Schedule

Transcription

1 1 Standards for Contents Delivery Systems - TCP/IP Model

2 2 2.1 TCP/IP Model 2.2 Transmission : Backbone Layer 2.3 Device Link 2.4 IP and Routing Layer 2.5 TCP / UDP Layer 2.6 RTP/RTCP : Application Layer 2.7 Example of CDS basedon TCP/IP Model

3 3 2.1 TCP/IP reference model (1/13)

4 4 2.1 TCP/IP reference model (2/13) Physical layer coordinates the functions required to transmit a bit stream over a physical medium deals with the mechanical and electrical specifications of the primary connections» cables, connectors, and signaling options receives a data unit from 2 layer puts it into a format capable of being carried by communication link oversees the changing of a bit stream into E-signals, and their transmission onto and across a medium

5 5 2.1 TCP/IP reference model (3/13) Data link layer ensures the delivering data units from one station to the next without errors generates a frame adds meaningful bits to the header and trailer that contain addresses and other control information» to move a data unit from here to a destination» carry information about synchronization (stop & start) and sequencing» added by sending node» checked and interpreted by the receiving node ensures the flow control and error controls regulate the right of a device to transmit how to keep transmissions from overwhelming the receiver how to ensure that errors introduced during transmission

6 6 2.1 TCP/IP reference model (4/13) Responsibilities of the data link layer Node-to-node delivery Addressing: Header and Trailer Access control determine which device has control over the line at any given time Flow control regulated the amount of data that can be transmitted at one time Error handling provide for data recovery, by re-transmission Synchronization a frame control by bit patter in header and trailer Two sub-layer LLC (Logical Link Control) MAC (Medium Access Control)

7 7 2.1 TCP/IP reference model (5/13) Network Layer is responsible for the source-to-destination delivery of a packet across multiple network links ensures that each packet gets from its point of origin to its final destination successfully and efficiently two related services» CF: Layer 2; node-to-node delivery Switching: refers to temporary connections between physical links example: a telephone conversation temporarily joined into a dedicated link for the duration of the conversation Routing: means selecting the best path for sending a packet from one point to another when more than one path is available take a different route to the destination considers the speed, cost, and the ability of transmission

8 8 2.1 TCP/IP reference model (6/13) A Header for routing and switching includes the source and destination addresses of the packet» are different from the physical addresses in layer 2»are addresses of the original source and the final destination» do not change during transmission» are often called the logical addresses Responsibilities Source-to-destination delivery Logical addressing Routing Address transformation Multiplexing

9 9 2.1 TCP/IP reference model (7/13) Transport layer is responsible for the source-to-destination delivery of the entire message CF: Layer 3 ensures end-to-end delivery of individual packets» does not recognize any relationship between those packets ensures that the whole message arrives intact and in order oversees both error control and flow control at the source-todestination header includes a type of address called a service-point address» supports a delivery for a specific application service» called a port address or socket address contains sequence, or segmentation, numbers for the entire message» divides it into transmittable segments» indicates the sequence of segments in the header» reassembled upon receipt at the destination

10 TCP/IP reference model (8/13) Transport layer creates a connection between the two end ports for security a single logical path between the source and destination that is associated with all packets in a message three steps» connection establishment» data transfer» connection release Responsibilities End-to-end message delivery Service-point (port) addressing Segmentation and Re-assembly Connection Control

11 TCP/IP reference model (9/13) Session Function in Application layer is the network dialog controller (upper-level middleware) establishes, maintains, and synchronizes the interaction between communication devices ensures that each session closes appropriately validates and establishes connections between users controls the exchange of data: whether the exchange occurs in both directions simultaneously or only one direction at a time divides the session into sub-sessions using checkpoint for reliability Header» allow a session to backtrack includes control information: the type of the data unit being sent and synchronization point information

12 TCP/IP reference model (10/13) Responsibilities of Session Function in Application layer Session Management» dividing a session into sub-session Synchronization» deciding in what order to pass the dialog unit to the layer 4 Dialog control» deciding who sends and when Graceful close» ensuring that the exchange has been completed before the session closes

13 TCP/IP reference model (11/13) Presentation Function in Application layer Ensures interoperability among communicating devices Functions make it possible for two computers to communicate even if their internal representations of data differ provides the translation method of different codes is responsible for security:» the encryption and decryption of data» validating passwords and log-in codes is responsible for transmission efficiency:» the compression and expansion of data» the translation of changing the format of a message Headers information on the type parameters of the transmission the length of the transmission

14 TCP/IP reference model (12/13) Application in Application layer Enables the user to access the network Provides user interfaces Support for Specific services Internet Broadcast Systems File access, transfer, and management services Information Retrieval services Distributed Information services

15 TCP/IP reference model (1/13)

16 16

17 Transmission Layer (1/19) PSTN GSDN Three hierarchical sub-networks local access and switching networks» LE: Local Exchange» EO: End Office inter-exchange trunk/carrier networks international networks Three inter-related systems for overall network Transmission Systems : Wide Area Network Switching Systems : Router, Switch Signaling Systems : Connection

18 Transmission Layer (2/19) Transmission systems customer line, subscriber line in PSTN, analog transmission» a BW of 200Hz to 3.4kHz in GSDN, digital transmission : digital subscriber line (DSL)» 1.5Mbps or 2Mbps (24calls/30calls) Switching system to support a defined number of simultaneous calls/connections Signaling system transfer of a defined set of control message» call control» connect control between calling and called subscriber

19 Transmission Layer (3/19) Transmission system in the local access network»pstn: 전화라인»xDSL: 전화라인를 Digital로변환시킨것» Digital line in the trunk network» digital transmission via switch» PDH: plesiochronous digital hierarchy» SDH: synchronous digital hierarchy Analog subscriber lines

20 Transmission Layer (4/19) Telephone components

21 Transmission Layer (5/19) PSTN modems The representation of digital information by an analog signal ex: transmit data from an computer to a public telecommunication line Digital/analog Encoding Based on Amplitude Shift Keying (ASK) Frequency Shift Keying (FSK) Phase Shift Keying (PSK) Quadrature Amplitude Modulation (QAM)

