Microsoft PowerPoint - isdn03.ppt

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1 整體數位服務網路簡介陳伯寧教授國立交通大學電信工程學系定義 ISDN 是從電話網路演進而來的一種端對端數位式連接網路, 能提供廣泛的資訊服務包括語音及非語音, 而使用者則透過幾種有限的用戶網路介面即可存取服務它採用數位式的傳輸方式, 更方便的提供語音數據影像視訊等服務

2 定義 Network ( 網路 ) Digital ( 數位 ) Services ( 服務 ) Integrated ( 整體 ) 電信網路演進全類比式 $ 電話長途傳輸數位化 96(T) 975 $ 電話交換機數位化 $ 服務用戶線數位化 980 4

3 ITU-T(CCITT) I-Series Recommendations (ISDN) ( 前國際電信電話諮詢委員會 I 系列建議書標準 ) I.00 Series Service Aspects ( 服務特性 ) I.00 Series Network Aspects ( 網路特性 ) I.00 Series - General ISDN Concept( 一般概念 ) -Structure Recs.( 建議書架構 ) - Terminologies( 用語 ) - General Methods( 使用方法 ) I.400 Series User-Network Interface Aspects ( 用戶 - 網路界面特性 ) I.600 Series Maintenance Principles ( 維護原則 ) I.500 Series Inter- -network Interfaces ( 網路與網路間介面 ) 5 ISDN 接線和資料通道

4 Functional Groupings and Reference Points ( 功能群組與參考點 ) Customer Premises Equipment Customer Premises Equipment Europe USA Network Network S T U V TE NT NT LT ET TE R TA Functional Groupings R, S, T and U : Reference points TE : Terminal Equipment TA : Terminal Adapter S Note: Up to 8 ISDN TEs can be connected to the same S or T reference point.( S 或 T 參考點最多可接八個 ISDN TEs) NT : Network Termination LT : Line termination ET : Exchange termination 7 介面之接頭與插座 8

5 Pin Assignment of S/T Interface TE NE Power source Power sink a b c+ d - e f transmit receive receive transmit a b c d -e +f Power source Power sink g h g h Power source 9 Pin Assignment of U Interface TE NT TIP or RING TIP or RING TIP or RING TIP or RING Pins,,, 6, 7 and 8 are not connected. 0

6 ISDN asic Access Subscriber Interface ISDN Terminal S/T G4 Facsimile ISDN Workstation S/T S/T +D NT +D U LT ISDN C.O. Switch Non-ISDN Terminal Digital Telephone Terminal Adapter S/T S/T Customer Premises Central Office Access Type - asic Access +D D Access Rate: +D = 9 Kbps worldwide and : 64 Kbps D : 6 Kbps Overhead : 48 Kbps

7 asic Rate Interface Frame Format 5 us D Control information Channels ISDN Primary Access Subscriber Interface ISDN Terminal ISDN Terminal S S +D ISDN PAX (NT) T +D (0+D) NT U LT ISDN C.O. Switch Terminal Adapter S Non-ISDN Terminal Customer Premises Central Office 4

8 Access Type - Primary Access Virtual Path Virtual Channel Physical Link 5 Primary Rate Interface Frame Format Channel: 5 us 4 +D D Framing bit 0+D Channel: ch. to 5 D ch. 6 to Channel 0 : sync. timing & control data 6

9 ISDN Channel Types D channel: for packet data and signaling 6 Kb/s in asic Rate ISDN 64 Kb/s in Primary Rate ISDN Channel: 64 Kb/s circuit switched channel for voice and data 7 ISDN Channel Types Some user applications require more bandwidth than a channel can provide, such as video teleconferencing. 8

10 ISDN Channel Types Standard configurations of bandwidth, known as H channels, provide such higher bit rate. H0 Channel: 84 Kb/s, a logical grouping of six (circuit switched) channels. H Channel: 56 Kb/s, made up of all available H0 (circuit switched) channels on a single-user interface employing a T line (+D) H Channel: 90 Kb/s (0+D), European Version of H 9 Open Systems Interconnection (OSI) Model of the International Standards Organization (ISO) User Equipment Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer User Equipment Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer Switching Network Switching Network 0

