Design Teams and Translating Plans into Design Criteria

IACT 424 IACT 924

Corporate Network Design and Implementation

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Summary Slide

• Design Criteria

• An Architectural Approach to Network Design

• Four(4) Guiding Principles

• Legacy System Analysis

• Creating Design Teams

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Design Criteria

• Design criteria are the explicit goals that a project must achieve in order to be successful

– In recommendation and feasibility reports the design and decision criteria determine the document's final recommendation for action

– Managers use these criteria as their basic tool in evaluating a project's potential for success and how well it fits into the goals of the organization

– Experts need explicit design and decision criteria in order to evaluate recommended designs of devices and test procedures.

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Design Criteria

• Primary criteria are those that constitute a successful project

– the project will be unsuccessful if it does not meet these goals

• Secondary criteria are those features that are highly desirable but not absolutely essential

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Design Criteria

• Separating primary and secondary criteria establishes a clear hierarchy in design choices

– Implementing one criterion makes the implementation of another infeasible or costly

– A secondary criterion may be sacrificed in favour of a primary criterion.

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Design Criteria• Make your design criteria short but as specific

as possible– Avoid vague language

– List your primary criteria first

– Then list the secondary criteria• Design criteria are often best displayed in

bulleted lists– Short titles preceding the explanation

– These titles may then be used later in the document to refer to the specific criteria being discussed

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Design Criteria

• If you number your criteria

– Avoid referring to them later solely by number

– This practice often confuses readers

• Use tables to show and summarize the relative effectiveness of different implementations in comparison with your design criteria

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An Architectural Approach to Network Design• Should not be confused with a detail design of

the network• Architectural design is a term that defines

– Technologies

– Protocols

– Communication capabilities

– Generic products

– interconnection of segments of a network

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An Architectural Approach to Network Design• Architectural design

– Supports the network concepts developed

– Expands on the conceptual design

• Where organisation-wide strategic directions are set and defined

• These are used as a way to identify the network design criteria

– criteria that are in line with the organisations direction and technology evolution

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An Architectural Approach to Network Design – Major Considerations

• Development of

– The conceptual design

• Linked with detailed research on

– The business characteristics and process of the organisation

– The competition the business is facing

• Particularly electronically

– What new customer interaction channels are required

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An Architectural Approach to Network Design – Major Considerations

• General technology trends

– Technology choices

– Lifespan of all technologies that might be utilised in the architecture

• User types

– Current and planned

– Need to be defined

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An Architectural Approach to Network Design – Major Considerations

• Security requirements in the form of an enterprise security policy developed

• Current, planned and the potential geographic reach of the network which

– Including locations, users and customer/ partner organisations

• Definition and identification of applications that run over the converged network

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An Architectural Approach to Network Design – Major Considerations

• Analysis of

– Current capacity of the network

– Future requirements

• Based on

– Services

– Reach

– Applications

– Users

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An Architectural Approach to Network Design – Major Considerations

• These will provide

– A streamlined design process

– Alignment of the network capability with current and future business requirements

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Outcomes of an Architectural Design• The architectural design will produce a

number of outcomes

– Design directions

– Architecture outline/ overview diagrams for the network segments detailing technology and features/functions.

• The architecture design will

– Outline high level network topology

– Detail interconnections of the network segments

– Identify the protocols that will be used

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Network Architectural Design – Elements• Design elements fall into two categories

– Concept elements

• Architecture concepts (characteristics)

– Technology elements

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Concept Elements• Business environment

– Business developments and direction

– New competitors and competitor channels

– Current and emerging customer interaction channels

• Technology– Available protocol choices

– Available/suitable generic product choices (groups)

– Ancillary/complementary technologies

– Business applications

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Concept Elements

• Scalability

– Scalability defined at network segment(s) level

– Scalability rules and limits

• Dependability

– Availability requirements

– Recoverability parameters/requirements

– Survivability requirements

– Fault tolerance requirements

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Concept Elements

• Security

– Security requirements (rules and limits set at each network segment level)

– Security requirements for user types

• Management and maintainability

– Management system requirements

– Maintainability functions, restore requirements

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Concept Elements

• Compatibility

– Compatibility requirements

– Compatibility rules between segments

– Legacy equipment, systems and protocols

• Limitations

– Limits for size of network

– Limits for volume

– Traffic types and traffic mix

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Concept Elements

• Flexibility

– Future reach

– User demographics and potential changes

– Services deployment intent

• Distribution and geography

– Geographic boundaries of the network (eg distance, location)

– Traffic distribution rules (based on geography)

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Concept Elements

• Optimisation and financials

– Cost ranges for network, operational and capital

– Service dependability versus cost ranges

• Risks

– Business environment risk

– Technology risks (early, lifecycle)

– Costs (equipment, installation, operational)

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Concept Elements

• Performance

– Objectives for delay/latency

– Network throughputs

– Potential and identified impairments

• Simplicity

– Protocol type reduction

– Configuration parameter reduction

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Network Components

• Nodes

– Node types

– Assignment/identification of generic products for node types

• Links

– Network link types

– Assignment/identification of generic products for link types

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Network Components

• Topology

– Node distribution, interconnection

– Network topology for control and management, interconnections

• Interfaces

– Applications and users

– Other networks

– Interface technology types

– Protocols

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Network Components

• Services

– Communication services types (focus on latency sensitive)

– Security services

– Management services

– Mapping/overlaying services to network topology

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Network Components

• Protocols

– Protocols for transport

– Protocols for nodes

– Protocols for interfaces

• Traffic mapping

– Segmentation

– QoS dependencies

– Bandwidth/volumes

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Four(4) Guiding Principles• The task of writing the design document needs to be

guided by the following– Functionality: will the end product work?

