Summer Youth Program:
Computer/Network
Architecture and Security
Introduction to Networking
Objectives:
Understand the physical connection that has to
take place for a computer to connect to the
Internet.
Recognize the components that comprise the
computer.
Install and troubleshoot network interface cards
and/or modems.
Use basic testing procedures to test the Internet
connection.
Demonstrate a basic understanding of the use
of web browsers and plug-ins.
Internet Connection Requirements
Internet is the largest data network on earth
Consists of many large and small networks that are
interconnected Individual computers are the sources and
destinations of information through the Internet
Connection to the Internet can be broken down into three parts:
Physical connection
Logical connection
Applications
Computer Basics
Electronic Components
Transistor, Integrated circuit (IC), Resistor, Capacitor,
Connector, and Light emitting diode (LED)
PC Subsystems
Printed circuit board, CD-ROM drive, Central processing unit
(CPU), Floppy drive, Hard drive, Microprocessor, Motherboard,
Bus, Random-access memory (RAM), Read-only memory
(ROM), System unit, Expansion slot, Power supply,
Backplane components
Network interface card (NIC), Video card, Audio card, Parallel
port, Serial port, Mouse port, Power cord
Network Interface Card
A NIC, or LAN adapter, provides network
communication capabilities to and from
a PC
These considerations are important
in the selection of a NIC:
Protocols – Ethernet, Token Ring, or
FDDI
Types of media – Twisted-pair,
coaxial, wireless, or fiber-optic
Type of system bus – PCI or ISA
NIC’s & Modems
A modem, or modulator-demodulator,
has two main functions:
provides the computer with connectivity to
a telephone line
converts data from a digital signal to an analog
signal that is compatible with a standard phone line
A NIC provides a network interface for each host
Situations that require NIC installation include the following:
Installation of a NIC on a PC that does not already have one
Replacement of a malfunctioning or damaged NIC
Upgrade from a 10-Mbps NIC to a 10/100/1000-Mbps NIC
Change to a different type of NIC, such as wireless
Installation of a secondary, or backup, NIC for network security reasons
Internet Connections for Consumers
Requires use of a Modem
Dial-up – slow
Always on High Speed Connections
DSL – Verizon
Cable – Comcast, Charter, Road-Runner
TCP/IP
TCP/IP
The operating system tools must
be used to configure TCP/IP on
a workstation
Testing Connectivity with Ping
Ping is a basic program that verifies a particular IP address exists
and can accept requests.
Ping stands for Packet Internet or Inter-Network Groper.
How can ping be used?
ping 127.0.0.1 - loopback test. It verifies the operation of the
TCP/IP stack and NIC transmit/receive function.
ping host computer IP address - verifies the TCP/IP
address configuration for the local host and connectivity to
the host.
ping default-gateway IP address - verifies whether the
router that connects the local network to other networks can
be reached.
ping remote destination IP address - verifies connectivity
to a remote host.
Information & Testing
NIC MAC Address Verification
http://standards.ieee.org/regauth/oui/index.
shtml
Traceroute Site:
http://www.traceroute.org
Web Browsers and Plug-ins
A Web browser is software that interprets HTML, which is one of
the languages used to code Web page content.
Two of the most popular Web browsers are Internet Explorer
(IE), Netscape Communicator, and FireFox
Plug-ins are applications that work
with the browser to launch the programs
required to view special files:
Flash – Plays multimedia files created by Macromedia Flash
Quicktime – Plays video files created by Apple
Real Player – Plays audio files
IE vs. FireFox
FireFox and all other Mozilla-based products are
generally more secure than IE
Reasons:
It is not integrated with Windows, which helps
prevent viruses and hackers from causing
damage if they somehow manage to compromise
FireFox.
There is no support for VBScript and ActiveX, two
technologies which are the reasons for many IE
security holes.
No spyware/adware software can automatically
install in FireFox just by visiting a web site.
FireFox doesn't use Microsoft's Java VM, which
has a history of more flaws than other Java VMs.
You have complete control over cookies.
Data Networks Creation
Data networks developed as a result of businesses
and governments agencies needing to exchange
electronic information across long distances.
