Transcript Network Design and Implementation

Network Design and
Implementation
IACT 918 July 2004
Gene Awyzio
SITACS University of Wollongong
Historical Background
• Traditionally based on developing and
applying a set of rules:
– The 80/20 rule [80% local traffic – 20% on the
backbone]
– “bridge when you can,
route when you must”
• Such rules were useful when there weren’t
many choices in
– network technology
– Network services
– Interconnection strategies
2
Historical Background
• Network analysis, architecture and
design has focused on capacity
planning
– The buffer provided by this reduced
customer congestion problems
• Bandwidth is only one of the
resources that must be considered
in network design
3
Historical Background
• Also need to consider
– Delay performance
– Reliability
– Maintainability
– Availability
4
Network Analysis
• Study of network components
– switches, routers, requirements and
performance levels
•
… and their inputs and outputs
• To gain an understanding of the
networks behaviour under various
circumstances
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Network Analysis
• Defines and determines:
– Relationships between components
– State of the current network and problems
– Network goals
– Traffic flows
– User and application behaviour
• Maps all of these within the network
environment
• Allows designers to understand what
problems need to be solved
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Network Architecture
• Uses network analysis data to develop:
– High-level end-to-end structure for network
– Major network functions as architectural
components that will be brought together to form
the network
• Addressing/routing, network management, performance,
security
– Goals for the network
– Interactions, trade-offs, dependencies and
constraints
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Design Processes
• Provides physical details
to the reference architecture
• Evaluation and choice of technologies
• Development of network strategies
• Mapping performance and requirements
to design goals
• Evaluating designs against goals
• Deciding on trade-offs
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Model for Network Design and
Implementation Planning
•
•
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•
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Define the problem to be addressed
Establish and manage customer expectations
Analyse data
Develop set of options for solving problems
Evaluate and optimise options
(including trade-offs)
• Selecting one or more options
• Planning the implementation
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Architectures & Components of
Network Design
• Requirements Analysis
• Conceptual:
– What is needed from the network
– Users’ needs
– Applications’ needs
– Devices’ needs
– Network’s needs
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Architectures & Components of
Network Design
•
•
Requirements Analysis
Process:
– Gathering
• Initial Conditions, Expectations
etc
– Developing service metrics
– Characterising behaviour
– RAS requirements
– Delay requirements
– Capacity requirements
•
– Mapping requirements
to Geographic locations
– Devices
– Applications
•
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Requirements map
shows location of:
From the map we can begin to
develop
flow specification
Architectures & Components of
Network Design
• Requirements Analysis
• Conceptual:
– What is needed from the network
– Users’ needs
– Applications’ needs
– Devices’ needs
– Network’s needs
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Architectures & Components of
Network Design
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•
Flow Analysis
•
Network designers need to:
–
Identify individual & composite flows
–
Identify critical flows
–
Focus may be on:
•
Particular applications
•
Specific profiles –
user, application, criticality
–
Develop an
Application Flow Map
–
Prioritise flows
–
Specify Flows any how they need to
be managed:
•
Best effort
•
Predictable Flows
•
Guaranteed Flows
Apps E & F
App G
App B
Flow level & Critical function
• NB: Flows are not necessarily tied to criticality
– Eg: a critical function may only require a best effort
flow!
• Must have database server available, but speed of
access not critically important
– Eg: a non-critical function may require a
guaranteed flow to operate at all!
• A VoIP service between two buildings may require
guaranteed flow, but maybe isn’t a critical function
• Critical/non-critical reflects business activity
• Flow level reflects network activity
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Architectures & Components of
Network Design
• The following Architectures need to be considered in
Network design:
– Component Architecture for:
• Addressing/Routing
• Network Management
• Performance
• Security
– Reference Architectures for external relationships
– Architectural models for
• Topology
• Flows
• Functionality
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Component Architecture
• Addressing/Routing
– Address Mechanisms
• Address classes
• Subnets
• Supernets
• Private and public addressing
– Routing Mechanisms
• Routing Flows
• Routing Boundaries
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Component Architecture
• Network Management
architectural considerations:
– In-band/ Out-of-band
– Centralised/distributed/hierarchical
– Scaling of management traffic
– Management of Network management data
• How much, how long, where, storage needs,
analysis needs etc
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Component Architecture
• Performance Architectures
– Quality of Service
– Prioritisation, Traffic management,
Scheduling, Queueing
– Service Level Agreements (SLAs)
– Polices
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Component Architecture
• Security and Privacy
– Threat Analysis
– Polices and procedures
– Physical security
– Protocol and application security
– Encryption/decryption
– Network perimeter security
– Remote access security
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Selecting Technologies
• Objectives
– To select network technologies for your
network design
– Using:
• Requirements
• Flows
• Goals
• Criteria
• and Guidelines
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Process
Requirements
Specification
Flow
Specification
Establishing
Design Goals
Developing Criteria for
Technology Evaluation
Guidelines for
Selecting Technologies
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Making Technology
Choices for the Design
Network
Architecture
Process
Requirements
Specification
Flow
Specification
Establishing
Design Goals
Developing Criteria for
Technology Evaluation
Guidelines for
Selecting Technologies
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Making Technology
Choices for the Design
Network
Architecture