PMMK Slides Combined Fall 2024 PDF Protocols for Multimedia Communications

Fall Term 2024, Department of Informatics IfI, University of Zürich UZH, Switzerland Protocols for Multimedia Communications (Protokolle für Multimediakommunikation, PMMK) Prof. Dr. Burkhard Stiller Communication...

Fall Term 2024, Department of Informatics IfI, University of Zürich UZH, Switzerland Protocols for Multimedia Communications (Protokolle für Multimediakommunikation, PMMK) Prof. Dr. Burkhard Stiller Communication Systems Group CSG Department of Informatics IfI, University of Zürich UZH Binzmühlestrasse 14, CH-8050 Zürich, Switzerland Phone: +41 44 635 6710, FAX: +41 44 635 6809 E-Mail: [email protected] Assistants: Daria Schumm, Weijie Niu Phone: +41 44 635 [4337¦7585], FAX: +41 44 635 6809 E-Mail: [schumm¦niu]@ifi.uzh.ch © 2024 Burkhard Stiller M00-1  Protocols and Multimedia  Means to bridge physical distances in support of multiple application requirements – Networks with service offerings – Protocols to extend such services – Internet-based applications © 2024 Burkhard Stiller M00-2  Lecture Outline (Plan)  Chapter 1 Telecommunications  Chapter 2 High Speed Networks (HSN)  Chapter 3 High-speed Optical Networks certain  Chapter 4 Passive Optical Networks  Chapter 5 ATM and ADSL  Chapter 6 IP Technology and MPLS  Chapter 7 QoS Basics and Modeling  Chapter 8 QoS Methods  Chapter 9 (QoS) Monitoring may still see updates  Chapter 10 Operations Management  Chapter 11 Transport Protocols  Chapter 12 Messaging and Overlays  Chapter 13 Optimized Transport  Chapter 14 Software-defined Networks (SDN) © 2024 Burkhard Stiller M00-3  Overview of Lecture (Chapter Dependency) Chapter 13: Chapter 14: Chapter 12: Optimized Transport Software-defined Networks Operations Management Chapter 10: Chapter 11: Transport Protocols Messaging and Overlays Chapter 7: QoS Basics and Modeling Chapter 8: Chapter 9: QoS Methods (QoS) Monitoring Chapter 6: IP Technology and MPLS Chapter 2: Chapter 3: Chapter 4: Chapter 5: High Speed High-speed Optical Passive Optical ATM and ADSL Networks Networks Networks Chapter 1: Telecommunications © 2024 Burkhard Stiller M00-4  Teaching Aids (1) Selected refs collected at module ends. Detailed studies of important aspects in Journal, conference, or workshop papers: IEEE Network Magazine ACM Computer Communication Review (includes SIGCOM) IEEE Communications Computer Communications IEEE Journal on Selected Areas in Communications IEEE Computer Computer Networks (formerly: Computer and ISDN Systems) IEEE Infocom and IEEE Globecom Recommendations (ITU-T) and Standards (ISO) Request for Comments (RFC) http://portal.acm.org/ http://ieeexplore.ieee.org/ http://www.ietf.org/rfc/ © 2024 Burkhard Stiller M00-5  Teaching Aids (2)  Basics and background information available within Textbooks and selected chapters – Jenq-Neng Hwang: Multimedia Networking: From Theory to Practice; 2009, Cambridge University Press, England, U.K., ISBN 978-0-521-88204-0. – B. Stiller: Quality-of-Service; 1996, International Thomson Publishing, Bonn, Germany, ISBN 3 – 8266 – 0171 – 8 – S. Keshav: An Engineering Approach to Computer Networking; 1997, Addison-Wesley, Reading, Massachusetts, U.S.A., ISBN 0 – 201 – 63442 – 2. – J. Walrand, P. Varaiya: High-performance Communication Networks; 2nd Edition, 2000, Morgan Kaufmann, San Francisco, California, U.S.A., ISBN 1 – 55680 – 574 – 6 – J. Sterbenz, J. Touch: High-Speed Networking (NC): A Systematic Approach to High- bandwidth Low-latency Communication, Wiley Networking Council Series, 2001 – R. Steinmetz, K. Nahrstedt: Multimedia: Computing, Communications, and Applications: Media Coding and Content Processing; 2002, Prentice Hall, New York, U.S.A., ISBN 0 – 13 – 031399 – 8.  Each part of the lecture carries a set of related references, either as overviews or as refinements and details (still under development) © 2024 Burkhard Stiller M00-6  Exercises, Organizational Issues, On-line Information  Theoretical exercises (paper-based) on a per student basis Background questions, reflecting the lecture content Knowledge questions, small tasks – Rules on passing the classes exercise sessions Submit in due time adequate solutions for at least 10 out of the 12 exercises Attend in at least 10 out of the 12 exercise sessions Present actively solutions or answers, when requested randomly during these exercise sessions, while being present – https://www.csg.uzh.ch/csg/en/teaching/HS23/pmmk/exercises.html  Lectures: Wednesday Exercises: Wednesday – Time: 8.15 – 9.45 hours Time: 10.00 – 11.30 hours  https://www.csg.uzh.ch/csg/en/teaching/HS24/pmmk.html – In case of questions, concerns, help, or ideas concerning the lecture please contact (see cover slide for contact details) – Prof. Dr. Burkhard Stiller and/or Daria Schumm and Weijie Niu © 2024 Burkhard Stiller M00-7  Key Question of the Lecture  How are multimedia (or demanding) applications and scenarios (all viewed separately and by being combined) supported sufficiently and operated successfully by (1) a corresponding communication architecture, (2) existing network/multiple networks, and (3) “suitable” communication protocols? – The different facets of the answer will be found while taking a look into Application Requirements and Telecommunications (Chapter 1) Multimedia and Communication Architectures (Chapter 2), Network Technologies (Chapters 3 to 6) Quality-of-Service Models and Mechanisms (Chapters 7 to 9) Protocols for Operations of Multimedia Communications (Chapters 10 to 14) © 2024 Burkhard Stiller M00-8  Chapter 1: Telecommunications © 2024 Burkhard Stiller M01-1  Content  Topics – Telecommunications – Transmissions – Basic Application Classifications – Application Characteristics – Example Systems – Multimedia  Objectives – To describe the major basis of communications – To discuss the wide variety of applications and their major classification – To explain how media are “combined” – To define multimedia (applications and systems) © 2024 Burkhard Stiller M01-2  Telecommunication  Communication: The method to call, contact, shout, yell, or alarm somebody. – Traditionally, using voice, letters, or drawings expressing abstract ideas in a negotiated language (natural language). – Face-to-face communication or some postal provider offer a communication service (still human-to-human).  Telecommunication: The method to call, contact, phone, or ring somebody or some machine, which is supported technologically. – Tele: (Greek) distant or remote. – Combination of telecommunication and computers is powerful to combine local processing power with distributed usage at remote places (already human-to- machine). © 2024 Burkhard Stiller M01-3  Information, Data, and Message  Information is defined as the knowledge of subjects, topics, activities, opinions, issues, devices – Informal definitions, a collection of contents.  Data are characters or continuous functions which represent information to be processed in a well-defined manner (DIN 44300) – Verarbeitung. – Digital data are coded in discrete characters. – Analog data are represented by continuous functions.  