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Logical Design

Logical Design. Flowspec (capacity plan Service plan) Requirements Specification Guidelines in Evaluating and Selecting Technology Guidelines for Interconnection. Establishing Design Goals. Developing Criteria for Technology Evaluation. Risk Analysis And Contingency Planning.

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Logical Design

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  1. Logical Design

  2. Flowspec (capacity plan Service plan) Requirements Specification Guidelines in Evaluating and Selecting Technology Guidelines for Interconnection Establishing Design Goals Developing Criteria for Technology Evaluation Risk Analysis And Contingency Planning Making Technology Choices for the design Applying Interconnection Mechanisms to the design Integrating Network Management and Security Into the design

  3. Logic Design Process • Determine your design _______ for the network • Translate the goals into evaluation ________ for making technology choices. • Segment the design __________ into small, workable areas and make technology choices based on evaluation criteria. • Determine how to ___________ areas of design. • Integrate _________ and network __________ into the design.

  4. Possible Design Goals • Minimizing network deployment or ____________s costs. • Maximizing one or more network _____________ characteristics. • Ease of ____ and manageability • Optimizing security • Adaptability to ____ and changing user needs.

  5. Design Goals (cont.) • The result of determining the design goals is a set of ________ goals, based on a primary design goal and one or more secondary goals. • The ________ goal drives the design • The __________ goal will finish the design.

  6. Cost/Performance Graph Deployment/Operating Costs Deployment Cost Operating Cost Cost threshold Can be adjusted As necessary A B C D Network Performance

  7. Budget Allocation Example Budget for PCs and Network ($) 600 500 400 300 PC costs Number of PCs Network cost A B C D Network Performance

  8. Criteria for Technology Evaluation • Use _________ used as evaluation criteria, or __________ them into evaluation criteria. • Minimize network deployment and operation costs. • Maximize ease of use for users and network personnel. • Maximize performance. • Adaptability • Use _______, ______ planning and ________ planning, to derive evaluation criteria.

  9. Design Goals, Capacity and Service Plans Capacity Plan Design Goal SUM(Cbe) minimizing _____ Service Plan Maximizing ___________ SUM(Cdet,Rdet,Ddet) SUM(Cbe) Adaptability Flowspec

  10. Technology Characteristics to Help Achieve Design Goals • Non-broadcast multiple access (NBMA) and ________ • Functions and _________s

  11. NBMA and Broadcasting • Native Broadcast support • Flexibility for broadcast and multicast • ____________ and simplicity • Connection support • ______ state, ______ sate, _________ • Tradeoff: • Amount of ______ and ______ over the end-to-end path offered by the state. • Configuration control and management. • Scalability and simplicity.

  12. Network State System _____ is gathered from each device end-to-end path Stateless: traffic is forwarded _______ knowledge of system state. Soft state: system knowledge is ___________ Hard state: system knowledge is long-lived or _____________

  13. System state as part of network connection Connection _______ information (Address, Flow Ids, Service Attributes) Kept in each _____________ in the path of the connection.

  14. (2) (1) Connection Establishment • ________ requests access to server resource • _____ information is used to establish connection. • Connection is established.

  15. Functions and Features • Mobility support • Service _______ offered (QoS, TOS) • Value added service (accounting, security, …) • Capacity upgrade

  16. Capacity Upgrade Path • The evolutionary paths that _______ capacity with time. • The upgrade paths can be one of the criteria for choosing a ________ for each part of the network. • Must consider potential ____ changes

  17. Expected Capacity Ranges for Selected Technologies 10 1 0.1 0.01 Ethernet FDDI ATM HiPPi

  18. Overlap in ATM/SMDS/Frame Relay Capacity Ranges 155 45 1.5 0.056 Frame Relay SMDS ATM

  19. Hierarchy < 4:1 4:1 to 6:1 7:1 to 9:1 Scaling Factor __ _____ _____ Backbone Flow Growth Prediction

  20. Modify Backbone Capacity by Degree of Hierarchy Hierarchy 5:1 Hierarchy 2:1 3.15 Mb/s 99.95% 80ms Scaling Factor Used – _____ Backbone Capacity – 3.15 Mb/s Modified Backbone Capacity – (___)*(3.15M) = 4.725Mb/s

  21. Flow Considerations • _____________ planning • Determine the required capacities of candidate technologies. • __________ planning • Evaluate the ability to provide the degree of specified service support required.

