Deployment and Design Issues of IP Over Optical Networks

Transcription

1 1 Deployment and Design Issues of IP Over Optical Networks Session 2

2 Agenda Overview Optical Transport Technology POS, SRP and GE Network Architecture Conclusion 3 Optical Transport Options Dark fiber SONET/SDH DWDM GE SONET/SDH IP DWDM Fiber GE 4

3 Dark Fiber Effective alternative if fiber plant capacity is not limited or there is no need for bandwidth multiplication Modest distance (80 Km or less) No other traffic a side from router traffic 5 Dark Fiber Considerations when deploying IP infrastructures over dark fiber Fiber plant capacity and topology Power budgets optics reach Signal loss (due to attenuation and dispersion) optics reach Network design must address protection 6

4 Fiber Fundamentals Attenuation Dispersion Nonlinearity Distortion It May Be a Digital Signal, but its Analog Transmission Transmitted Data Waveform Waveform after 1000 km 7 Analog Transmission Effects Attenuation: Reduces Power Level with Distance Dispersion and Nonlinearities: Erodes Clarity with Distance and Speed Signal Detection and Recovery Is an Analog Problem 8

5 Effects of Jitter and Noise Jitter Closes the Signal Horizontally Signal Amplitude Error if Signal Is in This Area Noise Closes the Signal Vertically Time 9 Optical Attenuation Specified in loss per kilometer (db/km) nm nm Loss due to absorption by impurities 1400 nm peak due to hydroxyl (OH) ion absorption 1310 Window 1550 Window 10

6 Calculating Link Loss Budget Link Loss Budget = Optical Power Budget Design Margin Power Penalties Connector and splice Optical Power Budget Design Margin (EOL) Power Penalties Connector and splice Link Loss Budget 26dB (OC-48c POS [1550nm]) 1dB 2dB (OC-48c POS [1550nm]) 3dB 20dB 11 Link Loss Budget Example Tx Transmitter Power 2dB Fiber Patch Fiber Distribution Panel 1dB 3dB 80Km Fiber Span 0.25dB/Km + 1dB for Splice Loss Link Loss Budget 20dB Fiber Distribution Panel Fiber Patch 1dB 19dB Rx 20dB at Receiver Receiver Sensitivity 28db 12

7 SONET/SDH Widely deployed optical transport technology TDM transmission Proactive fault and performance monitoring capability Fast restoration 50 msecs 13 SONET/SDH Limited to no availability of high speed OC-48/STM-16 tributary Almost no support for concatenated tributary on SDH TM or ADM Need to reserve bandwidth for protection Protection (tributary) APS/MSP 14

8 SONET/SDH Network Configurations Point-to-Point Linear Two Nodes, Terminal Mode Up to 16 Nodes, ADM Unidirectional Path Switched Ring UPSR All Traffic Homing to a Central Location Two Fiber Bidirectional Ring TX RCV 2F BLSR Traffic with Neighboring Pattern, Reusable Bandwidth Four Fiber Bidirectional Ring 4F BLSR Traffic with Neighboring Pattern, Reusable Bandwidth 15 SONET/SDH Overhead Layers Path Line Line Section Section Section Section PTE ADM, TM, ATM, Router, Telephony Switch STE Regen LTE ADM/ DCS STE Regen PTE ADM, TM, ATM, Router, Telephony Switch LTE PTE STE ADM DCS TM Regen Line Terminating Equipment Path Terminating Equipment Section Terminating Equipment Add/Drop Multiplexer Digital Cross-Connect System Terminal Multiplexer Regenerator 16

9 DWDM Used to provide bandwidth multiplication where fiber plant capacity is scarce No protection on tributary side Network design must address protection 17 Anatomy of a DWDM System Terminal A Terminal B Transponder Interfaces M U X Line Amplifiers Post- Amp Pre- Amp D E M U X Transponder Interfaces Direct Connections Direct Connections 18

10 DWDM Transponder Interfaces From Terminal Equipment DWDM TRANSMITTER SR RCVR SONET 3R PM LR-2 XMTR To Mux To Terminal Equipment SR-1 XMTR DWDM RECEIVER SONET 3R PM LR RCVR From DeMux One transponder required per wavelength Full 3R functionality (re-amp, re-shape, re-time) Tributary side is 1310 SR, line side is 15xx LR Limited SONET/SDH performance monitoring 19 Performance Monitoring SONET/SDH performance monitoring performed on a per wavelength basis through transponder Computation of B1 and monitoring J0 at each channel input and output B1 section bit error rate J0 section path trace No modification of SONET/SDH overhead Data transparency is preserved 20

11 TDM vs WDM Time division multiplexing Single wavelength per fiber Multiple channels per fiber 4 OC-3/STM1 channels in OC-12/STM4 4 OC-12/STM4 channels in OC-48/STM16 16 OC-3/STM1 channels in OC-48/STM16 Wave division multiplexing Multiple wavelengths per fiber 4, 16, 24, 40 channels per system Multiple channels per fiber Channel 1 Channel n λ1 λ2 λ n Single Fiber (One Wavelength) Single Fiber (Multiple Wavelengths) 21 Packet Over SONET/SDH (POS) Point-to-point protocol, RFC 1661 PPP in HDLC-Like framing, RFC 1662 PPP over SONET/SDH, RFC 2615 IP PPP HDLC SONET/SDH Framing Datagram Protocol Encapsulation Link Initialization PPP Packet Delineation Error Control Byte Delineation 22

