ITEC 275 Computer Networks – Switching, Routing, and WANs

1. ITEC 275 Computer Networks – Switching, Routing, and WANs Week 1

2. Agenda • Introductions • Review policies, procedures, and expected outcomes • Learning Activities • Introduce homework problems • Location of Power Point presentations http://cs.franklin.edu/~dandrear/itec275/Fall_2013_Network_Presentations/Week_One_Network_ppt or .pptx

3. Introductions • Professor Robert D’Andrea • Adjunct faculty at Franklin • Teaching ITEC275 and ITEC 400 • Cell phone 614.519.5853 • Industry experience in security, systems administration, networking, software development, and deployment of software and hardware.

4. Introductions • Program Chair Information Technology Security • Professor Brad Reed • Brad.reed@franklin.edu • Cell phone 614.918.8321 • Writing doctorate dissertation on Information Technology Security.

5. Introductions • Now your turn: • Name • Major • Interest level and experience in networking • Goal for this class

6. Administration Principles of Computer Networks Prerequisites: College Writing (COMM 120), and Principles of Computer Networks (COMP 204), or A Networking Fundamentals course. This course serves as an introduction to the function, design, administration, and implementation of computer networks. Topics include network infrastructure, architecture, protocols, applications, and the OSI networking model.

7. Administration Course Outcomes • Diagram an end-to-end network communication path, describing each intermediate step. • Design a small-scale network configuration, including addressing, routing, and switching. • Describe the functions of the TCP/IP and Ethernet protocols including select fields, flags, options, headers, and trailers for both.

8. Administration Course Outcomes (ctd) • Distinguish between types of data elements (segments, packets, frames, and bits). • Map the key elements of the TCP/IP protocol suite to the OSI model.

9. Administration Text Oppenheimer, P. (2011). Top-Down Network Design: A systems analysis approach to enterprise network design. (3rd ed.). Indianapolis, IN: Cisco Press. ISBN: 978-1-58720-283-4.

10. Administration • Academic integrity • Items on the Web can serve as “inspiration” for your solutions if: • You understand the solution as if you had written it yourself. • You cite your source of inspiration • Not citing your source can get you charged with cheating/plagiarism.

11. Administration • Academic integrity • Items on the Web can serve as “inspiration” for your solutions if: • You understand the solution as if you had written it yourself. • You cite your source of inspiration • Not citing your source can get you charged with cheating/plagiarism. Note: if a homework problem says “research X,” or “investigate Y,” then I’m expecting a citation! Technically, you should cite your textbook on almost every HW assignment.

12. Administration • Academic integrity • Other students cannot serve as a source for your “inspiration!" • The closer you move toward sharing answers with or soliciting answers from another person (student or not), the more likely it is that you are cheating.

13. Administration • Academic integrity • If you have a vague feeling that you wouldn’t want your instructor to know about what you’re doing… don’t do it. • When in doubt, ask your instructor.

14. Administration Points breakdown

15. Daily/weekly Activities • Daily: Check announcements and e-mail lists • Before class • Read the associated sections from the text books and key points • Read and consider the weekly homework problems • After class • Complete the homework assignment • Work on any scheduled lab assignments • Note significant learning

16. Course Outcomes Upon successful completion of this course students will be able to: • Determine an appropriate approach to design a network based on customer needs and consideration of financial and technological constraints. • Identify the design considerations and tradeoffs for campus, WAN, and data center infrastructure models. • Select appropriate WAN components used in a standard WAN architecture. • Compare and contrast routing and addressing schemas and the mechanisms for implementing each one. • Identify and describe the components and standards used for implementing telephony into a data network. • Configure routers and switches using Cisco IOS commands. • Effectively communicate how a network design plan meets a customer's connectivity needs.

17. COMP 204 • Map protocols and addressing, routing, and switching into the appropriate layer of the OSI model. • Identify the main characteristics of hubs, switches, and routers. • Outline the features of the following TCP/IP protocols: UDP, TCP, IP. • Explain the characteristics of virtual LANs (VLANs) and Spanning Tree Protocol (STP) and the advantages they provide.

18. Top-Down Verses Bottom-up Network Design Top-down network design is iterative process that recognizes that the logical model and the physical design can change as more information becomes available. Main goals of structured systems analysis. 1. Represent the user’s needs 2. Make the project manageable, using modules. Bottom-up network design is an unstructured approach to solving a network problem. This type of approach works on small or flat networks. The scalability isn’t a consideration using this type of network design approach.

19. Top-Down Network Design • Analyze your customers business goals Business goals are the capability to run network applications to meet an organizations business objectives, within the business constraints. These constraints could be limited network personnel, budgets, and limited timeframe. • Good network design subscribes to the customers requirements to the letter. This would include business and technical goals, requirements for availability, scalability, affordability, manageability, and security needs. Some customers will specify a required level of network performance, referred to as service level. • When a customer wants a quick fix design, it is referred to as a bottom-up network design. Associated with this type of design is unexpected scalability, poor performance, and does not meet the customers most important needs. • Top-down network design is a methodology for designing networks at the upper layers of the OSI model before referring to lower layers (devices, cabling, and switch configurations). • Top-down network design includes exploring organizational and group structures to find individuals the network is being designed to provide a services and from whom the design should get valuable information to make the design a success.

