Introduction to Network Technologies & Layered Architecture BUPT/QMUL

Transcription

1 Itroductio to Network Techologies & Layered Architecture BUPT/QMUL

2 Review What is the Iteret? How does it work? Whe & how did it come about? Who cotrols it? Where is it goig? 2

3 Ageda Basic Network Defiitios Layered Architecture Refer to Sectio 2.2, 2.3 ad Chapter 10 of the Textbook 3

4 Basic Network Defiitios Terms for Network Devices Terms for Network Performace Parameters Ways to coect to the Iteret Terms for Network Types 4

5 Basic Network Defiitios Terms for etwork devices Node a device that is coected as part of a etwork with a etwork address E.g. Computer, PDA, Cell Phoe, router, switch, bridge etc. Host Node the computer attached directly to the Iteret (eg: ISPs ad NSPs) - ed poit of a etwork Lik the iter-coectio betwee etwork devices Network Compoet the equipmet that is part of the etwork ifrastructure E.g. Gateway, router, bridge/switch, hub/repeater 5

6 Example of Nodes 6

7 Basic Network Defiitios Terms for Network Devices Terms for Network Performace Parameters Ways to coect to the Iteret Terms for Network Types 7

8 Basic Network Defiitios Terms for etwork performace parameters Badwidth Delay (Latecy) Jitter Error Rate Idicates how much stuff you ca sed through a coectio bps (bit per secod) Bps (Byte per secod) is a expressio of how much time it takes for a packet of data to get from oe desigated poit to aother Cotributors Propagatio Trasmissio Processig Storage (Queuig) The variatio i delay The probability of the data uits which are trasmitted i error, are lost or are retrasmitted BER (Bit Error Rate) FER (Frame Error Rate) PER (Packet Error Rate) 8

9 Sources of Delay 1. Trasmissio delay: R=lik badwidth (bps) L=packet legth (bits) time to sed bits ito lik = L/R 2. Propagatio delay: d = legth of physical lik s = propagatio speed i medium propagatio delay = d/s 3. Nodal processig delay: check bit errors determie output lik 4. Queuig delay: time waitig at output lik for trasmissio depeds o cogestio level of router 9

10 Basic Network Defiitios Terms for etwork performace parameters Other similar parameters used for QoS (Quality of Service) Throughput : the average rate of successful message delivery over a commuicatio chael (wikipedia) PLR (Packet Loss Rate) Differet applicatios have differet QoS requiremets E.g., four applicatio classes defied by 3GPP accordig to their sesitivity to delay Sessio Class high Iteractive Class Streamig Class low Backgroud Class 10

11 Basic Network Defiitios Terms for etwork performace parameters Class Requiremets Examples Sessio Class Iteractive Class Streamig Class Backgroud Class Low delay, low jitter, without high requiremets o BER Low BER, low respose delay, without high requiremets o jitter Low jitter, without high requiremets o delay ad BER Low BER, without high requiremets o delay ad jitter VoIP Video coferece Web browsig Video/audio streamig 11

12 Applicatio classificatio of 3GPP 12

13 Basic Network Defiitios Terms for Network Devices Terms for Network Performace Parameters Ways to coect to the Iteret Terms for Network Types 13

14 Basic Network Defiitios Ways to coect to the Iteret Dialup Via twisted pair phoe lies ISDN Itegrated Services Digital Network (64-128Kbps) (A)DSL (Asymmetric) Digital Subscriber Lie 8 Mbps dowload, 2Mbps upload 1M bps dowload, 256Kbps upload Usually provided by telephoe compaies Cable Modem CATV: 500 Kbps - 30 Mbps Usually provided by cable compaies LAN Etheret coectios Satellite Cellular GPRS/CDMA/3G/4G ad other cellular wireless techologies Broadbad wireless access WLAN(WiFi)/WiMAX 14

15 Basic Network Defiitios Ways to coect to the Iteret Dialup: MODEM (MOdulator-DEModulator) Covertig aalog sigal to digital ad vice versa Persoal Computer Digital Sigal Aalog Sigal Digital Sigal Maiframe Computer Modem Modem Telephoe Lie 15

16 Basic Network Defiitios Ways to coect to the Iteret Data codes Code Bits Max Chars Baudot 5 32 or 64 ASCII Exteded ASCII EBCDIC UNICODE 16 > 65,000 ISO > 4 billio 16

17 Basic Network Defiitios Ways to coect to the Iteret ISDN: Itegrated Services Digital Network Developed based o telephoy IDN (Itegrated Digital Network) A set of CCITT/ITU stadards TA TA ISDN Network TA TA TA: Termial Adaptor 17

18 Basic Network Defiitios Ways to coect to the Iteret Dialup Via twisted pair phoe lies ISDN Itegrated Services Digital Network (64-128Kbps) (A)DSL (Asymmetric) Digital Subscriber Lie 8 Mbps dowload, 2Mbps upload 1Mbps dowload, 256 Kbps upload Usually provided by telephoe compaies Cable Modem CATV: 500 Kbps - 30 Mbps Usually provided by cable compaies LAN Etheret coectios Satellite Cellular GPRS/CDMA/3G/4G ad other cellular wireless techologies Broadbad wireless access WLAN(WiFi)/WiMAX 18

