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S-72.1130 Telecommunication Systems Overview. HUT Comms. Lab, Timo O. Korhonen 2 Practicalities Lectures (Tuesdays & Thursdays 14-16 in hall S4): Timo.

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Presentation on theme: "S-72.1130 Telecommunication Systems Overview. HUT Comms. Lab, Timo O. Korhonen 2 Practicalities Lectures (Tuesdays & Thursdays 14-16 in hall S4): Timo."— Presentation transcript:

1 S-72.1130 Telecommunication Systems Overview

2 HUT Comms. Lab, Timo O. Korhonen 2 Practicalities Lectures (Tuesdays & Thursdays 14-16 in hall S4): Timo Korhonen (09 451 2351), Michael Hall (09 451 2322) Tutorials (Wednesdays 14-16 in hall S5): Mika Nupponen (09 451 5416), Naser Tarhuni (09 451 2362) Exam: 27.10.2006 Fri, 16-19 S1, S4 No need to buy any books, however, following references can be useful: James F. Kurose, Keith W. Ross: Computer Networking, 2nd ed. A. Leon-Garcia, I. Widjaja: Communication Networks, 2nd ed. M. Duck, R. Read: Data Communications and Computer Networks, 2nd ed. W. Stallings: Data and Computer Communications, 7th ed. (Ericsson, Telia: Understanding Telecommunications, Part I & Part II) Grading: Closed book exam and voluntary tutorials: Round[ e (5 p) +t (5p) *0.15] Tutorial guidelines published at the homepage Homepage: Course feedback: Last day to submit your feedback is 3.11.06

3 HUT Comms. Lab, Timo O. Korhonen 3 Course Objectives Course discusses structure and properties of telecommunications networks Network topologies Protocols Interfaces Physical realizations Role of abbreviations – understanding the concepts Abbreviations refer (define) concepts Abbreviations describe standardized protocols & parts of telecommunication systems More important to understand the meaning of concept than to remember the words building up abbreviation

4 HUT Comms. Lab, Timo O. Korhonen 4 History 1800 1850 1900 1950 2000 Volta:batteries; Fourier, Laplace, Cauchy: Mathematics Ampere, Faraday, Henry: Basic electronics 1826 Ohm’s law Morse, Kelvin: Early telegraphy 1844 Steinheil’s commercial telegraphy Bell, Edison: Telephony Heaviside, Pupin, Campbell: Theory of T. 1887 Strowger’s automated switch 1864 Maxwell’s electrodynamics 1897 Marconi’s wireless telegraphy Lee De Forrest: Triode-tube; Transcontinental telephone. Communication’s electronic 1918 Armstrong’s heterodyne radio 1998 Digital TV launched in USA Internet, Wide spread digital signal processing 1969 ARPANET Commercial data services: DSP, channel coding 1972 Motorola’s cellular system 1950 TDMA telephony1937 Alec Reeves’ PCM trans-Pacific, trans-Atlantic optical cables

5 HUT Comms. Lab, Timo O. Korhonen 5 Information Society “Information and Communication Anytime, Anywhere, and in Any Form” Key development fields: To understand how networks/terminals/services evolve consider especially services because all network costs are paid by service users: Services shape telecommunications’ evolution and effect greatly on which technology is chosen! ServicesGlobal Market Technology Legislation /Regulation /Standardization

6 HUT Comms. Lab, Timo O. Korhonen 6 Paradigm Shift Old view (circuit switched PSTN) Current view (packet switched Internet) Speech Low-rate data modems (V.90) + Other computers & agent-programs (M2M) SMS MMS VoIP DVB-H smtp ftp http

7 HUT Comms. Lab, Timo O. Korhonen 7 Components of Telecommunication Networks Core and access sub-network Access part terminated by terminals Network nodes and links are optimized for certain assumed traffic (source statistics) and transmission channels (transfer function and noise) This model of telecommunication networks applies both to data and voice networks (packet and circuit switching) Node 1Node 2 Node 3 Access Core Network Terminals Access Internal structure can follow different topologies: mesh/star/bus/ring (see supplementary material)

8 HUT Comms. Lab, Timo O. Korhonen 8 Network Topology Different topologies in different networks BUS - Ethernet Ring - FDDI Mesh - Internet; Number of connections required: N: number of nodes Selection of topology effects for instance applicable MAC scheme & network reliability Example: In local are networks IEEE 802 technology applied Optical networks Optical star-coupler

