Download
nete0510 isdn n.
Skip this Video
Loading SlideShow in 5 Seconds..
NETE0510 ISDN PowerPoint Presentation
Download Presentation
NETE0510 ISDN

NETE0510 ISDN

216 Vues Download Presentation
Télécharger la présentation

NETE0510 ISDN

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. NETE0510ISDN Dr. Supakorn Kungpisdan supakorn@mut.ac.th NETE0510: Communication Media and Data Communications

  2. Outline • ISDN Overview • Integrated Digital Network • A Conceptual View of ISDN • ISDN Interfaces and Functions • ISDN Tutorial NETE0510: Communication Media and Data Communications

  3. Traditional Telephone Network VS Integrated Digital Network • Traditional Telephone Networks • Separately designed and administrated transmission and switching systems • Demultiplexing and demodulating are necessary at each switching center • A repeated process results in an accommodation of noise as well as cost • Integration of transmission and switching systems • Achievable when both systems are digital • Using PCM modulation and TDM multiplexing • Switching without decoding along the way • Separate multiplex/demultiplex channel banks are not required NETE0510: Communication Media and Data Communications

  4. Analog Communications w/o ISDN NETE0510: Communication Media and Data Communications

  5. The Integrated Digital Network Multiplex and modulate signals Space-division switch Demultiplex and demodulate signals Analog telephone network PCM: pulse-code modulation NETE0510: Communication Media and Data Communications

  6. Digital Communications with ISDN NETE0510: Communication Media and Data Communications

  7. The Integrated Digital Network (cont’d) • The IDN will combine the coverage of the geographically extensive telephone network with the data carrying capacity of digital data networks in a structure called the “integrated services digital network (ISDN)” • “integrated” refers to the simultaneous carrying of digitized voice and a variety of data traffic on the same digital transmission links and by the same digital exchanges NETE0510: Communication Media and Data Communications

  8. Outline • ISDN Overview • Integrated Digital Network • A Conceptual View of ISDN • ISDN Interfaces and Functions • Transmission Structure • User-Network Interface Configurations • ISDN Protocol Architecture • ISDN Connection • Addressing • Interworking NETE0510: Communication Media and Data Communications

  9. Principles of ISDN 1. Support of voice and non-voice applications using a limited set of standardized facilities • Defines the purpose of ISDN and the means of achieving it 2. Support for switched and non-switched applications • Both circuit-switched and packet-switched connections • Support non-switched services in the form of dedicated lines 3. Reliance on 64-kbps connections • Fundamental block of ISDN • 64 kbps were chosen because it was the standard rate for digitized voice NETE0510: Communication Media and Data Communications

  10. Principles of ISDN (cont’d) 4. Intelligence in the network • Sophisticated serviced beyond simple setup a circuit-switched call • Sophisticated network management and maintenance capabilities • Use of SS7 ( (common channel) signaling system number 7) and intelligent switching nodes in the network • SS7 is a set of telephonysignaling protocols which are used to set up the vast majority of the world's public switched telephone network telephone calls. 5. Layered protocol architecture • User access to ISDN protocol is a layered architecture that can be mapped to OSI model • Standards can be developed independently for various layers and functions 6. Variety of configurations • More than one physical configuration is possible for implementing ISDN NETE0510: Communication Media and Data Communications

  11. The User Interface NETE0510: Communication Media and Data Communications

  12. The User Interface (cont’d) • User has access to ISDN via a local interface to a digital “pipe”. • Pipes of various sizes are available to satisfy different needs • Pipe to the user’s promises has a fixed capacity but the traffic on the pipe may be a variable mix up to the capacity limit • ISDN requires control signals to instruct how to sort out the time-multiplexed data and provide the required services • Control signals are multiplexed onto the same digital pipe NETE0510: Communication Media and Data Communications

  13. The User Interface (cont’d) • Recommendation from I.410: more than one size of pipe is needed • A single terminal (e.g. a residential telephone) • Multiple terminals (e.g. a residential telephone, PC, and alarm system) • A network of devices attached to a LAN or PBX (ISDN gateway) NETE0510: Communication Media and Data Communications

  14. The User Interface (cont’d) NETE0510: Communication Media and Data Communications

  15. Benefits • The principle benefits of ISDN to the customer can be expressed in terms of cost savings and flexibility • Integrated voice and data means that the user does not have to buy multiple services to meet multiple needs • Access charges to a single line only • Purchasing services based on actual needs • Product diversity, low price, and wide availability of equipment NETE0510: Communication Media and Data Communications

