
6
Copyright © 1997 Cisco Systems, Inc.
6-11CSE: Networking Fundamentals — WAN Basics
© 1999, Cisco Systems, Inc.
www.cisco.com
Transmission Options or WAN
Services
Type of ServiceType of Service Analog or DigitalAnalog or Digital
PermanentPermanent
or Temporaryor Temporary
POTS POTS
ISDNISDN
Leased line Leased line —— T1/E1T1/E1
Frame RelayFrame Relay
X.25X.25
AnalogAnalog
DigitalDigital
DigitalDigital
DigitalDigital
DigitalDigital
Temporary Temporary
PermanentPermanent
Temporary Temporary
PermanentPermanent
Permanent Permanent
DSLDSL DigitalDigital
Temporary Temporary
6-12CSE: Networking Fundamentals — WAN Basics
© 1999, Cisco Systems, Inc.
www.cisco.com
POTS Using Modem Dialup
• Widely available
• Easy to set up
• Dial on demand
• Asynchronous transmission
• Low cost, usage-based
• Lower bandwidth access requirements
Telecommuters
Mobile
Users
Modem
Corporate Network
Server
Modem
Access Router
Basic
Telephone
Service
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