POP's...

1. ECEN5553 Telecom SystemsDr. George Scheets Week 10Read [20] "All Optical Networking- Evolution, Benefits, Challenges"[21a] "The Great Spectrum Famine"[21b] "The Multinational Study of Brain Tumors in Cell Phone Users' Heads"[22a] "The Doctor Will See You Always"[22b] "Hospital Networks Take Key Role in Health Care"Exam #2 scheduled for 30 October – Local Remote DL no later than 6 November 1-1.5 pages off 2012 Exam #2 Covers Internet – Fiber, Readings [5] – [20]Term Paper 8 November (Local) 15 November (Remote DL)

2. POP's... • Customers can tie into Carrier's Network Here • Mix all sorts of traffic onto the fiber • Use either • Cross Connects to allocate trunk bandwidth via Circuit Switching & Time Division Multiplexing • Routers & Switches to allocate trunk bandwidth via Packet Switching and StatMux • Lambda Switches to allocate entire light waves via Circuit Switching • Or a mixture of these

3. Hybrid TDM Trunking(Potentially most efficient network) Fixed Rate TDM Switch PacketSwitch SONET OTN Bursty Data Fixed Rate traffic assigned sufficient bytes every 1/8000th second. Bursty Data Traffic is aggregated and StatMuxed onto a common fabric (such as Internet routers). Aggregate streams are TDM cross connected onto fiber.

4. Hybrid POP offers best potentialCarrying Capacity... Hybrid Carrying Capacity Cell Switch StatMux Packet Switch StatMux Circuit Switch TDM 0% Data 100% Data 100% TST 0% TST Offered Mix

5. A Typical Hybrid POP • Mixes all sorts of traffic onto the fiber... • ...using Cross Connects & multiplexers Circuit SwitchingTime Division Multiplexing • Fiber BW is dedicated to each service • May have other switches (Voice, Ethernet, Routers, SONET, OTN) • POP doesn’t have switch needed?Traffic is back-hauled to nearest switch.Trade-off: Fiber Bandwidth vs. Cost of more Switches

6. Backhauling... Tulsa POP OKCPOP If a OKC Customer wants an Ethernet connection & the nearest switch is in Tulsa, the carrier will cross connect the leased line to the Tulsa switch. Ethernet Switch Customer Switch Ethernet Trunk Backhauled Line Dallas POP Fiber in the ground Leased Line

7. Backhauling... Tulsa POP OKCPOP If a OKC Customer wants an Ethernet connection & the nearest switch is in Tulsa, the carrier will cross connect the leased line to the Tulsa switch. Ethernet Switch Customer Switch Ethernet Trunk Backhauled Line Dallas POP Fiber in the ground Leased Line

8. Hypothetical Hybrid POP Optical Switch Fiber 2.5, 10, 40 or 100 Gbps Fiber TD Mux TD Mux Cross Connects Leased Lines CO Trunks Internet Router Best Potential Carrying Capacity of any switched network. POTS TimeSpaceSwitch

9. Hypothetical Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch Will likely see... Through Traffic

10. Hypothetical Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch May see... Digitized TV

11. Hypothetical Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch May see... ISP Trunks

12. Hypothetical Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch Will likely see... ISP Local Connections

13. Hypothetical Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch Will likely see... Leased Lines

14. CO Connectivity CO TO CO TO CO CO Hierarchical Direct Connect 2nd Route Minimum of two diverse routes out of Central Office.

15. Hypothetical Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch May see... CO Direct Connections

16. Hypothetical Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch Will likely see... Tandem POTS Switch Traffic

17. Circuit Switch TDM Trunking(Eighties ‘Private Line’ Network Model) Fixed Rate Traffic TDM Switch Trunk Bursty Data Traffic Fixed Rate traffic assigned sufficient bytes every 1/8000th second. Bursty Data Traffic receives dedicated trunk BW based on peak input (line) rates.

18. Circuit Switched TDMNetwork POP Copper, RF, Fiber Copper, RF, Fiber Mux Mux Cross Connects Leased Lines CO Trunks No effort is made to aggregate bursty data leased line traffic onto fewer high speed packet switched StatMuxed trunks... POTS TimeSpaceSwitch ‘80’s Network Model. Evolved to Hybrid.

19. Hybrid POP Fiber Fiber Mux Mux Cross Connects Leased Lines CO Trunks Internet Router Best Potential Carrying Capacity of any switched network. POTS TimeSpaceSwitch ... which is done in a Hybrid network.

