Chromatic Dispersion Optical Fiber

IEG 4030 Optical Communications Part VI. Optical Networks Professor Lian K. Chen Department of Information Engineering The Chinese University of Hong Kong [email protected]

Prof. Lian K Chen

Part 6 - Optical Netwoks

1

Part VI. Optical Networks • • • • • • •

Lightwave System Evolution Undersea Transmission Systems Optical Network Hierarchy and Topologies Subscriber Loop Passive Optical Networks CATV systems LAN/WAN/MAN – FDDI – SONET/SDH

• •

All-optical Multiaccess Network Network Management – Protection and Restoration in Network Management

Prof. Lian K Chen

Part 6 - Optical Netwoks

2

Lightwave Systems •

Traditional Optical Fiber Transmission System

Low-Rate Data In

E

E

|

|

M U X

Low-Rate Data Out

REG RPTR

XMTR

REG RPTR

RCVR

D M U X

Traditional Regenerated Transmission Line

DET

AMP

EQ

DEC

AMP

TMG REC

Opto-Electronic Regenerative Repeater

Prof. Lian K Chen

Part 6 - Optical Netwoks

LASER

E-Mux: electronic multiplexer E-DMUX: elecrtonic demultiplexer XMTR: transmitter REG: regenerator RPTR: repeater RCVR: receiver DET: detector AMP: amplifier EQ: equalizer TMG REC: timing recovery DEC: decision circuit

3

Traditional Optical Fiber Transmission System • • • • • •

Single-channel operation Opto-Electronic TDM of synchronous data electronic regenerative repeaters 30-50km repeater spacing Distortion and noise do not accumulate Capacity upgrade requires higher-speed operation

Prof. Lian K Chen

Part 6 - Optical Netwoks

4

Optically amplified Fiber Transmission System • • • • • • •

Multi-channel WDM operation Data-rate and modulation-format transparent One optical amplifier (per fiber) supports many wavelength channels 80-140 km amplifier spacing Distortion and noise accumulate Graceful growth (upgrade) of channels Capacity upgrade by adding wavelength-multiplexed channels

Data In XMTR

λ1 λ2

O

λN

M U X

XMTR XMTR Prof. Lian K Chen

λ1

|

OA

OA

Part 6 - Optical Netwoks

OA

Data Out

O λ RCVR 2 | RCVR D M λ N U RCVR X 5

System Limitations •

Attenuation → system power budget – Solutions: optical amplifiers; coherent detection

•

Dispersion → pulse broadening → intersymbol interference – Solutions: dispersion compensation - use dispersioncompensating fibers, dispersion-shifted fibers, pre-chirping; soliton (dispersion and nonlinear effect compensate each other)

•

Polarization → polarization dependent gain/loss, polarization mode dispersion (PMD), polarization sensitive → power penalty – Solutions: polarization tracking+polarization controller to fix the polarization into components, polarization scrambling, polarization diversity, use polarization-maintaining fibers

Prof. Lian K Chen

Part 6 - Optical Netwoks

6

System Limitations •

Nonlinear effects → four-wave-mixing (FWM), stimulated Raman scattering (SRS), stimulated Brilluoin scattering (SBS), self-phase modulation (SPM), cross-phase modulation (XPM) → system degradation – Solutions: advanced modulation format, power control, phase modulation; frequency assignment

•

Noises → reflection noise, phase noise, back-scattering, modal noise, mode partition noise, thermal noise, shot noise, amplifier beat noise, RIN, etc. → power penalty – Solutions: isolator can reduce some types of noises

• All impairments can be remedied by using forward error correction; electronic equalizer can also resolve dispersion problems Prof. Lian K Chen

Part 6 - Optical Netwoks

7

Bit Rate -Distance ( Gb/s z km)

System Transmission Capacity 107 106 105 104 103 102 101 1 1970 Prof. Lian K Chen