Messages are information in digital representation (data) to be used for transmission – Übermittlung. – The structure of messages and its exchange rules are defined in communication protocols. © 2024 Burkhard Stiller M01-4  Inventions in Telecommunications X DWDM optical fiber 3,2 Tbit/s 1012 X Monomode optical fiber 16 Gbit/s X 1011 Multimode optical fiber 140 Mbit/s X Monomode optical fiber 565 Mbit/s X 1010 Multimode optical fiber 45 Mbit/s 109 X 108000 voice channels over cable X 32000 voice channels over cable 108 X 3600 voice channels over cable and microwave 107 X 1800 voice channels over cable and microwave 106 X 600 voice channels over cable (T3) and microwave 105 X 60 voice channels over coaxial cable 104 X Carrier telephony carries 12 voice channels on wire Years: 2002-2020: X First carrier telephony - Flattening effect for channels 103 -> Longer distances X First telephone channels constructed - WDM focus here: 102 - 2009: 155x15 Tbit/s 90 km x Baudot multiplex telegraph (6 machines on one line) - 2010: 432x69 Tbit/s 240 km 10 X Printing telegraph systems - 2011: 370x101 Tbit/s 165 km X Early telegraphy (Morse code dots and dashes) - 2011: 336x26 Tbit/s 50 km 1 X Oscillating needle telegraph experiments - 2017: 28x11 Tbit/s 250 km Bandwidth - 2020: 160x39 Tbit/s 76 km 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2001 bit/s Year © 2024 Burkhard Stiller M01-5  Transmission Media 2 Copper 10 (Coaxial) Attenuation Copper [dB/km] (UTP) Fiber (Gradient) Fiber 10 1 (Multimode) Fiber (Monomode) 10 0 0 1 2 3 Frequency 10 10 10 10 [MHz]  Especially, fiber optical media – Low error rates, long distances, low attenuation © 2024 Burkhard Stiller M01-6  Applications – Traditional and Advanced  Well-known and regularly used applications – Analog data communicating applications Telegraphy since 1850s Phone (invention 1879, establishment in Germany 1882) Television since 1950s – Digital data communicating applications (since early 1960s): File Transfer Protocol (FTP), Terminal emulation (telnet), … FAX (early 1980s)  “Demanding” applications – Digitized analog applications: video/audio broadcasting, streaming, picture phone, HDTV, conferencing – Digital applications per se: network management, secure messaging, virtual reality, and local gaming  Distributed applications – Collaborative desktop (CSCW) – CAx (x = Design, Manufacturing, Training, or Education) © 2024 Burkhard Stiller M01-7  High Performance Applications Delay  “Standard” Disk – Small volumes File Backups of data and high LAN Transfer – High delays Interconnection HDTV “Megabit” Networking Gigabit  “Emerging” Multimedia Networking Teleconferencing Remote – Medium volumes Visualization of data and – Medium delays Supercomputer Distributed Networking Virtual Computing Reality low RPC  “Gigabit” – High volumes of data and – Low delays small high Volume of Data © 2024 Burkhard Stiller M01-8  Conventional Classification of Data Timing/space dimension Continuous Audio Video Animation Discrete Still images Text Graphics Captured Synthesized Origin dimension Temporal vs. spatial dimensions: 2D images and 3D holography. © 2024 Burkhard Stiller M01-9  Text Variants  Plain text  Rich text – Unformatted – Formatted – Characters coded in binary form – Contains various format information – ASCII code besides pure codes of characters – All characters have same style and font – No predominant standards – Characters of various size, shape and style, e.g., bold, colorful © 2024 Burkhard Stiller M01-10  Graphics  Revisable document that retains structural information  Consists of objects such as lines, curves, and circles  Usually generated by graphical editor of computer programs © 2024 Burkhard Stiller M01-11  Still Images  A non-revisable document  Document format is unaware of any structural information  Semantic content is not preserved  Described as bitmaps formed of individual pixels – Monochrome image – pixel depth 1 bit – Gray-scale – pixel depth 8 bit – Color image High color – pixel depth 15/16 bit True color – pixel depth 24 bit Deep color – pixel depth 30/36/48 bit  1 bit = 2 colors, 8 bit = 256 colors, 24 bit = 16,277,216 colors © 2024 Burkhard Stiller M01-12  Video and Animation  Both type of images and graphics can be displayed as a successive view, which creates an impression of a movement  Video: Moving images or moving pictures – Captured or synthesized – Consists of a series of bitmap images – Each image is called a frame – Frame rate: the speed to playback the video (frame per second)  Animation: Moving graphics – Typically generated by computer program (animation authoring tools) – Consists of a set of objects – Movements of objects are calculated and the view is updated at playback time – No “frame rate” defined © 2024 Burkhard Stiller M01-13  TV Format Examples  Throughput TV: Television SD: Standard Definition – Video in digital formats: NTSC (National Television Systems Committee) PAL (Phase Alternating Line) HDTV (High Definition Television) UHDTV (Ultra High Definition Television) or “4k”/”8k” https://en.wikipedia.org/wiki/Ultra-high-definition_television – Scan/row x visible rows x bit/scan x frames/sec = data rate Name Bandwidth Requirements Frame Rate Resolution NTSC  90 Mbit/s (30 frames/s) 720 pixels NTSC with compression  3 … 6 Mbit/s PAL  95 Mbit/s (25 frames/s) 720 pixels HDTV  1,152 Gbit/s (60 frames/s) 1080 pixels HDTV with compression  25 … 34 Mbit/s UHDTV with compression  20-40 Mbit/s (50...120 frames/se) 3840 pixels UHDTV-2 uncompressed  144 Gbit/s (120 frames/s == Hz) 7680 pixels © 2024 Burkhard Stiller M01-14  Video File Formats  AVI (Audio Video Interleave) and WMV (Windows Media Video) – Long running digital video workhorse (Microsoft), smaller compression, limited  MOV or QT (QuickTime) – Supporting a wide range of codecs (Apple), cross-platform (PC, Apple)  AVCHD (Advanced Video Coding, High Definition) – Data compressed with H.264 codec (Panasonic and Sony)  MPEG (Motion Pictures Expert Group) – Integrates MPEG-1 and MPEG-2 video and audio compression  MP4 (MPEG-4 Video File) – Video and audio tracks are compressed separately (Web)  H.264 (ITU-T Recommendation – Standard) 16:9 resolutions in comparison [Wikipedia] – Standard for high definition digital video (MOV, AVC, AVCHD, MPEG, Divx)  H.265 or High Efficiency Video Coding (HEVC) – Stream full 1080p HD video (vertical resolution) – Streaming 4k (horizontal resolution in pixels) ≈ 20 Mbit/s © 2024 Burkhard Stiller M01-15  Audio  One-dimensional time-based signal  Speech vs. non-speech sound – Speech supports spoken language and has a semantic content – Non-speech does not convey semantics in general  Natural vs. structured sound – Natural sound is recorded – Generated sound is artificial – All represented as wave in digital signal Example: Audio in CD, WAV files – Structured sound conforms to a synthesized sound in a symbolic way Example: MIDI file © 2024 Burkhard Stiller M01-16  Audio Examples  Throughput – Audio in digital formats Telephone quality (Pulse Code Modulation, PCM) – 8,000 sample/s x 8 bit/sample = 64 kbit/s Compact Disk (CD) stereo quality – 44,100 sample/s x16 bit/sample x 2 = 1.4112 Mbit/s – Compression techniques Telephone standard G.711 with 32 kbit/s – More advanced techniques compress up to 4 kbit/s CD MUSICAM standard (MPEG) with 192 kbit/s – Studio quality needs 384 kbit/s  