Datasheet

Wide-Area Networking Basics
Answers
1
D, E. DCE and CSU/DSU. Data communications equipment (DCE), also referred
to as a channel service unit/data service unit (CSU/DSU), controls the timing
synchronization for WAN devices. Review “Data terminal equipment (DTE) and
data communications equipment (DCE).”
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B. A 60-pin DCE-to-DTE crossover cable is used to establish a simulated DCE-to-
DTE environment using the serial interface between Cisco routers. See “Cisco
serial interfaces” and “Introducing Cable Connections.”
3
D. Customer premises equipment (CPE) connects to equipment provided by
the telephone company at the demarcation point. Refer to “Data terminal
equipment (DTE) and data communications equipment (DCE).”
4
C. PPPoE. Many Internet service providers use PPPoE to authenticate customers
using a username and password over dialup connections. Take a look at
“Encapsulation Types.”
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A. ISDN. ISDN BRI (Basic Rate Interface) is a service using two 64-Kbps bearer
channels (2B) plus one 16-Kbps data channel (D) used for clocking, and is called
“out-of-band” signaling. Read “Introducing Cable Connections.”
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C. SLIP. Serial Line Internet Protocol is a very simplistic, nonstandard protocol
used to frame and transmit IP datagrams over serial connections. See
“Encapsulation Types.”
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B. HSSI. High-Speed Serial Interface (HSSI) is a proprietary smart-serial DTE/
DCE interface that uses a male, subminiature 50-pin connector with a maximum
cable length of 50 feet. Examine “Cisco serial interfaces.”
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B, E. POTS and ISDN. The two types of serial circuit-switched connections are
asynchronous plain old telephone system (POTS) dialup and synchronous
Integrated Services Digital Network (ISDN). Look over “Connection Types.”
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B, D. Frame Relay and X.25 are known as packet-switched technologies and
provide higher bandwidth and cost compared to ISDN and dialup alternatives.
Check out “Connection Types.”
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D. Dedicated leased line. A dedicated leased line establishes a permanent link
using a point-to-point serial connection, which provides guaranteed bandwidth
to remote networks. Review “Connection Types.”
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C. ATM. Asynchronous Transfer Mode establishes a point-to-point cell-switched
WAN that transmits 53-byte packets called cells. Refer to “Connection Types.”
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