Network Design and Implementation

Report
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
5
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
6
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
7
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
8
Model for Network Design and
Implementation Planning
•
•
•
•
•
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
9
Architectures & Components of
Network Design
• Requirements Analysis
• Conceptual:
– What is needed from the network
– Users’ needs
– Applications’ needs
– Devices’ needs
– Network’s needs
10
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
•
11
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
12
Architectures & Components of
Network Design
13
•
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
14
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
15
Component Architecture
• Addressing/Routing
– Address Mechanisms
• Address classes
• Subnets
• Supernets
• Private and public addressing
– Routing Mechanisms
• Routing Flows
• Routing Boundaries
16
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
17
Component Architecture
• Performance Architectures
– Quality of Service
– Prioritisation, Traffic management,
Scheduling, Queueing
– Service Level Agreements (SLAs)
– Polices
18
Component Architecture
• Security and Privacy
– Threat Analysis
– Polices and procedures
– Physical security
– Protocol and application security
– Encryption/decryption
– Network perimeter security
– Remote access security
19
Selecting Technologies
• Objectives
– To select network technologies for your
network design
– Using:
• Requirements
• Flows
• Goals
• Criteria
• and Guidelines
20
Process
Requirements
Specification
Flow
Specification
Establishing
Design Goals
Developing Criteria for
Technology Evaluation
Guidelines for
Selecting Technologies
21
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
22
Making Technology
Choices for the Design
Network
Architecture

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