Introduction to optical networking

Transcription

1 Inroducion o opical neworking hp://deisne.deis.unibo.i Fibers aenuaion Aenuaion (db/km) Rayleigh scaering Opical fiber Infrared absorpion UV absorpion Wavelengh (nm) Firs window 850 nm a=1.2 db/km Second window 1300 nm a=0.4 db/km Third window 1550 nm a=0.2 db/km

2 Traffic rends Relaive Load Voice Daa By 2007 Inerne users will access, download and share he 10 erabyes informaion equivalen of he enire Library of Congress more han 64,000 imes over every day (source: IDC/lighreading.com, February 2003) 3 Bandwidh is a limi? 4 2

3 Moivaion for opical neworks Cos and performance limiaions are more and more relaed o swiching and muliplexing rahar hen o ransmission bandwidh Bandwidh demand 200 Moore law ? Traffic /rouer Capaciy (bps) Proposed OC- 12/Node OC-3/Node Year Muli-erabi [opical rouer?] Terabi rouer Firs Generaion Rouers Second Generaion Rouers Third Generaion Rouers Inerne raffic 5 Economics: he sock marke in ,300 1, Apr-99 Feb-99 Dec-98 Oc-99 Aug-99 Jun-99 Apr-00 Feb-00 Dec-99 Aug-00 Jun-00 Equal weighed index of 16 opical sysems and componen socks Source: Conrad Leifur, U.S. Bancorp Piper Jaffrayinvied presenaion a Opicomm

4 Firs generaion opical neworks A firs he opical fibers replace copper wire in radiional neworks (layer 1 OSI) Examples: Submarine sysems SONET/SDH: synchronous neworks as an evoluion of radiional TDM plesiochronous nework (elephone nework) ESCON, FiberChannel, HIPPI: compuer and peripherals inerconnecion in he shor range FDDI, Gbi Eherne: high speed LANs and WANs RPR - Resilien Packe Ring (IEEE ) 7 Opical ransmission sysems evoluion

5 Transparen neworks Opaque neworks Transmission in opics Elecronics for Signal qualiy monioring and regeneraion Swiching Mulipexing O/E/O conversion a he edges of every nework span Transparen neworks Daa never leave he opical domain Requires Opical swiching All opical 3R regeneraion (Reshaping, Reamplificaion, and Reiming) All opical wavelengh conversion 9 Phoonics in swiching Opical circui swiching (OCS) Relaively maure echnology oday Providing lighpahs WDM nework elemens Fiber, Opical line amplifier (OLA) Opical line erminaion (OLT) Opical add-drop muliplexer (OADM) Opical cross-connec (OXC) Opical packe swiching (OPS) No available oday due o some echnological problems Conrollable opical memory for opical buffering Conrol funcions in he opical domain Synchronizaion, ec Opical burs swiching (OBS) Hybrid packe swiching: a feasible soluion? De-layering Reduce operaional coss Allow faser provisioning Inerne applica. TCP IP ATM SDH WDM IP/ATM/SDH/WDM Inerne applica. TCP IP daa link WDM IP over WDM 10 5

6 Opical Neworking Evoluion Flexibiliy WDM Neworks Opical Circui-Swiched Neworks Opical Burs/Packe Swiched Neworks Transpor Neworks Today Time 11 Opical circui swiching A lighpah corresponds o a circui Se-up a lighpah The whole lighpah is available during he connecion Disconnec The prism: wavelengh as a rouing ool λ whie λ g (1) λ verde λ rosso λ giallo λ v (1) λ g (2) λ v (2) λ g (2) λ v (2) λ g (1) λ v (1) 12 6

7 Opical Add-Drop Muliplexer Parallel srucure Arbirary channels Fixed loss Demux of all channels Inefficien for small drop Higher loss Many filers Serial srucure Each OADM drops one channel Modular cos More modules for more drops Disrups service Loss increases 13 Types of OXCs Elecronic or opical core Transparency Cos Size Transparen or opaque core Signal convered Elecronic signal Signal monioring Opical signal Transparency 14 7