20. Top-Down Network Design • Top-down network design is iterative. Initially, it is important to get the overall view of the customers requirements. Later, after digesting the high abstractions of the design, then focus on the finer details of the design like protocol behavior, scalability requirements, and technology preferences. Top-down network design recognizes that the logical model and the physical design can change as more information becomes available. • A top-down network design approach enables the designer to obtain “the big picture” initially, and the drilling down for specifics requirements and technical details. • Top-down network design is a methodology the grew out of structured software programming and structured systems analysis. • Top-down network design divides the project up into small logical pieces known as modules. These modules allow large projects to be more manageable and easier to debug.

21. Top-Down Network Design • Modules are split into logical functions. • The System Development Life Cycle (SDLC) is a top-down network design approach made up of four major phases and are carried out in a cyclical fashion: 1. Analyze requirements - interview users and technical personal to gain an understanding of their business and technical goals for new or existing networks. 2. Develop the logical design – logical topology for the new or existing network, security, switching, routing protocols. 3. Develop the physical design – This phase addresses the specific technologies and products that are realized in the logical design are selected. 4. Test, optimize, and document the design – update the documentation that represents the network design, create test scenario, build a prototype or pilot network, optimize the network design. • The major phases of the top-down network design repeats itself. The user and the network monitoring suggest enhancements or the need for new specifications.

22. Top-Down Network Design Network Design Plan Life Cycle • Plan – Identify the network requirements in this phase. • Design – Complete the bulk of the logical and physical design. • Implement – Implement the building of the proposed network design. • Operate – Final test the effectiveness of the network design. This includes monitoring the network and services. • Optimize – This phase is based on actual operations. Identifying and resolving problems that were encountered. • Retire – When part or the whole network design no longer meets the needs of the company and users, this should be an avenue of consideration. This component is not officially part of the life cycle model. Plan Design Implement Operate Optimize (PDIOO) Network Life Cycle.

23. Top-Down Network Design Plan Design Implement Operate Optimize (PDIOO) Network Life Cycle is one type of network life cycle. It is irrelevant which life cycle is used, as long as long as the network design implements a network design that is structured, planned, modularized, and that feedback from the user is used to enhance the new network design.

24. Top-Down Network Design Network Design Components • Analyzing Business Goals – knowing your customers business goals and constraints. With a thorough understanding of your customers business objectives, you will be able to provide a network design that will meet your customers approval. • Working with Your Client – Research the type of business your client is in before meeting with them. Learn all that you can about his or her market, suppliers, services, and competitive advantage. • Changes in Enterprise Network – Internal users is limited for todays network needs. Your customer now has to think about remote entries both domestically, mobile access, RFS, and globally. Security is a topic that cannot be underestimated in our current network environment. • Network Must Make Sense – Business leaders today are more involved with IT decisions than past administrations. Customers want to operate leaner in data center personnel, power usage, and technology for technology’s sake.,

25. Top-Down Network Design Network Design Components • Networks Offer a service – IT departments are more service oriented than they use to be in the past. • Governance refers to a focus on consistent, cohesive, policies, and processes that protect an organization from mismanagement and illegal operations of users of IT services. • Compliance refers to adherence to regulations that protect against fraud and the disclosure of private customer data. • Need to Support Mobile Users – Network users expect network performance to be uniform , regardless of where the user or data resides. • The Importance of Network Security and Resiliency – Enterprises have to protect themselves from internal, web, and external from more areas than past environments. • Typical Network Design Business Goals – listed on pages 13 and 14.

26. Top-Down Network Design Identify the scope of the network design project. • Small in scope – sales staff might be allowed to access the enterprise network via VPN • Large in scope – engineering personal and remote access through the Enterprise Edge Network designers should ask their customers to help them understand the scope of the network design project. Network design questions: 1. Is the design for a single segment 2. A set of LANs 3. A set of WANs 4. Remote-access networks 5. Entire enterprise network

27. OSI Reference Model Application • All People Seem To Need Data Processing • Each layer provides a different level of abstraction • Each layer has a well-defined function • Layer boundaries are chosen to minimize the information flow between layer boundaries • The number of layers is kept small enough to be feasible Presentation Session Transport Network Data Link Physical

28. OSI – Physical Layer Application • Transmits bits over communication channel • Bits can be encoded in digital form (“0” or “1”) or analog (varied voltage) (did you buy your TV converter?) • Does not have any knowledge of data that it transmits • Examples of media: • twisted-pair cable • coaxial cable • fiber optics • wireless Presentation Session Transport Network Data Link Physical

29. OSI – Data Link Layer Application • The bits that are send or received in the Physical Layer are grouped in logical units called frames • The beginning and end of each frame is usually marked by special characters • Examples: • Ethernet • Token Ring • FDDI • ISDN Presentation Session Transport Network Data Link Physical