  16. ISDN Architecture NETE0510: Communication Media and Data Communications

  17. ISDN Architecture (cont’d) • Physical interface provides a standardized means of attaching to the network • The interface supports a basic service consisting of three time-multiplexed channels, two at 64 kbps and one at 16 kbps • In addition, there is a primary service that provide multiple 64-kbps channels • An interface is defined between the customer’s terminal equipment (TE) and a device on the customer’s premises, known as a network termination (NT) • The subscriber loop is the physical path from the subscriber’s NT to the ISDN central office • Must support full-duplex digital transmission for both basic and primary data rates NETE0510: Communication Media and Data Communications

  18. Outline • ISDN Overview • ISDN Interfaces and Functions • ISDN Standard • Transmission Structure • ISDN Model • Reference Points and Functional Groupings • Access Configurations • ISDN Switch Types • ISDN Tutorial • Network Diagram • Type of Equipment • Configuring your ISDN Line and Equipment • Wiring your Location for ISDN NETE0510: Communication Media and Data Communications

  19. ISDN Standard NETE0510: Communication Media and Data Communications

  20. Transmission Structure • Digital pipe between central office and ISDN subscriber carry a number of communication channels, varies from user to user • The transmission structure of access links includes channels of: • B channel: 64 kbps • D channel: 16 or 64 kbps • H channel: 384 (H0), 1536 (H11), or 1920 (H12) kbps NETE0510: Communication Media and Data Communications

  21. B Channel • A user channel, carrying digital data, PCM-encoded digital voice, or a mixture of lower-rate traffic at a fraction of 64 kbps • The information is carried in frame format, using either high-level data link control (HDLC) or PPP as the Layer 2 protocol. PPP is more robust than HDLC because it provides a mechanism for authentication and negotiation of compatible link and protocol configuration. NETE0510: Communication Media and Data Communications

  22. D Channel • Carry common-channel signaling (CCS) information to control circuit-switched calls • Traffic over the D channel employs the Link Access Procedure on the D Channel (LAPD) protocol. LAPD is a data link layer protocol based on HDLC. • May be used for packet switching or low speed (e.g. 100 bps) telemetry (data transfer over media) when no signaling informationis waiting NETE0510: Communication Media and Data Communications

  23. ISDN Channel Functions NETE0510: Communication Media and Data Communications

  24. H Channel • Provides user information transmission at higher data rates • Use the channel as a high-speed trunk or subdivide it based on TDM • Examples: fast fax, video, high-speed data, high quality audio NETE0510: Communication Media and Data Communications

  25. Basic and Primary Channel Structures NETE0510: Communication Media and Data Communications

  26. ISDN Model NETE0510: Communication Media and Data Communications

  27. ISDN Protocols at the user-network interface NETE0510: Communication Media and Data Communications

  28. ISDN Physical Layer • Each ISDN BRI frame contains two sub-frames each containing the following: • 8 bits from the B1 channel, 8 bits from the B2 channel, 2 bits from the D channel, and 6 bits of overhead • So, each BRI frame contains 48 bits NETE0510: Communication Media and Data Communications

  29. ISDN Physical Layer (cont’d) • The overhead bits of an ISDN sub-frame are used as follows: • Framing bit — Provides synchronization • Load balancing bit- Adjusts the average bit value • Echo of previous D channel bits — Used for contention resolution when several terminals on a passive bus contend for a channel • Activation bit — Activates devices • Spare bit — Unassigned NETE0510: Communication Media and Data Communications

  30. ISDN Physical Layer (cont’d) • 4,000 frames are transmitted per second. • Each B channel, B1and B2, has a capacity of 8 * 4000 * 2 = 64 kbps, while channel D has a capacity of 2 * 4000 * 2 = 16 kbps. • This accounts for 144 kbps (B1 + B2 + D) of the total ISDN BRI physical interface bit rate of 192 kbps. • The remainder of the data rate are the overhead bits that are required for transmission: 6 * 4000 * 2 = 48 kbps. NETE0510: Communication Media and Data Communications

  31. ISDN Data-link Layer SAPI identifies the portal at which LAPD services are provided to Layer 3 NETE0510: Communication Media and Data Communications

  32. ISDN Data-link Layer (cont’d) • Layer 2 of the ISDN signaling channel is LAPD. LAPD is similar to HDLC. LAPD is used across the D channel to ensure that control and signaling information is received and flows properly. • The LAPD flag and control fields are identical to those of HDLC. • The LAPD address field is 2 bytes long. • The first address field byte contains the service access point identifier(SAPI), which identifies the portal at which LAPD services are provided to Layer 3. The command/response bit (C/R) indicates whether the frame contains a command or a response. • The second byte contains the terminal endpoint identifier(TEI). NETE0510: Communication Media and Data Communications