22 Transmission Layer (6/19) From analog signal to PCM digital code

23 Transmission Layer (7/19) PAM Quantized PAM signal

24 Transmission Layer (8/19) Quantizing using sign and magnitude PCM

25 Transmission Layer (9/19) Digital subscriber lines B-channel : Bearer 64kbps user channel D-channel : 16kbps signaling channel T1 line: Mbps PRI: frame and multi-frame structure 193 bits / 125 * 10-6 sec= Mbps E1 line: Mbps PRI: frame and multi-frame structure 256 bits / 125 * 10-6 sec= Mbps

26 Transmission Layer (10/19) Plesiochronous digital hierarchy A hierarchical way by progressively multiplexing together multiple lower-level multiplexed streams Justification bits compensate for the small differences in the timing of each stream example: E1 is Mbps E2 = 4 * JB = = 8.448Mbps Drop-and-Insert or Add-Drop Multiplexer (ADM) multiplexing and demultiplexing of BW for user requirement and transmission

27 Transmission Layer (11/19) PDH : Mbps derived multiplex hierarchy

28 Transmission Layer (12/19) PDH : Mbps derived multiplex hierarchy

29 Transmission Layer (13/19)

30 Transmission Layer (14/19) CSU(Channel Service Unit) CSU 는 Channel Service Unit 의약자로 T1 또는 E1 트렁크를수용할수있는장비로서각각의트렁크를받아서속도에맞게나누어분할하여쓸수있는장비 Mux 라는집중장비가여러개의채널들을모아서하나의대용량전송로를통하여한꺼번에전송되는트렁크방식으로전송 부호화 (Encoding) 하여상대방으로전송하고또한부호화되어들어오는정보를원래의신호인디지털로복호화 (Decoding) 하는것이 "CSU, 채널서비스장치 " 의역할

31 Transmission Layer (15/19)

32 Transmission Layer (16/19) DSU (Digital/Data Service Unit) DSU 는디지틀전용회선을사용할때필요한장비로 DSU 가처리할수있는속도는 9.6Kbps - 64Kbps 만약 128Kbps 이상의속도를사용하게될때는 DSU 가아닌 HDSL 등의장비사용 DSU 는대역폭이그렇게크지않은 56Kbps 를가장많이사용하기때문에일반실선에바로연결을해서사용

33 Transmission Layer (17/19) Synchronous Digital Hierarchy (SDH) developed by Bellcore under SONET Synchronous Optical NETwork basic transmission rate Mbps STM-1 : synchronous transport module level 1» STM-4: 622 Mbps» STM-16: 2.4 Gbps SONET synchronous transport signal (STS) optical signal (OC) STS-1/OC-1 : 51.84Mpbs

34 Transmission Layer (18/19) SDH/SONET multiplexing Container contains the information content to carry multiple 1.5/2/6/34/45/140 Mbps PDH streams contains additional stuffing bits, control information path overhead, control BER (bit error rate)» Virtual Container see Next Slide : SDH/SONET multiplexing hierarchy and terminology

35 Transmission Layer (19/19)

36 36

37 Device Link Concept (1/2) IEEE 802 (1) In 1985, the Computer Society of IEEE developed Project 802. It covers the first two layers of the OSI model and part of the third level

38 Device Link Concept (2/2) IEEE 802 (2) LLC takes the structure of an HDLC frame devides it into two sets of functions MAC contains the end-user portions of the frame» the logical addresses, control information, and data resolves the contention for the shared media contains the synchronization, flag, flow, and error control specification necessary to move information form one place to another are specific to the LAN using medium

39 IEEE 802 (1/19) Network Layer CSMA/CD Bus CSMA/CD Bus Internetworking/Briging IEEE Logical Link Sublayer (LLC) Token bus Token bus Token ring MAN Physical Layer Token ring MAN BBTAG BBTAG FOTAG FOTAG IS LAN IS LAN IEEE Overview and Architecture management 표 1-1

40 IEEE 802 (2/19) Network Layer Internetworking/Bridging Network layer IEEE Logical Link Sublayer (LLC) LLC LAN Security Wireless LAN Cable TV WPAN WMAN MBWA MAC Physical Layer LAN Security Wireless LAN Cable TV bluetooth UWB WMAN MBWA Phy. Layer

41 IEEE 802 (3/19) IEEE 802 조직도

42 42 각표준요약정리 IEEE 802 (4/19)

43 43 각표준요약정리 IEEE 802 (5/19)

44 44 각표준요약정리 IEEE 802 (6/19)

45 45 각표준요약정리 IEEE 802 (7/19)

46 IEEE 802 (8/19) <LAN 의표준정의 : IEEE802 위원회 > 명칭 : HlLI(High-level Layer Interface, 고위층인터페이스 ) - 목적 : OSI의데이터링크층을둘로나눈 MAC층과 LLC층그리고상위층 ( 데이터링크보다상위 ) 과의인터페이스를주로표준화대상으로한다. 1)IEEE 802위원회전체가다루는 LAN아키텍처와전체구성 2)LAN과 WAN접속에대한인터네트워킹 3) 네트워크관리 (LAN/WAN관리등 ) - 심의내용 : 1)LAN-WAN 접속, LAN간접속 2) 라우팅 ( 경로선택 ) 방식 (MAC Bridge)802.1의스패닝트리방식과 802.5의소스라우팅방식의정합성 3)OSI네트워크관리 (CMIP) 와의정합성

47 IEEE 802 (9/19) 명칭 : LLC(Local Link Control, 논리링크제어 ) - 목적 : OSI 참조모델제 2 층데이터링크층의반쪽인 LLC 를심의함. 제 2 층하위반쪽의 MAC 에독립적이면서, 데이터를주고 받는절차의표준화가대상이다. - 심의내용 : 1)LLC타입 1/2/3/4 2)802.10(LAN Security) 에서의심의중인제 2층의 SDE(Secured Data Exchange) 와이미표준화된 LLC와의정합성및 LLC 관리

