Transcript Top-Down Network Design

ITEC 275
Computer Networks – Switching,
Routing, and WANs
Week 1
Instructor Professor D’Andrea
Winter 2017
Agenda
• Introductions
• Review policies, procedures, and expected
outcomes
• Learning Activities
• Introduce homework problems
• Location of Power Point presentations
http://cs.franklin.edu/~dandrear/itec275/_Winter_201
7_Network_Presentations/Week_One_Network_ppt or
.pptx
Introductions
• Professor Robert D’Andrea
– Adjunct faculty at Franklin
– Fall term, teach ITEC275 and ITEC 400
– Cell phone 614.519.5853
• Industry experience in security, systems
administration, network administration,
software development, tester, and
deployment of software and hardware
systems.
• Domestic and international work
Introductions
• Program Chair Information Technology
Professor Laurie Crawford
– [email protected]
Administration
Principles of Computer Networks
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
Principles of Computer Networks
ITEC275 serves as an introduction to the
function, design, administration, and implementation of
computer networks. Topics include network
infrastructure, addressing, sub-netting, architecture,
protocols, applications, and the OSI networking model.
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
• Academic integrity
Submit Project #1, 2, and 3 to Turnitin.com
– Class name: Winter_2017_itec275
– Enrollment password: Winter275
– Class ID: 14297550
Evaluated projects shall be less than 45 percent
If your project contains graphics and your
experiencing problems getting the percentage to
lower, remove the graphics.
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% Adobe Connect
1000
Daily/weekly Activities
• Daily: Check for announcements in your email.
• 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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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, LAN, WAN, MAN, 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.
Course Outcomes
Upon successful completion of this course
students will be able to:
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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.
Know more about the differences in IPv4 and
IPv6 addressing.
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.
Cisco Certification Design Associate
(CCDA)
The Associate-level certification are typically network
design engineers, technicians, or support technicians. They are
expected to design basic campus-type networks and be familiar
with routing and switching, security, voice and video, wireless
connectivity, and IP (both v4 and v6). They often work as part
of a team with those who have higher-level Cisco certifications.
Salary: $95,602
Top-Down Verses Bottom-up
Network Design
Top-down network design is an iterative process that
recognizes a logical model and the physical design that can
change as more or less information becomes available.
Main goals of structured systems analysis.
1. Represent the user’s needs
2. Make the project manageable, using the latest techniques
and tools available.
Bottom-up network design is an unstructured approach
to solving a network problem. This type of approach works on
small or flat networks. Scalability isn’t a consideration when
using this type of network design approach.
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 number of
network personnel, budgets, and 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.
Top-Down Network Design
• 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. Topdown 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 then by drilling down
for specific requirements and technical details.
• Top-down network design is a methodology that grew out of
structured software programming and structured systems
analysis.
Top-Down Network Design
• 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 function entities.
• 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.
Top-Down Network Design
Modules are split into logical function entities.
3. Develop the physical design: This phase addresses the
specific technologies and products that are realized in the
logical design selected.
4. Test, optimize, and document the design: Update the
documentation that represents the network design, create
test scenarios, build a prototype or pilot network, optimize
the network design.
Top-Down 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 Design Implement
Operate Optimize (PDIOO)
• 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.
Top-Down Network Design
The Plan Design Implement Operate Optimize (PDIOO)
network life cycle is one of many types of network life cycles. 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.
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.
Top-Down Network Design
Network Design Components
• Changes in enterprise network: Internal users are limited for
todays network needs. Your customer now has to think about
remote entries both domestically, mobile access, 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. They
also want to know about the option of utilizing the cloud.
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.
Top-Down Network Design
Network Design Components
• 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.
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 request their customers to
help them understand the scope of the network design project.
Top-Down Network Design
Identify the scope of the network design project.
Network design questions:
1. Is the design for a single segment
2. A set of LANs or WLANs
3. A set of WANs or private network
4. Remote-access networks
5. Entire enterprise network
6. A set of MANs
OSI Reference Model
Application
Presentation
Session
Transport
Network
Data Link
Physical
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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
 Transmit bits over a
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:
n twisted-pair cable
n coaxial cable
n fiber optics
n 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
 Ensures reliable delivery of packets
 Error recovery
Presentation
Session
Transport
Network
Data Link
Physical
 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
 Provides enhanced session services
 Examples:
Presentation


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.
http://en.wikipedia.org/wiki/TCP/IP_model
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:
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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 vendor’s,
Evaluate Business Constraints
Company Politics
• Strategic business or IT plan
• Customers preference towards the use of certain
protocols
• Forbidden technologies
• Are there 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 and the
timeframe that the money is distributed.
Evaluate Project Scheduling
Review with Customer
• Timeframe for project
• Identify due date
• Identify the implementation dates
• What are the minor and major milestones
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 period of time.
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 - Network Terminology
Governance: Focuses on consistency, stability in
decisions, policies, and processes that protect a
company from being mismanaged and involved
in illegal activities of users of IT services.
Compliance: The agreement to follow
regulations that protect against fraud and the
privacy of private customer information.
Service level is when a customer specifies a
required level of network performance (QoS).
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
VLANs
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
• Class A Address
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IPv4 Addressing
Provides 16M hosts
Range of addresses: 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 Address
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Provides 65K hosts
Range of addresses: 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 Address
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Provides 254 hosts
Range of 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
IPv4 Addressing
• Class D Address
-Reserved for Multicasting. In multicasting data is
not destined for a particular host, that is why there is no
need to extract host address from the IP address, and
Class D does not have any subnet mask.
-IP address rage from 224.0.0.0 to
239.255.255.255.
• Class E Address
This IP Class is reserved for experimental purposes only
for R&D or Study.
-IP addresses ranges from 240.0.0.0 to
255.255.255.254. Like Class D, this class too is not
equipped with any subnet mask.
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
Classless IP address notation
– 128.35.17.25/17 (VLSM/CIDR)
This Week’s Outcomes
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Evaluating business goals and constraints
OSI Model
TCP Model
Network Devices
Definitions/Terms
Classes - IPv4 Addresses
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 goals and objectives
Next week
• Read chapters 1 and 2 in
Top-Down Network Design
• 1-3 – Concept questions 1
• Adobe Connect session 2
Q&A
• Questions, comments, concerns?