9 HUT Comms. Lab, Timo O. Korhonen 9 Tasks of a Telecommunication System Initialization and release of link/across network Synchronization RX & TX - carriers, start and end of packets Information exchange protocols determine protocols for communication in entities: CSMA, CDMA, … TCP/IP Error control - corrective measures Addressing and routing Message formatting, source coding Therefore, networks realized by following a layered structure (as Open System Interconnections (OSI) ) NOTE: “Entities” refer to network elements as routers and bridges or different OSI-layers Entity 3 Entity 2 Entity 1 Entity 3 Entity 2 Entity 1 interface Physical connection

10 HUT Comms. Lab, Timo O. Korhonen 10 Nodes, links & layers with well-defined (standardized) interfaces Network is optimized for certain, assumed traffic Earlier Voice and data services in PSTN or data in dedicated networks (X.25/Frame Relay) Nowadays Internet carries both data and voice - QoS important! Development of Data and Voice Networks Frame Relay: - applies virtual circuits - example to connect LANs - for high quality links (moderate error correction & flow control) - rates: 2-50 Mb/s Voice/modems in PSTN Leased lines Earlier Scenarios

11 HUT Comms. Lab, Timo O. Korhonen 11 Current Scenario Modified from W. Stallings: Data and Computer Communications, 7th ed (Home site / Lecturers’ slides) MPLS WLAN Router Bluetooth Device ISDN, V.90, Cable modem, ADSL etc.

12 HUT Comms. Lab, Timo O. Korhonen 12 Telecommunications Market Telecommunication network content and technology producers, operators and consumers form an interoperable hierarchy End-Users Content and Service Providers Service operators/ Telecommunications Networking Solutions Physical Telecommunication Network

13 HUT Comms. Lab, Timo O. Korhonen 13 Telecommunication Services PSTN-originated services 2G Services 2.5G-3G Services Voice Mail Call Holding/ Call Waiting Call Barring/ Call Forwarding Basic Voice BW ~ 4 kHz Pre-paid Services International Roaming Data: 9.6 Kb/s … 380 kb/s WAP 13 Kb/s Voice Catalog Enquiry Internet Access Mobile Commerce Instant Messaging/Chat Push-adds Streaming: Video, Audio Data up to 2 Mb Interactive Games Rich Call: “See what I see!” MMS Location Identification - Presence All-IP: Location, mobility management, presence, personalization, security Circuit/Packet Switching: Mobility, Data communication Circuit Switching: Voice services, IN-services, limited data SMS Data: 56 kb/s (V.90) Push-to Talk III Play* 10 Mb/s (HSDPA) *III Play=VoIP+DVB-H+Internet

14 HUT Comms. Lab, Timo O. Korhonen 14 Speech and Data Communications Teletraffic can be forced to fixed rate or bandwidth as speech in PSTN or in ATM traffic Waste of network resources follows if network resources can not be reallocated on request (=statistical multiplexing) Speech Data Delays Errors Limited to ~200 msDepends on service High tolerance Very limited tolerance Stream Continuous: Circuit switching Bursty: Packet switching

15 HUT Comms. Lab, Timo O. Korhonen 15 Different Services Require Different Transmission Rates 10k1M100M Streaming with MPEG, MP3 Fax Inter-LAN/PBX communications Video TV/HDTV Video conferencing Broadcasting Telephony Data Video Voice Bit rate (b/s) Maximum Rates of some Transmission Technologies GSM 14.4 kb/s HSCSD 56 kb/s POTS 56 kb/s GPRS 114 kb/s EDGE 384 kb/s Frame Relay 1.54 Mb/s T-1 1.54 Mb/s ADSL 8 Mb/s Cable modems 52 Mb/s Ethernet 10 M, 100 M, 1G FDDI 100 Mb/s OC-256 13.3 Gb/s Maximum Rates of some Transmission Technologies GSM 14.4 kb/s HSCSD 56 kb/s POTS 56 kb/s GPRS 114 kb/s EDGE 384 kb/s Frame Relay 1.54 Mb/s T-1 1.54 Mb/s ADSL 8 Mb/s Cable modems 52 Mb/s Ethernet 10 M, 100 M, 1G FDDI 100 Mb/s OC-256 13.3 Gb/s