Å

WHAT’S NEXT ?? z z z z WDM + Optical Amplifiers z ‹ Optical Amplifiers ‹z  Coherent Detection ‹ ‹ Œ 1.5μm Single-Frequency Laser „ 1.3μm SM Fiber ‹ Fourth Generation z 0.8μm MM Fiber Œ ‹ Œ Œ Œ  Second Œ Œ Generation

First Generation

z

1975

„ z„

„

1980

Å



 Third Generation

1985

1990 Year

Part 6 - Optical Netwoks

1995

2000

2005 8

System Transmission Capacity Capacity Toward 25 Tbit/s Higher Data Rate OC-48

OC-768

Closer Channel Spacing

Wider Optical Bandwidth 10 nm

100 GHz

300 nm

Higher Spectral Efficiency 0.05 Bits/Hz

>1 Bits/Hz

12.5 GHz • Chromatic Dispersion

• Fiber Nonlinearity

• Fiber Nonlinearity

• Channel Xtalk

• Polarization Mode Dispersion

• Available Components

Prof. Lian K Chen

• L-band EDFAs • Raman Amplifiers

Part 6 - Optical Netwoks

• Novel Modulation Format • Polarization or bidirectional interleaving

9

Undersea Transmission Systems • Design Considerations – – – – – –

span distance data rate repeater/amplifier spacing fault tolerance, system monitoring/supervision, restoration, repair reliability in components: aging cost

• Leading supplier – Tycom (formerly Tyco Submarine System) – KDD Submarine Cable Systems – Alcatel Submarine Networks http://www.telegeography.com/products/map_cable/index.php Prof. Lian K Chen

Part 6 - Optical Netwoks

10

Undersea Transmission Systems

Prof. Lian K Chen

Part 6 - Optical Netwoks

11

Undersea Transmission Systems

Prof. Lian K Chen

Part 6 - Optical Netwoks

12

Undersea Transmission Systems

Prof. Lian K Chen

Part 6 - Optical Netwoks

13

Undersea Transmission Systems

Prof. Lian K Chen

Part 6 - Optical Netwoks

14

Undersea Transmission Systems

Prof. Lian K Chen

Part 6 - Optical Netwoks

15

Undersea Transmission Systems

Prof. Lian K Chen

Part 6 - Optical Netwoks

16

Submarine cable systems

Prof. Lian K Chen

Part 6 - Optical Netwoks

17

Optical Networks Transmission Aspects

Network Management

• Dispersion

• Fault Management

• Power Budget

• Configuration Management

• Non-linearity

• Performance Management

• Polarization, etc.

Optical Networks Multi-Access

Services/Applications

• Network Topology

• Data/Voice

• Node Architecture

• Video/Image

• Multiplexing Scheme

• Interactive Multimedia

• Media Access Protocol

• Internet/Web Access

Prof. Lian K Chen

Part 6 - Optical Netwoks

18

Optical Network Hierarchy

Prof. Lian K Chen

Part 6 - Optical Netwoks

19

Carrier Optical Networks in US

About 50,00 Route Miles Of Fiber Cable Prof. Lian K Chen

Backbone Fiber Routes in China To Russia

Qiqihaer To Europe

Harbin Yining

Baicheng

Urumqi

Mudanjiang

Changchun Fuxin Yanji Shenyang Chengde Zhangjiakou Qinhuangdao Dandong To North

Korla Hohhot

Beijing

Ruoqiang Yinchuan

Golmud Xining

Tianjin Shijiazhuang Yulin Taiyuan Hengshui Lanzhou Zhengzhou Luoyang

XiAn Chengdu

Chongqing

Xiangfan Xinyang

Guiyang Guilin

Xingyi

The Existing Buried Fiber Optic Cables

To Southeast Asia

Prof. Lian K Chen

Nanjing Wuhu

Guangzhou Shenzhen Huizhou

Nanning Pingxiang

To South Korea

To Japan

Shanghai Huzhou Hangzhou

FLAG

Jiujiang Changsha Nanchang Jianyang Hengyang Fuzhou

Huaihua Kunming

Korea

Lianyungang

Hefei

Wuhan Shashi

Gejiu

Qingdao

Jinan

Kaifeng

Lhasa

The Existing Over-Head Fiber Optic Cables

Dalian

Beihai

Taipei

Hongkong

Zhanjiang Haikou

Part 6 - Optical Netwoks

21

Optical Networks •

Network Topologies

Ring

Star

Prof. Lian K Chen

Bus

Mesh

Part 6 - Optical Netwoks

Tree

Multi-hop

22

Network Types •

Network Types

Broadcast and Select Network λ1,λ2,λ3

λ1,λ2'’,λ3’