20. ATM StatMux Trunking(Tomorrow's Network Model? Nope.) Fixed Rate Traffic ATM Switch SONET OC-N Bursty Data Traffic Assumptions: Fixed Rate Traffic assigned to CBR VC's. CBR traffic gets near-TDM like service. Data Traffic is StatMuxed onto the remaining trunk BW.

21. Cell Switched StatMux Network POP SONET Fiber SONET Fiber Mux Mux ATM Switch Leased Lines CO Trunks Internet Router POTS TimeSpaceSwitch ATM Model

22. Packet Switch StatMux Trunking(Pure Internet Model) Fixed Rate Traffic Router SONET or OTN Bursty Data Traffic Assumptions: All Fixed Rate Traffic is packetized. All traffic is Statistically Multiplexed onto the trunk BW.

23. Packet Switched StatMux Network POP Fiber Fiber Mux Mux Routers Leased Lines & Local Connections VoiceSwitch 100% Internet Model Local Loops

24. Fiber Optic Cable 1 1/4 inch SC

25. 100 m Fiber Cable Suppose need to move OC-48 (2.5 Gbps) Would use light pulses (very hi freq EM waves) Energy centered up around 200,000 GHz 90% of power is within 2.5 GHz of center freq 99% of power is 25 GHz of center freq Wide Bandwidth → Loss same at all freqs 0.2 dB/Km loss → 0.02 dB loss over 100 m Power out = Power in * 0.9954 To get 1 mwatt out need 1.005 mwatt input

26. 100 m RG-58 Coax Cable Suppose need to move OC-48 (2.5 Gbps) Would use square electrical pulses (lower freq EM wave) 90% of power is < 2.5 GHz 99% of power is < 25 GHz Narrow Bandwidth → Loss not same at all freqs At 0 Hz, suppose 0 dB loss over 100 m Power out = Power in * 1 At 2.4 GHz, loss = 38.9 dB/100 feet(38.9 db/100 ft)(328.1 ft/100m) = 127.6 dB Power out = Power in * 173.7(10-15) Crude Average = 63.8 db loss over 100m Power out = Power in * 416.9(10-9) To get 1 mwatt out need 2.4 Kwatt in

27. Mechanical Fiber Splice • Corning CamSplice • Strip & Cleave Fibers • Insert until they touch • Twist cams until secure • Claims 3% - 7% Signal Loss • Short Haul splicing source: www.corningcablesystems.com

28. Fusion Fiber Splice • Automatically Aligns fibers • Electrically fuses • Claims < 1% Signal Loss • Long Haul splicing source: www.corningcablesystems.com

29. Elements of Optical Networks • Fiber • Ultra-pure GlassTypical Window absorbs ≈ 10% of light2 Km of typical fiber absorbs ≈ 10% of light • Core/Cladding Boundary will totally reflect light from Core hitting at shallow angles • Bending limitations for fiber cables • Multi-Mode Fiber used on short hauls (LAN’s) • Single-Mode Fiber used on long hauls (WAN’s)

30. Elements of Optical Networks • Erbium Doped Fiber Amplifier (EDFA) • All optical amplifiers. Boost signal power. • Add some noise to the signal in the process • Regenerative Repeaters (Regens) • Cleans up optical signal and restores timing at the cost of occasional bit errors • Requires Optical-Electronic-Optical (OEO) conversion • Basically a Fiber Optic Receiver (photo & bit detector) and Laser Transmitter stuck back-to-back

31. Fiber Span Example • Assumptions: 1 mw in0.2 db/Km2.5 GbpsRCVR Single Sample Bit Detector • 200 km → P(Bit Error) ≈ 50(10-9) • EDFA midway between XMTR & RCVR→ 300 km has about same P(BE)→ 200 km has P(BE) ≈ 0.0

32. Fiber Optic Transmission Systems • Short Haul • FOTS Transmitter... • ...connected to fiber... • ...connected to a FOTS Receiver. • Medium Haul • FOTS Transmitter connected to a fiber... • ....connected to an EDFA followed by fiber...(1 or more times) • ...connected to a FOTS Receiver

33. Fiber Optic Transmission Systems • Long Haul • FOTS Transmitter connected to a fiber... • ....connected to an EDFA followed by fiber...(1 or more times) • ...connected to a Regen followed by fiber... • (EDFA & Regen combo repeated 1 or more times) • ....connected to an EDFA followed by fiber...(1 or more times) • ...connected to a FOTS Receiver

34. SONET • Optical Signal Standard (OSI Level 1) • Optical Carrier - N (OC-N). Used on Fiber. • Electrical Standard (OSI Level 1 & 2) • Synchronous Transport Signal - N (STS-N) • Used internally in SONET hardware • STS-N signal is converted to OC-N signal at transmitter laser • Current technology requires optical-to-electrical (O-E-O) conversions at switches, hence STS protocol.