Delay – One-way (unidirectional) versus interactive (bidirectional) © 2024 Burkhard Stiller M01-17  Audio File Formats  High-resolution audio – No single standard – Formal definition as “Lossless audio that is capable of reproducing the full range of sound from recordings that have been mastered from better than CD quality music sources” – Typical sampling frequencies of 96 kHz or 192 kHz at 24 bit 88.2 kHz or 176.4 kHz https://www.whathifi.com/advice/high-resolution-audio-everything-you-need-to-know © 2024 Burkhard Stiller M01-18  Overview of Sample Application Data Bit Throughput Error Delay Jitter Rate Text (A4 page) 50 kbit/s < 10-5 1 - 10 s - Data some 10 Mbit/s 0 128 lasers at 10 Gbit/s > 1 Tbit/s (= 1.000.000.000.000 bits/s) * “Dense” WDM: More than 10 lasers used simultaneously. Today: WDM usually means dense WDM. © 2024 Burkhard Stiller M03-32  Protocol Transparency of WDM  Wavelengths (s) do not interfere  Each i can carry a different protocol at up to 10Gbit/s: Massive Capacity Expansion of installed fibers! IP IP SDH SDH Optical Fiber ATM ATM GE GE Optical Optical Coupler Coupler GE: Gigabit Ethernet Real-life Examples: http://www.convergedigest.com/search/label/Submarine%20Cable © 2024 Burkhard Stiller M03-33  Fixed WDM Multi-point Network  Optical Add/Drop Multiplexer selectively extracts is from the fiber using a static configuration Fiber Fiber Optical Add/Drop MUX Fiber Fiber  Allows to build a virtual topology for each i on top of a physical network © 2024 Burkhard Stiller M03-34  Re-configurable WDM Multi-point Network  Optical switches and cross-connects allow for a dynamic reconfiguration of virtual topologies Fiber Fiber Fiber Fiber Optical XC  Optical switching today is too slow to be used for data switching © 2024 Burkhard Stiller M03-35  Chapter 4: Passive Optical Networks (PON) © 2024 Burkhard Stiller M04-1  Content  Topics – Broadband Forum, residential access case, and Fiber-to-the-Home (FTTH) – PONs as fiber optical passive networks Devices and communications Standards and variants G-PON (Gigabit PON) as an access network – QoS (Quality-of-Service), queueing, multicast Applications Benefits and limitations  Objectives – To overview a technological instance of a broadband residential access network – To describe PON’s basics and key characteristics and their variants – To explain how G-PON is used as an access network’s service delivery platform © 2024 Burkhard Stiller M04-2  Broadband Communications  “The Broadband Forum is the central organization driving broadband solutions and empowering converged packet networks worldwide to better meet the needs of vendors, service providers and their customers.” http://www.broadband-forum.org  Addresses the development of multi-service broadband packet networking specifications wrt interoperability, architecture, and management to enable home, business, and converged broadband services, encompassing customer, access and backbone networks  Especially Broadband Network Layer – Goal: To establish network architecture specifications to support current and emerging services and applications – Focus: To deliver access, aggregation, and core specifications providing inherent interoperability, quality, scalability, and resiliency capabilities from end-to-end © 2024 Burkhard Stiller M04-3  Increasing Demand for Bandwidth  More applications everyday lead to more broadband users and more bandwidth per user and vice versa!  Applications http://www.broadband-forum.org – IPTV – Libraries – Photos – Videos – Radios – VoIP – Presence – Gaming – Blogging – Messaging – Metering – Health – Clouds … © 2024 Burkhard Stiller M04-4  Developing Residential Access Demand  Today’s residential access networks ( later chapter) reach limits – ADSL at either data rates or distances  Need for “cheap” and operationally efficient and longer distances- spanning networks with higher speeds – PON and G-PON (Gigabit PON) ADSL: Asymmetric Digital Subscriber Line, VDSL: Very High Data Rate DSL VoD: Video-on-Demand, HDTV: High Definition TV, TV: Television Based on Telecoms Consult, E. Saniard © 2024 Burkhard Stiller M04-5  Fiber-to-the-Home (FTTH)  Fiber optics architecture with fiber deployment to the home – Technology allows telephone, cable TV, high-speed Internet accessed via one fiber OLT: Optical Line Terminal Head-end is interfaced to PSTN ONU: Optical Network Unit PSTN: Public Switched Telephony Network Video services enter from Cable Television (CATV) head or a satellite feed Internet data feed provided by ISP – All signals are combined onto a single fiber using WDM and transmitted to end users via passive optical splitters – At home, optical signals converted into electrical signals using Optical Electrical Converters (OEC), splitting the signal into respective ports – Provisioning of high bandwidth services and content to customers w/o restrictions – Network architecture design remain flexible wrt fiber infrastructure (“churn”) – Fiber connectivity to each subscriber directly via serving equipment, avoiding intermediate active equipment inside the network, thus, Passive Optical Networks form an underlying FTTH network technology © 2024 Burkhard Stiller M04-6  PON Characterization  Passive Optical Network (PON)  Fiber-optic network  Passive fiber and splitting/combining components – “Unpowered” cables, plugs, sleeves, or splitters – Simultaneously transmitting signals in upstream and downstream directions – To and from user endpoints – No cooling or other ongoing maintenance activities  Topology and components – Broadband Point-to-Multipoint (PTMP) topology Based on standardization in 1998 of the ATM-PON G.983.1 specification – Single transmission point to multiple user endpoints – Passive optical splitters divide bandwidth between multiple user end-points  User endpoints – Electrical power required to send and receive signals  PON efficiently operable: low power demands, low cost © 2024 Burkhard Stiller M04-7  PON Devices and Example Topology  End user devices  Network devices – OLT: Optical Line Terminal – ODN: Optical Distribution Network – ONT: Optical Network Terminal – POS: Passive Optical Splitter or ONU: Optical Network Unit Based on Telecoms Consult, E. Saniard © 2024 Burkhard Stiller M04-8  PON Network Architecture – Comparison  Traditional network hierarchy  PON hierarchy – Core = Data Center – Core = OLT – Aggregation = Building Distribution – Aggregation = Splitter – Access = Network Cabinet – Access = ONT – User devices – User devices Core Core Aggregation Access Aggregation Access User Devices User Devices Based on: https://www.bicsi.org/uploadedfiles/PDFs/conference/2019/canada/GS_TUES_3.pdf © 2024 Burkhard Stiller M04-9  PON Devices in Detail (1) End-user devices – OLTs or ONUs https://carrier.huawei.com/en/products/fixed-  network/access/olt/smart-ng-olt-ma5800 – Starts the PON and is connected to a core switch through Ethernet pluggables – To convert frames and transmit signals for the PON network – To coordinate ONT multiplexing for shared upstream transmission – Signals on the feeder fiber split up to 256 users with one ONU  Terminology – ITU-T: ONT Example OLT: 5800-X17 – IEEE: ONU – Effectively interchangeable depending on PON service and standard products/fiber-ont/ https://www.nokia.com/networks/  Network devices – ONT Example ONT: Media Converter – Powered device of the PON at opposite (user) end of the network – Includes Ethernet ports for in home devices or network connectivity – ONTs convert signals and provide users with internet access Downstream OLT signal is divided or split before reaching the end user Defined as the “splitter ratio” or “split ratio”, e.g., 1:32 or 1:64 © 2024 Burkhard Stiller M04-10  PON Devices in Detail (2) https://www.fiberplcsplitter.com/sale-3213405-pon-lan- Splitters rack-mount-fiber-plc-splitter-1x2-1x4-1x8-1x16-1x32-  – PLC Splitters (Planar Lightwave Circuit) – FBT Splitters (Fused Biconical) – Attenuation of light through optical splitters is symmetrical Example LAN Rack Mount Fiber Plc Splitter  Advantages – Cost-effective – Contain no electronics, therefore, use no power – Replacing copper cables with smaller single-mode fiber optic cable 1x64.html  Drawbacks – Difficulties to locate problems – Bad splices and fiber damage cost-intense to repair – Dust, dirt, damaged connectors increase Return Loss (RL) and Insertion Loss (IL) – Macro-bends only detectable via tests (optical signals tested at 2 wavelengths on the optical fiber, especially 1,310 nm and 1,550 nm or 1,625 nm) © 2024 Burkhard Stiller M04-11  Attenuation of Optical Splitters  Example Attenuation 1:2 splitter: 3 dB Attenuation 1:4 splitter: 6 dB Attenuation 1:8 splitter: 9 dB … Attenuation 1:64 splitter: 18 dB Attenuation 1:128 splitter: 21 dB  Power attenuation as gain or loss – dB = 10 * log (Power_in / Power_out)  Input attenuation (< 1 dB) – Σ Power_input – Σ Power_output-of-all-branches Note: The decibel (dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Based on Telecoms Consult, E. Saniard © 2024 Burkhard Stiller M04-12  PON Devices in Detail (3) Catalogues/EX_PON_Catalogue.pdf https://excel-networking.com/uploads/ https://www.commscope.com/product-type/  (Exterior) Splice Enclosures Example Exterior Splice Enclosures – Allow fiber optical cables to be spliced and housed – Hosting up to a couple hundred fibers – In-house – IP68-rated durable enclosure for “harsh” environment applications IP: International Protection (Class) 1st digit: Object protection against contact (6 is highest) 2nd digit: Water resistance (8 is highest) cabinets/fiber-entrance-cabinets/item760245548/ cabinets-panels-enclosures/frames-racks- Example ODF-SPLCAB-24  Universal Splice Cabinets – Flex Frame holder – Up to 6912 fiber splices capacity – Rollable ribbon cables © 2024 Burkhard Stiller M04-13  PON’s Basic Communication Principles  Applying WDM (Wavelength Division Mux.) ( earlier chapter) – To enable bidirectional communications across a single fiber  Handling upstream and downstream signals of multiple users simultaneously requires – Multiplexing (Mux)  Multiplexing mechanisms in use in ODN – Downstream direction (from sender to receivers: OLT  ONU or ONT at 1,490 nm) Data packets transmitted in a broadcast manner – All PONs only “repeat” the same input signal to all ONUs attached – Different ONUs select respective data for delivery to final destinations – Upstream direction (from receivers backward: ONU or ONT  OLT at 1,310 nm) Data packets transmitted via TDMA (Time Division Multiple Access) – All ONTs generate data in certain time slots (if needed) and sent them to ONUs – OLTs broadcast “TIME REFERENCE SIGNAL”, all ONUs with internal counter, and a defined offset to transmit © 2024 Burkhard Stiller M04-14  PON Standards’ Progress Based on Telecoms Consult presentation B: Broadband; G: Gigabit-capable; XG: 10G; NG: Next-Generation XGS: Extended Gigabit-capable Symmetrical (10G); NG-E: NG Ethernet ITU-T Study Group 15, Question 2 responsible for development of Recommendations in the area of “Optical systems for access networks”: http://www.itu.int/ITU-T/studygroups/com15/sg15-q2.html © 2024 Burkhard Stiller M04-15  Example Optical Access Network – Topology Based on Telecoms Consult, E. Saniard © 2024 Burkhard Stiller M04-16 Example Optical Access Network – Components Based on Telecoms Consult, E. Saniard © 2024 Burkhard Stiller M04-17  PON’s Wavelength Usage  All wavelengths in “nm” https://www.viavisolutions.com/en-us/passive-optical-network-pon Depending on source slightly varying numbers available. PON Type Downstream Upstream G-PON 1,490 nm … 1,550 nm 1,290 nm … 1,500 nm Product-specific XGS-PON 1,578 nm 1,270 nm variance ± 10 … 50 nm NG-PON2 1,598 nm … 1,603 nm 1,524 nm … 1,544 nm © 2024 Burkhard Stiller M04-18  PON Variants – G-PON (1)  G-PON – Gigabit-capable PON by ITU-T in G.984 Formally adopted March 10, 2009 – IP-based protocols – Large flexibility with respect to traffic types Including “triple-play” applications for voice, Internet, and TV – Generic G-PON encapsulation method Packages IP, Ethernet, VoIP, and other data types  G-PON de facto PON standard in use today – Networks covering distances of between 20 to 40 km over single-mode fiber Depending on split ratio adopted Downstream speed at 2.4 Gbit/s Upstream speed at 1.2 Gbit/s © 2024 Burkhard Stiller M04-19  PON Variants – G-PON (2)  G-PON services – Triple-play, TDM (Time Division Mux), and RF (Radio Frequency) overlay services – Due to fixed upstream/downstream frame structure, periodic multi-frames exist – TDM service with guaranteed QoS (Quality-of-Service) Including end-to-end delay, jitter, bit error rate – Option for RF Video overlay at wavelength of 1,550 nm  Network Management and Service provisioning (NMS) – G-PON NMS GUI (Graphical User Interface) – Configuration “Zero” configuration on terminals and plug-and-play of terminals – Maintenance – Troubleshooting – Seamless integration into an OSS environment with Northbound interfaces – ONU/ONT plug and play OSS: Operation Support System – Possible support of integrated OTDR (Optical Time-Domain Reflectometer) Testing scheme of non-functional, damaged, broken fiber optical cables © 2024 Burkhard Stiller M04-20  PON Variants – G-PON (3)  G-PON transmission schemes – Downstream (OLT  ONU) Point-to-multi-point broadcast Based on “GPON in FTTx Broadband Deployments”, MR-246, October 2010 to all ONUs at PHY layer ONUs only process data addressed to them Security addressed by AES (Advanced Encryption Standard) with 128-bit keys High bandwidth Low and deterministic trigger latency – Upstream (ONU  OLT) Multi-point-to-point TDMA Arbitrated by OLT Low and shared bandwidth Low busy latency and high dynamic range High payload © 2024 Burkhard Stiller M04-21  PON Variants – G-PON (4)  GEM (G-PON Encapsulation Method) – Encapsulates user frame data for transport over the GPON – Delineates user data frames inside GPON partitions Based on “GPON in FTTx Broadband Deployments”, MR-246, October 2010 – Identifies each frame as belonging to a connection / user / ONU – Permits fragmentation and reassembly  DBA (Dynamic Bandwidth Allocation) – Since not all users need all their peak bandwidth all the time dynamic bandwidth allocation optimizes usage of shared medium – DBA enables OLTs to assess bandwidth needs of ONUs in real time and allocates upstream PON capacity accordingly – Allows service providers to define flexible service options, oversubscription levels, and SLAs (Service Level