Businesses needed solution to:
How to avoid duplication of equipment and
resources
How to communicate efficiently
How to set up and manage a network
The Creation of Standards
One solution to incompatibility was to
create standards within Local Area
Neworks (LANs)
LANs limitations prompted (Metropolitan
Area Networks) MANs and (Wide Area
Networks) WANs
Data Networks with Respect to
Distances
Networking Devices
Networking Devices:
Repeaters and Hubs
Repeaters
Hubs
Networking Devices:
NICs and Bridges
NICS
Bridges
Networking Devices:
Switches
Switches
Networking Devices - Routers
Routers
Network Topology
Network Topology:
Bus & Star Topology
STAR TOPOLOGY
BUS TOPOLOGY
Network Topology: Ring
Topology
RING TOPOLOGY
Network Topology Cont:
Partial & Full Mesh
Partial Mesh
Full Mesh
MS VISIO
Creating Network Diagrams
MS Visio
Network Example
CONFIDENTIAL
CONFIDENTIAL
Network Diagam
MaxPro
SiliconGraphics
LABORATORIES, INC.
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7/5/05
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Michigan Tech University’s
CNSA Progam
MS Visio
Network Example #2
Network Diagam
CONFIDENTIAL
CONFIDENTIAL
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SUPER
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10 00Base -SX
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ISDN Basic Rate Interface
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ISDN Basic Rate Interface
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LINE IN
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VGA Splitter 2-Channel
MONITOR T YPE
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VGA Splitter 2-Channel
MONITOR T YPE
POWER
Fiber Splitter
N C X 3E6
Michigan Tech University’s
CNSA Progam
System Status
System Status
BLACK BOXÒ
VGA Splitter 2-Channel
MONITOR T YPE
POWER
Fiber Splitter
Ò
Ò
BLACK BOXÒ
Next Generation Networks
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VGA Splitter 2-Channel
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N C X 3E6
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Circuit Status
Ethernet Status
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Circuit Status
Ethernet Status
TELECOM
TELECOM
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ATM Switch
ATM Switch
N C X 3E6
Next Generation Networks
Circuit Status
Ethernet Status
Ò
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GCH_v.2.7
7/5/05
ATM Switch
3Com
MS Visio
WAN Architecture Example
CONFIDENTIAL
WAN DIAGRAM
CONFIDENTIAL
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Model
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VoIP (On net call)
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GCH_v.1.2
7/2/05
California
MS Visio
Switch Architecture Example
CONFIDENTIAL
CONFIDENTIAL
SWITCHED ETHERNET NETWORK
Public Internet
Private Intranet
CENTRAL OFFICE
CHASSIS STATUS
TEMPERATURE
Output
Good
FAN
Output
Good
POWER SUPPORT
Output
Good
SYSTEM
Output
Good
Output
Good
Output
Good
LMP
TEST
PBX
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BRANCH OFFICE
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SiliconGraphics
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SiliconGraphics
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2000
ORIGIN
2000
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SiliconGraphics
SiliconGraphics
SiliconGraphics
2000
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SiliconGraphics
2000
SiliconGraphics
Ethernet Network
ORIGIN
SiliconGraphics
2000
MS Visio
Client Architecture Example
Syrex Network Architecture
CONFIDENTIAL
VLAN_E
CONFIDENTIAL
VLAN_B
R2
S0/0
BB1
S0/2
R1
ISDN
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Frame
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OSPF
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Legend
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10/100 Ethernet
ISDN Connection
R7
EIGRP
ATM
ATM 138.10.78.0/
24
R8
ATM Connection
Frame Relay Connection
GCH_ver3.7
6/11/05
Network Protocols
Local-area Networks (LANs)
Wide-area Networks (WANs)
Metropolitan-Area Network (MANs)
Storage-Area Networks (SANS)
Virtual Private Networks (VPNs)
VPN Architectures
Client-Initiated Access VPN
NAS-Initiated Access VPN
Intranet and Extranet VPN
Benefits of VPNs
Importance of Bandwidth
• Why is Bandwidth Important?
• What are Bandwidth’s limitations?
• What is Bandwidth’s effect on network
performance?