48 IEEE 802 (10/19) 명칭 : CSMA/CD(Carrier Sence Multiple Access with Collision Detection, 반송파감지다중액세스 / 충돌검출 ) - 목적 : OSI 참조모델제 2 층의하위반쪽에위치하는 MAC 인 - 심의내용 : CSMA/CD 방식의표준화를대상 ( 부호화방식은맨체스터 부호화방식 ) 으로한다. 1)10Base 5/10Base 2/1Base 5/10Broad 36/10Base-T/10Base-F 2)FOIRL(Fiber Optic Inter Repeator Link) 의표준화 3)100Base-T4 /100Base-TX /100Base-FX/100Base-T2 4)1GBase-T/1G-Base-Sx

49 IEEE 802 (11/19) 명칭 : Token Bus - 목적 : OSI 참조모델제 2 층의하위반쪽에위치하는 MAC 인토큰버 스 ( 브로드밴드 / 케리어밴드 ) 의표준화를대상으로한다. - 심의내용 : 1)1/5/10Mbps 브로드밴드방식 2) 캐리어밴드방식 ( 헤드엔드없는간이형 ) 3) 심의종료 명칭 : Tonen Ring - 목적 : OSI 참조모델제2층의하위반쪽에위치하는 MAC인토큰링 ( 베이스밴드 ) 방식의표준화를대상. - 심의내용 : 1)4/16Mbps 토큰링 (STP: 쉴드된트위스티드페어케이블 ) 2)MAC브릿지의한기능인라우팅방식과소스라우팅방식 3)4/16Mbps의 UTP( 케이블 ) 표준 / 광파이버표준 4) 전이중통신방식

50 IEEE 802 (12/19) 명칭 : MAN(Metropolitan Area Network, 도시규모네트워크 ) - 목적 : OSI 참조모델제2층의하위반쪽에위치하는 MAC인 DQDB(Distributed Queue Dual Bus, 역방향이중버스전송로방식 ) 의표준화를대상으로한다. - 심의내용 : 1) 미국규격 DS 1(Digital Signal Level 1,1.5Mbps) 용물리층인터페이스 2)DS3(45Mbps) 용물리층인터페이스 3)SONET( 광동기통신망 ) 용물리층인터페이스 4)B-ISDN( 광대역 ISDN) 의 ATM 셀과의호환성 5)622Mbps 전송속도에대한대응

51 IEEE 802 (13/19) 명칭 : LAN Security - 목적 : IEEE 802 표준 802.3/802.4/802.5의제정과정에서, 전송매체가동축 /U(S)TP/ 광파이버등으로다양화되고, 전송미디어가음성 / 데이터 / 영상으로멀티미디어화됨에따라 LAN에서의 Security 표준화의중요성이커져, 1988 년 7월부터심의를개시했다. - 심의내용 : 1)OSI 제7층 Application층에위치하는암호 key 관리의심의 2)OSI 제2층 Datalink층의 LLC와 MAC사이에위치하는 SDE(Secured Data Exchange) 의심의

52 IEEE 802 (14/19) 명칭 : Wireless LAN( 무선 LAN) - 목적 : 터미널의소형화 / 휴대화에따라다른 802 표준 LAN과정합성을갖는무선LAN의 MAC과물리규격의표준화를대상으로한다. - 심의내용 : 1)1Mbps/2Mbps의 Connectionless 형, 서비스지역 : 20m 20m 2) 물리층프로토콜 (PHY): 2.4GHz(ISM밴드 ) 의스펙트럼확산방식의 FH( 주파수호핑 ) DS( 직접확산방식 ) 와적외선의세개표준 3)MAC층으로서 CSMA/CD(Collision avoidance) 등의심의

53 IEEE 802 (15/19) IEEE 인가없이사용할수있는 ISM(Industrial, Scientific and Medical) 밴드의 2.4 GHz를사용하여 2Mbps 까지전송할수있는기존방식 b 기존변복조기술을일부변경하여전송속도를 11Mbps 까지고속화한방식. IEEE a ISM 밴드의 5 GHz대역에서 6 54Mbps 의전송속도를갖는 OFDM 방식. IEEE n 500Mbps 의전송속도를갖는방식. 250Mbps 가양산중

54 IEEE 802 (16/19) 명칭 : Cable-TV Protocol - 목적 : OSI 참조모델제2층의하위반쪽에위치하는 MAC인 Cable-TV프로토콜의표준화를대상으로한다. - 심의내용 : 1)CATV 헤드엔드 ( 주파수변환장치 ) 에의대응 2) 멀티미디어데이터의서비스품질 (QOS) 에대한대응 3) LAN 에뮬레이션기능의심의

55 IEEE 802 (17/19) 명칭 : Wireless Personal Area Network - 목적 : 근거리무선연결기술인 'bluetooth (Bluetooth) 의표준 이휴대폰과컴퓨터, handheld 기기를근거리범위에서무선 연결하는표준으로널리채택될것으로전망된다. - 명칭 : Broadband Wireless Access Working Group - 목적 : 광대역무선엑세스 ( 무선액세스 (wireless access) 는 무선을이용한코어네트워크로의사용자접속 ) 이러한무선액세스응용은 ITU 에서정의된무선서비스인 FS(Fixed Service), MS(Mobile Service), FSS(Fixed Satellite Service), 그리고 MSS(Mobile Satellite Service) 의틀에서제공될수있다

56 IEEE 802 (18/19) IEEE 802 무선인터넷 : WLAN (WiFi) : WPAN(Wireless Personal Area Network) Bluetooth UWB(Universal Wireless Broadband) : BWA(Broadband Wireless Access) WiMax(Worldwide Interoperability for Microwave Access) WiBro. HSDPA(High Speed Download Packet Access) HSUPA, HSHPA : MBWA (Mobile BWA) 각작업그룹의표준화프로젝트의특징은데이터속도및이동성측면에서 ( 그림 1) 에서와같이요약될수있으며각각상이한서비스를지향하고있음을알수있다

57 IEEE 802 (19/19)

58 LAN: Ethernet/IEEE802.3 (1/12) Ethernet/IEEE802.3

59 LAN: Ethernet/IEEE802.3 (2/12) Evolution of CSMA/CD Access method: CSMA/CD Addressing: its own network interface card (NIC) has 6bytes physical address Implementation: types of cable, connection, signals in MAC and PHY layer

60 LAN: Ethernet/IEEE802.3 (3/12)

61 LAN: Ethernet/IEEE802.3 (4/12)

62 LAN: Ethernet/IEEE802.3 (5/12)

63 LAN: Ethernet/IEEE802.3 (6/12) Fast Ethernet 규격 100BASE-TX : 100 Mbps의속도, baseband 전송, 2 쌍의 twsited pair를사용하는규격을말함. 100BASE-FX : 100 Mbps의속도, baseband 전송, 2 쌍의광섬유를사용하는규격을말함. 100BASE-T4 : 100 Mbps의속도, baseband 전송, 4 쌍의 twsited pair를사용하는규격을말함. 위의 3 가지규격들중에서 100BASE-TX 와 100BASE-FX 는 100BASE-X 라함.