  22. Evaluation Criteria for Selected Technologies

  23. Guidelines for Technology Evaluations based on Capacity and Service Plans • Rule1: • If _______ requirements are specified in the flowspec (the service plan), then either the technology or a combination of technology and supporting protocols or mechanisms must support ______ services.

  24. Rule 1 (cont.) • Deterministic service: • No ________ to provide a particular level of performance but more predictable service to end users. • Why not just best effort services? • Differentiating service type takes us toward offering multiple, various services to end users. • Deterministic service needs to be ensured to receive more ___________ performance characteristics from the network.

  25. Multipart Flowspec Best Effort: F 1 Deterministic F2, F3, CF1, CF3, CF6 Guaranteed F4, CF1, CF3

  26. Choose Technology • Deterministic service is a predictable, or bounded, service. • Technology candidates • QoS levels in _____ • ___ levels in Frame Relay • Access classes in _______ • NBMA or broadcast technologies, using RSVP.

  27. Rule 1: Guaranteed Services • Technology must be capable of • Determine the _____ of the end-to-end path of the flow • Controlling the ________ of each network element in the end-to-end path of the flow. • Providing a mechanism to arbitrate who gets or keeps the service when it is intended for. • Candidate technology for CF1 & CF3: • ATM ______ of 3.2 Mb/s. • Delay limit must constrain the physical distance.

  28. Rule 2 • If best-effort and/or specified capacities are specified in the flow spec, then the selection of technology may also be based upon __________ planning for each flow. • Capacity planning is using the _________ capacities from the flowspec to select candidate technologies, and determining scalability of the technologies based on capacities and growth __________.

  29. Threshold Capacity • Best effort: • Summary capacity below _______ of the threshold capacity. • Deterministic: • Contain deterministic and best effort MAX(60% BE, _______%DE) • _______ / (MDR/SDR) if burstiness is known. • Need to know the maximum throughput of candidate technologies.

  30. Estimated Maximum Throughput with TCP/IP

  31. Estimation of Maximum Capacity Needed

  32. Technology Choice • WAN F1, F2, and F3 • Frame Relay, SMDS, ATM, or dedicated circuits. • Backbone WAN BB1 • SMDS 4 Mbps, Frame Relay with CIR > 4 Mbps, or ATM with a CBR or VBR > 4 Mbps. • …..

  33. Estimating Scalability Growth estimation: 20% for year 1, 25% for year 2, and 10% for year 3 to 5.

  34. Constraints on Candidate Technologies • _______ • Preexisting networks • Their characteristics that impose _____________ on the design. •  to select a list of ________ for us to apply to the design.

  35. Cost Constraints

  36. Making Technology choice for the Design: Sizing Network • First step: Segment the design into workable parts, termed ______ • Based on ________: • Countries, states, or cities, campuses, buildings • Concentrations of _______ • The number of users, or their relative concentrations; useful for virtual groups of users. • Flow ________ • Use the flow analysis to show where potential hierarchies may exist in the network. • Has the benefit of showing end-to-end service needs.

  37. Sizing Network Design at LAN/WAN Level Boston WAN City LAN/WAN City LAN/WAN New York Chicago City LAN/WAN City LAN/WAN City LAN/WAN Denver Atlanta

  38. Sizing Based on User Concentration User group A 1400 users User group C 150 users User group B 5200 users User group D 2100 users User group F 200 users User group E 1600 users

  39. Sizing Based on Flow Hierarchies Sizing by flow hierarchy incorporates the _________ and ___________ methods.

  40. Alternate Method for Sizing Design • Based on _______s and ______s, e.g. WAN • ____s, often use service providers. • _____, interconnect and integrate the other areas; • ________ Areas, dictate particular tech. • ________s, several flows are consolidated. • _______ Areas, focus on more traditional requirements, such as capacity planning.

  41. Sizing by Functions and Features General General Specialized General Backbone Backbone WAN NAP Backbone Specialized Backbone

  42. Isolating Areas-The black box method output Input Black Box MAN Input output Hide areas as _____ boxes and expose elements That are being designed.

  43. Applying Evaluation criteria and Guidelines • Apply all of the information we have developed • Requirements, • Flowspec • Design ________s • Evaluation ______, and • Guidelines to make technology selections for the ______.

  44. Black Boxes Applied to Isolate Backbone Area Black Box Area A BB1 2.15 Mb/s Black Box Area B BB2 450 Kb/s MAN BB3 530 Kb/s Black Box Area C

  45. Next Isolation Black Box Area A Area A Area B Black Box Area A GW CF3 2.23 Mbps BB4 3.35 Mbps Area C

  46. Case Study

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