35. SONET Hierarchy • Basic Building Block: • 51.84 Mbps STS-1 • 8,000 frames/second • 810 bytes/frame, 36 bytes for OA&M • STS-N? • N byte interleaved STS-1 signals (TDM) • OC-1 51.84 MbpsOC-3 155.52 MbpsOC-12 622.08 MbpsOC-48 2.48832 GbpsOC-192 9.95328 GbpsOC-768 39.81312 Gbps

36. Leased Line Sizes • T1 1.5 Mbps • Fractional T3 (T1 increments) • T3 45 Mbps • OC-1 51.84 Mbps • OC-3 155.52 Mbps • OC-12 622.08 Mbps • OC-48 2.48832 Gbps • OC-192 9.95328 Gbps • OC-768 39.81312 Gbps At these speeds, customer might just lease a dark fiber strand, or wavelength.

37. SONET • Allows rapid fault recovery • Designed back in days when voice dominated. • Voice traffic tends to be geographically localized. • Web traffic geographically dispersed. • SONET Ring Architectures (50 msec recovery) have limited circumferences. Not so hot for web traffic. • SDH Synchronous Digital HierarchyITU version of SONETBasic building block is 155.52 Mbps • OTN ≈ SONET V2.0 • Designed for today where bursty traffic dominates • Uses packet switching

38. Many Ethernet Physical Layer Standards Exist source: "Evolution of Ethernet Standards in the IEEE 802.3 Working Group", IEEE Communications Magazine, August 2013

39. Traffic Growth • It’s becoming expensive to continually increase fiber line speeds • OC-768 (40 Gbps) fastest SONET currently available • OTU4 (111.8 Gbps) fastest OTN currently available • 104.8 Gbps usable • Cheaper to multiplex slower speed TDM signals onto the fiber • Take SONET OC-48’s, 192’s, or 768's... • ...driving lasers tuned to different frequencies... • ...shoot everything down one fiber. Result = WDM (OSI Layer 1) • As of 2013, gear is available to WDM up to 10 Tbps on a single strand

40. Fiber Capacity Growth Source: High-Capacity Optical Transport Networks, IEEE Communications, November 2012

41. Modulation • Up to 10 Gbps, typically OOASK • On-Off Amplitude Shift Keying • Detecting presence or absence of a light pulse • 40 Gbps, starting to see phase modulation • Differential Phase Shift Keying (DPSK) • Better BER than straight OOASK • 100 Gbps, starting to see Coherent Detection • More sophisticated, better BER than DPSK

42. Different channels use some of the frequency all of the time. FDM frequency f1 f2 f3 f4 OC-192 OC-192 OC-192 OC-192 time

43. FDM over fiber is called Wavelength Division Multiplexing. WDM frequency f1 f2 f3 f4 OC-192 OC-192 OC-192 OC-192 time

44. Zoom in on one laser frequency band, and you’ll either see TDM or Statmux. One λ frequency band f1 1 2 3 time 4 etc.

45. Early 90's… Laser @ f1 Detector STS-12 STS-12 OC-12 Fiber in the ground

46. WDM: 32 OC-768’s (1.274 Tbps) #1 STS-768 #1 STS-768 Laser @ f1 Detector #1 Laser @ f2 Detector #2 #2 STS-768 #2 STS-768 Fiber in the ground #32 STS-768 Laser @ f32 Detector #32 #32 STS-768 Optical Combiner Optical Splitter Systems are also available that can map an arbitrary input (doesn’t have to be SONET or OTN based) onto an optical wave.

47. Design Dilemma: Revisited Average Delay Average Offered Trunk Load Bandwidth Glut - WDM is keeping this option alive Keep Trunks Lightly Loaded Use simple Routers/Switches (FIFO) All StatMux traffic has low delays.

48. Design Dilemma: Revisited Low Priority Average Delay Average High Priority Bandwidth Crunch Keep Trunks Heavily Loaded Use complex Routers/Switches Prioritize Traffic High Priority Delays identical to BW Glut. Offered Trunk Load

49. Two main types of protection • Line Protection • all traffic on inop line treated as indivisible lump and routed around break • Path Protection • all affected end-to-end connections are individually rerouted • Line Protection is faster • Path Protection uses less resources

50. Line Switched RingAffected traffic treated as indivisible entity. OKC TUL 1+2 1+2 2+4+5 3 3 2+4+5 X 5+6 NYC DET 5+6