1. A N I NTRODUCTION T O ISDN By Mohammad AlianNejadi Fardin Sabouri Master Mahdy Abbasi Ph.D. Autumn 2009

2. W HAT 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. W HAT I S 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. P RINCIPLES O F ISDN 1. Support of voice and non-voice applications using a limited set of standardized facilities. 2. Support, for switched and non-switched applications. 3. Reliance on 64-kbps connections. 4. Intelligence in the network. 5. Layered protocol architecture. 6. Variety of configurations.

5. T HE U SER I NTERFACE 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. C ONCEPTUAL V IEW O F ISDN C ONNECTION F EATURES

7. ISDN C HANNELS 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. A CCESS T YPES 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 P ROTOCOLS 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. W HAT 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 P ROTOCOL 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 P ROTOCOL (CONT.)

13. 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. Q UESTION Q