11 ISDN Layer Model (CCITT Rec. I.0) M C U NT M C C NT M C U S/T S/T M C U Management Functions Control Functions (Signaling) User Functions S/T S or T reference point NT Network Termination ISDN Protocol Data Format PD CR M Additional data I.45 Layer I.45 Data Format PD CR M Additional data F A C Layer information FCS F I.44 Layer I.44 F A C Layer information FCS F I.40 I.4 Layer I.40 I.4 Layer : PD : Protocol Discriminator CR : Call Reference I.45 : CCITT standard M : Message type for ISDN layer protocol Layer (Link Access Procedure on the D-channel, D LAPD) : I.44 : CCITT standard F : 8-bit 8 Flag byte for ISDN layer protocol (LAP-D A : 6-bit Address word or D-channel link access protocol) C : 8-8 or 6-bit Control word I.4 : CCITT standard FCS : 8-bit 8 Frame Check Sequence for ISDN layer, basic rate protocol I.40 : CCITT standard Layer : -channel : 64 kbps channel for data or voice for ISDN layer, primary rate protocol D-channel : 6 kbps channel for signaling (Layer messages are transmitted through D-channel) D

12 經由頻道的線路交換模式 (NULL) TE D LE SS#7 STP SS#7 LE D TE (NULL) 4 & above D Level 4 (NULL) Signaling system #7 network Level 4 (NULL) 4 & above D STP = signal transfer point LE = local exchange 經由頻道的分封交換服務 Packet link Packet link TE LE LE TE D D Hot line signaling for access to packet facility Hot line signaling for access to packet facility 4

13 經由 D 頻道的分封交換服務 Packet link Packet link LE LE D D 5 ISDN 用戶網路介面 Physical Layer Link Layer Network Layer 6

14 S/T 界面需要四線 ( 兩對 ) 作信號傳輸位元速率 (it Rate) : 9 Kbps 數據速率 (Data Rate) : 44 Kbps (+D) 提供單點對單點與單點對多點的連線最多可有八部終端設備 7 佈線 (Wiring) 佈線的極性單點對單點 : 在一對線中, 其兩線之極性可以是相反的單點對多點 : 從終端設備到網路終端方向佈線的極性, 在終端設備間必需維持一致終端設備 TE 的連接線 I Aj, 0 j N, 不長於 0 公尺網路終端 NT 的連接線 I 不長於公尺終端電阻 TR=00 Ohm TE I A0 TR TR I NT I A I AN TE TE 8

15 點對點佈線長度之限制 : 傳 96KHz 的訊號衰減量達 6 d 時之距離 750 m ~ 000 m TE TR TR NT 9 點對多點佈線 Short Passive us 長度之限制來自 Roundtrip Delay 需在 0 us ~ 4 us, 不是由訊號衰減量所限制 TR 00 m ~ 00 m TR NT TE TE TE 0

16 點對多點佈線 Extended Passive us 500 m ~ 800 m TR 0 m ~ 5 m TR NT TE TE 最多四部 TE 碼框結構 (Frame Structure) 每碼框 48 位元 50us/frame 從 TE 到 NT 或 NT 到 TE 方向, 位元速率都為 9 Kbps

17 碼框結構 (Frame Structure) 0 0 NT to TE 48 bits in 50 us D L F L E D A F N E D M E D S E D L F L A bits offset Response D L F L L D L F L L D L L D L L D L F L A TE to NT F : Framing bit L : DC balancing bit : it within -channel E : D-echo-channel bit D : D-channel bit A : it used for activation F A : Auxiliary framing bit N : it set to a binary value N = /FA (NT to TE) : it within -channel M : Multiframing bit S : reserved Contention for D channel E (Echo, 迴音 ) 位元用來解決多部 TE 接在同一 us 上, 競爭 D 通道使用權的問題 Only one TE may use a channel at any one time, there is no problem with contention on the channel. ut all devices must share the D chanel for signaling. If a transmitting TE receives an E bit with a value different from that of its last D bit, it knows it no longer controls the channel and has to stop transmitting. 4