12 POS OC-3/STM-1 OC-192/STM-64 Encapsulation HDLC/PPP Connecting to SONET/SDH APS/MSP for protection Connecting to DWDM or dark fiber Multiple links for load sharing and protection 23 POS Framing TOH POH SPE 125µsec PPP Flag 0x7e Address 0xff Control 0x03 Protocol 8/16 bits Data Padding FCS 16/32 bits Flag 0x7e 0x0800 = IP 0x0806 = ARP 0x8035 = Keepalive Cisco HDLC Flag 0x7e Address Control 0x00 Protocol 8/16 bits Data FCS 16/32 bits Flag 0x7e 0x0F = Unicast Frame 0x80 = Broadcast Bit 0x40 = Padded Frame Bit 0x20 = Compressed Bit 24

13 POS APS/MSP SONET Automatic Protection Switching (APS) SDH Multiplex Switching Protection (MSP) Uses K1 and K2 byte; Protection Working Router Working Router W W SONET/SDH Network Protect Router P Protect Group Protocol P Protect Router 25 POS Optics Operating Wavelength (nm) Power Budget (db) Target Distance (Km) OC-192/ STM-64 OC-48/ STM-16 OC-12/ STM-4 OC-3/ STM-1 VSR Single-Mode (SR) Single-Mode (LR2) Single-Mode (SR) Single-Mode (LR2) Multi-Mode Single-Mode (IR) Multi-Mode Single-Mode (IR) Single-Mode (LR)

14 POS Application Dark Fiber POS WDM λ1 λ2 λn ~ ~ λ1 λ2 λn SONET/SDH 27 Spatial Reuse Protocol (SRP) Ring topology Spatial reuse Fairness algorithm Intelligent Protection Switching (IPS) IP SRP SONET/SDH Framing Datagram Protocol Encapsulation, Packet Delineation and Error Control Byte Delineation 28

15 SRP Priority high and low Topology discovery Media independent SONET/SDH framing D A C Inner Ring B Outer Ring 29 SRP OC-12/STM-4 and OC-48/STM-16 Layer 3 mesh Broadcast media like FDDI 30

16 SRP Other consideration when using SRP Ring diameter Number of nodes on the ring Remember the ring is a shared media All nodes on the same ring must be of the same speed Note SRP does not support APS/MSP 31 SRP Framing TOH POH SPE 125µsec SRP Flag 0x7e SRP Header Data FCS 32 bits Flag 0x7e 32

17 Ring Packet Flow L3 SRP-LC RAC Side B O-Tx I-Rx Side A O-Rx I-Tx RAC SRP-LC L3 RAC RAC Side A O-Rx I-Tx I-Rx O-Tx Side B Side B O-Tx I-Rx I-Tx O-Rx Side A RAC RAC L3 SRP-LC RAC I-Tx O-Rx Side A I-Rx O-Tx Side B RAC SRP-LC L3 33 SRP-fa Modeling Done on OPNET Modeling Tool by OPNET (Formerly Mil3) 34

18 IPS Intelligent Protection Switching (IPS) Automatically recovers from fiber facility or node failure, or signal degrade Analogous to self healing properties of SONET/SDH rings Without the need to reserve protection bandwidth 35 IPS Protection switching event hierarchy Ring wrap on fiber facility failure is transparent to Layer 3 Ring restores in 50 msecs 36

19 IPS A D B C Example IPS Operation 37 SRP Optics OC-48/ STM-16 OC-12/ STM-4 Single-Mode (SR) Single-Mode (LR2) Multi-Mode Single-Mode (IR) Single-Mode (LR) Operating Wavelength (nm) Power Budget (db) Target Distance (Km) Single-Mode (LR2)

20 Wiring Topology Ring Star Pentacom RingStar 8000 Passive O-E-O Switch Fiber Patch Panel 39 SRP Application Dark Fiber POS WDM λ1 λ2 λn ~ ~ λ1 λ2 λn SONET/SDH 40

21 Extending the Distance OC-48 POS/SRP (LR2) Regen Regen OC-48 POS/SRP (LR2) 80 Km 80 Km 80 Km Use regenerator 3R Re-amp, Re-shape and Re-time Can be used for both POS and SRP Cisco regen supports IP over DCC for management 30 regens can be cascaded to get a distance of 2400 Km ( 1500 miles) 41 Clocking and Synchronization SONET/SDH ADM or TM clocking derives from the PRC in the SONET/SDH network Applies to both POS and SRP Looped timed SONET/SDH Network PRC ADM ADM 42