64 LAN: Ethernet/IEEE802.3 (7/12)

65 LAN: Ethernet/IEEE802.3 (8/12) Gigabit Ethernet 규격 1000BASE-SX : 1 Gbps의속도, baseband 전송, 2 쌍의 Short wavelength multi-mode optical fiber를사용하는규격을말한다. 1000BASE-LX : 1Gbps의속도, baseband 전송, 2 쌍의 Long wavelength multi-mode 또는 single mode optical fiber를사용하는규격을말한다. 1000BASE-CX : 1 Gbps의속도, baseband 전송, 2 쌍의 short shielded Copper wire를사용하는규격을말한다. 1000BASE-T : 1Gbps의속도, baseband 전송, 4 쌍또는8 쌍의 category 5 UTP를사용하는규격을말한다.

66 LAN: Ethernet/IEEE802.3 (9/12) Gigabit Ethernet

67 LAN: Ethernet/IEEE802.3 (10/12)

68 LAN: Ethernet/IEEE802.3 (11/12)

69 LAN: Ethernet/IEEE802.3 (12/12)

70 IEEE 802 WLAN (1/5) IEEE 년부터사용되었음 Wireless LAN 기술에대한표준으로 CSMA/CA 의기술채택 과 b 는무선 Ethernet LAN 에적용 2.4GHz 주파수 (ISM 밴드 ) 에서운용 속도는 은 1~2Mbps IEEE a 1999 년에채택되었음 ATM 시스템에적용되고, 5GHz 주파수에서운용 데이터속도는최대 56Mbps IEEE b (WiFi) 1999 년에채택되었고, 일명 High Rate 또는 Wi-Fi 라함 의이후규격으로 2.4 GHz 대역사용 과호환성을갖고있으며최고전송속도는 11Mbps

71 IEEE 802 WLAN (2/5) IEEE g 2003년에채택되었음 IEEE b(WIFI) 의일종으로2.4GHz 주파수대역 54Mbps의속도로데이터전송 IEEE n: 5GHz 주파수대역에서최대 200Mbps 다중입력다중출력 (MIMO) 기술과대역폭손실의최소화를위한 MAC 계층과물리계층의변형을통해최대 600Mbps 속도가능 (?) 다중고선명텔레비전 (HDTV), 디지털비디오스트리밍등높은대역폭의동영상도처리할수있다. IEEE 의 n 표준화작업은인텔사가주도하는 TGnSync, 텍사스인스트루먼츠사가주도하는 WWiSE, 모토로라사와 MIT 대학교가주도하는 MITMOT 등 3 개표준제안그룹에의해시작되었다.

72 IEEE 802 WLAN (3/5) Wi-Fi (pronounced wye-fye, IPA: ) is a wireless technology brand owned by the Wi-FI Alliance intended to improve the interoperability of wireless local area network products based on the IEEE standards. Common applications for Wi-Fi include Internet and VoIP phone access, gaming, and network connectivity for consumer electronics such as televisions, DVD players, and digital cameras.

73 IEEE 802 WLAN (4/5)

74 IEEE 802 WLAN (5/5)

75 IEEE 802 WPAN (1/3) IEEE 근거리무선통신표준화위원회의명칭. PAN(Personal Area Network) 을위한표준으로적은파워소비, 낮은복잡성제공을목표로한다. 블루투스와마찬가지로가정내이동체통신기기나 PC, 기타주변기기의무선망구축목적 하부조직으로최대전송속도가 1Mbps 인 WPAN(Wireless Personal Area Network) 연구그룹과 최대전송속도 20Mbps 의 WPAN HRSG(WPAN High Rate Study Group) 등이있음

76 IEEE 802 WPAN (2/3) Bluetooth 에 2.4GHz ISM 대역에서 1Mbps 의전송속도 기존의 b 또는 g 의 WLAN 과 의 WPAN 과의공존 라이센스가없는대역을사용하는것을목표로만들어졌음 에서 2.4 GHz ISM 대역을이용하는 b 와 g 방식과의공존 WPAN-HR(Wireless Personal Area Network-High Rate) 를위한표준으로높은수준의전송률 (~55 Mbps) 을제공 TDMA 방식을이용한안정적인 QoS 를제공 보안을위해 AES(Advanced Encryption Standard) 128bit 이적용 WPAN-LR(Wireless Personal Area Network-Low Rate) 를위한표준으로적은파워를소비하고 CPU, Memory 등에제한이있는장비가낮은전송률로데이터를전송할수있도록하여센서네트워크등에적용

77 IEEE 802 WPAN (3/3)

78 IEEE 802 WMAN (1/5) IEEE 광대역무선접속규격개발을목적으로만든워크그룹 년 4 월 10~66GHz 대역을이용해 WMAN 서비스를제공하기위한규격으로, 양방향통신을위해 10.5, 25, 26, 31, 38, 39GHz 대역과같은인가대역에서 20, 25, 28MHz 폭의광대역전송률을갖게됐다. 이때각대역폭에서전송할수있는최대데이터전송률은 20MHz 대역에서 96Mbps, 25MHz 대역에서 120Mbps, 28MHz 대역에서 134.4Mbps 이다. Wibro / WiMax 라호칭 IEEE e 차세대표준 모바일와이맥스표준보다한단계진일보한 IMT-Advanced 표준에반영하기위해표준에대한어드밴스드에어인터페이스표준을개발 IMT-Advanceddms 이동시 100Mbps, 고정시 1Gbps 의전송

