
7
Copyright © 1997 Cisco Systems, Inc.
6-13CSE: Networking Fundamentals — WAN Basics
© 1999, Cisco Systems, Inc.
www.cisco.com
Integrated Services Digital
Network (ISDN)
•High bandwidth
•Up to 128 Kbps per basic rate interface
•Dial on demand
•Multiple channels
•Fast connection time
•Monthly rate plus cost-effective,
usage-based billing
•Strictly digital
LAN
Server
Company Network
Telecommuter/After-
Hours, Work-at-Home
BRI
2B+D
BRI/PRI
23B+D
30B+D (Europe)
ISDN
6-14CSE: Networking Fundamentals — WAN Basics
© 1999, Cisco Systems, Inc.
www.cisco.com
ISDN
• One physical connection
to the ISDN network
• 23 logical connections
(U.S./Canada)
• 30 logical connections
(Europe)
• Used at central site
Primary Rate Interface (PRI)
1.536
Mbps
23B
30B
D
64 Kbps
64 Kbps
}
• One physical connection
to the ISDN network
• Two logical connections
• Used at remote
telecommuter site
64 Kbps
64 Kbps
16 Kbps
144
Kbps
2B
D
}
{
Basic Rate Interface (BRI)
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