16 HUT Comms. Lab, Timo O. Korhonen 16 1 Physical Layer Electrical signals and cabling 3 Network Layer Routes data to different LANs and WANs based on network address 4 Transport Layer Ensures delivery of entire file or message 5 Session Layer Starts, stops session maintains order 6 Presentation Layer Encryption, data conversion: ASCII to EBCDIC, BCD to binary... BCD: Binary Coded Decimal (four bits present each decimal digit) EBCDIC - Extended Binary Coded Decimal Interchange Code (256 characters by 8 bits) 7 Application Layer Type of communications: E-mail, file transfer, client/server TCP/IP Suite works with 5 layers only RTP: Real-time Transport Protocol (for internet telephony applications) ICMP: Internet Control Message Protocol (errors/IP package processing) ARP: Address Resolution Protocol (data link address determination) RARP: Reverse ARP (for instance DHCP host can ask its IP address) 2 Data Link (MAC) Layer Transmits packets form node to node based on station address OSI Layers

17 HUT Comms. Lab, Timo O. Korhonen 17 Each OSI-layer Carries Standardized Service Protocols IEEE 802.X, HDLC, ANSI X3T9.5, SMT,... V.24, V.35, V.90, 10Base5, 10Base2, 10BaseT, FDDI, SDH, G.703... ACSE, ROSE, RTSE,... NCP, FTP, Telnet, SMTP, SNMP, LAT, AFP, SMB... 7. Application 6. Presentation 5. Session 4. Transport 3. Network 2. Data Link 1. Physical NetBIOS, NetBEUI, DNS,... SPX, PEP, TCP, UDP, NSP... IPX, RIP, SAP, IDP, IP, ARP, RSVP, ICMP, X.25, RIP... Valuable source for understanding abbreviations:

18 HUT Comms. Lab, Timo O. Korhonen 18 The user clicks on a link to indicate which document is to be retrieved. The browser must determine the Internet address of the machine that contains the document. To do so, the browser sends a query to its local name server. DNS, UDP, HTTP, FTP, HTML Once the address is known, the browser establishes a connection to the server process in the specified machine, usually a TCP connection. For the connection to be successful, the specified machine must be ready to accept TCP connections. TCP/IP The browser runs a client version of HTTP, which issues a request specifying both the name of the document and the possible document formats it can handle. The machine that contains the requested document runs a server version of HTTP. It reacts to the HTTP request by sending an HTTP response which contains the desired document in the appropriate format. Document sent to the receiver. The user may start to view the document. The TCP connection is closed after a certain timeout period. 1. 2. 3. 4. – 6. 7. – 8. Step: Protocols in Practice: Retrieving a Document from the Web From Leon-Garzia, Widjaja: Communication Networks, 2th ed., Instructor’s Slide Set Addressing TCP/IP connection Document specifications Document response Viewing the document, closing TCP/IP

19 HUT Comms. Lab, Timo O. Korhonen 19 ITU-T Standards ( G - Transmission Systems and media, digital systems and networks H - Audiovisual and multimedia systems I - ISDN Q - Switching and signalling V - Data communications over PSTN X- Data networks and open system communications Other important standardization organizations: - IEEE (Institute of Electrical and Electronics Engineers) - IETF (The Internet Engineering Task Force) - ISO (International Organization for Standardization) - ETSI (European Telecommunications Standards Institute)

20 HUT Comms. Lab, Timo O. Korhonen 20 Future Perspectives - PLMN Modest-rate Internet Portable, global virtual reality 19952010 1992 2G: Fax/data/ SMS 9.6 kb/s 1998 2G: Data compr. 2.5x 9.6 kb/s 2000 2.5G: HSCSD 28.8 kb/s 2001 2.5G: GPRS 92 kb/s 2003 2.5G: EDGE 384 kb/s 2004 3G: UMTS 2 Mb/s 2005 3G: HSDPA 10 Mb/s Single system support Multi-system support Terminal GSM, DECT GPRS, EDGE, HSCSD UMTS/4G Radio interface Radio interface PSTN, ISDN TCP-IP/UDP ATM, ISDN, B-ISDN Trunk /Core Trunk /Core Voice, low rate data Services Software radio Multimedia, Virtual reality Push-to-talk, VoIP