18 Contention for D channel Contention resolution scheme for D channel A TE with nothing to transmit sends out a series of binary s. A TE wishing to transmit monitors E bits. If it hears enough E bits with a value s, it assumes no transmission on the line and transmits. If a TE detects E bits with different values than it is transmitting, it assumes another TE is transmitting and breaks off contention for the D channel. 5 傳輸碼 (Line Code) 二進制假三階碼 (Pseudo-ternary line code) = 線上無訊號 0 = 線上訊號為正或負的脈波線上訊號 6

19 傳輸碼 (Line Code) 框構位元 (Framing it) 與平衡位元 (DC alancing it) 之下一個 0, 不需極性交替 ( 即極性必需相同 ) 接著之 0 必需極性交替如果自前一個平衡位元以後之 0 的數目為奇數, 則現在之平衡位元為 0 ; 如果自前一個平衡位元以後之 0 的數目為偶數, 則現在之平衡位元為 ( 簡言之 0 的總數需為偶數 ) 7 傳輸碼 (Line Code) Example. TE to NT F L L Case ) + 奇數個 0 F L L Case ) 0 + 偶數個 0 F L L 8

20 啟動之程序終端設備 (TE) 啟動命令通知發現已同步通知已啟動 S/T 界面 INFO 0 INFO INFO INFO INFO 4 網路終端 (NT) 通知啟動命令通知已啟動 9 定義 INFO 信號 (S/T 界面之信號種類 ) 信號從 TE 送往 NT INFO 0 = 沒有信號 = 全部為 INFO = 連續的信號, 正 0 負 0 接六個 INFO = 碼框同步, 及 D 通道可載送資料信號從 NT 送往 TE INFO 0 = 沒有信號 = 全部為 INFO = 所有的 D 回送位元 E 與 A 都填 0, N 與 L 依規則處理 INFO 4 = 所有的 D 回送位元 E 與 A 都填, N 與 L 依規則處理 40

21 ISDN 用戶網路介面 Physical Layer Link Layer Network Layer 4 D 通道存取程序之製作需求 SAPI C/R EA 0 TEI EA 控制欄 ~ 位元組資訊欄, 最多 60 位元組碼框偵錯碼 (CRC6) 0 0 開頭旗標 (Opening flag) SAPI : 服務存取點識別 TEI : 終端設備識別 ( 最多 8 台 ) EA : 位址延伸如果 EA=0 C/R : 命令或回應 CRC6 = I (X 6 +X +X 5 +) 之餘數結尾旗標 (Closing flag) 4

22 LAPD Functions Provision of one or more data link connections on a D-channel Frame delimiting, alignment and transparency Sequence control Error detection Error recovery Link by link flow control 4 Frame Structure Flag Flag 0 0 Octet 0 0 Octet Address(High Order) Octet Address(High Order) Octet Address(Low Order) Octet Address(Low Order) Octet Control a) Control a) Control a) Octet 4 Control a) Octet 4 Frame Check Octet N- Information : Sequence Octet N- Frame Check Octet N- Flag Sequence Octet N- 0 0 Octet N Flag 0 0 Octet N a) Unacknowledged Operation - One Octet Multiple Frame Operation - Two Octets for Frames with sequence numbers - One Octet for Frames without sequence numbers 44

23 Address Field SAPI C/R EA Octet TEI EA Octet EA = Address field extension bit C/R = Command/response field bit SAPI = Service Access Point identifier TEI = Terminal endpoint identifier SAPI Value All others TEI Value Related Layer or Management Entity Call Control Procedures Reserved for Packet Mode Comm s. Using Q.9 Call Control Procedure Packet Communication Conforming to X.5 Level Procedures Layer Management Procedures Reserved for future standardization User Type * Non-automatic TEI Assignment User Equipment ** Automatic TEI Assignment User Equipment Group TEI for roadcasting * Non-automatic TEI values are selected by the User. ** Automatic TEI values are selected by the Network. 45 Control Field Format Control field bit(mdoulo 8) I format N(S) 0 Octet 4 N(R) P Octet 5 S format X X X X S S 0 Octet 4 N(R) P/F Octet 5 U format M M M P/F M M Octet 4 N(S) : Transmitter Send Sequence Number N(R) : Transmitter Receive Sequence Number S : Supervisory Function it M : Modifier Function it P/F : Poll it When Issued As a Command/Final it When Issued As a Response X : Reserved and Set to 0 46