– Scalability: is the network able to grow without major problems

– Adaptability: will the project be able to incorporate new technologies in the future?

– Manageability: can we monitor network operations and make necessary changes easily?

• May also wish to consider– Standards Compliance

– Security

– Reduced Institutional Risk

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Functionality

• Functionality:

– Does the network support each job function so that strategic goals can be attained?

– Does the network deliver end-to-end connectivity that is both reliable and sufficiently fast

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Scalability

• Any network design must allow for future growth

• In physical terms, this means

– Allowing space in equipment racks for more equipment

– Spare connection points in main and intermediate distribution frames (MDFs and IDFs)

• In logical terms, well structured IP addressing schemes

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Adaptability

• Design Criteria should incorporate possible changes to design through the advent of new technology

• The design should not have features that makes the future provisioning of new technology impossible

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Manageability

• The network should facilitate both monitoring and manageability

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A Closer Look at Design Requirements• Two important sources of information should be

exploited

– The Design Requirements section of your Design Document is a summary of requirements that have been developed during your strategic analysis phase.

– It also draws on past experience by

• Describing the existing network (legacy system)

• Listing current applications, protocols, users

• Describing the current performance of the network

• Brings together all the knowledge that will be used to develop next section, the Design Solution.

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Characterising the Network• Strategic objectives are used to:

– Specify business goals, business processes, customers, suppliers. This has implications for functionality.

– Define corporate structure. This has implications for LAN and VLAN design where networks servicing different workgroups need to be separated.

– Define geographic structure. This has implications for where workgroups, suppliers, customers are physically located. Mostly relevant to determining WAN typologies.

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Legacy System Analysis

• Identify currently used applications

– Necessary in determining how work is currently carried out in the organisation

• Information flows should be documented

– Including those that are transferred in hard copy, on discs or verbally

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Legacy System Analysis

• New designs have the potential to disrupt established information sharing relationships between people

• Shared data sources should be identified

– Policy manuals

– Servers

– Intranets

– Bulletin boards

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Legacy System Analysis

• Determine network traffic and access

– Identify the amount of data that travels within segments and between segments

– Determine the volumes of data that are obtained externally from the Internet.

• Determine network performance

• Identify protocols in use

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Network Performance Guide(Teare, 1999)

• No shared Ethernet segment to be saturated (no more than 40% network utilisation)

• No shared Token Ring segments are saturated (no more than 70% network utilisation)

• No WAN links are saturated (no more than 70% network utilisation)

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Network Performance Guide(Teare, 1999)

• Response time <100 milliseconds• No segment have more than 20%

broadcasts/multicasts• No segments have more than one CRC

(Cyclic Redundancy Check) error per million bytes of data

• On Ethernet segments, less than 0.1 % of packets result in collisions

• On the Token Ring segments, less than 0.1% of the packets are soft errors not related to ring insertion

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Network Performance Guide(Teare, 1999)

• On FFDI segments, there has been no more than one ring operation per hour not related to ring insertion

• Routers are not over-utilised (5 minute CPU utilisation no more than 75%

• The number of output queue drops has not exceeded more than 100 in any hour on any router

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Network Performance Guide(Teare, 1999)

• The number of input queue drops has not exceeded more than 50 in any hour on any router

• The number of buffer misses has not exceeded more than 25 in an hour on any router

• The number of ignored packets has not exceeded more than 10 in an hour on any interface on a router

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Creating Design Teams

• Different skills are required of project leaders through the life of a project.

• In the early stages, the emphasis should be on leadership

• In the later stages, the emphasis should be on management

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Leadership and Management (Verma, 1996, p. 223)

Leaders focus on Managers focus on Vision Objectives Selling what and why Telling how and when Longer range Shorter range People Organisation & structure Democracy Autocracy Enabling Restraining Developing Maintaining Challenging Conforming Originating Imitating Innovating Administering Directing Controlling Policy Procedures Flexibility Consistency Risk (opportunity) Risk avoidance

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The people you’ll need

• Telecommunications Manager

– Conceptualiser & visionary

– Articulate & persuasive

– Understand organisations problems & how communications tech can be applied to them

– Able to grasp technical subjects but doesn’t have to be a ‘techie’

– Able to plan & make decisions

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The people you’ll need

• Designers & Implementers

– Good understanding of communications systems & products

– Creative & innovative

– Project management skills

– Verbal & written communications skills

– Team player

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The people you’ll need

• Network operations staff

– the ‘manufacturing’ arm

– Service oriented

– Strongly motivated to maintain the system

– Good verbal skills with ‘customers’

– Able to swap between sections (say: network ops & computer ops) to spread skills and experience

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The people you’ll need

• Technical support staff

– Understand hardware & software

– Self-starters

– Analytical problem solvers

– Often have advanced technical education, frequently vendor based

• Novel

• Microsoft

• Cisco etc.

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The people you’ll need

• Administrative support staff

– Largely clerical

– Some grasp of IT issues & jargon

– Accounting & business administration skills