λ1’,λ2',λ3’

λ1’,λ2,λ3’’

λ1’’,λ2'’,λ3’’

λ1’’,λ2’,λ3

Static Wavelength Routing Network

Prof. Lian K Chen

Space Switches λ1 λ2 λ3 Dynamic Wavelength Routing Network

Part 6 - Optical Netwoks

23

Broadcast and Select WDM Networks

Tunable receiver/ fixed transmitter

Prof. Lian K Chen

Part 6 - Optical Netwoks

24

Subscriber Loop •

Fiber-In-The-Loop (FITL) /Passive Optical Networks (PON) RT EU

DLC

O E

Traditional Fiber Feeder (Digital Loop Carrier) ONU EU

RT CO

O E O E M E O U X Fiber To The Curb (Active Star)

Prof. Lian K Chen

Part 6 - Optical Netwoks

25

Subscriber Loop (contd.) ONU

1 CO

EU

O E

P O S N

Fiber To The Curb (Passive Optical Network)

POS: Passive Optical Splitter RT: Remote Terminal EU: End-User

Prof. Lian K Chen

ONU: Optical Network Unit CO: Central Office

Part 6 - Optical Netwoks

26

Fiber-In-The-Loop (FITL)

Prof. Lian K Chen

Part 6 - Optical Netwoks

Okada, FSAN, 1988.

27

Passive Optical Networks (PON) Optical Network Terminal

Optical Line Terminal

Optical Network Unit Network Terminals Prof. Lian K Chen

Part 6 - Optical Netwoks

28

PON Architecture •

At CO: – Optical Line Terminal (OLT) generates downstream traffic on its own or takes the Sonet signal from a co-located Sonet XC. – OLT aggregates traffic from multiple customers sites using TDM to ensure no interference.

•

At Outside plant, – passive optical splitters are used to split signal 2 to 32 branches using various topologies

•

At Customer premises – PON terminates in Optical network unit (ONU), or a.k.a. Optical network terminations (ONT) – The ONU converts optical signal to specific types of bandwidth (e.g. 10/100 Mb/s Ethernet, ATM, or T1 voice and data) and passes it on to routers, PBX, switches. ONU also uses laser to send upstream traffic to CO.

Prof. Lian K Chen

Part 6 - Optical Netwoks

29

Evolution of Passive Optical Networks APON

BPON

(155Mb/s-622Mb/s)

(155Mb/s-1.25Gb/s)

Downstream: 1550nm Upstream:

EPON (1.25Gb/s)

1310nm

GPON

WDM PON

(1.25Gb/s-2.5Gb/s)

(1.25Gb/s-10Gb/s)

Downstream: 1550nm for video, 1490nm for data Upstream:

TDM-PON Prof. Lian K Chen

1310nm

Part 6 - Optical Netwoks

30

TDM-PON

Prof. Lian K Chen

Part 6 - Optical Netwoks

31

Upstream: Burst-Mode Transmission ONU

OLT

ONU ONU

• Each ONU has different propagation distance from the OLT • At the OLT, the receiver will see packets from ONUs with varying amplitudes and phases, also varying inter-packet time-gaps • For each packet: • Require fast clock recovery to get the clock • Require fast peak detector to get the best threshold level