24 Control Field Format I frame (information transfer frame) carry user information S frame (supervisory frame) provide flow control and error control data, which control the transmission of I frames on the link U frame (unnumbered frame) establish, maintain and terminate the logical links. 47 Frame Types Application Format Commands Responses Oct. Information N(S) 0 4 Exchange I(Information) Transfer N(R) P 5 User data RR(Receive RR(Receive Positive Ready) Ready) N(R) P/F 5 Ack Supervisory RNR(Receive RNR(Receive Positive Not Ready) Not Ready) N(R) P/F 5 Ack REJ(Reject) REJ(Reject) Negative ack N(R) P/F 5 Go back N SAME(Set Request Asynchronous 0 P 4 Logic alanced Mode Channel Extended) Unacknowledged And Multiple Frame Acknowledged Information Transfer Connection Management Unnumbered UI (Unnumbered Information) DISC (Disconnect) XID(Exchange Identification) DM (Disconnect Mode) UA (Unnumbered Acknow- -ledgement) FRMR (Frame Reject) XID (Exchange Identification F P P F F P/F 4 Unable to est. Or Maintain Logic channel Terminate Logic Channel Ack for SAME or DISC Reports receipt of unacceptable frame Exchange Identity Information 48

25 The Management Entity Flag C/R 0 Address(SAPI=6) Address(TEI=7) P 0 0 Control(UI) Management Entity Identifier (cf. next slide) Information Reference Number (cf. next slide) Message Type (cf. next slide) Action Indicator Frame Check Sequence 0 0 Flag E 49 TEI Management Entity Message Name Identity Request (User to Network) Identity Assigned (Network to User) Identity Denied (Network to User) Identity Check Request (Network to User) Identity Check Response (User to Network) Identity Remove (Network to User) Identity Verity (User to Network) Management Entity Identifier Reference Number Ri Message Type Action Indicator Ai Ai = 7, Any TEI Value Acceptable Ai = 64 6, Assigned TEI Value Ai = 7, No TEI Value Available Ai = 7, Check 0000 Not Used (Coded 0) Not Used (Coded 0) Not Used (Coded 0) ALL TEI Values Ai = 0 6, TEI Value To e Checked Ai = 0 6, TEI Value in Use Ai = 7, Request For Removal of All TEI Values Ai = 0 6, TEI Value To e Removed Ai = 0 6, TEI Value To e Checked 50

26 Example V(A) : # of acked frames V(S) : # of transmitted frames V(R) : # of received frames V U (A) = V U (S) = V U (R) = 0 N(S)=V U (S); N(R)=V U (R); V U (S) = 0 V U (R) = 0 N(S)=V U (S); N(R)=V U (R); V U (S) = error in processing N(S)=V U (S); N(R)=V U (R); V U (S) = Start T00 N(R)=V U (R) N(S)=V U (S); N(R)=V U (R); V U (S) = User UI [ ID request, Ri, Ai] UI [ID assigned, Ri, Ai] SAME( 邏輯通道設定 ) UA( 設定確認 ) I, N(S) = 0, N(R) = 0 I, N(S) = 0, N(R) = I, N(S) = 4, N(R) = REJ, N(R) = I, N(S) =, N(R) = RNR, N(R) = ( 不可受信 ) RR, N(R) = ( 可受信 ) RR, N(R) = ( 可受信 ) I, N(S) =, N(R) = RR, N(R) = ( 可受信 ) DISC( 切斷 ) UA( 確認切斷 ) Network V N (A) = V N (S) = V N (R) = 0 V N (R) = 0 N(S)=V N (S); N(R)=V N (R); V N (S) = 0 N(S) not equal to V N (R) means error N(R)=V N (R) V N (R) = N(R)=V N (R) N(R)=V N (R) V N (R) = N(R)=V N (R) 5 ISDN 用戶網路介面 Physical Layer Link Layer Network Layer 5

27 Reference Model ( 參考模式 ) TE TE Upper Layer/Layer Primitives Upper Layer/Layer Primitives Upper Layer/Layer Primitives UPPER LAYER Layer Layer Peer-To-Peer Protocol Message-oriented UPPER LAYER Layer Layer Layer Layer Physical connection 5 Module Diagram ( 模組方塊圖 ) Primitives Primitives Call Control Upper Layer Resource management Q.9 and Q.9 protocol control Message To/From Network side Data Link Layer Physical Layer LAYER Procedure call lock described by the SDL Diagrams User-Network Interface SDL : Specification and Description Language Network 54