79 IEEE 802 WMAN (2/5) IEEE a 일명 WiMAX (World Interoperability for Microwave Access) 라함 a 규격에서는 2 11GHz 를이용하도록개정되었다. 사각지대의단말과도통신할수있도록개량되어있다. 통신속도나최대거리는변하지않고, 한대의안테나로반경약 50km(30 마일 ) 을커버하며, 최대 70Mbps 로통신이가능하다. WLAN 과는달리, 현재전화회선이나광섬유가담당하고있는가입자계통신망의말단부분에서이용 IEEE 에의한가입자계억세스망을 Wireless MAN ( 무선 MAN:Wireless Metropolitan Area Network) 이라고말한다. 인구밀도가낮은지역에서도염가로브로드밴드접속서비스를제공하는수단으로주목받고있다. WiMAX 는업계단체 WiMAX Forum 에의한애칭으로, 동규격에대응한각사의통신기기호환성과상호운용성을테스트하여, 인증을부여하고있다. WiMAX 표준 기기끼리는메이커가달라도조합하여사용할수있도록보증된다.

80 IEEE 802 WMAN (3/5)

81 81 IEEE IEEE 802 WMAN (4/5)

82 82 IEEE 네트워크의 IEEE 802 주요 WMAN 요소 (5/5)

83 IEEE 802 MBWA (1/3) IEEE 모바일기기에이동성을제공해주기때문에기존의셀룰러기반의이동통신기술과도경쟁하게될것으로예상돼업계가주목하고있는표준이다. MBWA(Mobile Broadband Wireless Access) 로도불리는이표준은 3.5GHz 대역을이용하며도시지역통신망 (MAN) 에서데이터전송률을현재의전화선연결속도보다빠른 1Mbps 까지끌어올려준다. 15Km 또는그이상의셀범위내에서노트북 PC, PDA, 기타배터리로작동되는모바일기기등에유비쿼터스광대역네트워킹을제공한다. 빠른속도로이동하면서도초고속인터넷망에준하는속도로무선데이터통신을이용할수있는표준이만들어진다. 즉, 최고시속 250Km 로이동하는모바일사용자에게현재의케이블이나 DSL 등을기반으로하는초고속인터넷망과유사한수준의무선서비스를제공하기위한무선인터페이스표준인 IEEE 제정

84 IEEE 802 MBWA (2/3) IEEE 표준화목표 무선사용자들이실제광대역서비스를체험할수있도록하는새표준은오늘날시스템보다 2 배이상높은 1 비트 /s/hz/ 셀의스펙트럼효율을목표로하고있다. 높은스펙트럼효율과낮은레이턴시를갖는고품질무선접속을가능케해사용자들이고속으로유선과같은품질의무선데이터서비스를이용할수있게해줄것으로기대된다. IEEE 은이밖에 VoIP(Voice-over-Internet Protocol) 를채택한기술의사용이가능하며다른인터넷프로토콜 (IP) 애플리케이션을지원해이를변경없이사용할수있고빠른네트워크응답시간을요구하는모바일기기에적합하도록만들어진다. 현재이표준프로젝트는 IEEE 산하 LAN/MAN 표준위원회 (LMSC) 의 WG 가주도하고있으며모바일무선시스템, 무선인터페이스, 모바일등의분야전문가들이작업에참여하고있다.

85 IEEE 802 MBWA (3/3) Mobile Internet 개념 인터넷접속시유비쿼터스및이동성을보장. MBWA 는 15Km 이상의반경내에서모바일기기에광대역네트워킹을제공, 기존이동통신기술은물론와이브로에볼루션등과경쟁할것으로업계는이기술을주목하고있다. 유비쿼터스, 이동성보장 - 3.5GHz 허가대역을이용, 최고시속 250Km 의이동시에도현재의케이블이나 DSL 등을기반으로한초고속인터넷과동일한수준의데이터전송속도를제공 -MBWA 는패킷데이터및적응성안테나에최적화된 PHY 와 MAC 을사용하며, 완전한이동성에최적화되어있고, 3.5GHz 이하의주파수대역을사용하고, 대역폭은 5MHz 이하이다. 패킷전용시스템이며, 모바일 IP 기반의 QoS 멀티미디어서비스를위한채널화및제어를사용하며 e 와같이링크및다운링크데이터전송에고능률적이며지연이낮은구조를가지고있다.

86 Connection Concepts (1/4) Physical Layer OSI Layer 2 OSI Layer 3-7 Repeater Bridge Router Gateway Same Different Different Different Same Same Different Different Same Same Same Different

87 Connection Concepts (2/4) Repeaters

88 Connection Concepts (3/4) Bridges

89 Connection Concepts (4/4) Gateway

90 90

91 IP Concept (1/6) Internet Packets are like Postcards To/From addresses Finite but variable content Delivery failures Duplication (not normally a postal service) Disorderly arrival Variable delays Alternate routes/carriers

92 IP Concept (2/6) IP Addresses Assigned by the NIC (Network Information Center) 호스트의인터넷주소에대응하는숫자주소 4개의숫자와마침표로구성 구성 네트웍주소 호스트주소 세계적으로고유함 NIC (NIDA: National Internet Development Agency) 에등록 국제적협조필요

93 93 IP Address Format 2.4 IP Concept (3/6) Class A Class B Class C Class D 7 bits 24 bits 0 netid hostid [1-127] 1 0 netid netid hostid [ ] 14 bits 16 bits [0-255] netid netid netid hostid [ ] [0-255] 21 bits 8 bits 28 bits [0-255] Multicast address

94 IP Concept (4/6) Domain of IP 인터넷호스트의지정방식 계층적으로구성 Top-level domain 국가별 기관별 Sub Domain eg) sookmyung.ac.kr

95 IP Concept (5/6) Internet networking components and protocols

96 IP Concept (6/6) IP Adjunct protocols

97 IP Datagrams (1/8) Basic unit of Internet transfer Analogous to physical network packet Composed of Header that contains source and destination Internet addresses, datagram type field, etc. Data area that contains data being carried Encapsulation IP datagram travels in physical network packet or frame Complete datagram is treated as data by the hardware TCP/IP defines standards for encapsulation on most network hardware

