Datasheet

Introducing WANs
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Figure 1-1:
WAN.
Corporate
Headquarters
Mobile User
Remote/Home
Office
Branch
Office
T3 Dedicated
Leased Line
Remote
Satelittle
VPN
Frame Relay
ADSL
Managed
WAN
Purpose of WANs
A wide variety of options exist to interconnect remote LAN sites. LANs are
brought together into WANs for the purpose of sharing network resources
between authorized users and devices. Collaborative data and resource
sharing between corporate sites and business partners allows WANs to
globally interconnect any business.
Data terminal equipment (DTE) and data
communications equipment (DCE)
Basic WAN connectivity between the subscriber and provider relies on two
types of serial communications devices:
✦ Data terminal equipment (DTE)
✦ Data communications equipment (DCE), also known as data circuit
terminating equipment
A DCE device is typically a modem known as either
• Terminal adapter/network termination 1 (TA/NT1)
• Channel service unit/data service unit (CSU/DSU)
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