28 呼叫之建立 Enbloc vs. overlap Human Pick up Call_proc_ind Add_info_ind Call_proc_ind Ring_back indication Ring_back indication stops Calling ST(A) ET ET Setup Call proceeding (enbloc) Setup ack(overlap) Info(overlap) Call proceeding Alerting Connect Connect ack Start duration charging Setup Alerting Connect Called ST(X) (Setup_ind) Ringing Pick up Human (X) Called ST(X) Data flow 55 Functions of Q.9 Establish, maintain, and clear network connections at the IDSN user-network interface by exchanging messages over D- channel. Processing of primitives from LAPD or Call Control. Generation and interpretation of Q.9 messages for peer-level communication. Management of timers and logical entities (call references) 56

29 Functions of Q.9 4. Administration of access resources including -channel and packet-layer logical channels; 5. Consistency checking (compatibility, address such as caller address and callee address) 57 呼叫之清除 Human Calling ST(A) ET ET Called ST(X) Human (X) Hang up Called terminal hands up first Disc_ind Release_conf Disconnect Release Release complete Stop duration charging Disconnect Release Release complete Release_ind Calling terminal hands up first Hang up Release_ind Disconnect Release Release complete Stop duration charging Disconnect Release Release complete Disc_ind Release_conf 58

30 asic Calls vs. Supplementary Services asic Call Control means that the call is simply established, maintained, and disconnected. A single connection is setup between the calling and called parties. (Q.9) Supplementary Services refer to features that provide additional capabilities so that users have greater control over how the network handles their transmission paths. E.g., Call Forwarding, Call Waiting, Call Transfer, and Call Hold. (Q.9) 59 Q.9 Message Format Flag Address Control Information FCS Flag LAPD frame format Octet Protocol Discriminator (Q.9) Length CRF Call Reference Value 0 Message Type Other information elements as required Q.9 message format 60

31 Call Reference The Call Reference is used to identify the call at local user-network interface; there is no end-to-end significance Octet Length CRF Call Reference Value etc. CRF = Call Reference Flag 0 : Message sent from the side originating the call : Message sent to the side originating the call Length = Number of octets for CRV 6 Call Reference At a minimum, all networks and users must be able to support a one-octet CRV for a RI and a two-octet CRV for a PRI. The dummy call reference is a single zerofilled octet. Its use is specified in Rec. Q Octet

32 Call Reference The global call reference is used to refer to all calls associated with a given data link address. The numerical value of the CRV is zero (a two-octet CRV is shown here.) Octet / Message Types Call establishment messages Alerting, Call Proceeding, Connect, Connect Acknowledge, Progress, Setup, Setup Acknowledge Call information phase messages Resume, Resume Acknowledge, Resume Reject Suspend, Suspend Acknowledge, Suspend Reject Hold, Hold Acknowledge, Hold Reject Retrieve, Retrieve Acknowledge, Retrieve Reject User Information 64

33 Message Types Call clearing messages Disconnect, Release, Release Complete, Restart, Restart Acknowledge Miscellaneous messages Information, Notify, Status, Status Enquiry, Facility, Segment 65 Formats of Information Element a) Single octet information element format Information element Identifier Contents of Information element Octet b) Variable-length information element format Octet 0 Information element identifier Length of information element (octets) Contents of information element etc. 66