Î Burst-Mode Receivers Prof. Lian K Chen

Part 6 - Optical Netwoks

32

Ethernet PON

Prof. Lian K Chen

Part 6 - Optical Netwoks

33

Prof. Lian K Chen

Part 6 - Optical Netwoks

34

Major TDM-PON Technologies Summary

Characteristics

BPON

EPON

GPON

Standard

ITU-T G.983

IEEE 802.3ah

ITU-T G.984

Protocol

ATM

Ethernet

ATM and Ethernet

Speed (Mbps)

D/S: 622/1244 U/S: 155/622

D/S: 1244 U/S: 1244

D/S: 1244/2488 U/S: 155/2488

Span

20km

10km

20km

Number of split

32

16 nominal, 32 allowed

64

Ref: G Keiser, FTTX concept and application Prof. Lian K Chen

Part 6 - Optical Netwoks

35

WDM-PON

Q: what are the pros and cons for WDM-PON, compared to TDM-PON? Prof. Lian K Chen

Part 6 - Optical Netwoks

36

WDM-PON

• WDM-PON: Wavelength Division Multiplexed Passive Optical Network • use multiple wavelengths, each serves a certain group of users • higher capacity, future-proof Prof. Lian K Chen

Part 6 - Optical Netwoks

37

Hybrid Fiber-Coax (HFC) • • •

To provide new interactive service, cable TV systems are gradually upgraded to HFC architecture. Cable modem is used to provide internet access (IEE802.14). Telephone service can be provided through VoIP.

Central Office

200-1000 Homes

Fiber Node Fiber

Coax Amplifier

Down-link: 50-750MHz, @1.55μm Up-link: 5-40MHz, @1.3μm

Prof. Lian K Chen

Part 6 - Optical Netwoks

38

CATV (Community Antenna TeleVision) Trunk amplifier Headend

Hub

Hub

subscriber

Drop line subscriber

• • • •

Headend : distribution source; include programs received from satellite, local TV station, together with in-house production programs. Super-trunk : no fan-out, connection from headend to the hub. HUB : distribution node; requires high carrier-to-noise ratio (CNR) ~52-56 dB. Subscriber : home users, required CNR ~ 35 dB

Prof. Lian K Chen

Part 6 - Optical Netwoks

39

Modulation format of CATV system (1) AM-VSB (vestigial side-band) : • simple modulation scheme • compatible to existing modulation format • requires high CNR Æ limited power budget, unless high-power diodepump solid state laser (>20 dBm) with external modulation is used. • NTSC : 6MHz spacing, 4.2MHz VSB bandwidth

(2) FM : • easier to achieve since the required CNR ~16.5 dB. • requires more bandwidth (40MHz spacing, 30MHz bandwidth) • typically used in satellite broadcasting and by some CATV operators.

Prof. Lian K Chen

Part 6 - Optical Netwoks

40

Modulation format of CATV system (contd.) (3) Digital : – baseband – FSK and PSK - spectral efficiency not as good as baseband (0.5-1.0 bit/s/Hz), but easier channel tuning – QPSK - spectral efficiency (2.0 bit/s/Hz) – required large bit-rate (>100Mbit/s) if uncompressed – compression schemes - JPEG(ISO), MPEG(ISO), H.261(CCITT), …

•

Channel multiplexing scheme : SCM (subcarrier multiplexing)

Prof. Lian K Chen

Part 6 - Optical Netwoks

41

Distortion in CATV •

Sources of noise or distortion : – transmitter - relative intensity noise (RIN), clipping noise, intermodulation. (RIN is very sensitive to reflection) – receiver noise - shot noise, thermal noise, circuit noise, APD noise.

•

Performance index : CNR (carrier-to-noise ratio) per channel ~ 52 dB CSO (composite-second-order distortion) ~ -65 dBc CTB (composite-triple-beat distortion) ~ -65 dBc

dBc: dB respect to carrier

Prof. Lian K Chen

Part 6 - Optical Netwoks

42

CNR calculation 1 (m ⋅ I dc ) 2 2 CNR = 2 ⋅ e ⋅ I dc ⋅ BW + 4 ⋅ k ⋅ T ⋅ BW ⋅ Ft / Req + RIN ⋅ I dc2 ⋅ BW

where m : modulation index per channel I dc : d.c. photo current BW : receiver bandwidth Ft: electronic preamp noise figure R eq: receiver equivalent resistance RIN: laser relative intensity noise The last term (laser intensity contribution) in the denominator is introduced since the noise becomes non-negligible when I dc is large. Note that the above CNR is per channel.

