Network Applications and Flow Models

Network Analysis Architecture & Design

• True collaboration involves team members sharing responsibility for developing quality networks.
• Internet usage is increasing daily, with applications including research, shopping, travel bookings, news, and weather checks.

Contents

• Part I: Identifying Customer Needs & Goals
  • Chapter 1: Analyzing Business Goals and Constraints
  • Chapter 2: Analyzing Technical Goals and Tradeoffs
  • Chapter 3: Characterizing the Existing Internetwork
• Part II: Logical Network Design
  • Chapter 4: Characterizing Network Traffic
  • Chapter 5: Designing a Network Topology
  • Chapter 6: Designing Models for Addressing and Numbering
  • Chapter 7: Selecting Switching and Routing Protocols
  • Chapter 8: Developing Network Security Strategies
  • Chapter 9: Developing Network Management Strategies

Lecture 1

• Top-down network design principles are based on structured software programming and systems analysis.
• Structured systems analysis aims to accurately portray user needs, which are often overlooked or inaccurately represented in system designs.
• The architecture also aims to create manageable designs through modular design, for easier maintenance and modification.
• The design process is arranged in a top-down sequence.
• Models are used to characterize the existing system, identify user requirements, and develop a future system structure.
• Data flow, data types, and processes that access or alter data are significant considerations throughout the process.
• Understanding user community data accesses/modifications and processes is part of the analysis.
• Logical and physical models are developed, where the logical model identifies basic building blocks and system structure, while the physical model describes devices, technologies, and implementations.

Lecture 2

• The model for network analysis, architecture, and design aligns with other engineering processes, involving identifying issues, managing customer expectations, monitoring the existing system/environment, analyzing data, developing solutions, evaluating options based on tradeoffs, selecting options, and planning implementation.

Lecture 3

• Requirements Analysis: Concepts
  • Requirements describe network functions and performance necessary to support users, applications, and devices.
  • User Requirements:
    • User requirements are the needs gathered from input of end users, system administrators, and management.
    • Application requirements are derived from application data, experience, or testing. These specify what the application needs for successful system operation.
    • Different types of application requirements include real-time and non-real-time requirements. Interactivity is a common feature of applications, with variations in timing relationships between source and destination.
    • Device requirements specify the types of devices, performance characteristics, and location.
    • Network requirements for existing networks include scaling dependencies, location dependencies, performance constraints, and network obsolescence.
  • Other Requirements:
    • Other requirements include supplemental performance requirements, financial requirements, and enterprise requirements. In these areas, detailed analyses of requirements for various types of applications and devices can inform architectural decisions.

Lecture 4

• Flow Analysis: A flow is a set of network traffic exhibiting common attributes, such as source/destination address, type of information, directionality, or other end-to-end information and is transmitted during a single application session and is end-to-end between source and destination applications.
• Common Flow Characteristics: Flow characteristics include performance requirements (e.g., bandwidth, latency, reliability, availability), importance/priority levels, business/enterprise considerations, directionality, common sets of users, applications, devices, and scheduling, protocols used, security, and privacy.
• Types of Flows:
  • Individual Flows: The basic unit of traffic flows, related to individual application sessions, often come with guaranteed requirements (such as those for essential business transactions within an organization).
  • Composite Flows: Composed of multiple application requirements or flows and often share a common link, path, or network.
• Identifying and Developing Flows: The process of defining and creating flows includes identifying applications, determining flow source and sink locations, applying flow models if needed, and combining flow performance requirements into flow specifications. Techniques for identifying flow requirements from an application perspective include focusing on a specific application, or building a profile of applications common to a user group (for instance, analyzing the top-N applications used by the majority of employees for network design)

Lecture 5

• Architectural Models
  • Topological Models: LAN/MAN/WAN and Access/Distribution/Core models.
    • LAN/MAN/WAN Model for networks with geographical and/or topological separations.
    • Access/Distribution/Core Model for function-based separation.
  • Flow-Based Models: (peer-to-peer, client-server, hierarchical client-server, distributed computing) Flow-based models relate directly to flow characteristics identified in Chapter 4.
    • Peer-to-Peer Model for scenarios where user and application behavior are fairly consistent across a network.
    • Client-Server Model for scenarios with consistent client-server requests/responses.
    • Hierarchical Client-Server Model for multi-tiered organizational structure.
    • Distributed Computing Model for models with highly varied data sources and sinks, for example, a distributed computing system might employ a task manager coordinating multiple computing devices.
  • Functional Models: Service provider, intranet/extranet, single/multi-tiered performance, end-to-end models.

Lecture 6

• Performance Architecture: A framework for fulfilling user, application, device, and existing network requirements concerning capacity, delay, and reliability, and availability.
• Key elements include identifying performance goals for the network, addressing performance issues like response times and throughput, grouping/prioritizing users and applications, changing the network from a cost center to profit-generating entity, merging traffic types, differentiating customers, and addressing QoS (Quality of Service).
  • QoS:
    • QoS implementation mechanisms include prioritization, traffic management (admission control, traffic conditioning, and scheduling), and queuing strategies.
    • Service-level agreements (SLAs) are formal contracts between providers and users setting up specific performance levels and responsibilities. SLAs can be user-level or service-provider level, and they are important for measuring and managing service expectations.

Lecture 7

• Midterm examination related to the network analysis and design course.

Lecture 8

• Developing Network Security Strategies
  • Security and Privacy Plan: Creation of strategies addressing threats, policies, and procedures.
  • Security and Privacy Mechanisms: Physical, protocol, application, encryption/decryption, and network perimeter security are crucial aspects as well as remote access security.
  • Architectural Considerations: Internal and external relationships, security mechanism assessment, design factors for security.

Test your knowledge on common approaches to identifying flows in applications and the various flow models used in network environments. This quiz covers definitions, characteristics, and challenges related to data sources, sinks, and functional modeling. Perfect for students studying computer networks and distributed computing.