34 Information Elements Single Octet Locking Shift, More Data, Sending Complete, Congestion Level Variable Length Segmented Message Keypad Facility Called Party Number earer Capability Signal Called Party Subaddress Cause Information Rate Redirecting Number Call Identify End-to-End Transit Delay Transit Network Selection Call State Transit Delay Selection and Indication Restart Indicator Channel Identification Packet Layer inary Parameters Low-layer Compatibility Facility Packet Layer Window Size High-layer Compatibility Progress Indicator Packet Size User-User Information Network-specific Facilities Connected Number Escape for Extension Notification Indicator Connected Subaddress Display Calling Party Number Data/time Calling Party Subaddress 67 Call States User State Network State U0 Null N0 Null U Call Initiated N Call Initiated U Overlap Sending N Overlap Sending U Outgoing Call Proceeding N Outgoing Call Proceeding U4 Call Delivered N4 Call Delivered U6 Call Present N6 Call Present U7 Call Received N7 Call Received U8 Connect Request N8 Connect Request U9 Incoming Call Proceeding N9 Incoming Call Proceeding U0 Active N0 Active U Disconnect Request N Disconnect Request U Disconnect Indication N Disconnect Indication U5 Suspend Request N5 Suspend Request U7 Resume Request N7 Resume Request U9 Release Request N9 Release Request N Call Abort U5 Overlap Receiving N5 Overlap Receving 68

35 Timers in the User Side Timer Number Time-out value State of Call T0 4 s Call Initiated T05 0 s Disconnect Request T08 4 s Release Request T09 90 s Any stable state Cause of start Normal stop At the first expiry At the second expiry SETUP sent Disconnect sent RELEASE sent Data link disconnection calls in stable states are not lost. ALERTING, CONNECT SETUP ACK, CALL PROC, or RELEASE COMPLETE received RELEASE or DISC received RELEASE COMPLETE or RELEASE received Data link reconnected Retransmit SETUP; restart T0, If REL COMP has been received, clear the call. RELEASE sent. Retransmit RELEASE restart T08 Clear internal connection release -channel and call reference Clear internal connection. Send REL COMP. Enter Null state. Timer is not restarted Place -channel in maintenance condition. Release call reference. Timer is not restarted. 69 Timers in the User Side Timer Number Time-out value State of Call T 4 s Connect Request T8 4 s Resume Request T9 4 s Suspend Request Cause of start Normal stop At the first expiry At the second expiry CONNECT sent RESUME sent SUSPEND sent CONNECT ACKNOWLEDGE received RESUME ACKNOWLEDGE or RESUME REJECT received SUSPEND ACKNOWLEDGE or SUSPEND REJECT received send DISCONNECT Clear internal connect. Release call reference. Enter Null state. Enter Active state. Notify user application. Timer is not restarted Timer is not Restarted Timer is not restarted 70

36 ISDN 應用和 Internet Access Ascend Internet Access & Remote LAN Access Ascend Pipeline 50 RI ISDN Hinet/Internet Ascend Pipeline 400 RI ISDN RI RI Ascend Pipeline 50 Ascend Pipeline 50 RI RI Ascend Pipeline 50 Ascend Pipeline 50 7

37 Ascend Internet Access & Remote LAN Access RI Ascend Pipeline 50 Ascend MAX Digital Modem RI PRI ISDN PSTN M M 7 ISDN CPE 與 Internet Access Server 互連架構 C-plain (D-channel) U-plane (-channel) U-plane (-channel) C-plain (D-channel) Q.9 IP IP Q.9 Q.9 LAPD HDLC PPP PPP HDLC Q.9 LAPD I.40/I.4 ISDN CPE ISDN RI/PRI I.40/I.4 IAS 74

38 附錄 ISDN 相關系統參數 System Parameters ) T00 = second Max. time between transmission of command frames and reception of their corresponding response or acknowledgement frames ) N00 = Max. number of retransmissions ) N0 = 60 Max. number of octets in an information field 76

39 System Parameters 4) N0 = Max. number of TEI assignment requests 5) K = for an SAP supporting signaling, = for SAPs supporting packet information Max. number of outstanding I frames 77 System Parameters 6) T0 = second Min. time between retransmission of TEI check User Side ASP UI(SAPI, TEI) [ID check request, Ai] UI(SAPI, TEI) [ID check response, Ri, Ai] Start T0 * ASP = Assignment Service Point 78

40 System Parameters 7) T0 = seconds Min. time between transmission of TEI request. User Side ASP Start T0 UI(SAPI, TEI) [ID request, Ri, Ai] UI(SAPI, TEI) [ID assigned, Ri, Ai] UI(SAPI, TEI) [ID denied, Ri, Ai] 79 System Parameters 8) T0 = 0 seconds Max. period of Link inactivity 9) T04 = seconds Min. time between transmission of XID commands 0) N04 = Max. number of XID retransmissions 80

lan03_yen

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