Agreement) – DBA basic model supports Fixed bandwidth (highest priority) Assured bandwidth and non-assured bandwidth Best-effort bandwidth (lowest priority) and multiple weighted traffic classes © 2024 Burkhard Stiller M04-22  PON Variants – E-PON and 10G-EPON  E-PON – Ethernet PON based on the IEEE 802.3 standard – Developed for seamless compatibility with Ethernet devices – No additional encapsulation or conversion protocols needed to connect to Ethernet- based networks Identical for upstream and downstream data transfer directions  Conventional E-PON – Symmetrical speeds of up to 1.25 Gbits/s upstream and downstream – Ranges of between 20 to 40 km Depending on split ratio E-PON and G-PON cannot be deployed on the same PON (same wavelengths)  10G-EPON – Increases speeds to a symmetrical 10 Gbit/s upstream and downstream – Operating at different wavelengths to E-PON 1,577 nm downstream and 1,270 nm upstream Same PON to be used for both E-PON and 10G-EPON simultaneously © 2024 Burkhard Stiller M04-23  PON Variants – XG(S)-PON  XG-PON – 10G version of G-PON – Speeds of 10 Gbit/s downstream and 2.5 Gbit/s upstream – Physical fiber, data formatting conventions identical to the original G-PON – Wavelengths have shifted (like for 10G-EPON) to 1,577 nm for downstream and 1,270 nm for upstream – Enabling the same PON network to be used for both G-PON and XG-PON simultaneously  XGS-PON – Enhanced version of XG-PON – Same wavelengths as XG-PON – Symmetrical 10 Gbit/s both for upstream and downstream © 2024 Burkhard Stiller M04-24  PON Variants – NG-PON2  NG-PON2 – Is the beyond XG(S)-PON variant – Utilizes WDM with multiple 10G wavelengths Both upstream and downstream – Delivering a symmetrical 40 Gbit/s speed – Uses different wavelengths to G-PON and XG/XGS-PON to allow for service co- existence of all three on the same PON network  As speed demands are foreseen to continue to increase, XG-PON, XGS-PON and NG-PON2 provide an upgrade path – Benefits for large, multi-tenant, or business client settings – Becoming part of wireless 5G networks © 2024 Burkhard Stiller M04-25  G-PON in the Access Network https://www.broadband-forum.org/download/TR-156_Issue-4.pdf  Ethernet-based architectures – Became a global standard for triple-play deployments – Similar for residential and business customers using DSL (Digital Subscriber Line) as broadband access technology  Broadband Forum’s TR-101 architecture specifications are – Access agnostic https://www.broadband-forum.org/download/TR-101_Issue-2.pdf – Widely used today with other access technologies, especially FTTx / PON  Definition: T-CONT is a traffic-bearing object within an ONU that represents a group of logical connections, which is managed via the ONU Management and Control Channel (OMCC), and which is treated as a single entity for the purpose of upstream bandwidth assignment on the PON. © 2024 Burkhard Stiller M04-26  Network Architecture for Ethernet-based GPON Aggregation NSP: Network Service Provider; ASP: Application Service https://www.broadband-forum.org/download/TR-156_Issue-4.pdf Provider; BNG: Broadband Network Gateway; RG: Residential Gateway; L2TP: Layer Two Tunneling Protocol  G-PON now is now “in the role of” of the Access Node – Approach integrates seamlessly into broadband service providers’ deployments © 2024 Burkhard Stiller M04-27  G-PON QoS Architecture  Efficient use of bandwidth resources – Statistical multiplexing gain – Providing a forwarding class that can support low-latency flows – QoS mechanisms should allow for use of unutilized bandwidth among traffic classes  Network U and V interfaces as before are Ethernet-based – OLT-ONU G-PON link employs GEM protocol for the transport of services – GEM adaptation block performs mapping for transport of Ethernet over GPON – GEM also encapsulates other protocols  To provide QoS, two main mechanisms are employed – Classification of traffic – Forwarding resulting traffic classes into GEM ports  ONU may support Ethernet data service on U interface using Ethernet, DSL technology at PHY, also supports POTS, T1/E1, … © 2024 Burkhard Stiller M04-28  Upstream Queuing and Scheduling Model  Example of 4 T-CONTs on 1 PON interface, each representing a specific Traffic Class (TC) – Upstream traffic received from U interfaces mapped to queues according to the mapping rules using associated GEM ports – Other upstream traffic received by other ONTs is mapped to other sets of 4 T- CONTs according to the TC – At OLT level each TC is mapped into a separate queue – T-CONTs from various PON interfaces sharing the same TCs are mapped to the same queue, and a scheduler is used among the queues toward the network facing port © 2024 Burkhard Stiller M04-29  IGMP-controlled Multicast in G-PON  Unidirectional, multicast GEM ports allow distribution of multicast traffic from the OLT to all of the ONUs on a given ODN  GEM ports allocated for downstream-multicast flows are shared by all ONUs on that PON – Enables sending a single instance of the content downstream – Single GEM port transports its multicast groups to all ONUs – ONUs need to perform filtering at the MAC layer to only forward those groups required by its own U interfaces  Multicast GEM ports – See GPON AES encryption always disabled – Are always unidirectional Upstream control flows use existing bidirectional data GEM ports with the appropriate TC © 2024 Burkhard Stiller M04-30  G-PON-specific Multicast Requirements IGMP: Internet Group Management Protocol  Multicast traffic – Consists out of a set of multicast groups and downstream IGMP messages – Forwarded using one or more N:1 VLANs – Multicast traffic may be forwarded using one or more dedicated N:1 VLAN or may be inserted into one of the N:1 VLANs that are also used for unicast traffic IPTV content segregated into multiple N:1 VLANs facilitating access control.  Multicast optimization in the Access Node (OLT and ONU) – Uses IGMP snooping to control flooding of Ethernet multicast frames – Multicast GEM port is typically used to transport the multicast-VLAN traffic required by all ONUs © 2024 Burkhard Stiller M04-31  PON Applications (1)  PON is the “last mile” between the provider and user – Fiber-to-the-X (FTTX): “X” = home (FTTH), building (FTTB), premises (FTTP), depending on where the optical fiber is terminated – FTTH has been the main application for PON  Key characteristics – Reduced cabling infrastructure (no active elements) – Flexible media transmission attributes of passive optical networks  Ideal for residential, home Internet, voice, and video applications  New application: 5G fronthaul – Connection between baseband controller and remote radio head at cell site – Due to the bandwidth and latency demands imposed by 5G, utilizing PON networks to complete the fronthaul connections can reduce fiber count and improve efficiency without compromising performance – As source signal is split between users for FTTH here signal from baseband units can be distributed to an array of remote radio heads Based on https://www.viavisolutions.com/en-us/passive-optical-network-pon © 2024 Burkhard Stiller M04-32  PON Applications (2)  Additional applications well suited PON – College campuses and business environments – Advantages with respect to