ITEC 275 Computer Networks – Switching, Routing, and

WANs

Week 1

Agenda

• Introductions• Review policies, procedures, and expected

outcomes• Learning Activities• Introduce homework problems

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.

Introductions

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

AdministrationPrinciples of Computer NetworksPrerequisites: 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.

Administration

Course Outcomes1. Diagram an end-to-end network communication

path, describing each intermediate step.2. Design a small-scale network configuration,

including addressing, routing, and switching.3. Describe the functions of the TCP/IP and Ethernet

protocols including select fields, flags, options, headers, and trailers for both.

Administration

Course Outcomes (ctd)4. Distinguish between types of data elements

(segments, packets, frames, and bits).5. Map the key elements of the TCP/IP protocol suite

to the OSI model.

Administration

TextOppenheimer, 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.

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.

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.

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.

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.

Administration

Points breakdownPct Type Coun

tEach Total

20%

Homework 10 20 200

15%

Labs 3 50 150

25%

Design Projects 3 75,75,100 250

30%

Midterm/Final Exam

2 150 300

10%

FranklinLive! 14 Variable 100

1000

Daily/weekly Activities

• Daily: Check announcements and e-mail lists• Before class

1. Read the associated sections from the text books and key points

2. Read and consider the weekly homework problems• After class

1. Complete the homework assignment2. Work on any scheduled lab assignments3. Note significant learning

Course OutcomesUpon 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 datacenter 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.

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.

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.

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.

Top-Down Network Design• Modules are split into logical functions. • A top-down network design approach is divided into four majoe phases

and are carried out in a cyclical fashion:– Analyze requirements - interview users and technical personal to gain an

understanding of their business and technical goals for new or existing networks.– Develop the logical design – logical topology for the new or existing network, security,

switching, routing protocols.– Develop the physical design – This phase addresses the specific technologies and

products that are realized in the logical design are selected.– 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.

Top-Down Network DesignNetwork 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.

Top-Down Network DesignNetwork 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.,

Top-Down Network DesignNetwork 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 fraudand 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.

OSI Reference Model• 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

Physical

Data Link

Network

Transport

Session

Presentation

Application

OSI – Physical Layer 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 wirelessPhysical

Data Link

Network

Transport

Session

Presentation

Application

OSI – Data Link Layer 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

Physical

Data Link

Network

Transport

Session

Presentation

Application

OSI – Network Layer 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?)

Physical

Data Link

Network

Transport

Session

Presentation

Application

OSI – Transport Layer 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)

Physical

Data Link

Network

Transport

Session

Presentation

Application

OSI – Session Layer Provides enhanced session services Examples:

Telnet session FTP session rlogin session Cookies (web)

Physical

Data Link

Network

Transport

Session

Presentation

Application

OSI – Presentation Layer Manages the way data is

represented: Encryption Encoding

Examples: ASCII EBCDIC HTML XML

Physical

Data Link

Network

Transport

Session

Presentation

Application

OSI – Application Layer Provides a protocol for a certain

application Examples:

DNS HTTP FTP SMTP TELNET SNMP

Physical

Data Link

Network

Transport

Session

Presentation

Application

OSI versus TCP/IP

Physical

Data Link

Network

Transport

Session

Presentation

Application

Network Access

Internet

Transport

Application

TCP/IP Model Boundaries

Network Access

Internet

Transport

Application

Application address (port)for TCP and UDP

MAC address (NIC)

IP address (host)

Protocol Data Unit (PDU)

• Contains information about the source and destination of a message. In the header.

http://en.wikipedia.org/wiki/TCP/IP_model

Figure 1-2

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

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

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

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

VLAN

• Physical LAN vs. Logical VLAN

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

Switching

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

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

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)

This Week’s Outcomes

• OSI Layers• Network Devices• Routing Protocols• Switching• Addressing

Software required

• Provided CD\resources\software– Visio 2007

• Instructions - InstallingMSVisio2007.pdf• CISCO.vss – Documents\MyShapes

– MIMIC Virtual Lab• MIMIC software installation is NOT required• Virtual Machine

– VMware View Client v4.6 is needed– Download from http://vlab.franklin.edu– System provisioning takes some time – Logins may not work until week 2

or 3

• Purchase (If desired)– Instructions – installvlab.pdf

Due this week

• Software installation (no points)• Review course golas and objectives

Next week

• Read chapters 1 and 2 in Top-Down Network Design

• Obtain proctors for midterm and final exams• 1-3 – Concept questions 1• FranklinLive session 2

Q & A

• Questions, comments, concerns?