Year 2 Network design and set-up for computer Science student
- 1. CSE 550 Computer Network Design Dr. Mohammed H. Sqalli COE, KFUPM Spring 2008 (Term 072)
- 2. CSE-550-T072 Lecture Notes - 1 2 Introduction What is a Network? What is “Network Design”? Top-Down Network Design Network Development Life Cycle (NDLC) Network Analysis and Design Methodology Types of Network Design And Then What?
- 3. CSE-550-T072 Lecture Notes - 1 3 What is a Network? Management view Technical view
- 4. CSE-550-T072 Lecture Notes - 1 4 The Management View (1/3) A network is a utility Computers and their users are customers of the network utility The network must accommodate the needs of customers As computer usage increases so does the requirements of the network utility Resources will be used to manage the network The Network Utility is NOT free! Someone must pay the cost of installing and maintaining the network Manpower is required to support the network utility
- 5. CSE-550-T072 Lecture Notes - 1 5 The Management View (2/3) Utilities don’t bring money into the organization Expense item to the Corporation Cannot justify Network based on “Productivity Improvements” As a network designer, you need to explain to management how the network design, even with the high expense, can save money or improve the company’s business If users cannot log on to your commerce site, they will try your competitor, and you have lost sales If you cannot get the information your customers are asking about due to a network that is down, they may go to your competitor
- 6. CSE-550-T072 Lecture Notes - 1 6 The Management View (3/3) You need to understand how the network assists the company in making money and play on that strength when you are developing the network design proposal Try to show a direct correlation between the network design project and the company’s business “Because you want a faster network” is not good enough, the question that management sends back is WHY DO I NEED A FASTER ONE?
- 7. CSE-550-T072 Lecture Notes - 1 7 The Technical View (1/2) A “Network” really can be thought of as three parts and they all need to be considered when working on a network design project: Connections Communications/Protocols Services Connections Provided by Hardware that ties things together Wire/Fiber/Wireless Transport Mechanisms Routers Switches/Hubs Computers
- 8. CSE-550-T072 Lecture Notes - 1 8 The Technical View (2/2) Communications/Protocols Provided by Software A common language for 2 systems to communicate with each other TCP/IP (Internet/Windows NT) IPX / SPX (Novell Netware 4) AppleTalk Other Network OS Services The Heart of Networking Cooperation between 2 or more systems to perform some function - Applications telnet FTP HTTP SMTP
- 9. CSE-550-T072 Lecture Notes - 1 9 Traditional Network Design Based on a set of general rules “80/20” “Bridge when you can, route when you must” Can’t deal with scalability & complexity Focused on capacity planning Throw more bandwidth at the problem No consideration to delay optimization No guarantee of service quality Less importance given to network RMA (Reliability, Maintainability, and Availability) compared to throughput
- 10. CSE-550-T072 Lecture Notes - 1 10 Application Characteristics Applications Message Length Message arrival rate Delay need Reliability need Interactive terminals Short Low Moderate Very high File transfer Very long Very low Very low Very high Hi-resolution graphics Very long Low to moderate High Low Packetized voice Very short Very high High Low
- 11. CSE-550-T072 Lecture Notes - 1 11 Application Bandwidths Word Processing File Transfers Real-Time Imaging 100s Kbps Few Mbps Few Mbps 10s Mbps 10s Mbps 100s Mbps Transaction Processing 100 Bytes Few Kbps
- 12. CSE-550-T072 Lecture Notes - 1 12 A Look on Multimedia Networking Video standard Bandwidth per user WAN services Digital video interactive 1.2 Mbps DS1 lines ISDN H11, Frame Relay, ATM Motion JPEG 10 to 240 Mbps ATM 155 or 622 Mbps MPEG-1 1.5 Mbps DS1 lines ISDN H11, Frame Relay, ATM MPEG-2 4~6 Mbps DS2, DS3, ATM at DS3 rate
- 13. CSE-550-T072 Lecture Notes - 1 13 Some Networking Issues LAN, MAN and WAN Switching and routing Technologies: Ethernet, FDDI, ATM … Wireless/Mobile networking Internetworking Applications Service quality Security concerns
- 14. CSE-550-T072 Lecture Notes - 1 14 Generations of Networking
- 15. CSE-550-T072 Lecture Notes - 1 15 Network Design: Achievable? Response Time Cost Business Growth Reliability
- 16. CSE-550-T072 Lecture Notes - 1 16 Where to begin? WAN Campus Campus Traffic Traffic Patterns Patterns Dial in Dial in Users Users Security Security WWW WWW Access Access Users Users Network Network Management Management Addressing Addressing