Speed Energy consumption Reliability Access distances – And cost of build/deployment and on-going operation  PON enables integration of campus functions and medium to large sized business complexes – Building management, security, and parking – Reduced dedicated equipment, cabling, and management systems Based on https://www.viavisolutions.com/en-us/passive-optical-network-pon © 2024 Burkhard Stiller M04-33  PON Benefits  Efficient use of Power Based on https://www. viavisolutions.com/en-us/ passive-optical-network-pon – No need for powering required for within the access network Less electrical components in the system, reduce maintenance requirements and less opportunities for powered equipment failures  Simplified infrastructure and ease of upgrade – Passive architecture eliminates the need for wiring closets, cooling infrastructure, or midspan electronics; optical fiber and splitter infrastructure remains constant Only endpoint devices (OLT, ONT, ONU) require upgrade or replacement  Efficient use of infrastructure – Various PON standards combined with services such as RF video overlay can coexist on the same PON to offer multiple services (triple play) on the same fiber  Ease of maintenance – Copper nets replaced by PONs vulnerable to electro-magnetic interference, noise – PON networks not susceptible to such interference and preserve signal integrity well over the planned distance – Caring about active devices (ONT, ONU, OLT) only on timing, signal transmission © 2024 Burkhard Stiller M04-34  PON Limitations Based on https://www.  PONs compared to active optical networks viavisolutions.com/en-us/ passive-optical-network-pon  Distance – Range for PON is limited to between 20 to 40 km – Active optical networks may reach up to 100 km  Passive components – Can cause signal loss (optical attenuation) in case of splicing errors or bend cables  Test access – Fiber optics troubleshooting challenging under some conditions Test access can be forgotten or ignored when designing a PON Test tools must allow in-service troubleshooting without disrupting services Tests can be performed with a portable or a centralized test solution using out- of-band wavelength, such as 1,650 nm, to avoid any clash with existing PON wavelengths. Test access must be gained from one or other endpoints at the OLT or ONT or a section of the PON must be taken out of service temporarily © 2024 Burkhard Stiller M04-35  PON Vulnerabilities  PTMP architecture leads to the feeder line and the OLT to service multiple end users (potentially up to 256) – No redundancy Based on https://www.viavisolutions.com/en-us/passive-optical-network-pon – In case of an accidental fiber cut or a faulty OLT, service disruptions extensive FCP: Fiber Concentration Point PTMP: Point-to-Multipoint (“Synonym” for PON) © 2024 Burkhard Stiller M04-36  And the Future? https://cdatatec.com/next-generation-pon-technology-war-25g-pon-vs-50g-pon/ © 2024 Burkhard Stiller M04-37  The Future Has Arrived … (One Example) TSP: Telecommunications and Signal Processing © 2024 Burkhard Stiller M04-38  Chapter 5: ATM and ADSL © 2024 Burkhard Stiller M05-1  Content  Topics – Packet sizes and cells – Broadband Integrated Services Digital Network (B-ISDN) – Asynchronous Transfer Mode (ATM) Layers, SAR, connections, switching, signaling – Asymmetric Digital Subscriber Loop (ADSL) Residential access based on DSL Overview, capabilities, modulation, architectures  Objectives – To understand the principles of an ATM networks’ operation – To discuss essential remainder AAL5 in today’s access networks – To discuss residential DSL-based access technologies for high(er)-speed access © 2024 Burkhard Stiller M05-2  Packets and Cells – Which Size to Use?  Traditionally, packets are the organizational unit of networks to transfer user data – User data split into packets: header (and trailer), data – Packet header and trailer stripped, data reassembled  In contrast, ATM utilizes cells at its lowest layer – Definition: A cell is a fixed-size, small packet  Important decision: What is the size of the cell ? – Effects on higher layer protocols – Ratio of control information and data per cell Large cells: More control tolerable Small cells: Less control necessary, less wasted space  There is no general perfect size of a cell available © 2024 Burkhard Stiller M05-3  Cell-based Switching  Operational goal: Service integrated networks shall support many kinds of application requirements simultaneously  Delay problems occur in case of sending packets of different length. Extremely long blocking can be avoided, if cells of fixed size are used. If the overall cell length is too big, a similar problem appears  Asynchronous Transfer Mode (ATM) is a concept for handling cells and dealing with cell-based switching independent of a particular physical network © 2024 Burkhard Stiller M05-4  Broadband Integrated Services Digital Network  Original target of a high performance, service integrated, and wide area network, was called Broadband-ISDN – Initially, Synchronous Transfer Mode (STM) approach Missing flexibility due to fixed bandwidth of 2 and 140 Mbit/s – Late 1987, Asynchronous Transfer Mode (ATM) adopted  High data rates – 155 Mbit/s, 622 Mbit/s, 2.4 Gbit/s, and up Following the SDH capacity hierarchy – Upward compatibility (support of 64 kbit/s channels) Usable in the LAN, MAN, and WAN environment  Separation of concerns – Data transfer – Signaling in terms of out-of-band control data © 2024 Burkhard Stiller M05-5  B-ISDN Standardization  International Telecommunication Union (ITU) – Formerly, CCITT and CCIR – Telecommunication Standardization Sector (ITU-T) Wide area communications, such as – Packet-based network (X.25) – B-ISDN (I.121, I.150, I.361, I.362, I.363, … ) – Broadband signaling (Q.2931) Radio Communication Standardization Sector (ITU-R)  ATM Forum (since fall 1991) – Industry, equipment development and marketing – Fast employment of ATM technology – Support of the ITU-T standardization process  ATM remained so far in place, but B-ISDN never existed – ATM AAL 5 (see later this chapter) used in xDSL technology (see later this chapter) © 2024 Burkhard Stiller M05-6  B-ISDN Reference Model – I.321  Modeling communication systems is done in a logical hierarchical structure as in, e.g., the ISO/OSI BRM – Relation between OSI and B-ISDN/ATM undefined – Similar plane approach has been used within N-ISDN Management Plane Plane Management Layer Management Control P. User P. Higher Layer Protocols ATM Adaptation Layer ATM Layer Physical Layer P: Plane © 2024 Burkhard Stiller M05-7  B-ISDN Reference Model – Planes  User plane  User Plane details – Transmission of user data – Physical Layer (PHY) – Supervision of data transfer – Transmission of bits – It is comparable to an N-ISDN B- – Generating of transmission frames – Detection of cell boundaries channel – ATM Layer (ATM)  Control plane – Transport of ATM cells – Transmission of signaling data – Addressing of virtual connections, – Establishment, monitoring, and – Multiplexing/demultiplexing of ATM tear-down of connections cells – Flow- and access control for end- – It is comparable to an N-ISDN D- systems channel – ATM Adaptation Layer (AAL)  Management plane – Support of