9 r
ow
s
...
...
frame 1125 sec
...
frame 2125 sec
......1 2 3 2430 1 2 3 2430
STM-1 frame1 byte/frame = 64 kbit/s
Higher order frames (e.g. STM-4): byte interleaving (1 byte from first VC-4, 1 from second,
…)
Transport networks:
Technology Examples 48
261 columns
...9 ro
ws
RSOH
MSOH
pointer Virtual ContainerVC-4
VC-4: 261 x 9 bytes every 125 sec ==> 150.336 Mbit/s
STM-1 frame
Transport networks:Technology Examples 50
DXC
A
DXC
B
DXC
C
......
...
...
...
...
DXC
Z
...
STM-1
STM-1
STM-1
STM-4
• frame synchronisation• clock synchronisation
...
referenceclockclck
clck
clck
clck
Timing issues
Transport networks:Technology Examples 51
VC TIMING PHASE MAINTAINEDSECTION
OVERHEADALIGNED
A, B, C denote transport signalsF denotes framing bytePx denotes pointer byte value x
FRAMESYNCHRONISATION
MACHINE
"A" in
"B" in
"C" in
"A" out
"B" out
"C" out
A4 A3 A2 A1 P7 F
B3 B2 B1 P5 F
C1 P4 F
P2 F
P3 F
P5 F
A5 A4 A3 A2 A1
B4 B3 B2 B1
C2 C1
Frame Synchronisation
Transport networks:Technology Examples 52
PT J
neg
ati
ve ju
sti
ficati
on
:carr
ier
clo
ck s
low
er
than
receiv
ed
data
clo
ck
PT J
JI J
PT-1 J
frame N
frame N+1
frame N+2
frame N+3
positiv
e ju
stifica
tion :
carrie
r clock is fa
ster
than
rece
ived d
ata
clock
J
PT
PT J
J
JI
PT+1
J
J
Clock Synchronisation: pointer processing
Transport networks:Technology Examples 53
Outline
1. Transport network examples2. Synchronous Digital Hierarchy (SDH)
2.1 Introduction2.2 Main layer structure2.3 Detailed layer structure2.4 Frame structure and synchronisation2.5 Network elements2.6 Network architectures
3. WDM
Transport networks:Technology Examples 54
63xVC12
•••
2Mb/s2Mb/s
2Mb/s
STM-1
VC12VC3VC4
•••
•••
2Mb/s
34Mb/s
140Mb/s
STM-1STM-1STM-1
•••
STM-4STM-4
STM-1STM-1
STM-1
VC4
Multiplexer (MUX)
Transport networks:Technology Examples 55
STM-1 STM-1
bidirectional• • •
2Mb/s2Mb/s
e.g.: 10 tributaries
• • •
STM-16 STM-16
140Mb/s2Mb/s
• • •
34 Mb/s
unidirectional
Add-Drop Multiplexer (ADM)
Transport networks:Technology Examples 56
2Mb/s 34Mb/s 140Mb/s140 Mb/s 140 Mb/s
STM1
STM1
STM1
STM1
STM1
STM1
broadband DXCAU-DXCHO-DXCDXC 4/4
wideband DXCTU-DXCLO-DXC
DXC 4/3/1
Digital Cross-Connects (DXC)
Transport networks:Technology Examples 57
Outline
1. Transport network examples2. Synchronous Digital Hierarchy (SDH)
2.1 Introduction2.2 Main layer structure2.3 Detailed layer structure2.4 Frame structure and synchronisation2.5 Network elements2.6 Network architectures
3. WDM
Transport networks:Technology Examples 58
Ring network architecture
Meshed network architecture
Hybrid network architecture
General architecture
Network architectures
Transport networks:Technology Examples 62
ADMADM
RING 2
ADMADM
RING 1
cloverleaf
hierarchical
centralring
Ring network
Transport networks:Technology Examples 63
DXCDXCring1
ring2
ring1
ring2
AD
MA
DM
AD
MA
DM DXCDXCring
1
ring2
AD
MA
DM
AD
MA
DM
Ring network: Interconnection between rings
Transport networks:Technology Examples 66
STM-4 local
regional
core
STM-16
overlayring
STM-16
mesh
General network architecture
Transport networks:Technology Examples 67
Outline
1. Transport network examples2. SDH3. WDM
3.1 Introduction3.2 WDM point-to-point transmission3.3 Components for optical networking
(OTN)3.4 Network elements in OTN3.5 Layer structure in OTN3.6 Network architectures in OTN
Transport networks:Technology Examples 68
fiber
mux demux
6 x 10 Gb/s
...