Bandwidth Pipe Analogy
Bandwidth Highway Analogy
Bandwidth Measurements
Bandwidth Limitations
Bandwidth Throughput
Digital Transfer Calculation
Cabling
LANs and WANs
LAN Physical Layer
LAN Physical Layer Symbols
Ethernet on a Campus
There are several ways that Ethernet
technologies can be used in a campus
network:
10Mbps can be used at the user level
Clients or servers that require more bandwidth
can use 100-Mbps Ethernet
Fast Ethernet is used as the link between user
and network devices. Fast Ethernet can be used
to connect enterprise servers.
Fast Ethernet or Gigabit Ethernet should be
implemented between backbone devices, based
on affordability.
Connection Media
UTP Implementation
Patch Panels used for
Organization in Wiring
Closets. Sometimes referred
to as punch downs.
UTP Cable
•8 colored wires
•2 twisted pair
UTP Implementation Continued
EIA/TIA T568-A or T568-B
Standards
Note: Only 4 wires
being used for Tx and
Rx
UTP Implementation
Straight-Through and
Cross-Over Comparison
Console Connections
Used to manage a device, such as
switch or router, locally
Uses a DB-9 to RJ45 adapter
Uses Rollover cable
Straight-Through and CrossOver Comparison Continued
Summer Youth Program:
Computer/Network
Architecture and Security
Using Layers to Analyze
Problems
Using Layers to Describe Data
Communication
OSI Model
Layer 1
Layer 2
•Provides reliable transit of data across a physical link
•Provides physical address
•Error correction, best effort delivery.
Layer 3
Layer 4
Layer 5
Layer 6
Layer 7
Peer-to-Peer Communication
TCP/IP Model
Encapsulation & Decapsulation
Names for Data at Each
Layer
Network Environments
Peer-to-Peer Networks
All Peers are equal
10 Host max (recommended)
Client/Server Environment
network services are located on a
dedicated computer called a server
Peer-to-Peer vs. Client/Server
Advantages
Advantages of a Peer-to-Peer
Network
Advantages of a
Client/Server Network
Less expensive to
implement
Provides for better
security
Does not require
additional specialized
network administration
software
Easier to administer when
the network is large due
to centralized
administration
Does not require a
dedicated network
administrator
All data can be backed up
on one central location
Peer-to-Peer vs. Client/Server
Disadvantages
Disadvantages of a Peer-toPeer Network
Disadvantages of a
Client/Server Network
Does not scale well to a
large networks and
administration becomes
unmanageable
Requires expensive
specialized network
administrative and
operational software
Each user must be trained
to perform administrative
tasks
Requires expensive, more
powerful hardware for the
server machine
Less secure
Requires a professional
administrator
All machines sharing
resources negatively
impacts performance
Has a single point of
failure. User data is
unavailable if the server
is down
Ethernet Switching
Layer 2 Bridging

What is a Bridge?

What is the Bridging process?
Bridge Types
Bridge Operations
Switches
Switching Table
Latency

What is Latency?

How does it affect a network?
Switch Modes
Store-and-forward switching
Cut-through switching
Fragment-free switching
Collision Domains and
Broadcast Domains
How to reduce the impact of
broadcasts and collisions
on the performance of the
network?
Types of Networks
Data Collisions
When two bits are propagated at the same
time on the same network, a collision will
occur.
Collisions and Collision
Domains
Extended by a hub
and repeater
Segmentation
Breaking Up Collision
Domains Using Segmentation
Segmenting with Bridges
Segmenting with Switches
Segmenting with Routers
Layer 2 Broadcasts
Layer 2 devices must flood all broadcast
and multicast traffic.
The accumulation of broadcast and
multicast traffic from each device in the
network is referred to as broadcast
radiation.
Broadcast Domains
A group of collision domains that are
connected by Layer 2 devices
Controlled at Layer 3 (router)
Routers do not forward broadcasts
Data Flow
Network Segment


If the segment is used in TCP, it would be
defined as a separate piece of the data.
If segment is being used in the context of
physical networking media in a routed
network, it would be seen as one of the parts
or sections of the total network.
Routing Fundamentals
And Subnets
Routable and Routed
Protocols
A routed protocol allows the router to forward data
between nodes on different networks.
In order for a protocol to be routable, it must provide the
ability to assign a network number and a host number to
each individual device.