different ATM transport services – Transmission of management data – Convergence functions, such as – Coordination between levels in the error control, synchronization entire system – Segmentation and Reassembly – Management within a certain level © 2024 Burkhard Stiller M05-8  ATM Layer – UNI Cell Format 5 Byte 48 Byte  GFC: Generic Flow-Control used at the service interface Header Payload Byte  PT: Payload Type defines content of a cell 1 GFC VPI – User data congested – User data non-congested 2 VPI VCI – Operation And Maintenance (OAM) cells 3 VCI – Resource management cells 4 VCI PT CLP  CLP: Cell Loss Priority to identify 5 HEC low/high priority cells bit 1 2 3 4 5 6 7 8  HEC: Header Error Control UNI: User-Network Interface © 2024 Burkhard Stiller M05-9  ATM Layer – NNI Cell Format 5 Byte 48 Byte  VPI: Virtual Path Identifier comprises of 12 bit length Header Payload Byte  PT: Payload Type defines content of a cell 1 VPI – User data congested 2 VPI VCI – User data non-congested – Operation And Maintenance 3 VCI (OAM) cells – Resource management cells 4 VCI PT CLP  CLP: Cell Loss Priority to identify 5 HEC low/high priority cells bit 1 2 3 4 5 6 7 8  HEC: Header Error Control NNI: Network-Network Interface © 2024 Burkhard Stiller M05-10  Handling Cells – Segmentation/Reassembly  To sent packets over cell-based networks, packets have to be segmented and reassembled again. Packet Cells Packet  The segmentation and reassembly functionality is placed right above the cell level. User Data HLP User Data Cell Header SAR HLP UD SAR User Data... SAR User Data SAR Header Higher Layer Cell SAR HLP UD Cell SAR User Data... Cell SAR User Data Protocol Header Cell Payload Length Total Cell Length © 2024 Burkhard Stiller M05-11  ATM Connections (1)  Simultaneous support of many thousands of VCs (216) requires the ATM cell to carry the VCI field  Supporting many semi-permanent connections between endpoints, carrying many grouped VPs (28 or 212) requires the ATM cell to carry the VPI field VCI: Virtual Channel Identifier VCI1 VPI1 Link VCI2 VCIn VPIk VCIm VP Virtual Path VC Virtual Channel © 2024 Burkhard Stiller M05-12  ATM Connections (2)  Connections, links, ATM equipment, and identifiers: VCC 1 “Connections” VPC 1 VPC 2 VPC 3 VCI 1 VCI 2 VCI 3 Links Equipment Identifiers VPI 1 VPI 2 VPI 3 VPI 4 VPI 5 ATM ATM ATM ATM ATM ATM End-system Cross-connect Switch Switch Cross-connect End-system VPL 1 VPL 2 VPL 3 VPL 4 VPL 5 VC: Virtual Channel, VP: Virtual Path, L: Link, I: Identifier, C: Connection © 2024 Burkhard Stiller M05-13  ATM Connections (3)  Hierarchical connection concept includes – Virtual Connections are identified by two identifiers, which are significant only locally per link in the virtual connection Error-control is done end-to-end only, if required – High quality links and a good call acceptance control Flow-control is not provided – High bandwidth delay product – Virtual Channel (VC) is a unidirectional channel, identified by the Virtual Channel Identifier (VCI) Dynamically allocated connections – Virtual Path (VP) contains a group of VCs, identified by the Virtual Path Identifier (VPI) Statically allocated connections © 2024 Burkhard Stiller M05-14  ATM Switching (1)  Two types of switching may be performed  VP switching (ATM Cross-connect) – Switching between VPs – No evaluation and change of VCIs – Change of VPIs – Variable number of VCs per VP possible  VC/VP switching (ATM Switch) – Switching in close cooperation between VCs and VPs – Evaluation of VCI and VPI in an intermediate system – Change of VCI and VPI if necessary – Incoming VCs of one VP may be distributed between many outgoing VPs © 2024 Burkhard Stiller M05-15  ATM Switching (2)  Use of VPI in a B-ISDN network (ATM Cross-connect) VPIin VPIout VPI = 7 5 7 VCI = 1, 2, 3 VPI = 5 VPIin VPIout VCI = 1, 2, 3 ATM B 7 5 9 7 1 PHY VPI = 7 VPIin VPIout VCI = 1, 2, 3 2 B-ISDN Network 7 3 A ATM VPI = 9 ATM C VCI = 3, 4 PHY 3 VPI = 3 PHY VCI = 3, 4 VPI = 7 VCI = 3, 4 © 2024 Burkhard Stiller M05-16  ATM Switching (3)  Use of VPI-VCI in a B-ISDN network (ATM switch) VPI-VCIin VPI-VCIout VPI-VCIin VPI-VCIout 5.1 7.2 VPI = 7 7.1 5.1 5.2 7.1 VCI = 1, 2, 3 VPI = 5 5.3 7.3 ATM 7.2 7.3 VCI = 1, 2, 3 B 7.3 5.2 9.3 7.4 1 PHY 9.4 5.3 VPI = 7 VPI-VCIin VPI-VCIout VCI = 1, 2, 3 7.3 3.4 2 B-ISDN Network 7.4 3.3 A ATM VPI = 9 ATM C VCI = 3, 4 PHY 3 VPI = 3 PHY VCI = 3, 4 VPI = 7 VCI = 3, 4 © 2024 Burkhard Stiller M05-17  ATM Adaptation Layer (AAL)  Services are offered using the AAL Service Classes based on – Timing between source and sink, the bit rate, and the connection modus (cf. later chapter)  Each class is supported by different AAL types – Class A: AAL 1 – Class B: AAL 2 – Class C: AAL 3/4 or AAL 5 – Class D: AAL 3/4 or AAL 5  ATM Layer (AAL) connections are service-independent – Cell-based multiplexing and transport  AAL connections are service-dependent – Particular protocols provided © 2024 Burkhard Stiller M05-18  Structure of the AAL  AAL includes sub-layers Class A Class B Class C/D Class C/D – Segmentation and Reassembly (SAR) between packets/cells SSCS-2 SSCS-3/4 SSCS-5 – Convergence sub-layer (CS) for CS-1 service-dependent adaptation CPCS-2 CPCS-3/4 CPCS-5 Common Part Convergence Sub-layer (CPCS) SAR-1 SAR-2 SAR-3/4 SAR-5 Service Specific Convergence Sub-layer (SSCS) AAL 1 AAL 2 AAL 3/4 AAL 5 ATM Adaptation Layer – Layers may be empty ATM Layer © 2024 Burkhard Stiller M05-19  ATM Service Interfaces – AAL 3/4 Figure from W&G. AL: Alignment CRC: Cyclic Redundancy Check PAD: Padding BA: Buffer Allocation ETag: End Tag SAR: Segmentation and Reassembly BTag: Begin Tag LI: Length Indicator SN: Sequence Number CPI: Common Part Indicator MID: Multiplexing Identifier ST: Segment Type © 2024 Burkhard Stiller M05-20  ATM Service Interfaces – AAL 5  AAL 5 provides a Variable Bit Rate (VBR) service – More efficient than AAL 3/4 Less protocol overhead due to 8 Byte trailer End of AAL 5 PDU is defined in ATM cell (PTI) – No multiplexing in AAL.  Trailer contains – Padding (PAD) to shift the relevant content to the end CPI: Common Part Identifier PAD: Padding PTI: Payload Type Information Figure from W&G. UU: User-to-user Information © 2024 Burkhard Stiller M05-21  ATM Functions per Layer – Overview Layer Sub-layer Function AAL CS Handles transmission errors Handles lost and mis-inserted cell conditions Handles timing between source and destination Handles cell delay variation SAR Segments higher-layer information into 48 Byte fields Reassembles cell payload in higher layer information ATM Multiplexes cells from different ATM channels Generates cell header (first four bytes) Performs payload type discrimination Performs traffic shaping and flow control Routes and switches cells as needed Indicates cell loss priority and selects cells for discarding PHY TC HEC header sequence generation and verification Cell delineation Transmission frame generation and recovery PM Bit timing © 2024 Burkhard Stiller M05-22  ATM Signaling and Interfaces  Signaling is part of the control plane SVC: Switched Virtual Circuit PVC: Permanent Virtual Circuit – Setup of VPI/VCI per link – Reservation of resources – Manual configuration by administrator: PVC – Automated configuration (signaling protocol): SVC