- 17. CSE-550-T072 Lecture Notes - 1 17 Traditional Network Design Methodology Many network design tools and methodologies in use today resemble the “connect-the-dots” game These tools let you place internetworking devices on a palette and connect them with LAN or WAN media Problem with this methodology: It skips the steps of analyzing a customer's requirements, and selecting devices and media based on those requirements
- 18. CSE-550-T072 Lecture Notes - 1 18 Top-Down Network Design Methodology (1/2) Good network design Recognizes that a customer’s requirements embody many business and technical goals May specify a required level of network performance, i.e., service level Includes difficult network design choices and tradeoffs that must be made when designing the logical network before any physical devices or media are selected When a customer expects a quick response to a network design request A bottom-up (connect-the-dots) network design methodology can be used, if the customer’s applications and goals are well known
- 19. CSE-550-T072 Lecture Notes - 1 19 Top-Down Network Design Methodology (2/2) Network designers often think they understand a customer’s applications and requirements. However, after the network installation, they may discover that: They did not capture the customer's most important needs Unexpected scalability and performance problems appear as the number of network users increases
- 20. CSE-550-T072 Lecture Notes - 1 20 Top-Down Network Design Process (1/2) Begins at the upper layers of the OSI reference model before moving to the lower layers Focuses on applications, sessions, and data transport before the selection of routers, switches, and media that operate at the lower layers Explores divisional structures to find the people: For whom the network will provide services, and From whom to get valuable information to make the design succeed
- 21. CSE-550-T072 Lecture Notes - 1 21 Top-Down Network Design Process (2/2) It is an iterative process: It is important to first get an overall view of a customer's requirements More detail can be gathered later on protocol behavior, scalability requirements, technology preferences, etc. Recognizes that the logical model and the physical design may change as more information is gathered A top-down approach lets a network designer get “the big picture” first and then spiral downward into detailed technical requirements and specifications
- 22. CSE-550-T072 Lecture Notes - 1 22 Structured Network Design Process - A Systems Approach (1/2) - The system is designed in a top-down sequence Several techniques and models can be used to characterize the existing system, new user requirements, and a structure for the future system A focus is placed on understanding: Data flow, data types, and processes that access or change the data The location and needs of user communities that access or change data and processes
- 23. CSE-550-T072 Lecture Notes - 1 23 Structured Network Design Process - A Systems Approach (2/2) - A logical model is developed before the physical model The logical model represents the basic building blocks, divided by function, and the structure of the system The physical model represents devices and specific technologies and implementations For large network design projects, modularity is essential The design should be split functionally to make the project more manageable
- 24. CSE-550-T072 Lecture Notes - 1 24 Network Development Life Cycle Management Analysis Design Simulation/ Prototyping Implementation Monitoring
- 25. CSE-550-T072 Lecture Notes - 1 25 Network Design and Implementation Cycle
- 26. CSE-550-T072 Lecture Notes - 1 26 Network Design and Implementation Cycle (1/3) Analyze requirements: Interviews with users and technical personnel Understand business and technical goals for a new or enhanced system Characterize the existing network: logical and physical topology, and network performance Analyze current and future network traffic, including traffic flow and load, protocol behavior, and QoS requirements
- 27. CSE-550-T072 Lecture Notes - 1 27 Network Design and Implementation Cycle (2/3) Develop the logical design: Deals with a logical topology for the new or enhanced network Network layer addressing and naming Switching and routing protocols Security planning Network management design Initial investigation into which service providers can meet WAN and remote access requirements
- 28. CSE-550-T072 Lecture Notes - 1 28 Network Design and Implementation Cycle (3/3) Develop the physical design: Specific technologies and products to realize the logical design are selected The investigation into service providers must be completed during this phase Test, optimize, and document the design: Write and implement a test plan Build a prototype or pilot Optimize the network design Document your work with a network design proposal