Prof. Lian K Chen

Part 6 - Optical Netwoks

43

CNR for analog modulation Ex: Assume a laser with Pdc= 2mW, m= 0.01, RIN = -150 dB/Hz, BW = 4MHz, Ft= 3, R eq= 75Ω, Ro= 1.0 mA/mW

Baseline (without distribution loss, fan-out, ….) CNR is 1 (0.01 ⋅1.0 ⋅ 2 ×10−3 ) 2 2

CNR = −3

2 ⋅ e ⋅ (1.0 ⋅ 2 × 10 ) ⋅ 4 ×10 + 4 ⋅ k ⋅ T ⋅ 4 ×10 ⋅ 3 / 75 + 10 6

6

−150 10

⋅ (1.0 ⋅ 2 ×10−3 ) 2 ⋅ 4 ×106

Q : How to determine the modulation index? Q : When will shot noise/thermal noise/RIN noise dominate? Q : What are the effects when we change the value of m, loss, BW, RL, or RIN? Prof. Lian K Chen

Part 6 - Optical Netwoks

44

Broadband Local Access Several approaches • xDSL (digital subscriber line) by Telco (telephone company). (http://www.adsl.com)

dedicated bandwidth (<10Mb/s)

•

Cable modem by CATV industry (http://www.cablemodem.com) 40Mb/s share bandwidth; low cost; reliability and security issues; need

•

FTTx (Fiber-to-the-x) bring fiber close to residential building

•

Wirelss - LMDS (local multipoint distribution service) (+ WiFi, WiMax) At 28 GHz with 1.3GHz bandwidth by FCC; fast deployment; inexpensive; limits by rain-fade;

• •

Powerline (http://en.wikipedia.org/wiki/Power_line_communication) Satellite wide-coverage; down link traffic only

Ref: Scientific America Oct. 1999. Prof. Lian K Chen

Part 6 - Optical Netwoks

45

Internet Users Projection

Prof. Lian K Chen

Part 6 - Optical Netwoks

Optical Fiber Telecommunications V.B

46

LAN/MAN •

Various network protocols by IEEE

and others • 802.11: wireless LAN (WLAN) • 802.12: 100 VG-Any LAN • 802.15: Wireless PAN (WPAN) • 802.15.1 bluetooth • 802.15.2 UWB • 802.15.4 ZigBee • 802.16: WiMax • 802.17: Resilient Packet Ring

Prof. Lian K Chen

Part 6 - Optical Netwoks

47

Fiber Distributed Data Interface (FDDI), ANSI X3T9.5 • • • • • • •

Outer ring used for data

dual counter-rotating token passing ring, one ring is the protection ring data rate: 100Mb/s, clock rate: 125Mb/s support 1000 physical connections (500 terminals) support a total fiber path length of 200km (100km dual ring) line coding: 4B5B frame format (packet) protocol: Timed -Token Rotation Protocol – Ref: R. Jain, “Performance Analysis of FDDI Token Ring Networks: Effect of Parameters and Guidelines for Setting TTRT”, Computer Communications Review, vol. 20, no. 4, pp. 264-275, 1990.

