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North American Digital Hierarchy

ECEN5553 Telecom Systems Dr. George Scheets Week 10 [21] "Evolution of Packet-Optical Integration …" [ 22] "All Smart, No Phone" No Class Friday (Fall Break) Exam #2 31 October – Local No later than 7 November – Remote DL Term Paper 7 November – Local 14 November – Remote DL.

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North American Digital Hierarchy

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  1. ECEN5553 Telecom SystemsDr. George Scheets Week 10[21] "Evolution of Packet-Optical Integration…"[22] "All Smart, No Phone"No Class Friday (Fall Break)Exam #2 31 October – Local No later than 7 November – Remote DLTerm Paper 7 November – Local 14 November – Remote DL

  2. 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)

  3. Digital Carriers • North American T-Carrier • 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

  4. 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

  5. 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

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

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

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

  9. 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/

  10. 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

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

  12. 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)

  13. 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)

  14. 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)

  15. 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)

  16. 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)

  17. 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)

  18. 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)

  19. 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)

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

  21. 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)

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

  23. 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.

  24. 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

  25. 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

  26. 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.

  27. 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

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

  29. 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

  30. 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

  31. 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

  32. 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

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

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

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

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

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

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

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

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

  41. Circuit Switch TDM Trunking(Eighties ‘Private Line’ Network ModelEvolved 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.

  42. 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.

  43. 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.

  44. 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.

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

  46. 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.

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

  48. Fiber Optic Cable 1 1/4 inch SC

  49. 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

  50. 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

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