STM-6
4
..
.
STM-64
WDM Principle
Transport networks:Technology Examples 69
Technology evolution: • PDH: up to 565 Mbit/s• SDH: up to 10 Gbit/s• WDM: up to Tbit/s
Why WDM ?
year
worldtrafficvolume
Voice (+ 5 % / y)
2001 2002200019991998 2003 2004
IP (+ 50-100 % / y)
Transport networks:Technology Examples 70
0.0
1
0.1 1 10
10
0
10
00
10
000
10
000
0Teleph
PDH
SDH
WDM
switch
gra
nula
rity
link
capa
city
Mbit/s
Technology History
Transport networks:Technology Examples 71
0,1
1994 1998 2002 2006 2010
volume of installedWDM equipment
volume of installedSDH equipment
Cap
acit
y in
Gb
it/s
Year
volume of installedPDH equipment
0,01
1
10
100
1000
10000 next generationequipment
Capacity in
crease
at 100% ra
te per year
Technology Introduction
Transport networks:Technology Examples 72
Outline
1. Transport network examples2. SDH3. WDM
3.1 Introduction3.2 WDM point-to-point transmission3.3 Optical switching (OTN)3.4 Network elements in OTN3.5 Layer structure in OTN3.6 Network architectures in OTN
Transport networks:Technology Examples 73
1
0.5
01.3 1.61.0
attenuationdB/km
wavelengthm
• low attenuation (1.3 and 1.55 m)• high bandwidth• dispersion• non-linear effects
Optical Fiber
Transport networks:Technology Examples 74
• transmitter: laser diode (tunable / multi-wavelength)
• receiver: photodetector
• wavelength multiplexer / demultiplexer
• optical amplifier
Tx
Tx
Tx
...
WDM
Rx
Rx
Rx
...
WDM
1000 km20 Gb/s
wavelength multiplexing
OA OA OA
Optical components
Transport networks:Technology Examples 75
1520 1540 1560(nm)
gain(dB)
20
10
FIBER FIBER
OPTCALAMPLIFIER
EDFA: Erbium Doped Fiber Amplifier
• limited wavelength band (around 1.54 mm)• gain not flat• no regeneration • noise
Optical components: Optical Amplifier: EDFA
e.g. 8 WDM (no modulation)
with modulationwith modulation
Transport networks:Technology Examples 78
Outline
1. Transport network examples2. SDH3. WDM
3.1 Introduction3.2 WDM point-to-point transmission3.3 Optical switching ( OTN)3.4 Network elements in OTN3.5 Layer structure in OTN3.6 Network architectures in OTN
Transport networks:Technology Examples 79
WDM pt-to-pt OTN
Point-to-point connections betw een IP routers Optical netw orking w ith OXCs
IP routers sw itchpackets Opto-electrical
conversion
OXCs sw itchlightpaths
Transport networks:Technology Examples 80
• power splitter / combiner• optical space switch• wavelength (de)multiplexer• wavelength filter• wavelength convertor• optical amplifier (pre- and booster-)• optical regenerator (1R, 2R, 3R)
Basic Components required for OTN
Transport networks:Technology Examples 81
MicroElectroMechanical System (MEMS)
© Lucent
Microscopic mirror• Principle:
• Characteristics:+ limited loss
+ integration ( scalability)
- slow reconfiguration
Transport networks:Technology Examples 82
. . .