98 IP Datagrams (2/8) IP datagram Format

99 IP Datagrams (3/8) Fragmentation and Reassembly

100 IP Datagrams (4/8) Network MTU Each network h/w technology imposes a fixed limit on the maximum size of a packet Size limit called Maximum Transmission Unit (MTU) Encapsulated datagram must be less than network MTU Datagram Fragmentation Needed when datagram larger than network MTU over which it must travel Performed by routers Divides datagram into several, smaller datagrams called fragments Each fragment routed as independent datagram Final destination reassembles fragments

101 IP Datagrams (5/8) Datagram Fragmentation Details Each fragment is a datagram Router replicates initial datagram header for all fragments Offset field in header gives offset in original datagram for data in this fragment Fragment bit in header indicates this is a fragment Additional bit set in header to indicate last fragment header Data1 400bytes Data2 400bytes Data3 400bytes header1 Data1 Fragment #1 (offset of 0) header2 Data2 Fragment #2 (offset of 400) header3 Data3 Fragment #3(offset of 800)

102 IP Datagrams (6/8) MTU 의중요성 TCP 의 throughput 을근사화. TCP 의수율 = MSS * 1.2 / ( sqrt(p) * rtt), p: 패킷손실확률 rtt : round trip time, MSS : maximum segement size: TCP 에서의최대패킷 ( 혹은세그먼트 ) 의길이인데 MTU 단위로 TCP 데이타가짤라지니 MTU 를크게하면당연히 TCP 의 throughput 도증가 TCP 를사용하는대부분의인터넷프로그램 (ftp, http, etc) 등은 throughput 이중요하고, 또한기본적으로윈도우에서 MTU 값이실제망의값보다작은값으로설정될수있음. 이럴때는 MTU 값을높여주고그패킷이운좋게짤려지지않고목적지까지보내진다면 throughput 을높일수있음.

103 IP Datagrams (7/8) MTU 사이즈알아내기 %ping -f -l 실행시켜서 fragment 발생하지않으면그사이즈가 icmp 의 data 부분사이즈이다 icmp data (1472 ) + icmp header (8) + ip header (20) = MTU (1500) %ping f f Packet needs to be fragmented but DF set. MTU 값변경 Windows XP C> regedit Unix, Linux %ifconfig eth0 mtu 1300

104 IP Datagrams (8/8) 최대 UDP datagram 크기 이론적 IP datagram 최대크기 byte IP Header : 20byte UDP header 8byte Payload: 65507byte 실질적 API 버퍼크기 UDP socket : 8192 byte 이상

105 Subnet addressing (1/3)

106 Subnet addressing (2/3) 32bits 구성됨. Class A, Class B, Class C 가있음 인터넷을위한 IP Address 는공인기관으로부터할당받아야하며, Network Number 만을할당받음 Host Number 는네트웍관리자가원하는대로활용가능 Network (N) Host (H) bits 8bits 8bits 8bits Class A Class B Class C N H H H N N H H N N N H

107 Subnet addressing (3/3) Class A Class B Class C N H N H N H Network # 갯수 1 개의 Network # 내의이용가능한 Host Number 수 첫 1Byte의십진수범위 Class A Class B Class C 1 ~ 126 (126 개 ) 개 (256^3-2) 1 ~ ~ (32766개) ~ ( 개 ) 개 (256^2-2) 128 ~ 개 (256^1-2) 192 ~ 223

108 Routing Concepts (1/15) Routing in an Internet Host delivers datagrams to directly connected machines Host sends datagrams that can not be delivered directly to router Routers forward datagrams to other routers Final router delivers datagram directly Routing protocol 데이타를 encapsulation해서전달하기위한 protocol로 IP, IPX, Appletalk등이이에해당된다. routing protocol이라는것은 IP packet, IPX packet, Appletalk packet등을전달할때경로정보를교환, 관리하기위한 protocol이다. IP는 routing protocol로 RIP, IGRP, OSPF, BGP등을, IPX는 Novell RIP, NLSP등을, Appletalk은 RTMP를이용한다.

109 Routing Concepts (2/15) Line ID, cost

110 Routing Concepts (3/15) Network Layer 는시작 (source) 에서부터목적지 (destination) 까지 Packet 을전달 Routing Protocol 은라우터간에경로정보를주고받는 Protocol S S app pre ses trans net data phy r1 net data phy 1 2 r2 r3 net data phy r4 r5 net data phy 6 7 r6 r1 r3 r4 r6 net data phy D D app pre ses trans net data phy

111 Routing Concepts (4/15) Efficient Routing Routing decisions based on table lookup Routing tables keep only network portion of addresses size proportional to number of networks not number of hosts Algorithm is efficient and easy to understand Easy to automate routing table update

112 Routing Concepts (5/15) 경로결정영향요소 Bandwidth Delay Reliability Load MTU Hop Count money S 1 로직접가? 아니면 2, 3 으로가? D OSPF : Bandwidth RIP : hop count IGRP : Bandwidth, Delay, Reliability, Load, MTU

113 Routing Concepts (6/15) Routing 관련 Keyword advertising 혹은 announcement neighbor next hop 주기적 update cost = function (metric factors) RIP 의 metric factor 는 hop count IGRP 의 metric factor 는 bandwidth, delay, reliability, load, MTU OSPF 의 metric factor 는 bandwidth partial update 및 full update metric factor 및 metric cost Autonomous System Number (AS Number, ASN)

114 Routing Concepts (7/15) IP Routing 설정절차 Global Configuration IP routing protocol 중에하나를선택 Routing Update 에참여할자신의 Interface 에할당된 IP Network Address 선언 Interface Configuration IP Address 및 netmask 지정 RIP RIP / IGRP IGRP netb netd A B C neta netc nete

115 Routing Concepts (8/15) Static Route vs. Dynamic Route Static Routing Static Route Default Route Dymanic Routing Interior Gateway Protocll RIP, IGRP(cisco), OSPF, EIGRP(cisco) Exterior Gateway Protocol BGP 라우터는 Static Route 및 Dynamic Route 를 Routing Table 에관리 라우터는동시에여러개의 Routing Protocol 을운영할수있음