B-ICI Public UNI Public Public ATM ATM Public UNI Private UNI Private Private ATM ATM Private NNI UNI: User Network Interface, NNI: Network Network Interface, B-ICI: Broadband Inter-Carrier Interface © 2024 Burkhard Stiller M05-23  UNI, P-NNI, and B-ICI  User Network Interface (UNI) approaches – ATM Forum UNI 3.0, 3.1, and 4.0, and ITU-T Q.2931 – Setup of ATM connections (1:1 and 1:n) – Negotiation of traffic characteristic and QoS parameter  Private Network-Network Interface (P-NNI) – Protocol to setup ATM connections (1:1 and 1:n) – Routing based on topology and QoS (bandwidth)  Broadband Inter-Carrier Interface (B-ICI) – Interface between public ATM providers – Version 2.0 supports PVCs only (manual configuration) – Metering of traffic, traffic management (shaping), and network management (operation and management) © 2024 Burkhard Stiller M05-24  Other (Residential) Access Technologies  Telephone system and traditional modems – Phone channels, low-speed, widely deployed ISDN advances, as a 2 x 64 kbit/s bearer service – Deployment: a few billion customers on twisted pair  Hybrid cable systems and cable modems – Hybrid Fiber Coax (HFC) as a shared bus, 27 Mbit/s down-, 768 kbit/s upstream Permanent access, noise levels, variable performance – Deployment: large regional differences Changes and upgrades in access  Wireless Local Loop (WLL) network areas to be performed! – Utilization of air interface between residential customer and backbone provider Deployment: basically not existing  Digital Subscriber Loop systems (DSL) Changes and upgrades in access – Exploiting spectrum of phone copper cables network areas to be performed! – Deploy modulation, equalization, and error-control technique advances – Dedicated line, dozens of Mbit/s down-, 2+ Mbit/s upstream – Deployment: a few billion customers on twisted pair © 2024 Burkhard Stiller M05-25  DSL Alternatives DSL Downstream Upstream Voice Scheme [kbit/s] [kbit/s] Support IDSL 144 144 Active UDSL 1,000 300 Splitterless SDSL 160 – 1,168 160 – 1,168 No HDSL 2,048 2,048 No ADSL 1,500 – 8,000 64 – 800 Passive VDSL 1,500 – 25,000 1,600 Passive ADSL: Asymmetric DSL HDSL: High bit-rate DSL IDSL: ISDN DSL SDSL: Symmetric DSL UDSL: Universal DSL VDSL: Very high bit-rate DSL © 2024 Burkhard Stiller M05-26  ADSL Technology – Overview (1)  Twisted pair access to the information highway: – Delivering video und multimedia data. – Avoids the replacement of existing cabling. – Transformation of existing telephone network into a multi-service network by applying modulation. – Use of full copper frequency spectrum (app. 1.1 MHz). 144 kbit/s (POTS) 16 … 640 kbit/s Server *) ADSL Existing ADSL Core Network Modem Copper Modem Internet 1.5 … 9 Mbit/s *) depending on the implementation architecture © 2024 Burkhard Stiller M05-27  ADSL Technology – Overview (2)  ADSL Forum Reference Model ATU: ADSL Terminal Unit R: Remote C: Central Office SM: Service Module Vc Va UC-2 U-C U-R U-R2 T-SM T-P T Digital Broadcast T.E. Broadband ATU-C Network ATU-R Narrowband ATU-C Splitter Splitter Network ATM-SM Network ATU-C POTS-C POTS-R Management Access Premises PSTN Phone Sets Node Distribution Network © 2024 Burkhard Stiller M05-28  ADSL Technology – Challenges  Attenuation – Frequency dependent (next slides)  Crosstalk – Near-end crosstalk (NEXT) appears between TX and RX of the near-end – Far-end crosstalk (FEXT) appears between TX and RX of the far-end  Interference: other lines, overlapping RF-spectra  Bridged taps, loading coils  Weather-conditions (moisture, temperature) affect crosstalk and line impedance © 2024 Burkhard Stiller M05-29  ADSL Technology – Capabilities  Data rates depend on Data Rate Wire Gauge Distance – Length of copper line [Mbit/s] [mm] [km] – Wire gauge 1.5 or 2 0.5 (26 AWG) 5.5 – Presence of bridged taps 1.5 or 2 0.4 (24 AWG) 4.6 – Cross-coupled interference 6.1 0.5 (26 AWG) 3.7 6.1 0.4 (24 AWG) 2.7  95% of today’s loop plants AWG: American Wire Gauge meet these measures Downstream Duplex Bearer Channels Bearer Channels [Mbit/s] [kbit/s]  But, requires advanced digital n*1.536 1.536 C Channels 16 signal processing and 3.072 64 advanced coding schemes 4.608 Optional 160 to deal with varying noise 6.144 Channels 384 n*2.048 2.048 544 figures. Recent advances applied! 4.096 576 © 2024 Burkhard Stiller M05-30  ADSL Technology – Modulation  Competition on modulation techniques due to market and patents  Carrier-less Amplitude Phase (CAP) Modulation – Multilevel, multiphase encoding Combination of amplitude and phase Real-time adjustment of bit rate – Frequency range from 35 kHz up and 240 kHZ up to 1.1 MHz used as two channels (up- and down-link) – Applied in some standards, such as V.32/V.32bis  Quadrature Amplitude Modulation (QAM) – Two traffic classes for bypassing a FEC (Forward Error Correction)  Bellcore test in 1993, Committee T1E1.4 decided on Discrete Multi Tone Modulation (DMT) © 2024 Burkhard Stiller M05-31  ADSL Technology – DMT Modulation POTS: Plain Old Telephony System  To work simultaneously with POTS on copper line – Lower 4 kHz are used by POTS – Discrete Multi Tone (DMT) wirth 256 separate sub-frequencies from 4 kHz, each 64 kbit/s  Amplification varies dependent on frequency © 2024 Burkhard Stiller M05-32  ADSL Standards ADSL Standards Semiconductors & devices: www.adsl.com International/national G.full standardization: ITU, G.lite ETSI, ANSI... UAWG: Universal ADSL Working Group (makes ADSL more commercially adaptable) SNAG: Service network architecture group International level Examples: ITU: International Telecommunications Union - Hierarchy of yields recommendations that may be adapted by companies Standards Regional/national level Examples: ANSI (American Standards Institute) /ETSI (European Technical Standards Institute) Multi-corporate level Examples: ADSL forum/ATM forum Corporate level Open or proprietary standard created by a company See also: http://www.ktl.com/testing/telecoms/xdsl-standards.htm © 2024 Burkhard Stiller M05-33  ADSL Network Architectures (1)  ADSL-ATM network architecture, point-to-point NSP: Network Service Provider (BAS) DSLAM: Digital Subscriber Line Access Multiplexer © 2024 Burkhard Stiller M05-34  ADSL Network Architectures (2)  ADSL-ATM including L2TP (cf. for protocol later chapter) LAC: Local Access Carrier © 2024 Burkhard Stiller M05-35  ADSL Network Architectures (3)  ADSL-ATM including IP © 2024 Burkhard Stiller M05-36  Chapter 6: IP Technology, Overlays, and MPLS © 2024 Burkhard Stiller M06-1  Content  Topics – Internet Protocol (IP) technology ISPs, users, and relationships Internet hierarchy and example networks Internet peering and exchange structures – Business models and example policies Networking alternatives: IntServ and DiffServ – Overlays and IP Switching – Multi-protocol Label Switching (MPLS)  Objectives – To describe the major elements of today’s IP-based networks – To discuss essential principles of IP-based network structure and operations – To explain why lower and higher layer principles are combined © 2024 Burkhard Stiller M06-2  The Internet World  Internet Service Provider (ISP) – Access provider vs. service provider vs. content provider Roles and relationships Peering and exchanges – IP basic and advanced techno