ECEN5553 Telecom Systems Dr. George Scheets ECEN5553 Telecom Systems Dr. George Scheets Week 10 Read [19] ""Evolution of Packet-Optical Integration in Backbone and Metropolitan High-Speed Networks" [20a] "Great Leaps of Light" [20b] "Breaking the Light Barrier" [21a] "Is the U.S. Stock Market Rigged" [21b] "The Multinational Study of Brain Tumors in Cell Phone Users' Heads" Exam #2: Covers Internet thru Fiber Optics 1 - 2 pages will be from Fall 2015 Exam #2 Next Time (Live & Local DL) No Later than 31 October (Remote DL)

The Legacy Phone System... 4 Wire to 2 Wire Conversion at Central Office Hybrids can cause some problems Singing (Cure: Attenuation) Echoes (Cure: Echo Canceler) Analog to Digital Conversion points also cause some problems CO Switch filters on analog voice lines, necessary to limit noise and interference on voice circuits, limit dial-up modem data speeds to about 33 Kbps Trend is to an all-digital system U.S. long haul POTS voice circuits use digital Time Division Multiplexing or VOIP

TDM 1 2 3 time 1 etc. One 8 bit time slot provided for each phone call every 1/8000th second. frequency 1 1/8000 second (192 Kbps) 24 bits in 2 3 time 1 etc.

Integrated Services Digital Network Copper Local Loop Copper Local Loop Fiber Optic Trunk CO CO Phone Phone 4 Wire 2 Wire ‘4 Wire’ 2 Wire 4 Wire Digital TDM 64 Kbps

PC Modems & POTS Band Pass Filter suppresses energy outside voice bandwidth (about 3,500 Hz) A/D Converter Twisted Pair Cable Band Pass Filter ≈ 3.5 KHz Sampler Fs = 8 KHz Code 8 bits/sample Quantize 256 levels 64 Kbps

PC Dial-Up Modems & POTS PC Bit Stream has a significant amount of energy outside 3.5 KHz filter BW. Modems squash the energy into the pass band of the filter (at a much reduced bit rate). A/D Converter Twisted Pair Cable PC Band Pass Filter ≈ 3.5 KHz) Sampler Fs = 8 KHz Code 8 bits/sample Quantize 256 levels 64 Kbps

PSTN Digital Hierarchy Now obsolete except for some T1 & T3 on Local Loops

North American Digital Hierarchy Obsolete... ...except for ‘last mile’ connectivity T1 byte interleaved, > T1 bit interleaved T1 Frame (Format for 1/8000th second) A 4 Wire T1 Connection: is Full Duplex (1.544 Mbps in two directions) Carriers often sell bandwidth in T1 & T3 chunks (& fractions thereof)

Digital Carriers North American T-Carrier ITU DS-0 64 Kbps T-1 1.544 Mbps 24 phone calls T-3 44.736 Mbps 28 T-1 ITU E-1 2.048 Mbps 30 phone calls

Switching Crosspoint Switches Used for Space Division Switching Key component of CO switches Time Slot Interchange Used for Time Division Switching CO switches perform Space Division Switching Any POTS switch handling TDM lines (such as a Tandem) performs Time & Space Division Switching

Switching Packet Switches Handle Statistically Multiplexed traffic Require Buffers May use Crosspoints or Busses to switch between input/output lines Cross Connects Under Network Control Long Term Trunk Switching Circuit Switching & TDM

Telephone Space Switching Version 1.0 Human Operator source: Salt Lake City Tribune

Telephone Space Switching Version 2.0 Mechanical Crosspoint Switch (a.k.a. Crossbar Switch) source: wikipedia.com & ebay.com

Telephone Space Switching Version 3.0 Transistorized Crosspoint Switch ←5ESS sources: english.turkcebilgi.com , porticus.org, & www.mrmartinweb.com

Telephone Space Switching V4.0 IP Routers & Gateways IP device to IP device → Straight VoIP IP device to PSTN phone → VoIP Provider (Such as Skype) → VoIP Gateway (Corporate owned Interface box) Server (IP PBX) → Provides PBX-like functionality Image source: http://t1town.com/voice-services/pbxip-pbx/

PSTN TDM The system was designed to move voice But can & does haul other traffic Bytes organized into frames 8,000 frames/second Phone call bytes occupy specified slots in each frame slots are byte sized T-1 has 24 slots per frame

Switching Example Two Phone calls Stillwater to Enid Tulsa to Stillwater

CO Connectivity Enid CO CO Tulsa 3 17 TO 6 3 Stillwater CO CO Hierarchical Direct Connect 2nd Route Minimum of two diverse routes out of Central Office.