116 Routing Concepts (9/15) Dynamic Route vs Static Route Dynamic Routing Protocol Distance Vector <-> Link State 주기적 update <-> 변화시즉시 update Singleprotocol <-> Multiprotocol IP, IPX 를동시에처리불능 <-> 동시처리가능 Interior <-> Exterior 네트웍그룹내 <-> 외부네트웍그룹간 Singlepath <-> Multipath Cost 가다른 link 를동시에이용하지않음 <-> 동시에이용함 Hierarachical <-> Flat 계층적인정보교환 <-> 계층적이지않음

117 Routing Concepts (10/15) Distance Vector 인접한라우터의관점으로전체네트웍정보를얻음 인접한라우터가갖고있는 cost 와인접한라우터까지의 cost 를더함 주기적으로정보를 update convergence time 이길다 Routing Table 을인접한라우터에게전달 Link State 각라우터가전체네트웍상태판단 자신이직접목적지까지의 cost 를계산함 변화즉시정보를 update convergence time 이짧다 변화된정보만을다른라우터들에게전달

118 Routing Concepts (11/15) RIP (Routing Information Protocol) RIP 은 RFC1058 에규정되어있다. RIP 은 BSD UNIX 의 routed 로처음발표되었었다. distance vector routing protocol interior gateway protocol metric factor 로 hop count 를이용하며가능한최대값은 15 single path routing protocol 이다.

119 Routing Concepts (12/15) IGRP(Internet Gateway Routing Protocol) IGRP 는 cisco 사에서개발한것임. distance vector routing protocol interior gateway protocol metric factor 로 bandwidth, delay, reliability, load, mtu 를이용한다. 90 초마다 routing information 을전달한다. 추가적으로네트웍의변화를인지했을경우이를인접한라우터에게즉시전달해준다. 이런것을 Flash Update 라고한다. 이러한특성때문에 convergence time 이 rip 보다빠르다 multi path routing protocol 이다. 그렇지만기본적으로 single path routing 으로설정되어있으므로 multi path routing 을할수있도록설정해주어야한다.

120 Routing Concepts (13/15) OSPF(Open Shortest Path First) a routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working group of the Internet Engineering Task Force (IETF) published as Request For Comments (RFC) 1247 was formed in 1988 to design an IGP based on the Shortest Path First (SPF) algorithm for use in the Internet Similar to the Interior Gateway Routing Protocol (IGRP) was created because in the mid-1980s, the Routing Information Protocol (RIP) was increasingly incapable of serving large, heterogeneous internetworks. a link-state routing protocol, contrasts with RIP and IGRP

121 Routing Concepts (14/15) RAM 실행명령어 program bootstrap program IOS(Internetwork OS) active config file tables buffers NVRAM Flash backup config file IOS ROM bootstrap program subset IOS Interfaces LAN Interfaces (e, t, f) WAN Interfaces (s, hssi) Console Auxiliary

122 Routing Concepts (15/15) Hierarchical routing over the Internet

123 123 Tunneling Example

124 ICMP (1/3) Internet control message protocol an integral part of all IP implementation Used mostly by routers to report delivery or routing problems to original source Uses IP to carry control messages main functions error reporting reachability testing congestion control route-change notification performance measuring subnet addressing

125 ICMP (2/3) Error reporting Destination Unreachable Time Exceeded Parameter error ICMP messages Reachability testing Echo Request/Reply Congestion Control Source Quench Route exchange Redirect (change route) Performance measuring Time-stamp request/reply Subnet addressing Address Mast Request/Reply

126 ICMP (3/3) ICMP Message Encapsulation Type Code Checksum UNUSED (Must be Zero) Internet header + 64 bits of data ICMP message IP header IP data Frame header Frame data ICMP message has header and data areas Complete ICMP message is treated as data in IP datagram Complete IP datagram is treated as data in physical network frame

127 Address Resolution Protocol (ARP) (1/3) Internet standard for dynamic address binding Allows machine A to find machine B s physical address knowing only B s Internet address Uses hardware broadcast ARP only used to map addresses within a single physical network, never across multiple networks ARP details ARP table is merely a cache Entries should time out and be invalidated Machine can broadcast new binding when it boots

128 Address Resolution Protocol (ARP) (2/3) ARP request and reply messages (1) Machine A broadcasts ARP request with B s IP address All machines on local net receive broadcast Machine B replies with its physical address Machine A adds B s address information to its table Machine A delivers packet directly to B

129 Address Resolution Protocol (ARP) (3/3) ARP request and reply messages (2) A broadcasts request for B (across local net only) A X B Y B replies to request A X B Y

130 QoS support (1/3) To meet more varies set of QoS requirements IntServ : integrated services DiffServ : differentiated services type of service field in IP packer header be used by routers

131 QoS support (2/3) Three different classes service in IntServ solution guaranteed class a specified Max. delay and jitter an assured level of bandwidth» are guaranteed for application involving the playout of real-time streams controlled load (as predictive) class no firm guarantees are provided a constant level of service equivalent to that obtained with the best-effort service at light loads for application involving real-time streams that have the capability of adjusting the amount of real-time data best-effort for text-based applications

132 132 Control mechanisms for QoS QoS support (3/3) Token bucket filter an amount of buffer/queue space is reserved for each flow in a container called a bucket token: the quaranteed QoS requirements Weighted fair queuing a queue management to ensure the quaranteed QoS requirements compares the time-stamp of the packet Random early detection a queue management to ensure the quaranteed QoS requirements compare the queue length Resource reservation protocol (RSVP)

133 133

134 TCP/IP TCP (Transmission Control Protocol) Connection-oriented service Sequencing Error Control re-transmission Flow Control sliding windows Reliable Transmission UDP (User Datagram Protocol) Connectionless Service Datagram Un-Reliable Transmission Application Layer Reliable Stream (TCP) User Datagram (UDP) Internet Protocol (IP) Network Interface Services

135 TCP/IP Reference Model 네트워크프로그래밍의계층별분류

136 계층별분류와특징 계층 응용계층 예 http CORBA RPC 특징 이미작성된유틸리티활용 개발, 변경, 운영의편리 트랜스포트계층 Socket Winsock 패킷단위의송수신처리 인터넷프로그램의기초 디바이스드라이버계층 Packet Driver NDIS, ODI MAC 프레임단위의송수신 흐름제어, 오류제어가없음

