1. Introducing Network
Design Concepts
Designing and Supporting Computer Networks – Chapter 1
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2. Objectives
 Explain how a hierarchical network design creates a stable,
reliable, scalable network
 Explain what factors need to be considered when the Core Layer
of a network is designed and implemented
 Explain which factors need to be considered when the
Distribution Layer of a network is designed and implemented
 Explain which factors need to be considered when the Access
Layer of a network is designed and implemented
 Describe the benefits and security implications of creating server
farms
 Describe the considerations of an implementation of a wireless
network design
 Describe the factors that affect the implementation of VPNs,
including how remote workers can be supported
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3. Explain How a Hierarchical Network Design
Creates a Stable, Reliable, Scalable Network
Network requirements:
 Ease of management
 Fast recovery
 Application response time
 Fast troubleshooting
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4. Explain How a Hierarchical Network Design
Creates a Stable, Reliable, Scalable Network
Four fundamental network design goals:
 Scalability
 Availability
 Security
 Manageability
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5. Explain How a Hierarchical Network Design
Creates a Stable, Reliable, Scalable Network
 Core Layer: connects Distribution Layer devices
 Distribution Layer: interconnects smaller LANs
 Access Layer: provides connections for hosts and end
devices
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6. Explain How a Hierarchical Network Design
Creates a Stable, Reliable, Scalable Network
Subdividing the three-layer model into modular areas:
 Enterprise campus
 Server farm
 Enterprise edge
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7. Explain How a Hierarchical Network Design
Creates a Stable, Reliable, Scalable Network
Steps in network design projects:
 Identify the network requirements
 Characterize the existing network
 Design the network topology and solutions
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8. Explain what Factors Need to be Considered
when Designing the Network Core Layer
 Network backbone
 Goals of the Core Layer
Provide 100% uptime
Maximize throughput
Facilitate network growth
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9. Explain what Factors Need to be Considered
when Designing the Network Core Layer
 Combining routing and switching in the same device
 Redundancy and load balancing
 High-speed and aggregate links
 Quick convergence
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10. Explain what Factors Need to be Considered
when Designing the Network Core Layer
 Full mesh topology
 Partial mesh topology
 Failure prevention
 Reducing human error
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11. Explain which Factors Need to be Considered when
Designing the Distribution Layer of a Network
 Filtering and managing traffic flow
 Access control policies
 Route summarization
 Isolating Core Layer from Access Layer failures
 Routing between VLANs
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12. Explain which Factors Need to be Considered when
Designing the Distribution Layer of a Network
 Explain how redundant links improve network reliability
and stability
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13. Explain which Factors Need to be Considered when
Designing the Distribution Layer of a Network
 Explain how ACLs filter traffic for security and traffic
management
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14. Explain which Factors Need to be Considered when
Designing the Distribution Layer of a Network
 Explain the concept of route summarization and
describe how it is implemented at the Distribution Layer
of the network
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15. Explain which Factors Need to be Considered
when Designing the Access Layer of a Network
 Physical location of equipment
 Wiring closets
 Converged networking
 Availability
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16. Explain which Factors Need to be Considered
when Designing the Access Layer of a Network
 Naming structures
 VLAN architecture
 Traffic patterns
 Prioritization strategies
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17. Explain which Factors Need to be Considered
when Designing the Access Layer of a Network
 Star topologies
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18. Explain which Factors Need to be Considered
when Designing the Access Layer of a Network
Functions of VLANs:
 Separate and classify traffic
 Control broadcasts
 Contain VLANs within a single wiring closet
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19. Explain which Factors Need to be Considered
when Designing the Access Layer of a Network
QoS at the network edge:
 Classification
 Assigned priority
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20. Explain which Factors Need to be Considered
when Designing the Access Layer of a Network
Security risks at the network edge:
 Authentication
 Wireless security
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21. Explain which Factors Need to be Considered
when Designing the Access Layer of a Network
Security measures at the Access Layer:
 Physical security
 Strong passwords
 SSH
 Disabling unused ports
 Security policy
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22. Describe the Benefits and Security
Implications of Creating Server Farms
 Defined entry and exit points for network traffic
 Redundant, high-capacity links
 Load balancing and failover
 Lower cost of providing services
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23. Describe the Benefits and Security
Implications of Creating Server Farms
 Firewalls
 LAN switch security features
 Intrusion and prevention systems
 Load balancers
 Network analysis and management devices
 DMZs
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24. Describe the Benefits and Security
Implications of Creating Server Farms
 Building in redundancy for high availability
 Virtualization
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25. Describe the Considerations of an Implementation
of a Wireless Network Design
Customer requirements:
 Roaming
 Authentication
 Services and applications
 Encryption
 Coverage and number of users
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26. Describe the Considerations of an Implementation
of a Wireless Network Design
 Physical WLAN design
 Site survey
 Logical WLAN design
 Open guest access vs. secured employee access
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27. Describe the Factors that Affect the
Implementation of VPNs
 Cost of bandwidth
 QoS
 Security
 Remote access
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28. Describe the Factors that Affect the
Implementation of VPNs
Interconnection options:
 Traditional WAN technologies
 Newer WAN technologies
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29. Describe the Factors that Affect the
Implementation of VPNs
 Explain ways to provide redundant connectivity to
remote sites
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30. Summary
 The four fundamental technical requirements of network
design are scalability, availability, security and
manageability.
 Network projects involve identifying the requirements,
characterizing the existing network, and designing the
network topology and solutions.
 Redundancy at the Core Layer keeps the network
functioning even when a device or link fails.
 Routing efficiency at the Distribution Layer isolates the
Core from Access Layer failures.
 Using VLANs and IP subnets is the most common way
to segregate user groups and traffic within the Access
Layer.
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31. © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 31