21 HUT Comms. Lab, Timo O. Korhonen 21 Future Perspectives Summarized PLMNs and especially wireless LANs develop very fast in home & office networks Increasing data rates, also in mobile terminals QoS very important Traffic gets more symmetrical (P2P) PSTN: Is used to transfer more and more data traffic Voice services of PSTN use IP (VoIP) and move to Internet Need of seamless communication of NGN means that different networks must link efficiently -> Inter(net)working between different kind of networks important (example: Bluetooth-WLAN- UMTS) PLMN: Public Land Mobile Network, IP:Internet Protocol SLIP: Serial line IP, NGN: Next Generation Networks

22 HUT Comms. Lab, Timo O. Korhonen 22 Web Resources Tutorials, links, abbreviations : Mpirical bank of abbreviations: companion/mpirical_companion.html Wikipedia: A set of standards available online in the Library, as for instance ITU-standards Have a look on course reference books homepages! 3:rd generation PLMN:, Finish Spectral Regulation: IEEE standards: ITU standards: xDSL development:

23 HUT Comms. Lab, Timo O. Korhonen 23 Review Questions What does the concept of information society means? Describe implications to technology/service development. What are the basic components and tasks of generalized telecommunication network? Give an example how telecommunication services have evolved? What were the enabling changes in technology? What are the OSI layers? Give examples of their tasks. Summarize the expected development of mobile telecommunication networks in terminals, radio interface core network and in services

24 S-72.1130 Telecommunication Systems - Annex What is … (Some important concepts)

25 HUT Comms. Lab, Timo O. Korhonen 25 What is Ethernet? Ethernet is the most widely-installed local area network (LAN) technology. Specified in a standard, IEEE 802.3, Ethernet was originally developed by Xerox and then developed further by Xerox, DEC, and Intel. An Ethernet LAN typically uses coaxial cable or special grades of twisted pair wires. Ethernet is also used in wireless LANs. The most commonly installed Ethernet systems are called 10BASE-T (100 m / CAT 3 cables) and provide transmission speeds up to 10 Mbps. Devices are connected to the cable and compete for access using a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol. Fast Ethernet or 100BASE-T provides transmission speeds up to 100 megabits per second and is typically used for LAN backbone systems, supporting workstations with 10BASE-T cards. Gigabit Ethernet provides an even higher level of backbone support at 1000 megabits per second (1 gigabit or 1 billion bits per second). 10-Gigabit Ethernet provides up to 10 billion bits per second. Source:

26 HUT Comms. Lab, Timo O. Korhonen 26 What is FDDI? FDDI (Fiber Distributed Data Interface) is a set of ANSI and ISO standards for data transmission on fiber optic lines in a local area network (LAN) that can extend in range up to 200 km (124 miles). The FDDI protocol is based on the token ring protocol. In addition to being large geographically, an FDDI local area network can support thousands of users. FDDI is frequently used on the backbone for a wide area network (WAN). An FDDI network contains two token rings, one for possible backup in case the primary ring fails. The primary ring offers up to 100 Mbps capacity. If the secondary ring is not needed for backup, it can also carry data, extending capacity to 200 Mbps. The single ring can extend the maximum distance; a dual ring can extend 100 km (62 miles). FDDI is a product of American National Standards Committee X3-T9 and conforms to the Open Systems Interconnection (OSI) model of functional layering. It can be used to interconnect LANs using other protocols. FDDI-II is a version of FDDI that adds the capability to add circuit-switched service to the network so that voice signals can also be handled. Work is underway to connect FDDI networks to the developing Synchronous Optical Network (SONET). Source:

27 HUT Comms. Lab, Timo O. Korhonen 27 Multiprotocol Label Switching (MPLS) Multiprotocol Label Switching is a standards-approved technology (IETF: RFC 3031) for speeding up network traffic flow and making it easier to manage. MPLS involves setting up a specific path for a given sequence of packets, identified by a label put in each packet, thus saving the time needed for a router to look up the address to the next node to forward the packet to. MPLS is called multi-protocol because it works with the Internet Protocol (IP), Asynchronous Transport Mode (ATM), and frame relay network protocols. With reference to the standard model for a network (the Open Systems Interconnection, or OSI model), MPLS allows most packets to be forwarded at the layer 2(switching) level rather than at the layer 3(routing) level. In addition to moving traffic faster overall, MPLS makes it easy to manage a network for quality of service (QoS). Note: ATM header overhead always at least 10 %, for MPLS it is order of magnitude smaller. Source:

