Transcript ITEC275v2

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
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.
Administration
Course Outcomes
1. 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
Text
Oppenheimer, P. (2011). TopDown Network Design: A
systems analysis approach to
enterprise network design.
(3rd ed.). Indianapolis, IN:
Cisco Press. ISBN: 978-158720-283-4.
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
Note: if a homework problem says
or “investigate
Y,” then for
– Items on the“research
Web canX,”serve
as “inspiration”
I’m expecting a citation! Technically,
your solutions
if:
you should cite your textbook on
• You understand
the
solution
as if you had written it
almost
every
HW assignment.
yourself.
• You cite your source of inspiration
– Not citing your source can get you charged with
cheating/plagiarism.
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 breakdown
Pct Type
Count
Each
Total
10
20
200
15% Labs
3
50
150
25% Design Projects
3
75,75,100
250
30% Midterm/Final Exam
2
150
300
14
Variable
100
20% Homework
10% FranklinLive!
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 assignment
2. Work on any scheduled lab assignments
3. Note significant learning
Course Outcomes
Upon successful completion of this course students will be able to:
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•
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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
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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 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.
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.,
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 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
Application
Presentation
Session
Transport
Network
Data Link
Physical
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•
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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
OSI – Physical Layer
Application
Presentation
Session
Transport
Network
Data Link
Physical
 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
OSI – Data Link Layer
Application
Presentation
Session
Transport
Network
Data Link
Physical
 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
OSI – Network Layer
Application
Presentation
 Makes it possible to send units of

Session

Transport

Network
Data Link
Physical

information (packets) across
different network (routing)
Uniform addressing scheme
Helps eliminate network
congestion
Regulate flow of data
Examples:
 IP
 IPX (Novell anyone?)
OSI – Transport Layer
Application
Presentation
Session
Transport
Network
Data Link
Physical
 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)
OSI – Session Layer
Application
Presentation
 Provides enhanced session services
 Examples:


Session
Transport
Network
Data Link
Physical


Telnet session
FTP session
rlogin session
Cookies (web)
OSI – Presentation Layer
Application
Presentation
Session
Transport
Network
Data Link
Physical
 Manages the way data is
represented:
 Encryption
 Encoding
 Examples:
 ASCII
 EBCDIC
 HTML
 XML
OSI – Application Layer
Application
Presentation
Session
Transport
Network
Data Link
Physical
 Provides a protocol for a certain
application
 Examples:
 DNS
 HTTP
 FTP
 SMTP
 TELNET
 SNMP
OSI versus TCP/IP
Application
Presentation
Application
Session
Transport
Transport
Network
Internet
Data Link
Physical
Network Access
TCP/IP Model Boundaries
Application
Transport
Internet
Network Access
Application address (port)
for TCP and UDP
IP address (host)
MAC address (NIC)
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
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
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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
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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
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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
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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?