. . .
Broadcast-and-Select architecture with Semi-conductor Optical Amplifier (SOA) gates
broadcast select
• Principle:
• Characteristics:- split losses (light signal must be regenerated / limited scalability)
+ multicast possible
+ fast reconfiguration
Transport networks:Technology Examples 83
Arrayed Waveguide Grating (AWG) and Tunable Wavelength Convertors (TWCs)
TWC
TWC
TWC
TWC
TWC
TWC
TWC
TWC
AWGAWG
• Principle:
• Characteristics:+ no splitt losses
+ switching element itself (AWG) is passive device
• fast reconfiguration if TWC fast tunable
Transport networks:Technology Examples 84
Outline
1. Transport network examples2. SDH3. WDM
3.1 Introduction3.2 WDM point-to-point transmission3.3 Optical switching (OTN)3.4 Network elements in OTN3.5 Layer structure in OTN3.6 Network architectures in OTN
Transport networks:Technology Examples 85
passivesplitter
passivecombiner
A C
1
2
3fiber
drop add
filter
space switch
Network Elements: Wavelength Routing ADM
Transport networks:Technology Examples 86
passivesplitter
fixedfilterspace switch
passivecombiner
A
B
C
D
1
2
3
1
2
3
fiber
Network Elements: Wavelength Routing OXC
Transport networks:Technology Examples 87
passivesplitter
fixedfilter wavelength
convertor
spaceswitch
passivecombiner
1 1
2 2
3 3
1
2
3 3
A
B
C
D
1
2
3
1
2
3
2
1
Network Elements: Wavelength Translating OXC
Transport networks:Technology Examples 88
Outline
1. Transport network examples2. SDH3. WDM
3.1 Introduction3.2 WDM point-to-point transmission3.3 Optical switching (OTN)3.4 Network elements in OTN3.5 Layer structure in OTN3.6 Network architectures in OTN
Transport networks:Technology Examples 89
OC trail
optical m
ultiplex
sect
ion layer
fiber fiber
optical
transm
ission
sect
ion layer
physical la
yer
.. ..
OC link connection
OC link
OC link connection
OC link
optical
channel l
ayer OC network connection
matrixconnection
fiber
opticalamplifier
OTN layer structure
Transport networks:Technology Examples 90
OPTICALMULTIPLEX
SECTION
OPTICALMULTIPLEX
SECTION
optical transmission
section
TRIBUTARYSIGNALS(e.g. STM-64)
WDMMULTI-PLEXER
WDMMULTI-PLEXER
OPTICAL CROSS-CONNECT
optical amplifieroptical amplifier
TRIBUTARYSIGNALS(e.g. STM-64)
OPTICAL CHANNEL
optical transmission
section
optical transmission
section
OTN layer structure
Transport networks:Technology Examples 91
SDHMULTI-PLEXER
SDH regeneratorSDH regenerator
SDHMULTI-PLEXER
DIGITAL CROSS-CONNECT
SDH PATH
WDMMULTI-PLEXER
WDMMULTI-PLEXER
OPTICAL CROSS-CONNECT
optical amplifieroptical amplifier
OPTICAL CHANNEL
SDH over OTN
Transport networks:Technology Examples 92
• no access to digital signal !
? communication channel ???
? BER measurement ???
? … ???
• monitoring: optical power, wavelength, spectrum, SNR
• signaling: separate wavelength, pilot tone, separate network
OTN Overhead
Transport networks:Technology Examples 93
Outline
1. Transport network examples2. SDH3. WDM
3.1 Introduction3.2 WDM point-to-point transmission3.3 Optical switching (OTN)3.4 Network elements in OTN3.5 Layer structure in OTN3.6 Network architectures in OTN