Table of Contents
Introduction - A Small- to Medium-Sized Business Solutions
Framework
Section Objectives
Upon completion of this introduction, you will be able to describe a framework
you can use to simplify the complexities associated with analyzing customer
network problems and creating Cisco scalable solutions.
Time Required to Complete This Section
Approximately 30 minutes
Media/Resources Required to Complete This Section
This section consists of one short reading assignment. You will need the
following resources:
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Access to Cisco's Web site or the World Wide Web
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A downloaded or printed copy of this section
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Paper and pencil
Reading Assignment
Role of the Cisco Certified Design Associate
Your role as a Cisco Certified Design Associate is to be a network design
consultant. You will act like an architect, building comprehensive designs
that solve your customer's internetworking problems and provide the required
functionality, performance, and scalability. In the same way that an architect
designs a building or house for a client, you will develop blueprints for
an overall internetwork design, as well as components plans for various
pieces of the internetwork.
CiscoFusion
Cisco has developed an integrated network architecture, called CiscoFusion.
With the CiscoFusion architecture, multiple networking technologies, operating
at different networking layers, can provide the right capabilities to handle
different networking issues.
Many of your customers may already be aware of the recent internetworking
trend toward an integrated view of networking technologies. As a Cisco
Certified Design Associate, you will be uniquely positioned to produce
network designs, based on CiscoFusion, that meet the needs of state-of-the-art
networks that integrate Layer 2, Layer 3, and ATM services. For example,
the intelligent networking services associated with Layer 3 can be combined
with the cost-effective, high-capacity services provided by Layer 2 in
both LANs and WANs.
Evolution of Layer 2 and Layer 3 Services
Layer 2, also known as the data link layer, operates within a specific
LAN or WAN segment. In the last two years, LANs have been revolutionized
by the exploding use of switching at Layer 2. Companies are replacing hubs
with switches at a quick pace. LAN switches provide performance enhancements
for new and existing data networking applications by increasing bandwidth
and throughput for workgroups and local servers.
Layer 3, also known as the network layer, operates between and across
segments. Protocols such as Internet Protocol (IP), Internetwork Packet
Exchange (IPX), and AppleTalk's Datagram Delivery Protocol (DDP) operate
at Layer 3. In the wide area, Layer 3 networking allows businesses to build
global data networks. As an example, the global Internet is based on Layer
3 technology.
Layer 3 networking, implemented with routing, interconnects the switched
workgroups and provides services such as security, quality-of-service (QoS)
options, and traffic management. Routing provides the control needed to
build functional, scalable networks.
Traditionally, Layer 2 switching has been provided by LAN switches,
and Layer 3 networking has been provided by routers. Increasingly, these
two networking functions are integrated into common platforms. There will
still be a wide range of platforms providing different performance and
capacity ranges for each networking function, but users will gain fundamental
benefits from integration of the layers. Users will be able to reduce the
number of networking devices that need to be purchased, installed, supported,
and serviced. In addition, users will be able to efficiently apply Layer
3 services, such as security and QoS capabilities, to specific individual
users and applications.
Mirroring the integration of Layer 3 networking technology into LAN
switching devices, WAN switching equipment likely will increasingly incorporate
Layer 3 networking capabilities. As traditional Layer 3 routers gain support
for higher capacity and bandwidth, the integration of Layer 2 technologies
will enable routers to achieve optimum levels of performance, port density,
and cost effectiveness.
The following diagram shows how Layer 2 and Layer 3 switching can be
used to facilitate communications between Client X and Server Y, with or
without routing.
When Do You Use Layer 2 or Layer 3 Functionality?
The decision to use Layer 2 or Layer 3 functionality in a network design
depends on what problems you are trying to solve for your customer. These
problems can be any of the following:
A Small- to Medium-Sized Business Solutions Framework
To help reduce the complexity associated with identifying and analyzing
customer problems, and designing solutions, Cisco has developed a basic
framework into which most customer problems fit. The small- to medium-sized
business solutions framework is represented as a triangle, as shown as
follows:
Use the following simple rules when designing solutions to customer
problems:
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If the problems involve media contention, use LAN switching.
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If the problems are protocol related, for example, excessive number of
broadcasts, use routing.
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If the customer needs to transport payloads that require high bandwidth,
use Fast Ethernet switching. In large networks where high bandwidth and
predictable low latency are required, consider ATM.
Job Aids
Throughout this course, you will find job aids such as procedures, charts,
and checklists. The job aids will help you design scalable solutions that
maximize your customer's satisfaction. Review the job aids quickly, keeping
an eye open for procedures, charts, and checklists that will help you do
your work. The job aids:
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Provide steps for designing internetworks.
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Document scalability constraints that affect internetwork designs.
Steps for Designing Scalable Networks
This course teaches you the steps for designing networks. Each module and
section includes reading assignments, job aids, and exercises or case studies.
After you review the following module descriptions, proceed with the course
by clicking on the "Module 1 - Identify Customer Needs" link.
Module 2: Design the Network Structure
In Module 2, you will learn how to provision hardware devices and software
(Cisco IOSTM) features. An understanding
of the problems you are trying to solve will help you simplify the task
of designing end-to-end solutions for your customer.
Module 3: Build a Prototype or Pilot for the Network Structure
In Module 3, you will learn to build a test case to verify your network
design. With some knowledge of the different types of customer problems,
you will know how to test for collisions, broadcasts, and bandwidth.
Module 4: Sample CCDA Sylvan Exam
In Module 4, you can practice for the CCDA Sylvan exam.
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