Optical Networks Evolution

2 N+I_2k © 2000, Peter Tomsu 02_onw_evol Evolution of Optical Networks Greater Network Scale Improved Costs Requisites  Traffic Continues to Grow  Reducing Networking Costs Is A Priority Multi-Wavelength Transmission Multi-Wavelength Networking Single Wavelength Transmission

3 N+I_2k © 2000, Peter Tomsu 02_onw_evol Single Wavelength Transmission Long haul traffic aggregation Narrowband traffic Reliable transmission Efficient tributary access Service level switching Isolated knowledge “Dumb pipes” 1 Wavelength Per Fiber 1 Wavelength per Network Element Electronic Multiplexing Electronic Regeneration SDH-MUX

4 N+I_2k © 2000, Peter Tomsu 02_onw_evol OC-3/12 Tx OC-48/192 TDM MUX Byte Interleave Rx Single wavelength per fiber Multiple channels per fiber Sync and async signals are muxed to a single higher optical bit rate E/O signal conversion Signals are multiplexed in the time domain Composite Optical Signal TDM Transmission

5 N+I_2k © 2000, Peter Tomsu 02_onw_evol SONET Optical Carrier (OC) and SDH Synchronous Transport Module (STM) Levels Optical Level Electrical Level Line Rate (Mbps) Payload Rate (Mbps) Overhead Rate (Mbps) OC-1 STS-1 OC-3/STM-1 STS-3 OC-9/STM-3 STS-9 OC-12/STM-4 STS-12 OC-18/STM-6 STS-18 OC-24/STM-8 STS-24 OC-36/STM-13 STS-36 OC-48/STM-16 STS-48 OC-96/STM-32 STS-96 OC-192/STM-64 STS SONET Overhead is 3% independent of Data Rate

6 N+I_2k © 2000, Peter Tomsu 02_onw_evol ADM or DCS ADM or DCS Multiplex Section Termination PTE (ADM, DSLAM,… PTE (ADM, DSLAM,… PTE (ADM, DSLAM,… Service (E1, E3…) Mapping Demapping Path Termination Path Termination Service (E1, E3…) Mapping Demapping Regenerator Section Regenerator Section Termination Regenerator Section Termination REG PTE = Path Terminating Element MUX = Terminal Multiplexer REG = Regenerator ADM = Add/Drop Multiplexer DCS = Digital Cross-Connect System SDH Components and Overhead Layers Regenerator Section

7 N+I_2k © 2000, Peter Tomsu 02_onw_evol Total STM-1 Transmission Overhead 9 Rows x 9 Columns STM-1 AUG (261 Byte/Columns) Regenerator Section Overhead (3 Byte/Rows, 9 Columns) Multiplex Section Overhead (5 Byte/Rows, 9 Columns) A1 x x x x B2 x x x x x x x B1 D1 B2 x x x D7 D10 S1 xxD4 1 2 Order of Transmission The Basic Building Block of SDH: STM-1 A2 x x x x x x x M1 x x x x E1 D2 x x x x K1 D8 D11 x xxD5 J0 x x x x x x x x x x x x x x D2 F1 D3 x x x x K2 D9 D12 E2 xxD6 AU Pointers J1 B3 C2 F2 F3 K3 N1 H4 G1 Path Overhead 1 Row x 9 Columns APS Signaling Section Trace Bit Errors Path Signal Label Basic building block: SDH STM-1 frame 9 columns of SDH transmission overhead (x9, byte rows) = 81 bytes 261 cols of STM-1 “administrative units group (AUG)” (x9, byte rows) = 2349 bytes 125 microseconds/frame = 155,52 (150,34) mbps

8 N+I_2k © 2000, Peter Tomsu 02_onw_evol POS Standards Based Encapsulation Telcordia GR-253 ITU-T G.957 ITU-T G.958 PPP in HDLC Like Framing, IETF RFC 1662 Section + Line OH Section + Line OH Path OH Concatenated Payload Concatenated Payload Flag 8 Address 8 Control 8 PPP Packet FCS 16/32 Flag 8 Point-to-Point Protocol, IETF RFC 1661 Packet over SONET/SDH, IETF RFC 2615

9 N+I_2k © 2000, Peter Tomsu 02_onw_evol POS Provides Fast Restoration Protection switching - ADM Support both SONET APS and SDH MSP protocols Protection for port, LC or chassis Protection Switching - DWDM Optical protection protects transmission infrastructure Layer 3 provides path restoration Opportunity for differentiation at the service level (Load-Balancing & MPLS-TE) Protect Router Working Router Cisco’s Protect Group Protocol via IP SONET APS signaling protocol (K1/K2 BYTES) ADM TX RX Optical Cloud