Inner ring for protection

MAC

Part 6 - Optical Netwoks

MAC

B

A

B

A

B

A

A

B

A

B

A

B

MAC

Prof. Lian K Chen

MAC

MAC

MAC

48

Fault-tolerance in FDDI In case of a link failure, the dual rings will be automatically configured into a single ring as shown below: MAC

failed station

station adjacent to failure loops back

MAC

MAC

B

A

B

A

B

A

A

B

A

B

A

B

MAC

MAC

No Node Failure

MAC Node Failure

Station

Station Bypass Switch

To Ring 1 To Ring 2 Prof. Lian K Chen

Part 6 - Optical Netwoks

To Ring 1 To Ring 2 49

SONET and SDH • •

Synchronous Optical Network (SONET) ANSI T1.105.06 Synchronous Digital Hierarchy (SDH) ITU-T G.957

•

SONET: North America standards, SDH: standards in Europe and Japan robust for transporting all types of voice, video and data services

•

SONET/SDH Signal Rates Rate (in MHz)

SONET Frame

SDH Frame

Physical Signal

Capacity

51.84

STS-1

-

OC-1

28 DS1

155.52

STS-3

STM-1

OC-3

84 DS1

622.08

STS-12

STM-4

OC-12

336 DS1

2488.32

STS-48

STM-16

OC-48

1344 DS1

9953.28

STS-192

STM-64

OC-192

5376 DS1

STS: Synchronous Transport Signal Level (for SONET) STM: Synchronous Transport Module Level (for SDH) “SONET: now it's the standard optical network”, IEEE Communication Mag. Vo.40, no.5, 2002. Prof. Lian K Chen

Part 6 - Optical Netwoks

50

SONET and SDH (contd.) •

direct synchronous multiplexing: individual tributary signals may be multiplexed, using Add-Drop Multiplexer (ADM) and Digital CrossConnect, directly into a higher rate SONET signal without intermediate stages of multiplexing → cost-effective, flexible telecommunications networking

•

provides flexible signal transportation capabilities, capable of transporting all existing and future signals → can overlay to existing networks

Prof. Lian K Chen

Part 6 - Optical Netwoks

51

SONET network spans Path: end-to-end; (path) Line: between transport nodes; (multiplex section) Section: between line regenerators (regenerator section)

LINE

LINE SECTION

TRIBUTARY SIGNALS

SECTION

SECTION

SONET TERMINAL MULTIPLEXER

TRIBUTARY SIGNALS

SONET TERMINAL MULTIPLEXER SONET SONET DIGTIAL CROSS_CONNECT REGENERATOR

SONET REGENERATOR

PATH

Prof. Lian K Chen

Part 6 - Optical Netwoks

52

SONET STS-1 Frame Format STS-1 Synchronous Payload Envelope (SPE) (87 columns) 3 rows Section overhead 6rows Line overhead 3 columns

• •

Path Overhead (1 column)

Frame rate: 8000 frames per second; 125μs per frame Line rate of STS-1

STS-1=(90 bytes/row)(9 rows/frame)(8 bits/byte)/(125 μ s/frame) =51.84 Mb/s Prof. Lian K Chen

Part 6 - Optical Netwoks

53

SONET ring architecture •

SONET ring architecture Integrated Timing System Clock Central Exchange

Digital Cross Connect ADM

ADM Dual Ring

DS1, E1, etc.

Prof. Lian K Chen

Terminal Multiplexer

ADM

Part 6 - Optical Netwoks

Protection Ring

54

Key features of WDM Network •

Simple Capacity upgrade System capacity can be increased easily by adding more channels operating on different wavelength sufficient apart from the existing ones.

•

Transparency Different modulation formats (analog AM, FM, PCM, … or digital ASK, FSK, PSK, QAM, …) on different channels.

•

Wavelength routing Wavelength is used as the intermediate or final address for routing datagram. Wavelength selective devices such as WGR (wavelength grating router) or AWG (array waveguide grating) can be used as the router.

•

Wavelength switching Wavelength-switched networks provide re-configurable network architecture on optical layer. Key components for implementing these networks include optical cross-connect, wavelength converter, wavelength router, and optical add-drop.

Prof. Lian K Chen

Part 6 - Optical Netwoks

55

Wavelength Routing Networks •

Broadcast-and-select networks are difficult to scale to wide-area networks – no. of wavelength channel required – passive star couplers exhibit high insertion loss as the no. of ports increases.

