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Access Networks

Explore the basics of telecommunications and access networks, including structure, evolution, and terminology. Learn about TN architecture, types of TNs, and differentiation aspects. Discover the various parts of both access and transport networks.

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Access Networks

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  1. foto: http://www.ctuf.za.org/26telcodirections.htm Access Networks lectures 2008/09 part: 1 Telecommunications network Ing. Ľudmila Maceková, PhD.ludmila.macekova@tuke.skVysokoškolská 4, 119A

  2. Access Network (AN) = the part of communications network, which connects (joins?) users – subscribers, customers to their immediate provider (in PSTN: to the first/ local telecomm. exchange) - so called the “first mile”

  3. AN - The Plan of Lectures • Telecommunications Networks = TN • Access Networks = AN • xDSL Technologies • (ISDN Networks) Telecommnications Networks: - Introduction - abbreviations and some basic terms (their list will be updated step by step) - the term and evolution of TN - structure (architecture) of TN - types (sorts) of TN

  4. Telecommunications - Introduction • telecommunications = interchange (relaying) of information (remote) • the main tasks of telecommunications from the point of view of customers (end-users) • evolution = enhancing of Quality of Services(QoS / p.17) – ... sequential transformation from partially analogous to completely digital networks • the requirements to system from the side of operator ... • history...(fire-light signaling, ..., cipher signalling, electric signals - telephone and telegraph = telecommunications, ...)

  5. Some basic terms in area of AN: • 4-Wire Transport(switching) • duplex • …etc. - see ‘TN_basic_terms.doc’ • a good terminology source - see [4]

  6. Term and evolution of TN • Networkvs. system • TN = ... (nowadays also PC networks) • VoiceTNs = • Evolution ... , digitizing

  7. The sorts of TNs(TN classification)and their differentiation aspects Tab.1

  8. a)...Structure (architecture) of TN – Layer model of TN 7. 6. 5. 4. 3. 2. 1. Intelligent network T M N Signalling network Transmission (transport) network Switching network Access network End devices network Fig. 1

  9. 1.= end devices (=terminals)+ transmission networkconnectingthem to interface (end point of AN)- in the PSTN, it deals with subscribers TN Architecture - continue • 2. . . ........ - subscriber (connecting) net • 3.... - exchanges and interconnection between them, different types of exchanges [1]/p.38-fig.2.12 , terms: switched network, switching, PSTN = Public Switched Telephone Network • 4.(tr.n.)(transport network) ... – transmission systems utilizing (SDH!) a transport media (optical! andothers) • several levels (national transmission n., regional tr.n. ....) • Backbone n.,Core Network = tr.n. + switch.n. • (connections of any-to-any devices on the network)

  10. TN Architecture – continue 2: TMN t.n. SDH, PDH, ATM Tr.n. t.n. t.n. WAN e.n e.n. LAN AN C MD TD TD TD TD TD TD TD TU-terminal device (end d.), K-concentrator, MD–muldex,LAN-local area network, e.n.- end node (terminal n.), t.n.-transitnode, TMN-telecom.management network, SDH-synchr.dig.hierarchy,PDH-plesiochron.dig.hierarchy,ATM-asynchr.transport mode,WAN- wide area network Fig.1The basic parts of both access and transport networks

  11. TN Architecture – continue 3: 5. Signalling network – logical independent, packet oriented net -sig.system CCITT/ITU No.7 6. Intelligent network– IN -(virtual)– the all-network services; they are appended to existing technology; distributed intelligence 7. TMN = Telecomm. Management Network - monitoring and control systems – controling of whole network; under condition of the following the interface and protocols standards

  12. Continue: segmentation (classification) of TNs: b) The transport media - wire vs. wireless (radio waves) Classification of wire media: -according to material: metallic (copper) optical (light conducting) -according to construction.:symetrical vs. assymetrical (…) -further survey: - wire -metallic outdoor (conductiong)media – telephone copper line above earth surface - telephone lines with broadening band -very high voltage power lines - cables - symetrical pairs – LFcopper lines (with load coils – Pupin Coils; pupinization) (additional inductance was required to balance the cable capacitance andto voice signal spectrum flatten; but – disadvantage: HP suppressing →loid coils must be removed /or switched befor DSL - technology installing) -without load coils (unloaded lines) -HF cables - Coaxial cables (asymmetrical lines) – microcoax. - small coax - Waveguides

  13. Transmission lines – continue: Opticalfibres: single-mode fibre (for long distances) - multimode fibres – with stepped index - with graded index s Wireless (radiofrequency) telecomm. media: - microwave lines - tropospheric - stratospheric (HAPS – High Altitude Platform systems) – in developing – comunications airships and small unmanned airplains flowing in the about 17-25 km above earth -satellite

  14. c)user access to network: public or private (closed) networks, branch netw. d) transport an switch equipment (time-, freq.-,apce-, code-division; analogous- digitalor hybrid networks e) Classification accordig to type of terminal equipments: Specialty networks – telephone, telegraph, teleprint, PC – networks, radio broadcasting or TV networks Integrated – based only on digital principles (IDN, ISDN), NISDN, BISDN – the aim: services , economical aim - profit (!)... f) according to creation of connection: fixed network, commuted, unidirect or bidirect network

  15. g) according to transmission type: 2-Wire or 4-Wire • h) according to process of switching: circuit switching or message switching, packet switching, …, virtual channels and virtual network • topology: (see next –Fig.3: spider net, star net, lattice (trellis, grid?) net., combined (mixed) net, tree net, ring -, and line (tandem) net • j)according to evolution (progress) of digitization: digital islands and overlaping nets

  16. Fig.3Some net topology examples

  17. Applications and requirements: access to information sources ... TB parameters: data speed, etc. (Requirements from the side of user: ...) -Quality of Services (QoS)- ... ITU-T G.1000 and - 1010 Tab.2 Basic quality criteria for transport of voice and video information

  18. Tab.3Zákl.kvalitatívne ukazovateľe pre prenos dát [3]

  19. Požiadavky na TS zo strany zriaďovateľov a poskytovateľov služieb: ... • * Pozn: Iný pohľad na štruktúru TS: • Zariadenia sieťových uzlov • -Chrbtová sieť • -Prístupová sieť Ešte niektoré ďalšie druhy sietí v súlade s PC technológiami: TS [3] /13: WAN –rozsiahla.. MAN- metropolitná – súčasť PrS LAN- miestna – v objekte účastníka TS PAN- Personal Area Network- v rámci miestnosti –BlueTooth a IR prenos

  20. References [1] V.Kapoun: Přístupové a transportní síte. VUT v Brně, 1999. [2] Vaculík: Prístupové siete. ŽU v Žiline, 2000. [3] J. Vodrážka: Přenosové systémy v přístupové síti. ČVUT, 2003. [4] L. Harte: Introduction to Digital Subscriber Line (DSL). Technologies, Operation and systems, Althos, 2005.

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