  33. ISDN Layer 3: Q.931 Messaging Call Setup NETE0510: Communication Media and Data Communications

  34. (Q.931 Messaging Call Setup) NETE0510: Communication Media and Data Communications

  35. Reference Points and Functional Groupings • ITU-T approach for actual user’s physical configuration • Functional grouping: certain arrangements of physical equipment or combination of equipment • NT1, NT2, TE1, TE2, TA • Reference points: conceptual points of separation of group function • R, S, T, U NETE0510: Communication Media and Data Communications

  36. Functional Groupings • NT1 (Network Termination 1) • Includes functions similar to OSI layer 1 • May be controlled by ISDN provider (a boundary to network) • Isolate the user from the transmission technology of subscriber loop • Supports multiple channels (e.g. 2B+D) using TDM • Might support multiple devices in a multidrop arrangement • E.g. a residential interface might include a telephone, PC, and alarm system, all attached to a single NT1 interface via a multidrop line NETE0510: Communication Media and Data Communications

  37. Functional Groupings (cont’d) • NT2 (Network Termination 2) • An intelligent device that may include up to OSI layer 3 • Perform switching and concentration functions • Switching: the construction of a private network using semi-permanent circuit among a number of sites • Concentration: multiple devices, attached to a digital PBX, LAN, or terminal controller, may transmit data across ISDN • E.g. digital PBX, a terminal controller, LAN • Digital PBX provides NT2 functions at layers 1, 2, and 3 • A simple terminal controller provides layers 1 and 2 • A simple Time Division MUX provides layer 1 NETE0510: Communication Media and Data Communications

  38. Functional Groupings (cont’d) • TE1 (Terminal Equipment type 1) • Devices that support the standard ISDN interface • E.g. digital telephone, integrated voice/data terminal, digital fax • TE2 (Terminal Equipment type 2) • The existing non-ISDN equipment • E.g. physical interface RS-232, host computer with X.25 • Requires a terminal adaptor (TA) to plug into an ISDN interface NETE0510: Communication Media and Data Communications

  39. Functional Groupings (cont’d) • TA (Terminal Adaptor) • Converts standard electrical signals into the form used by ISDN • Needed for connection with TE2 devices • The ISDN TA can be either a standalone device or a board inside the TE2 NETE0510: Communication Media and Data Communications

  40. Reference Points and Functional Groupings NETE0510: Communication Media and Data Communications

  41. Reference Points • Reference point R (connect TE2-TA) • Provides a non-ISDN interface between user equipment that is non-ISDN compatible and adaptor equipment • Comply with X or V series ITU-T recommendation • Reference point S (connect TE1-NT2, TA-NT2) • The interface of individual ISDN terminals • Separate user terminal from network communications functions • Reference point T (connect NT2-NT1) • A minimal ISDN network termination at CPE • Separate network’s provider equipment from the user’s one • Reference point U (connect NT1-provider) • Describes full-duplex data signal on the subscriber line NETE0510: Communication Media and Data Communications

  42. Access Configurations • Based on definitions of functional grouping and reference points, several possible configurations for ISDN user-network interface have been proposed by ITU-T • The most straightforward configuration is that one or more pieces of equipment correspond to each functional grouping: NETE0510: Communication Media and Data Communications

  43. Access Configurations (cont’d) • In second case, the line termination function is combined with other ISDN interface functions • ISDN provider may provide the NT1 function e.g. NT1 may be integrated into a PBX NETE0510: Communication Media and Data Communications

  44. Access Configurations (cont’d) • In the third case, NT2 and TE functions are combined • A host that supports users, but also acts as a packet switch in a private packet-switching network that uses ISDN for trunking NETE0510: Communication Media and Data Communications

  45. Access Configurations (cont’d) • Final case: an ISDN subscriber device can connect directly to the subscriber loop terminator or into a PBX or LAN using the same interfacespecifications and thus ensuring portability NETE0510: Communication Media and Data Communications

  46. Examples of implementation of NT1 and NT2 functions NETE0510: Communication Media and Data Communications

  47. Examples of implementation of NT1 and NT2 functions NETE0510: Communication Media and Data Communications

  48. NT1 equipment NT1 circuit card NETE0510: Communication Media and Data Communications

  49. Routers must be configured to identify the type of switch with which they will communicate. Available ISDN switch types vary, depending in part on the country. As a consequence of various implementations of Q.931, the D channel signaling protocol used on ISDN switches varies from vendor to vendor. Each switch type operates slightly differently, and has a specific set of call setup requirements. Before the router can be connected to an ISDN service, it must be configured for the switch type used at the CO. ISDN Switch Type NETE0510: Communication Media and Data Communications

  50. ISDN Switch Type (cont’d) NETE0510: Communication Media and Data Communications