1. Services in a
Converged WAN
Accessing the WAN – Chapter 1
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2. Objectives
 Describe how the Cisco Enterprise Composite
Model (ECNM) provides integrated services
over an Enterprise network.
 Describe the key WAN technology concepts.
 Identify the appropriate WAN technologies to
use when matching ECNM best practices with
typical enterprise requirements for WAN
communications.
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3. Wide Area Networks
WAN
An enterprise must subscribe
LAN connects computers, peripherals, and other to a WAN service provider to
devices in a single building or other small use WAN carrier network
geographic area services.
A WAN is a data communications network that
operates beyond the geographic scope of a LAN.
WAN allows the transmission of data across greater
geographic distances
WANs use facilities provided by a service provider, or
carrier.
WANs use serial connections.
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4. WAN’s – The need
 Sharing of data
 Organization to organization
 Remote users
 Over large distance
 LAN – Falls short
 Company Growth
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5. Evolving Enterprise
 Stages of business growth.
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6. The Evolving Network Model
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7. Describe How ECNM Provides Integrated
Services over an Enterprise Network
 Problems with the Hierarchical Design Model that Cisco's
Enterprise Composite Model has been designed to address
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8. Describe How ECNM Provides Integrated
Services over an Enterprise Network
 Explain the purpose of Cisco Enterprise Architectures
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9. Key WAN Technology Concepts
 WAN functions in terms of the OSI Reference Model
The physical layer (OSI Layer 1) protocols describe
how to provide electrical, mechanical, operational, and
functional connections to the services of a
communications service provider.
The data link layer (OSI Layer 2) protocols define how
data is encapsulated for transmission toward a remote
location and the mechanisms for transferring the
resulting frames. A variety of different technologies are
used, such as Frame Relay and ATM. Some of these
protocols use the same basic framing mechanism,
High-Level Data Link Control (HDLC), an ISO standard,
or one of its subsets or variants.
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10. Key WAN Technology Concepts
 WAN physical layer concepts for network and Internet
communications
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11. Key WAN Technology Concepts
•WAN physical-layer protocols describe how to provide electrical, mechanical,
operational, and functional connections for WAN services.
• The WAN physical layer also describes the interface between the DTE and the DCE.
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12. Key WAN Technology Concepts
 WAN data link layer protocols used in today’s
Enterprise WAN networks
Data link layer protocols define
how data is encapsulated for
transmission to remote sites
ATM uses small and the mechanisms for
fixed-size cells transferring the resulting
of 53 bytes (48 frames.
bytes for data),
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13. Key WAN Technology Concepts
 Switching technologies used for WANs in an Enterprise
setting Packet switching splits traffic data into packets that
are routed over a shared network. Packet-
A circuit-switched network is one that switching networks do not require a circuit to be
establishes a dedicated circuit (or channel) established, and they allow many pairs of nodes to
between nodes and terminals before the users communicate over the same channel. Packets are
may communicate. divided and sent through available connections.
PSTN and ISDN are two types of circuit-
switching technology that may be used to There are two approaches to this link
implement a WAN in an enterprise setting. determination, connectionless or connection-
oriented.
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14. Select the Appropriate WAN Technology to meet
ECNM Requirements
 List the various options for connecting subscribers to
the WAN
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15. Select the Appropriate WAN Technology to meet
ECNM Requirements
 Enterprises use leased line services to provide a WAN
connection
Point-to-point lines are usually leased from a
carrier and are called leased lines.
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16. Select the Appropriate WAN Technology to meet
ECNM Requirements
 Circuit switching options available to provide a WAN
connection
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17. Select the Appropriate WAN Technology to meet
ECNM Requirements
 Packet switching options available to provide a WAN
connection
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18. Select the Appropriate WAN Technology to meet
ECNM Requirements
 List factors to consider when selecting a WAN
connection
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19. Summary
 A WAN is defined as
A data communications network that operates beyond the
geographic scope of a LAN
 WAN primarily operate on layer 1 & 2 of the OSI model
 WAN technologies include
–Leased line
–ISDN
–Frame relay
–X.25
–ATM
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20. Summary
 Cisco Enterprise Architecture
–This is an expansion of the hierarchical model that further
divides the enterprise network into
•Physical areas
•Logical areas
•Functional areas
 Selecting the appropriate WAN technology requires
considering some of the following:
–WAN’s purpose
–Geographic scope of WAN
–Traffic requirements
–If WAN uses a public or private infrastructure
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21. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 21