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An Introduction To ISDN

An Introduction To ISDN. By Mohammad AlianNejadi Fardin Sabouri Master Mahdy Abbasi Ph.D. Autumn 2009. What is ISDN? (cont.). Rapid advances in computer and communication technologies. Demands for efficient and timely collection and processing of information.

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An Introduction To ISDN

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  1. An Introduction To ISDN By Mohammad AlianNejadi FardinSabouri Master MahdyAbbasi Ph.D. Autumn 2009

  2. What is ISDN?(cont.) • Rapid advances in computer and communication technologies. • Demands for efficient and timely collection and processing of information. • Integrated Services Digital Network • Worldwide public telecommunication • Standard user interface • Multiple networks in national boundaries • A single network from the user’s point of view

  3. What Is ISDN? • Generations of ISDN • First: Narrowband ISDN • Based on use of 64 Kbps channel • Circuit-switch orientation • Major technical: Frame Relay • Second: Broadband ISDN • Supports very high data rates: 100s Mbps • Packet-switch orientation • Major technical: ATM

  4. Principles Of ISDN • Support of voice and non-voice applications using a limited set of standardized facilities. • Support, for switched and non-switched applications. • Reliance on 64-kbps connections. • Intelligence in the network. • Layered protocol architecture. • Variety of configurations.

  5. The User Interface • A local interface is between the user and digital pipe. • The digital pipe has a certain bit rate. • A complex control must an appropriate service. • The user is charged according to the capacity used rather than “connect time”.

  6. Conceptual View Of ISDN Connection Features

  7. ISDN Channels • B Channel: • 64 Kbps • Basic user channel • D Channel: • 16 or 64 Kbps • Signaling information for circuit-switch • Used for packet-switch • H Channel: • H0: 384 Kbps • H11: 1536 Kbps • H12: 1920 Kbps • High-speed use like video

  8. Access Types • Basic Access • Two full-duplex 64-kbps B Channels • One full-duplex 16-k-kbps D Channel • Framing and other overheads • Simultaneous use of voice and other data applications • Primary Access • For users with greater capacity requirements • U.S., Canada and Japan: 1.544 Mbps • Europe: 2.048 Mbps • May user B and D structure or H and D structure 192 Kbps

  9. ISDN Protocols • Layer 1-3 Protocols • Physical Layer • Basic and Primary Access • B and D Channels are multiplexed over the same physical interface • Data Link Layer: LAPD • Based on HDLC • Channel B • Circuit-switched connection • Packet-switched connection

  10. What is LAPD? • Link Access Protocol-D Channel • Unacknowledged information-transfer service • No error control • Fast data transfer • Broadcast • Acknowledged information-transfer service • Like HDLC

  11. LAPD Protocol • Frame format: • Address field • Two-level Multiplexing: • Subscriber site • Multiple types of traffic • Terminal Endpoint Identifier • Automatically • Manually • Service Access Point Identifier • Corresponds layer-3 protocol

  12. LAPD Protocol (CONT.)

  13. LAPD Protocol (CONT.) • Acknowledged: Same as HDLC • Unacknowledged: • User Information (UI) frame • UI is sent to a LAPD entity • Sent to the destination with no ack returned • Physical Layer • Basic Access: Pseudoternary Coding • Primary Access • 1.544 Mbps: B8ZS • 2.048 Mbps: HDB3

  14. Question Q

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