137 137 TCP/IP 내부구조 2.5 개요 (Cont d)

138 Application Protocols (1/10) RTP transport protocol for the delivery of real time data RTCP a part of RTP Helps with lip synchronization, QOS management RTSP A control protocol for initiating, directing delivery of streaming multimedia from media server No delivery data

139 Application Protocols (2/10) RTP (Real-time Transport Protocol) RTCP (Real-time Transport Control Protocol) 실시간전송프로토콜 멀티미디어스트림을실시간으로처리 멀티미디어스트림을송수신하는통신모듈설계 오디오, 비디오데이터는 실시간특성 데이터의연속성유지와현장성 오류허용성 다중사용자의동시성과멀티캐스팅기능 화상회의,VOD 시스템

140 Application Protocols (3/10) RTSP (Real-Time Stream Protocol) Client Server multimedia presentation control protocol enables controlled delivery of streamed multimedia data Works both large audience and single viewer media on demand Work with lower level protocol RTP, RSVP Developed by RealNetworks, Netscape communication and Columbia University published as a proposed Standard by the IETF in 1998

141 Application Protocols (4/10) How to relate?

142 Application Protocols (5/10) RTP / MPEG-4 Standard Both an IETF and ITU A packet format for multimedia data streams Used by many standard protocols RTSP, H.323, SIP Provides the data delivery format A standard issued of the Motion Picture Experts Group Comprised of Video codec and file format How to relate to RTSP / RTP MPEG 4 : specify set of data types and a file format RTSP / RTP : specify the necessary client server interaction

143 Application Protocols (6/10) Why not use the HTTP? HTTP Based on TCP Only rudimentary mechanisms for random access to files Not suited to time based seeking RTSP Work with time based media Control multicast delivery of streams Provide a framework for multicast-unicast hybrid solutions

144 Application Protocols (7/10) RTP A one way protocol Used to send live or stored streams from server to client After the data is displayed, it s discarded RTSP Used when viewers communicate with a server Two way communication Viewers can communicate with the streaming server and do things like rewind the movie, go to a chapter

145 Application Protocols (8/10)

146 Application Protocols (9/10) RTP 전체블록구성도 Device 상위멀티미디어응용 상위상위응용응용연결연결인터페이스인터페이스블럭블럭 RTP 통신모듈 QoS QoS관리관리정보처리정보처리블럭블럭 RTP/RTCP RTP/RTCP 패킷패킷처리블럭 네트워크네트워크인터페이스인터페이스블럭블럭 UDP 네트워크

147 Application Protocols (10/10) Sink A/V stream 멀티미디어응용으로부터의세션및스트림제어 Source A/V stream A/V stream Codec(decoded) Codec(encoded) 상위응용연결인터페이스블럭 도착간지터모니터메시지유효성검사기 실시간 QoS 관리블럭 세션멤버관리자 순서번호발생기타임스탬프발생기 RTP/RTCP 메시지처리블럭 RTP/RTCP message RTP/RTCP 메시지해독기 RTP/RTCP 메시지생성기 네트워크인터페이스블럭 UDP UDP datagram

148 148

149 149 Electronic Mail Internet mail clients/servers message transfer agent (MTA) Protocol stack for RFC 822 Message store (MS) : mailbox : Post Office Protocol, version 3 (POP3): RFC1939 user agent function Simple Mail Transfer Protocol (SMTP): RFC 821 application protocol to transfer of messages between MTA in two servers Domain Name Server (DNS) to refer the Internet address of the recipient server Multipurpose Internet Mail Extensions (MIME) : RFC 2045 different languages and media types (audio, images, video) gateway

150 150 over the Internet

151 151 Protocol stack to support over Internet

152 152 Protocol stack to support information browsing

153 153 protocol stack to support the browsing of pages cotaining Java applets

154 클라이언트 - 서버통신모델 서버 : 서비스제공 클라이언트 : 서버가제공하는서비스를이용하는장비와이에필요한프로그램 서버가먼저실행 클라이언트가요구 (request) 를보내면서버가이에대한응답 (response) 를보내준다

155 Client/Server Architecture

156 Application Tasks in C/S User Interface what the user actually sees Presentation logic what happens when the user interacts with the form on the screen Application logic Data requests and results acceptance Data integrity such as validation, security, completeness Physical data management such as update m retrieval, deletion, and addition

157 Spectrum of Client/Server Definitions Presentation Application Data management Network Presentation Presentation Processing Logic Business Processing Logic Data Processing Logic DBMS Database

158 Client/Server Components: Role of Client (1) Client Server Presentation logic Application logic. Application Logic. Data Access Logic Presentation logic Application logic

159 Client/Server Components: Role of Client (2) Definition: The client is any application/function/launcher/requester process The client extends the user s workplace Access to remote functions and data Communication with other peer processes Resource sharing as required The client allows the user to personalize the workplace Custom interface design Hardware/software rightsized to requirements Sense of ownership The client hides complexity of underlying infrastructure Network, operating system, and data access are hidden User has a common syntax and lexicon across all application s A client may also be a server concurrently

160 Client/Server Components: Role of Server (1) Client Server Presentation logic Application logic. Application Logic. Data Access Logic Presentation logic Application logic

161 Client/Server Components: Role of Server (2) Definition: The server is a specialized responder to requests That is, the server is a process The server implements specific functions Access to data, services, custom applications May provide some aspects of presentation Servers can be arranged in a variety of configurations Tiered, star, network New servers can be implemented with minimal impact Multiple servers may exist on the same hardware platform Servers may exist on a variety of hardware/software platforms Not restricted to microcomputers A server may also be a client concurrently

162 Client/Server Types S E R V E R Network Data 관리 Application Presentation Presentation Data 관리 Application Presentation Data 관리 Application Application Presentation Data 관리 Application Presentation Data 관리 Network Data 관리 Application Presentation C L I E N T Distributed Presentation Remote Presentation Distributed Function Remote Data Management Distributed Data Management