These protocols also require a network mask in order to
differentiate the two numbers.
The reason that a network mask is used is to allow groups
of sequential IP addresses to be treated as a single unit.
IP as a Routed Protocol
IP is a connectionless,
unreliable, best-effort
delivery protocol.
As information flows
down the layers of the
OSI model; the data is
processed at each layer.
IP accepts whatever data
is passed down to it from
the upper layers.
Packet Propagation and Switching
Within a Router
Packet Propagation and Switching
Within a Router
As a frame is received at a router interface.
The MAC address is checked to see if the frame is
directly addressed to the router interface, or a broadcast.
The frame header and trailer are removed and the
packet is passed up to Layer 3.
The destination IP address is compared to the routing
table to find a match.
The packet is switched to the outgoing interface and
given the proper frame header.
The frame is then transmitted.
Internet Protocol (IP):
Connectionless
The Internet is a gigantic, connectionless network
in which all packet deliveries are handled by IP.
TCP adds Layer 4, connection-oriented reliability
services to IP.
Telephone Calls:
Connection-Oriented
A connection is established between the
sender and the recipient before any data is
transferred.
Anatomy of an IP Packet
While the IP source and destination addresses
are important, the other header fields have
made IP very flexible.
The header fields are the information that is
provided to the upper layer protocols defining
the data in the packet.
Routing Overview
A router is a network layer device that uses one or more
routing metrics to determine the optimal path.
Routing metrics are values used in determining the
advantage of one route over another.
Routing protocols use various combinations of metrics
for determining the best path for data.
Routing Versus Switching

This distinction is routing and switching
use different information in the process of
moving data from source to destination.
Routing Versus Switching
Classes of Network IP
Addresses
Introduction to Subnetting
Host bits must
are reassigned
(or “borrowed”) 3 bits borrowed allows 2 -2 or 6 subnets
as network bits.
The starting
point is always 5 bits borrowed allows 2 -2 or 30 subnets
the leftmost
host bit.
3
5
12 bits borrowed allows 212-2 or 4094 subnets
Reasons for Subnetting
Provides addressing flexibility for the network
administrator.
Each LAN must have its own network or subnetwork
address.
Provides broadcast containment and low-level security
on the LAN.
Provides some security since access to other subnets is
only available through the services of a router.
Establishing the Subnet Mask
Address
Determines which part of an IP address is the network field
and which part is the host field.
Follow these steps to determine the subnet mask:
1. Express the subnetwork IP address in binary form.
2. Replace the network and subnet portion of the
address with all 1s.
3. Replace the host portion of the address with all 0s.
4. Convert the binary expression back to dotted-decimal
notation.
Establishing the Subnet Mask
Address
To determine the number of bits to be used, the network
designer needs to calculate how many hosts the largest
subnetwork requires and the number of subnetworks
needed.
The “slash format” is a shorter way of representing the
subnet mask:
/25 represents the 25 one bits in the subnet mask
255.255.255.128
Establishing the Subnet Mask
Address
Subnetting Class A and B
Networks
The available bits for assignment to the subnet
field in a Class A address is 22 bits while a Class
B address has 14 bits.
Calculating the Subnetwork
With ANDing
ANDing is a binary process by which the router
calculates the subnetwork ID for an incoming packet.
1 AND 1 = 1; 1 AND 0 = 0; 0 AND 0 = 0
The router then uses that information to forward the
packet across the correct interface.
11000000.10101000.0000101 0000
0.010
1
Packet Address
192.168.10.65
Subnet Mask
255.255.255.22 11111111.11111111.11111111.1 0000
4
11
0
Subnetwork
Address
192.168.10.64
11000000.10101000.0000101 0000
0.010
0
Routed Versus Routing
A routed protocol:
Includes any network protocol suite that provides
enough information in its network layer address to
allow a router to forward it to the next device and
ultimately to its destination.
Defines the format and use of the fields within a
packet.
A routing protocol:
Provides processes for sharing route information.
Allows routers to communicate with other routers to
update and maintain the routing tables.
Path Determination
Path determination enables a router to compare the
destination address to the available routes in its routing
table, and to select the best path.
End of Presentation