19 ADSL: typical cofiguratio 19

20 FTTH: Fiber to the Home PON(Passive Optical Network) 20

21 A Network based o Cable TV 21

22 Basic Network Defiitios Terms for Network Devices Terms for Network Performace Parameters Ways to coect to the Iteret Terms for Network Types 22

23 Basic Network Defiitios Terms for etwork types Accordig to the switchig fuctio i the etwork Circuit switchig etwork Message switchig etwork Packet switchig etwork Hybrid switchig etwork 23

24 Timig i CS, MS ad PS 24

25 Basic Network Defiitios Terms for etwork types Differet chael access techologies Multi-access meas shared medium May ed-systems share the same physical commuicatio resources ( wire, frequecy, etc.) There must be some arbitratio mechaism Complex chael access cotrol, efficiet resource usage Example: LANs poit-to-poit Betwee two poits i the etwork, there must exists a physical chael No cotetio or collisio Simple access cotrol, badwidth waste Example: WANs 25

26 Chael access techologies Multi-access etwork Poit-to-poit etwork 26

27 Basic Network Defiitios Terms for etwork types Accordig to the rage of the etwork WAN (Wide Area Network) - etwork that spas a large geographic area MAN (Metropolita Area Network) - etwork that spas a medium area such as a campus to a city LAN (Local Area Network) - etwork that spas a limited area such as a lab, or a buildig PAN (Persoal Area Network) etwork that spas a small space such a room, less tha 10m 27

28 Basic Network Defiitios Terms for etwork types LAN (Local Area Network) Features Coects computers that are physically close together Rage: < 1 km high speed multi-access Techologies Etheret 10 M, 100M, 1000M/1G, 10G, 100Gbps Toke Rig 16 Mbps FDDI 100 Mbps Wireless IEEE802.11b/a/g//ac 28

29 Basic Network Defiitios Terms for etwork types MAN (Metropolita Area Network) Features Larger tha a LAN ad smaller tha a WAN Rage: < 10 km Example: city etwork multi-access Techologies coaxial cable Microwave, IEEE802.16/WiMAX 29

30 Basic Network Defiitios Terms for etwork types WAN (Wide Area Network) Features Coects computers that are physically far apart. log-haul etwork Traditioally slower ad less reliable tha a LAN Rage: km Poit-to-poit rig or partial mesh Techologies D-WDM, SDH + ATM, Frame Relay PSTN Telephoe lies Satellite commuicatios Cellular mobile commuicatios 30

31 Basic Network Defiitios Terms for etwork types Accordig to the user of the etwork Public etwork The large scale etwork built by the telecommuicatio compaies All the users ca use the etwork as log as they pay the moey Private etwork The etwork built by a certai agecy for its special requiremets Oly providig services to the user iside this agecy E.g., the military etwork, the railway etwork 31

32 Basic Network Defiitios other related terms NIC (Network Iterface Card) - circuit board that allows a PC to coect to a etwork Respose time - time waitig for host computer to reply back to termial Real-Time - where the respose time betwee remote etities is sufficietly low to provide iteractive commuicatio ( < 400msec roud-trip) Cotetio - 2 or more devices tryig to use the same resource at the same time Protocol - rules that defie how devices commuicate data o a commuicatio etwork 32

33 Layered Architecture OSI Layer Model TCP/IP Layer Model Beefits from layered structure: simplify the task to Desig Implemet Maitai 33

34 Layered Architecture OSI Layer Model 34

35 Layered Architecture OSI Layer Model 35

36 Layered Architecture TCP/IP Layer Model 36

37 TCP/IP Model: i details 37

38 Widely Used Protocols 38

39 Layered Architecture Revisory Model Applicatio Layer Presetatio Layer Sessio Layer Trasport Layer Network Layer Data Lik Layer Physical Layer OSI Model Applicatio Layer Trasport Layer Iteret Layer Network Access Layer TCP/IP Model Applicatio Layer Trasport Layer Network Layer Data Lik Layer Physical Layer Revisory Model 39

40 Layered Architecture devices ad addresses at differet layers Address Edpoit Idetificatio Routig & Switchig Devices Gateway Applicatio Layer Trasport Layer IPv4/IPv6 Address MAC Address Coectors, Patch Pael Router Bridge/Switch Hub Network Layer Data Lik Layer Physical Layer 40

41 Abbreviatios (1) ISP NSP BER FER PER QoS 3GPP ISDN (A)DSL CATV GPRS Iteret Service Provider Network Service Provider Bit Error Rate Frame Error Rate Packet Error Rate Quality of Service The 3rd Geeratio Partership Project Itegrated Services Digital Network (Asymmetric) Digital Subscriber Lie cable TV Geeral Packet Radio Services 41

42 Abbreviatios (2) CDMA MODEM ASCII EBCDIC IDN CCITT ITU WAN MAN LAN PAN FDDI Code Divisio Multiple Access MOdulator-DEModulator America Stadard Code for Iformatio Iterchage Exchaged Biary Coded Decimal Iterchage Code Itegrated Digital Network Iteratioal Telephoe ad Telegraph Cosultative Committee Iteratioal Telecommuicatios Uio Wide Area Network Metropolita Area Network Local Area Network Persoal Area Network Fiber Distributed Data Iterface 42

43 Abbreviatios (3) DWDM SDH ATM NIC Dese wavelegth divisio multiplexig Sychroous Digital Hierarchy Asychroous Trasfer Mode Network Iterface Card 43