28 HUT Comms. Lab, Timo O. Korhonen 28 Streaming Technologies Major streaming video and streaming media technologies include RealSystem G2 from RealNetwork, Microsoft Windows Media Technologies (including its NetShow Services and Theater Server), and VDO. Microsoft's approach uses the standard MPEG compression algorithm for video. The other approaches use proprietary algorithms. (The program that does the compression and decompression is sometimes called the codec.) Microsoft's technology offers streaming audio at up to 96 Kbps and streaming video at up to 8 Mbps (for the NetShow Theater Server). However, for most Web users, the streaming video will be limited to the data rates of the connection (for example, up to 128 Kbps with an ISDN connection). Microsoft's streaming media files are in its Advanced Streaming Format (ASF). MPEGalgorithmcodecKbpsMbps Source:

29 HUT Comms. Lab, Timo O. Korhonen 29 Security and Secrecy* Services require security & secrecy, e. g. reliable, shielded transfer (Example WEP of Wi-Fi). Especially important for NGN-services that are ‘near to users’ Vulnerable services: medical/health as tele-surgery rescue, police, defense Networks can provide this in several network levels (problem: overheads); fixed lines (PSTN, frame relay) flexible routing (SS7) scrambling or encryption (PLMNs) coding or ciphering (in all modern telecom links & nets) Often used concept: AAA: Authentication, Authorization, Accounting Message goes to the right receiver Others can’t do eavesdropping *

30 HUT Comms. Lab, Timo O. Korhonen 30 What is AAA? Short for authentication, authorization and accounting, a system in IP-based networking to control what computer resources users have access to and to keep track of the activity of users over a network.IP networkingusers  Authentication is the process of identifying an individual, usually based on a username and password. Authentication is based on the idea that each individual user will have unique information that sets him or her apart from other users. Authenticationusernamepassword  Authorization is the process of granting or denying a user access to network resources once the user has been authenticated through the username and password. The amount of information and the amount of services the user has access to depend on the user's authorization level. Authorization  Accounting is the process of keeping track of a user's activity while accessing the network resources, including the amount of time spent in the network, the services accessed while there and the amount of data transferred during the session. Accounting data is used for trend analysis, capacity planning, billing, auditing and cost allocation. Accounting AAA services often require a server that is dedicated to providing the three services. RADIUS is an example of an AAA service.RADIUS Source:

31 HUT Comms. Lab, Timo O. Korhonen 31 What is Bluetooth? Bluetooth is an industrial specification for wireless personal area networks (PANs).personal area networks Bluetooth provides a way to connect and exchange information between devices like personal digital assistants (PDAs), mobile phones, laptops, PCs, printers and digital cameras via a secure, low-cost, globally available ISM short range radio frequency.personal digital assistantslaptopsPCsprintersdigital camerasradiofrequency Bluetooth lets these devices talk to each other when they come in range, even if they are not in the same room, as long as they are within up to 100 metres (328 feet) of each other, dependent on the power class of the product. Products are available in one of three power classes:metresfeet  Class 3 (1 mW) is the rarest and allows transmission of 10 centimetres (3.9 inches), with a maximum of 1 metre (3.2 feet)centimetres inchesmetrefeet  Class 2 (2.5 mW) is most common and allows a quoted transmission distance of 10 metres (32 ft)metresft  Class 1 (100 mW) has the longest range at up to 100 metres.metres The specification was first developed by Ericsson, and was later formalized by the Bluetooth Special Interest Group (SIG). SIG was established by Sony Ericsson, IBM, Intel, Toshiba and Nokia, and later joined by many other companies as Associate or Adopter members. Bluetooth is also IEEE 802.15.1 that specifies its radio interface by using frequency hopping.EricssonBluetooth Special Interest GroupSony EricssonIBMIntelToshiba NokiaIEEE 802.15.1

32 HUT Comms. Lab, Timo O. Korhonen 32 Quality of Service (QoS) ATM, MPLS and UMTS support wide range of services that posses different quality of service (QoS) requirements. Transportation system differentiated into constant rate, real-time and higher-latency services by Multi-Protocol Label Switching (MPLS) or Differentiated Services (DiffServ) User services can be divided to different groups, depending on QoS requirements. Four traffic classes can been identified for ATM: Conversational class (very delay-sensitive traffic) Streaming class Interactive class Background class (the most delay insensitive) Hence TCP (Connection-oriented transport-layer) is not a good choice if errors can be tolerated UDP (Connectionless transport-layer protocol) appropriate for many streaming applications (error control in upper layers)

33 HUT Comms. Lab, Timo O. Korhonen 33 Example from mpirical - database

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