•

Wavelength routing networks overcome the problems by wavelength reuse, wavelength conversion, and optical switching. Station 1

Station 2

λ1 λ1

Wavelength reuse λ2 Station 3 Prof. Lian K Chen

Station 4 Part 6 - Optical Netwoks

Station 5 56

All-Optical Multiaccess Networks •

“All-Optical” Networks – transparent to multiple signal format and bit rate → facilitates upgrade and compatible with most existing electronics – reduce number of costly electrical interface (?) – manage the enormous capacity on the information highway – provide direct photonic access, add-drop and routing of broadband full wavelength chunk of information

•

“Multiaccess” Networks (don’t confuse with access network) – efficient network resource sharing among network nodes – need multiplexing, routing and switching – techniques: SCMA, WDMA, TDMA, CDMA and their hybrids

Prof. Lian K Chen

Part 6 - Optical Netwoks

57

Design Considerations of Multiaccess Networks •

Design Considerations architectures/topologies → network capacity and connectivity multi-access schemes and protocols→ network throughput and delay node complexity → cost all-optical processing vs. opto-electronic processing switching speed → multi-/demultiplexing, switching channel accessibility → device tunability (Tunable Transmitters-Tunable Receivers, Fixed Transmitters-Tunable Receivers or Tunable Transmitters-Fixed Receivers) – timing and synchronization – control signaling → network management – optical technology → dispersion, nonlinear effects, crosstalk, noise, …

– – – – – –

Prof. Lian K Chen

Part 6 - Optical Netwoks

58

Network Management • • • •

Network management is essential to operate and maintain any networks. However attractive a technology might be, it can be deployed only if it can be managed. The cost of managing a large network typically dominates the cost of the equipment deployed in the network. For optical networks, certain factors such as transparency limit the number of parameters that can be monitored.

Prof. Lian K Chen

Part 6 - Optical Netwoks

59

Network Management Function • • • • •

Configuration Management Performance Management Fault Management Security Management Accounting Management

•

+ Safety Management (optical power) Fault management

Configuration management

Network Management

Performance management Prof. Lian K Chen

Accounting management

Security management

Part 6 - Optical Netwoks

60

Network Management Performance Management: • • •

measure and monitor the network performance such as network throughput, user response times, line utilization, signal quality, etc. ensure network can perform at acceptable level. gather data Î analyse data Î check for thresholds Î alarms if below threshold

Configuration Management: • •

monitor network and system configuration such as equipment inventory, topology, connection setup, etc. effects on network operation of hardware and software can be tackled and managed.

Accounting Management: • •

measure network utilization to regulate network usage of users, maximize fairness of network access usage validation, billing

Prof. Lian K Chen

Part 6 - Optical Netwoks

61

Network Management Fault Management: • • •

fault detection Î generate alarms, fault isolation automatically fix/recover network problems (restoration) keep log of faults

Security Management: • •

control and monitor access to network resources prohibits information and resource access without appropriate authorization Management System Network Management Protocols

Prof. Lian K Chen

NM agent

NM agent

NM database

NM database

Network Element

Network Element

Part 6 - Optical Netwoks

62

Network Protection • •

In a network, each link carry data from different sources to different destination. Two ways to protect the traffic (1) path switching - restoration is handled by the source and destination nodes of each individual stream (2) line switch - restoration is handled by the nodes at both ends of the failed link Line switching can be implemented by span protection and line protection reroute path

(a) normal

(b) path switching connection

(c) line switchingspan protection Prof. Lian K Chen

x

(c) line switching line protection Part 6 - Optical Netwoks

x

x 63

Different Protection Techniques for Pointto-point Links 1+1 1:1 (only one fiber is on) 1:N

switch

switch

switch

• • •

switch

(a) 1+1

Working fiber

switch

switch

switch

Working fiber

Low priority data

Protection fiber

switch

Working fiber

switch

splitter

switch

Working fiber

switch

• • •

Protection fiber

(c) 1:N

(b) 1:1 Prof. Lian K Chen

Part 6 - Optical Netwoks

64