10 N+I_2k © 2000, Peter Tomsu 02_onw_evol POS Applications Connect to tributary interfaces on SONET/SDH muxes (OC3c/STM1c to OC48c/STM16c) Connect to transponders in a WDM system (typically OC12c/STM4c or OC48c/STM16c) Interconnect GSR directly over dark fiber with regenerators to extend the distance of LR interfaces (typically OC48c/STM16c) within a POP (typ. OC3c/STM-1 or OC-12c/STM-4c) Backbone Routers Edge Routers

11 N+I_2k © 2000, Peter Tomsu 02_onw_evol DPT Ring Eliminate SONET/SDH equipment while retaining benefits Destination stripping Bandwidth consumed only on traversed segment No dedicated restoration bandwidth Dynamic, per-packet spatial reuse Control via SRP-fa instead of token passing Dynamic Packet Transport (DPT) Working BFP

12 N+I_2k © 2000, Peter Tomsu 02_onw_evol SRPNew layer 2 MAC technology SRP Spatial Reuse Protocol Uses SONET/SDH framing Bandwidth efficient Fairness (SRP-fa) Scalable Fast protection switching and service restoration Multicasting and priority (CoS)enables DPT functionality Spatial Reuse Protocol …… MAC IP Packet MAC IP Packet Section plus Line Overhead Section plus Line Overhead Path Over- head Path Over- head Concatenated Payload Concatenated Payload TTL RI DS PRI Mode Usage PP Destination Address Source Address Protocol Type Payload :::: :::: :::: :::: FCS SONET/SDH Frame MAC Frame DPT Packet Format

13 N+I_2k © 2000, Peter Tomsu 02_onw_evol DPT fairness algorithm Distributed algorithm Propagates and uses MAC usage info Rate controls for sourced and forwarded traffic Rapid adaptation and convergence Transitive control DPT Fairness Example (1) (3) A B (2) (4)

14 N+I_2k © 2000, Peter Tomsu 02_onw_evol Sink A B 200Mbps C D E 622Mbps 155Mbps DPT-fa Operation Example

15 N+I_2k © 2000, Peter Tomsu 02_onw_evol Layer 3 Switching SRP MAC Layer Rx Fiber Tx Fiber Rx Fiber Tx Fiber Rx Queuing Tx Queuing Transit Buffer Tx Queue Rx Packets DPT Features (1) (3) A B (2) (4) Fiber Cut Detects Alarms and Events and Wraps Ring ~100 ms SRP Fairness Algorithm Intelligent Protection Switching DPT Packet Processing

16 N+I_2k © 2000, Peter Tomsu 02_onw_evol DPT Cooperates With Layer 3 CoS to Extend Functionality Layer 3 provides rich functionality and granular controls MAC provides speed and simplicity Enables low delay/jitter for voice and video packets Layer 3—IP Layer 2— SRP MAC Precedence SettingRate Control Congestion Control RED/WRED Granular Scheduling DRR on Eight Classes Big Fat Pipes High-Priority Bypass Low-Priority Fairness Precedence Mapping

17 N+I_2k © 2000, Peter Tomsu 02_onw_evol Backbone ~ ~ ~~ WDM ~ ~ ~~ GSR Building Access Mux Packet Concentrator 2.4G Metro Access Ring 10Gb Regional Transport Ring 10Gb Regional Transport Ring Cable Data Ring Network Architecture Migration Si Dedicated Access PoP Ring Leased Lines GSR Si

18 N+I_2k © 2000, Peter Tomsu 02_onw_evol Evolution of Optical Networks Single Wavelength Transmission Greater Network Scale Improved Costs Multi-Wavelength Networking Multi-Wavelength Transmission

19 N+I_2k © 2000, Peter Tomsu 02_onw_evol DWDM System Design Amplify DWDM Filter Optical Combiner 15xx nm1310 nm Reamplify Reshape Retime Rx Tx 1310 nm Rx External Modulator Laser 15xx nm

20 N+I_2k © 2000, Peter Tomsu 02_onw_evol Optical IP - using WDM

21 N+I_2k © 2000, Peter Tomsu 02_onw_evol Multi-Wavelngth Transmission Fiber exhaust due to traffic growth Increased data use Higher data rates Enabling technologies DWDM - fiber savings EDFAs – regenerator savings Transparent fiber aggregation “Virtual Fiber” “N” Wavelengths Per Fiber 1 Wavelength per Network Element

22 N+I_2k © 2000, Peter Tomsu 02_onw_evol DWDM Transmission OC-48 x 40 ch. = 100 G/bs OC-192 x 16 ch. = 160 G/bs OC-48 x 80 ch. = 200 G/bs Composite Optical Signal Wavelength (nm) OC-48/192   WDM MUX Tx Rx Tx Rx Tx Rx Tx Rx Signals are multiplexed in the wavelength domain Multiple wavelengths per fiber Multiple channels per wavelength (TDM) Statistically multiplexed data traffic No signal format conversion

23 N+I_2k © 2000, Peter Tomsu 02_onw_evol ITU Wavelength Grid ITU-T grid is based on THz GHz Its purpose is to standardize lasers not DWDM systems There is no standard for DWDM systems Number and spacing of s are design variables nm nm 0.80 nm

