CCNA 4 v3.1 Module 2
WAN Technologies
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Purpose of This PowerPoint
• This PowerPoint primarily consists of the Target
Indicators (TIs) of this module in CCNA version
3.1.
• It was created to give instructors a PowerPoint to
take and modify as their own.
• This PowerPoint is:
NOT a study guide for the module final assessment.
NOT a study guide for the CCNA certification exam.
• Please report any mistakes you find in this
PowerPoint by using the Academy Connection
Help link.
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To Locate Instructional Resource
Materials on Academy Connection:
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materials created by the instructor community
• Go to the Tools section
• Go to the Alpha Preview section
• Go to the Community link under Resources
• See the resources available on the Class home
page for classes you are offering
• Search http://www.cisco.com
• Contact your parent academy!
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Objectives
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WAN Technology
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WAN Service Providers
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Physical Layer: WANs
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WAN Line Types and Bandwidth
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WAN Devices
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CSU/DSU
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Modem Transmission
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WAN Standards
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WAN Encapsulation
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WAN Data-Link Protocols
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Circuit Switching
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Packet Switching
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WAN Link Options
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WAN Link Options
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Analog Dialup
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ISDN
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ISDN
Router with
standard serial
interface,
connected to a
terminal adapter
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Router with native
ISDN BRI U or S/T
interface or PRI
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Leased Line
• Leased lines are not only used to provide direct
point-to-point connections between Enterprise
LANS, they can also be used to connect
individual branches to a packet switched
network.
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WAN with X.25
• X.25 provides a low bit rate,
shared-variable capacity that
may either be switched or
permanent
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Frame Relay
• Most Frame Relay connections are based on PVCs rather
than SVCs.
• It implements no error or flow control. This leads to
reduced latency.
• Frame Relay provides permanent shared medium
bandwidth connectivity that carries both voice and data
traffic.
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ATM
• Asynchronous Transfer Mode (ATM) is a
technology capable of transferring voice, video,
and data through private and public networks.
• It is built on a cell based architecture rather than
on a frame-based architecture.
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DSL
• DSL uses existing twisted-pair telephone lines to
transport high-bandwidth data
• DSL service is considered broadband, as it uses
multiple frequencies within the same physical
medium to transmit data
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ADSL Technology
Splitter
• The local loop connects the splitter to the DSLAM
• DSLAM connected to ISP using ATM technology
• Voice and data use separate frequency ranges
(voice 0-4Khz, data 20Khx – 1Mhz)
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Cable Modem
• Enhanced Cable Modems enable twoway. High speed data transmissions
using the same coaxial lines that
transmit cable television.
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Cable Data Network Architecture
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Modern WAN
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WANs Operate at the Lower Three
Levels of the OSI Model
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Comparing WAN Traffic Types
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Steps In WAN Design
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WAN Topology
Star Topology
Full-Mesh Topology
Partial-Mesh Topology
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Three-Layer Design Model
• The links connecting the various sites in an
area that provide access to the enterprise
network are called the access links or
access layer of the WAN.
• Traffic between areas is distributed by the
distribution links, and is moved onto the
core links for transfer to other regions,
when necessary.
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Advantages of the Hierarchical Approach
• Scalability: networks can grow without sacrificing
control or manageability
• Ease of Implementation: clear functionality at each
layer
• Ease of troubleshooting: Isolation of problems in the
network is easier
• Predicatability network modelling and caapacity
plannng easier
• Protocol Support: mixing current and future
applications and protocols is easier
• Manageability: all the above improve the
manageability of the network
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Internet for WAN Connectivity
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One-Layer Hierarchy
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Using the Internet as an Enterprise WAN
• Enterprise WANs will have
connections to the Internet.
• This poses security problems but also provides an
alternative for inter-branch traffic.
• VPN technologies can solve security issues
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Summary
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