chapter 1 services in a converged wan
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TRANSCRIPT
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE I Chapter 6 1
Services in a Converged WAN
Accessing the WAN – Chapter 1
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 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.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 3
Wide Area NetworksWAN
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.
LAN connects computers, peripherals, and other devices in a single building or other small
geographic area
An enterprise must subscribe to a WAN service provider to
use WAN carrier network services.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 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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Evolving Enterprise
Stages of business growth.
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The Evolving Network Model
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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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Describe How ECNM Provides Integrated Services over an Enterprise Network Explain the purpose of Cisco Enterprise Architectures
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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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Key WAN Technology Concepts WAN physical layer concepts for network and Internet
communications
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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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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
and the mechanisms for transferring the resulting
frames.
ATM uses small fixed-size cells of 53 bytes (48 bytes for data),
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Key WAN Technology Concepts
Switching technologies used for WANs in an Enterprise setting
A circuit-switched network is one that establishes a dedicated circuit (or channel)
between nodes and terminals before the users may communicate.
PSTN and ISDN are two types of circuit-switching technology that may be used to implement a WAN in an enterprise setting.
Packet switching splits traffic data into packets that are routed over a shared network. Packet-switching networks do not require a circuit to be
established, and they allow many pairs of nodes to communicate over the same channel. Packets are
divided and sent through available connections.
There are two approaches to this link determination, connectionless or connection-
oriented.
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Select the Appropriate WAN Technology to meet ECNM Requirements
List the various options for connecting subscribers to the WAN
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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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Select the Appropriate WAN Technology to meet ECNM Requirements
Circuit switching options available to provide a WAN connection
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Select the Appropriate WAN Technology to meet ECNM Requirements
Packet switching options available to provide a WAN connection
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Select the Appropriate WAN Technology to meet ECNM Requirements
List factors to consider when selecting a WAN connection
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Summary
A WAN is defined asA 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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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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 21