24 N+I_2k © 2000, Peter Tomsu 02_onw_evol EDFA Schematic Pump Laser WDM Coupler WDM Coupler EDF DCF Optical Isolator 1480 Pump Laser Optical Filter Optical Isolator EDF EDFAs amplify all s in 1550 window simultaneously Key performance parameters include Saturation output power, noise figure, gain flatness/passband

25 N+I_2k © 2000, Peter Tomsu 02_onw_evol Anatomy of a DWDM System Terminal A Terminal B Post- Amp Pre- Amp Line Amplifiers MUXMUX DEMUXDEMUX Transponder Interfaces Transponder Interfaces Direct Connections Direct Connections Basic building blocks Optical amplifiers Optical multiplexers Stable optical sources

26 N+I_2k © 2000, Peter Tomsu 02_onw_evol Basic Optical Protection Protection migrates to DWDM equipment Only 1 DWDM with protection modules needed Switching decision controlled by transponders Technologies include optical switching and OA gating Working Protect

27 N+I_2k © 2000, Peter Tomsu 02_onw_evol DWDM State-of-the-art Data Rate Point-to-point systems 40 x OC-48 deployed 16 x OC-192 deployed 160 x OC-192 announced Configurable OADMs Metro rings 1-10 Tbps per fiber is just around the corner!

28 N+I_2k © 2000, Peter Tomsu 02_onw_evol Evolution of Optical Networks Single Wavelength Transmission Greater Network Scale Improved Costs Multi-Wavelength Transmission Multi-Wavelength Networking

29 N+I_2k © 2000, Peter Tomsu 02_onw_evol “Virtual Transport” Multi Wavelength Networking Network and operations scaling v.S. Raw capacity Single wavelength elements not keeping pace Operations need to scale Enabling technologies Scalable and ultra dense architectures of electronic Networking intelligence “N” Wavelength Per Fiber “N” Wavelength per Network Element

30 N+I_2k © 2000, Peter Tomsu 02_onw_evol Moving From Static to Intelligent Traditional Static Transport Network Point-to-Point WDM Physical Transport Overlays Static Provisioning Limited Line Rate Linear or Ring Protection Reduces total Cost of Ownership Intelligent Optical Transport Network Intelligent Optical Networks Virtual Transport Networks Dynamic Provisioning Flexible Capacity Flexible Protection

31 N+I_2k © 2000, Peter Tomsu 02_onw_evol Emergence Of Intelligent Optical Core Layer 3 IP Layer 2 ATM Layer 1 Voice/P.L. Distributed Intelligence Provisioning & Intelligent Grooming Full Suite of Protection Methods Scalable and Granular Capacity STM-1 to Wavelengths

32 N+I_2k © 2000, Peter Tomsu 02_onw_evol Next Generation Optical Protection Protection controlled by large cross-connects on tributary side of DWDM running a routing protocol Protection migrates from fiber to level Line, ring and mesh restoration options

33 N+I_2k © 2000, Peter Tomsu 02_onw_evol Flexible & Rapid Restoration Restore virtual wavelength paths end-end in 50ms using a wavelength routing protocol Linear, ring & mesh options No preplans, no dedicated restoration bandwidth Wavelength routing protocol will be very similar to IP+ATM MPLS approach Multiprotocol Lambda Switching

34 N+I_2k © 2000, Peter Tomsu 02_onw_evol All Optical Networking Optical dial tone O-E sub-systems present only at network end points Potential for cost savings No more equipment upgrades? Enabling technologies: Lower cost optical systems Ubiquitous compliance to optical standards Optical OAM&P No need for granular capacity Multi-Wavelength Networked Transparent Services Fabric

35 N+I_2k © 2000, Peter Tomsu 02_onw_evol Optical CrossConnect with Full Wavelength Conversion M demultiplexers at incoming side M multiplexers at outgoing side Mn x mn optical switch has wavelength converters at switch outputs 1, 2,..., n 1, 2,..., n 1, 2,..., n 1 2 m Optical CrossBar Switch Wavelength Converters Wavelength Mux Wavelength Demux 1, 2,..., n 1, 2,..., n 1, 2,..., n n 1 2 n 1 2 n 1 2 n 1 2 n n m

36 N+I_2k © 2000, Peter Tomsu 02_onw_evol Optical Add/Drop Multiplexer OADM similar to OXC uses only 2 trunk ports uses remaining incoming ports as Add-ports uses remaining outcoming ports as Drop-ports1 Trunk port 1, 2,..., n 1 2 n 1, 2,..., n 1 2 n outin

37 N+I_2k © 2000, Peter Tomsu 02_onw_evol Wavelength Routing Streamline layers, remove functional overlap Deliver optical transport and traffic- engineering at wavelength level complementing IP, MPLS New functions Rapid end-to-end provisioning Fast path restoration Bandwidth efficiencies

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