2D Switching: The Animation To: Stillwater From: Stillwater 6 3 TSI Enid Enid TSI Crosspoint Tulsa Tulsa 3 TSI Watch this one From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

2D Switching: The Animation To: Stillwater From: Stillwater 6 3 TSI Enid Enid TSI Crosspoint Tulsa Tulsa 3 TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

2D Switching: The Animation To: Stillwater From: Stillwater 6 3 3 TSI Enid Enid 3 TSI Crosspoint Tulsa Tulsa 3 TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

2D Switching: The Animation To: Stillwater From: Stillwater 6 3 TSI Enid Enid 3 TSI Crosspoint Tulsa Tulsa TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

2D Switching: The Animation To: Stillwater From: Stillwater 6 TSI Enid Enid TSI Crosspoint Tulsa Tulsa TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

2D Switching: The Animation To: Stillwater From: Stillwater 6 3 TSI Enid Enid TSI Crosspoint Tulsa Tulsa 6 3 TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

2D Switching: The Animation To: Stillwater From: Stillwater 3 TSI Enid Enid 3 TSI Crosspoint Tulsa Tulsa 6 TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

2D Switching: The Animation To: Stillwater From: Stillwater 3 TSI Enid Enid 3 TSI Crosspoint Tulsa Tulsa TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

Crosspoint Switch: Time Slot 6 From: Stillwater Crosspoint Closed (On) Enid Crosspoint Open (Off) Tulsa Byte To: Stillwater To: Tulsa Enid

2D Switching: The Animation To: Stillwater From: Stillwater 6 TSI Enid Enid TSI Crosspoint Tulsa Tulsa TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

Simplified Central Office Switch Space Switch TDM deMux D/A Local Loops Echo Canceler Hybrid + A/D TDM Mux POTS Time & Space Switching Local Loops Space Switch TDM deMux D/A Echo Canceler Hybrid + A/D TDM Mux

Carrier Leased Line Network Trunks Leased Line Cross-Connect Carrier reserves BW from pool for our use. Cross-Connects assign N byte sized time slots 8,000 times/second = N*8*8000 bps.

Cross Connect: Same Innards To: Stillwater From: Stillwater 6 TSI Enid Enid TSI Crosspoint Tulsa Tulsa TSI From Stillwater (3) to Enid (17) From Tulsa (3) to Stillwater (6) From Stillwater (6) to Tulsa (3) From Enid (17) to Stillwater (3)

Packet Switch using Crosspoint Switching Input: Line 1 Crosspoint Closed (On) Line 2 Crosspoint Open (Off) Line 3 Packet Output: Line 1 Line 3 Line 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

Hybrid TDM Trunking (Potentially most efficient network) Fixed Rate TDM Switch Packet Switch 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.

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

Hybrid Network Trunks Leased Line Cross-Connect Byte Aware Fixed Rate Traffic: CSTDM bandwidth based on Peak Rates Bursty Traffic: Access lines aggregated onto higher load trunk. Packet Switch StatMux Trunks are CSTDM.

A Typical Hybrid POP Mixes all sorts of traffic onto the fiber... ...using Cross Connects & multiplexers Circuit Switching Time 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

Backhauling... Tulsa POP OKC POP 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 Dallas POP Backhauled Line Fiber in the ground Leased Line

Backhauling... Tulsa POP OKC POP 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 Dallas POP Backhauled Line Fiber in the ground Leased Line

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 TimeSpace Switch

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

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

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

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

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

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

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

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

Circuit Switch TDM Trunking (Eighties ‘Private Line’ Network Model Evolved into Hybrid Network) 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.

Circuit Switched TDM Network 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... ‘80’s Network Model. Evolved to Hybrid. POTS TimeSpace Switch

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

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.

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

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.

Packet Switched StatMux Network POP Fiber Fiber Mux Mux Routers Leased Lines & Local Connections 100% Internet Model Voice Switch Local Loops

Fiber Optic Cable SC 1 1/4 inch

100 m Fiber Cable Suppose need to move 2.5 Gbps binary bit stream 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 within + 25 GHz of center freq Fiber has 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

100 m RG-58 Coax Cable Suppose need to move 2.5 Gbps binary bit stream Would use square electrical pulses (lower freq EM waves) 90% of power is < 2.5 GHz 99% of power is < 25 GHz Coax has 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) To get 1 mwatt out at 2.4 GHz, need to inject 5.8 Gwatts High Frequency energy gets severely attenuated Can't move a 2.5 Gbps bit stream 100m over RG-58 coax

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

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

Elements of Optical Networks Fiber Ultra-pure Glass Typical Window absorbs ≈ 10% of light 2 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)

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

Fiber Span Example Assumptions: 1 mw in 0.2 db/Km 2.5 Gbps RCVR 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

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

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 a FOTS Receiver