8 WDM neworks design WDM nework objecive is o esablish lighpahs o suppor he clien raffic demands Given he fiber (physical) opology and he raffic marix Deermine he lighpah opology (logical nework) Lighpah opology design (LTD) According o rouing and wavelengh availabiliy consrains Rouing and Wavelengh Assignmen (RWA) Given a raffic marix (a forecas) and a fiber (physical) opology: design he nework ha fis he raffic forecas Seale New York 15 Saic WDM nework opimizaion Complexiy Rouing and Wavelengh Assignmen (RWA) [OzBe03] The capaciy of each link is given I has been proven o be a NP-complee problem [ChGaKa92] Two possible approaches Maximal capaciy given maximize roued raffic (hroughpu) Offered raffic given minimize wavelengh requiremen Rouing Fiber and Wavelengh Assignmen (RFWA) The capaciy of each link is a problem variable Furher erm of complexiy Capaciaed nework The problem conains mulicommodiy flow (rouing), graph coloring (wavelengh) and localizaion (fiber) problems I has been proven o be a NP-hard problem (conains RWA) 16 8

9 OBS nework Conrol and daa informaion ravel separaely on differen channels Daa coming from legacy neworks are aggregaed ino a burs uni in edge node The conrol packe is sen firs in order o reserve he resources in inermediae nodes The burs follows he conrol packe wih some offse ime, and i crosses he nodes remaining in he opical domain OBS node Reserv. manager Assembly manager OBS nework Swiching imes: ms µs Burs size: kb MB Conrol channels offse Legacy neworks WDM links Daa channels... Ou-of-band signal. 17 OBS principles Variable-lengh packes, named burss Asynchronous node operaion A srong separaion beween he conrol and daa planes Conrol burs (wih conrol informaion) ransmied on dedicaed conrol channel and processed elecronically Daa burs ransmied and swiched all-opically Burs Signaling Proocols Burs ransmission is preceded by a seup message o reserve resources Signaling packes undergo E/O conversion a every hop while burs daa ravel ransparenly Two differen ypes of proocols Tell-and-Wai (TAW): wo-way reservaion schemes Tell-and-Go (TAG): one-way reservaion schemes 18 9

10 r r r TAG sae-of-ar OBS signaling JIT (Jus in Time) proocol: explici seup and explici or implici release S δ Offse S OXC se R R δ Horizon and Jus Enough Time proocols: employ esimaed seup and esimaed release Horizon doesn suppor void filling JET suppors void filling Processing delay S δ S Offse S T se δ δ δ S T se OXC se R R δ δ Processing delays T se δ S 19 OBS Neworks Nodes Edge node Elecronic rouer and OBS inerface Funcions Elecronic daa buffering and processing Burs Aggregaion (BA), responsible for collecing daa from legacy neworks and building he burs uni Seing up he pre-ransmission offse ime Sending he conrol packe Sending he burs Core node Processing of incoming conrol packes (elecronically) and sending i o he nex node ha lays on he rouing pah Reservaion of opical resources for ransferring he burs Jus-In-Time (JIT) Horizon Reservaion Mechanism (HRM) Jus-Enough-Time (JET) he mos efficien bu of high complexiy 20 10

11 Opical packe swiching Convenional rouers archiecure Rouing componen Exchange of rouing informaion Build he rouing able Forwarding componen Forwarding algorihm Packe header processing Rouing able look-up Swiching Transfer packe from inpu o oupu por Transmission Opics applicable o swiching and ransmission 21 OPS main open issues Header processing Elecronics or opics Congesion resoluion No opical RAMs Time muliplexing wih delay lines Wavelengh and space muliplexing as alernaives Tuneable wavelengh conversion Swiching ime Complexiy and cos increase wih decreasing swiching ime Synchronizaion Packe alignmen, header rewriing 22 11

12 Opical rouers De-couple rouing and forwarding from swiching and ransmission Use elecronics for processing Use opics for high speed daa ransfer Packe payload and header reaed differenly O/E/O conversion of header a any node Transparen swiching of packe payload Alernaives In band header Packe header ravelling wih he payload Ou of band header Packe header carried on a separae wavelengh 23 Opical packe Header and payload bi raes may be differen Guard band beween header and payload o cope wih opical devices swiching speed Payload mus be larger han guard bands Overhead mus be limied in he order of 10% Payload longer han average ime needed for header processing Limi guard bands beween packes Payload mus be he shores possible Limi he packeizaion delay Payload should fi wih carried raffic Any padding needed is an addiional overhead Payload Header Guard Band 24 12