22 Clocking and Synchronization DWDM or dark fiber Clocking derive from the interface internal oscillator ± 20ppm Applies to both POS and SRP No BITS interface DWDM DWDM Regen Straight Dark Fiber 43 Clocking and Synchronization Internal Clock Linecard Tx Rx Linecard Linecard Tx Rx Linecard Looped Timed Rx Tx Internal Clock Switch Fabric Rx Tx Internal Clock Linecard Tx Rx ADM SONET/SDH Network ADM Tx Rx Linecard Rx PRC Rx Tx Looped Timed Looped Timed 44

23 Gigabit Ethernet High speed LAN Server connectivity POP interconnect MAN 45 GE Protocol Stack IEEE Ethernet IEEE LLC IEEE CSMA/CD IEEE Physical Layer ANSI X3T11 FibreChannel FC-4 Upper Layer Mapping FC-3 Common Services FC-2 Signaling IEEE LLC CSMA/CD or FDX Mac 8B/10B Encode/Decode Serializer/ Deserializer Connector IEEE 802.3z Gigabit Ethernet FC1 Encode/Decode FC-0 Interface and Media 46

24 Ethernet Frame Format Preamble DA SA Type/ Length LLC Data CRC DSAP SSAP Control 47 GE Standards Specification Cable Type Maximum Distance Full Duplex Half Duplex 1000BaseCX Shielded Balanced 25M 25M 1000BaseSX 62.5 Micron MMF 260M 260M 1000BaseLX 62.5 Micron MMF 10 Micron SMF 440M 3Km 320M 320M *1000BaseZX 10 Micron SM (NDSF) 10 Micron SM (DSF) 70Km 100Km * Non-Standard Specification (N)DSF (Non) Dispersion Shifted Fiber 48

25 Agenda Overview Network Architecture Backbone Aggregation Metro Conclusion 49 Optical Network Infrastructure Router SONET/ SDH DWDM Fiber Plant 50

26 Design Considerations (Backbone) Infrastructure redundancy Routers Links No single point of failure Path redundancy Load sharing Protection 51 Design Considerations (Backbone) Capacity planning and traffic engineering Topology KISS (keep it simple stupid) 52

27 Topology Options (Backbone) Mesh Full or partial Point-to-point POS Ring POS or SRP 53 Full Mesh POPA POPB POPC POPD Primary Path Secondary/Load Share Path 54

28 Full Mesh All the backbone routers are connected to each other Single hop from any backbone router to the other Depending on the number of routers in the backbone, may require a lot of slots/ports n(n-1)/2 ports 55 Connecting to SONET/SDH POPA POPB W W P P SONET/SDH POPC POPD W W P Working Protect P 56

29 Connecting to DWDM POPA POPB DWDM POPC POPD Primary Path Secondary/Load Share Path 57 Partial Mesh (1) POPA POPB POPC POPD Primary Path Secondary/Load Share Path 58

30 Partial Mesh Each backbone router is connected to two or more backbone routers Multi-hop to some backbone router Uses less slot/port and fiber compared to full mesh topology Cost effective 59 Partial Mesh (2) POPA POPB POPC POPD Primary Path 60

31 Partial Mesh POS SRP 61 SRP OC-48/STM-16 Ring Example of a 6 Node SRP Ring 62

32 Example Backbone Design POPF POPA POPB POPE POPD POPC 63 CEF Load Balancing CEF supports per packet and per destination load balancing Up to 6 parallel path In the event that one of the path fails traffic is move to another path Incoming Packet OC-48/STM-16 CEF Switching 64

33 Design Considerations (Aggregation) Choice of data link technology FDDI, ATM, GE, POS and SRP Bandwidth requirements 65 Topology (Aggregation) Point-to-point POS or GE Ring SRP Shared GE and ATM 66

34 Point-to-Point Each aggregation router is connected to 2 backbone router for redundancy and load sharing Scalability? Slots/ports increases by the number of aggregation router that needs to be connected POS or GE W GE W W POS (155Mbps) P 67 Ring Logical full mesh (at Layer 3) More scalable uses less slots/ports SRP SRP 2X622 Mbps SRP Concentrator 68

35 Shared GE ATM 69 Metro Access Router MAN Backbone Router 70

36 Design Considerations (Metro) Choice of data link technology POS, GE or SRP Topology Fiber layout 71 Topology (Metro) Point-to-point Hub and spoke or ring topology POS or GE Ring SRP 72

37 Point-to-Point (Hub and Spoke) Backbone Backbone Backbone Routers POS/GE Access Routers Customer 73 Point-to-Point (Ring) POS/GE Backbone Router Access Router MAN Customer Backbone Router 74

38 Ring SRP Backbone Router MAN Backbone Router Access Router Customer 75 Agenda Overview Network Architecture Conclusion 76

39 Conclusion Services that will be deployed on the infrastructure Impact on the design parameters (e.g. reliability, restoration, bandwidth capacity, etc.) Existing network Designing for flexibility Minimize design complexity KISS 77 Discussion Q & A 78

40 Related Talks Session 3000 introduction to optical technology and components Session 3007 advance optical technology and concept Session 3003 deploying DWDM for delivery of lambda-based networks 79 Deployment and Design Issues of IP Over Optical Networks Course 80

41 Please Complete Your Evaluation Form Session 81 82