ISDN

• Basic Rate (BRI) is 3 data channels
• 2 for 64 Kbps - 64 Kbps channels are known as B (Bearer) channels, carry voice, data or image
• 1 for 16 Kbps - the 16 Kbps channel is D channel which carries signaling and link management data
• This makes a total of 144 Kbps of bandwidth.
• basic rate is called 2B+D
• The two B channels can be used together for 128 Kbps data stream
• Primary Rate (PRI) ISDN takes the entire bandwidth of a T1 link by providing
• 23 B Channels at 64 Kbps
• 1 D Channel at 64 Kbps
• ISDN is a dial-up service, not dedicated, not bandwidth on demand
• Right now, ISDN is about 5 times as fast as the fastest modem
• You can transmit voice and data with ISDN