30. OSI – Network Layer Application • Makes it possible to send units of information (packets) across different network (routing) • Uniform addressing scheme • Helps eliminate network congestion • Regulate flow of data • Examples: • IP • IPX (Novell anyone?) Presentation Session Transport Network Data Link Physical

31. OSI – Transport Layer Application • Ensures reliable delivery of packets • Error recovery • Multiplexing the network connection (the use of the network by multiple applications simultaneously) • Examples: • TCP • UDP • SPX (yeah, that Novell thing) Presentation Session Transport Network Data Link Physical

32. OSI – Session Layer Application • Provides enhanced session services • Examples: • Telnet session • FTP session • rlogin session • Cookies (web) Presentation Session Transport Network Data Link Physical

33. OSI – Presentation Layer Application • Manages the way data is represented: • Encryption • Encoding • Examples: • ASCII • EBCDIC • HTML • XML Presentation Session Transport Network Data Link Physical

34. OSI – Application Layer Application • Provides a protocol for a certain application • Examples: • DNS • HTTP • FTP • SMTP • TELNET • SNMP Presentation Session Transport Network Data Link Physical

35. OSI versus TCP/IP Application Application Presentation Session Transport Transport Network Internet Data Link Network Access Physical

36. TCP/IP Model Boundaries Application Transport Application address (port) for TCP and UDP Internet IP address (host) Network Access MAC address (NIC)

37. Protocol Data Unit (PDU) • Contains information about the source and destination of a message. In the header. Figure 1-2 http://en.wikipedia.org/wiki/TCP/IP_model

38. Evaluate Business Constraints Company Politics Throughout your discussion with the customer, try to learn who the individuals are that do the authorization, buying process, and fiscal period when buying occurs Be on the alert for: • Hidden agendas • Turf wars • Biases • Group relations • Individuals within the company that could cause the network project to fail (engineers or managers) • Number of employees affected by the new design • Customers preference towards the use of certain protocols,

39. Evaluate Business Constraints Company Politics • Strategic business or IT plan • Customers preference towards the use of certain protocols • Forbidden technologies • Are the governmental guidelines that need to be followed • Determine the amount of risk the customer is willing to tolerate • Determine the group that controls the budget

40. Evaluate Project Scheduling Review with Customer • Timeframe for project • Identify due date • Identify the implementation dates • What are the minor and major milestones

41. Devices - Network Terminology • Domain – A specific part of a network • Bandwidth – The amount of data that can be carried across a network in a given time period • Unicast data – Data meant for a specific device • Broadcast data – Data meant for all devices • Multicast data - Data that is meant for a specific group of devices • Bandwidth domain – All devices that share the same bandwidth (Collision domain) • Broadcast domain – All devices that receive each other’s broadcasts and multicasts

42. Devices - Hubs • Layer 1 device • Also known as repeaters • Connects multiple devices so that they are logically on one LAN • Has no intelligence • Sends data received on one port to all other ports • Devices connected receive all data other connections send • All devices are on one collision and broadcast domain

43. Devices - Switches • Layer 2 device • Segregates multiple devices into smaller LANs • Has some intelligence • Reads source and destination MAC addresses and sends data to the appropriate port based on that • All devices connected to one switch port are in the same collision domain • Devices connected to individual switch ports are in their own collision domain • All devices connected to a switch are in the same broadcast domain

44. Devices – Multilayer Switches • Does all that a layer 2 does but adds layer 3 and 4 capabilities • Acts as a router with some functions in hardware when used for VLAN functions • Groups ports into one or more VLANs that are configured (using management software) so that they can communicate as if they were attached to the same wire • VLANs are identified by different IP ranges • Trunk – A port that carries more than one VLAN between switches

45. VLAN • Physical LAN vs. Logical VLAN

46. Devices - Routers • Layer 3 device • Network perimeter device • Has much more intelligence than switches • Reads source and destination logical addresses and sends data only where it is needed • Transfers data between LANS but blocks broadcasts • All devices connected to one router port are in the same collision/broadcast domain

47. Switching • Switches learn which devices are connected their ports by examining traffic

48. IPv4 Addressing • Class A • Provides 16M hosts • 1.0.0.0 through 126.0.0.0 • Mask 255.0.0.0 • Restricted addresses 10.0.0.0 – 10.255.255.255 • Class B • Provides 65K hosts • 128.0.0.0 through 191.255.0.0 • Mask 255.255.0.0 • Restricted addresses 172.16.0.0 – 172.31.255.255 • Class C • Provides 254 addresses • 192.0.0.0 through 223.255.255.0 • Mask 255.255.255.0 • Restricted addresses 192.168.0.0 – 192.168.255.255

49. Mask Notation • Values • Network = 1 • Host = 0 • Classful example (Class B address) • 128.35.17.25 • 255.255.0.0 • 11111111.11111111.00000000.00000000 • Subnets – borrow bits • 255.255.128.0 • 11111111.11111111.10000000.00000000 • 128.35.17.25/17 (VLSM/CIDR)

50. Terms Service level is when a customer specifies a required level of network performance.