- 29. CSE-550-T072 Lecture Notes - 1 29 Another Perspective Data collection Traffic Costs Constraints Design process Performance analysis Fine tuning A painstaking iterative process
- 30. CSE-550-T072 Lecture Notes - 1 30 PDIOO Network Life Cycle (1/3) (Cisco) Plan: Network requirements are identified in this phase Analysis of areas where the network will be installed Identification of users who will require network services Design: Accomplish the logical and physical design, according to requirements gathered during the Plan phase Implement: Network is built according to the Design specifications Implementation also serves to verify the design
- 31. CSE-550-T072 Lecture Notes - 1 31 PDIOO Network Life Cycle (2/3) (Cisco) Operate: Operation is the final test of the effectiveness of the design The network is monitored during this phase for performance problems and any faults, to provide input into the Optimize phase Optimize: Based on proactive network management which identifies and resolves problems before network disruptions arise The optimize phase may lead to a network redesign if too many problems arise due to design errors, or as network performance degrades over time as actual use and capabilities diverge Redesign may also be required when requirements change significantly
- 32. CSE-550-T072 Lecture Notes - 1 32 PDIOO Network Life Cycle (3/3) (Cisco) Retire: When the network, or a part of the network, is out-of-date, it may be taken out of production Although Retire is not incorporated into the name of the life cycle (PDIOO), it is nonetheless an important phase
- 33. CSE-550-T072 Lecture Notes - 1 33 One More Look Define Objectives and Requirements Create Initial Solution Define Deployment Strategy Develop Architecture Create Build Documentation Develop Detailed Design Review and Verify Design Create Implementation Plan Procure Resources and Facilities Stage and Install Certify and Hand-off to Operations Develop Operations Policies and Capabilities Configuration Management Fault Management Change Management Performance Management Review and Approve Business Business Planning Planning Operations Operations Implement Implement Network Network Network Network Design Design
- 34. CSE-550-T072 Lecture Notes - 1 34 Information Flows between Network Analysis, Architecture, and Design
Editor's Notes
- #10: Networks must be work independent of the fine details of applications, e.g., message arrival scheme.
- #12: This table provides a bandwidth-based choice. The ability to add or subtract bandwidth on demand is a key requirement. Video conferencing.
- #13: There are still more to come, if we look into deeper networking layers.
- #16: A puzzle.
- #24: 80 percent of the traffic on a given network segment should be local (destined for a target in the same workgroup), and not more than 20 percent of the network traffic should need to move across a backbone (the spine that connects various segments or "subnetworks"). Backbone congestion can indicate that traffic patterns are not meeting the 80/20 rule. In this case, rather than adding switches or upgrading hubs, it may be easier to improve network performance by doing one of the following: Move resources to contain traffic locally within a workgroup. Move users (logically, if not physically) so that the workgroups more closely reflect the actual traffic patterns Add servers so that users can access them locally without having to cross the backbone. After you have ensured proper network design and resource location, the next step is to determine the optimal technology to meet your growing needs.
- #25: 80 percent of the traffic on a given network segment should be local (destined for a target in the same workgroup), and not more than 20 percent of the network traffic should need to move across a backbone (the spine that connects various segments or "subnetworks"). Backbone congestion can indicate that traffic patterns are not meeting the 80/20 rule. In this case, rather than adding switches or upgrading hubs, it may be easier to improve network performance by doing one of the following: Move resources to contain traffic locally within a workgroup. Move users (logically, if not physically) so that the workgroups more closely reflect the actual traffic patterns Add servers so that users can access them locally without having to cross the backbone. After you have ensured proper network design and resource location, the next step is to determine the optimal technology to meet your growing needs.
- #29: This can be basically an iterative process and a painstaking one!