13 Opical packe forma Use exising packe forma? IP daagram ATM cell The duraion of small packes a high speed is comparable wih Guard imes Forwarding able look up The nework is inefficien A specific packe forma is necessary 25 Packe forma: ime srucure Unsloed variable lengh (UVL) Sloed fixed lengh (FLP) Sloed variable lengh (SVLP) UVL ne load = ρ FLP SVLP T real load = ρ F >ρ real load = ρ S <ρ F 26 13

14 Opical Packe Swich Archiecure Demux, Header Exracion and Wavelengh Conversion Non-Blocking, Opical Space Swich w Se of Fiber Delay Lines w Wavelengh Conversion, Header Inserion and Mux N N Swich Conrol Logic 27 The KEOPS broadcas and selec 28 14

15 David Opical Packe Rouer All opical space swich WDM inles/oules Conenion resoluion: Wavelengh muliplexing Time muliplexing Targe 256 x 256 marix Link speed 10 Gbi/s Throughpu 2.56 Tbi/s M inpus B pors λ conversion All Opical Space Swich w λs k λs M oupus Opical Buffer 29 Mulisage Buffer Swich m FDLs a each sage 0 λ 1 0 λ 1 IN Wavelengh Conversion Dm k-1 D (m-1)d OUT (m-1)dm k-1 λ L λ L Buffering sage 1 Buffering sage k 30 15

16 Technology aper AR coaing Amplifying region p layer GaInAsP n-inp Semiconducor Opical Amplifier I N T E G R A T I O N Mach-Zehnder inerferomeer Wavelengh demux, mux Clamped Gain SOA gaes Space Swiching Marix SOA for cross-phase modulaion All Opical Wavelengh Converer On Off Off On SOAgaes Wavelengh Selecor Couresy of Alcael CRC 31 Opical neworks research a DEIS Naional projecs IPPO (PRIN): , Inrepido (PRIN): , Grid.IT (FIRB): , Inernaional projecs ATMOS (RACE II) : KEOPS (ACTS) : , DAVID (IST VFP) : , e-phoon/one (IST VIFP) : , e-phoon/one+ (IST VIFP) : , Toal funding = saff members + 1 in

17 The KEOPS Projec Parners: Alcael Alshom Recherche* (F) France Télécom CNET (F) Cenro Sudi E Laboraori Telecomunicazioni (I) Technical Universiy of Denmark (DK) Alcael SEL** (D) Alcael CIT*** (F) Universiy of Bologna (I) Eidgenössische Technische Hochschule Zürich (CH) Universiy of Srahclyde (UK) * now, Alcael CIT, Eablissemen de Marcoussis ** acive ill Feb.97, *** acive ill Dec.96 Objecive Analysis and demonsraion of bi rae ransparen all-opical packe swiching wihin all-opical nework archiecure including nework & sysem sudies, lab. rials based on componens developed in he projec 33 The DAVID Projec Parners: Alcael CIT (F) Alcael SEL (D) Opo+ (F) BT (UK) IMEC (B) COM (DK) NTUA (G) Universiy of Bologna (I) Polyechnic of Torino (I) Universiy of Essex (UK) UPC (E) LRI (F) INT (F) hp://david.com.du.dk Goals Develop conceps and echnologies for fuure opical neworks Traffic engineering in packe-over- WDM based neworks Conrol sysems for opical neworks 34 17

18 e-phoon/one ( 38 parner insiuions (from Porugal o Turkey) 32 academic insiuions 3 elecom operaors (Telenor, France Telecom, TID) 2 manufacurers (Alcael, Siemens) ~400 researchers acively involved in he NoE Coordinaor: Poliecnico di Torino Projec sar dae: February 2004 End of Phase 1: March 2006 funded for 2 years wih 2.9 M End of Phase 2: March more years wih exra 3.75 M 35 Reshaping, Reamplificaion, and Reiming (3R) Mulilongiudinal Mode (MLM) Laser : An injecion laser diode which has a number of longiudinal modes Single-longiudinal Mode Laser (SLM): An injecion laser diode which has a single dominan longiudinal mode. A single-mode laser wih a side mode suppression raio (SMSR)< 25 db