Transcript Networking Basics

WebPro Series
•Networking
•Practical Application of skills
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Introduction
You have just completed an intensive course on
networking. In this lesson we will underscore the
skills from that course that are important to you as a
webmaster. After this lesson, you will complete a
hands-on exercise using these skills.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Lesson Objectives
• Identify hardware components of
a network
• Explain how TCP/IP is used to
transmit data over the Internet
• Write a proposal to construct a
local Ethernet network
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Network Topology
• There are two typical types of
network topology
– linear bus
– star
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Linear Bus Topology
• Computers are arranged in a straight series, and are
typically connected with coaxial cable (RG 58)
– main advantage is its simple layout, no hub is
required
– disadvantage is that if there is any break in the
line, the network fails
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Star Topology
• Computers are arranged in a star pattern using
Twisted-Pair Category 3 (10 Mbs/sec) or Category 5
(10/100 Mbs/sec) cable. A hub in the center connects
the machines.
•this arrangement
is more costly, but
generally more
reliable than Linear
Bus
•not every
machine has to be
connected in order
for the network to
function
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Cabling
• In this lesson we’re going to discuss the most popular
type of cabling, Category 5 or cat-5 as it is commonly
known. This is the best solution for most office
applications and the one we will focus on for our
project.
• Cat-5 cable consists of eight strands of wire twisted
into pairs.
• These wires fit into a connector called an RJ-45 plug
on one end and a patch panel in the wiring closet.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Cabling
• The RJ-45 plug looks like a standard
telephone plug, except it carries eight wires
instead of four.
• Cabling a local network with Cat-5 is similar
in many ways to telephone wiring. Each
room has a receptacle with one or more
connectors. The cables for each receptacle
are run to a central location in the office
(commonly called the wiring closet).
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
The Wiring Closet
• Typically consists of the following hardware:
– 19” metal rack to mount hardware on
– patch panel to wire cabling into bridge or hub
• The wiring closet may also have the
following:
– surge protection unit
– system diagnostic hardware
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
What is TCP/IP
• TCP/IP is the network protocol that
computers on the Internet use to
communicate with one another.
• The name TCP/IP is a combination of two of
the four protocols that make up the suite of
protocols that the Internet uses. The four
protocols are:
–
–
–
–
IP
TCP
UDP
ICMP
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Archimedes Performance, Inc.
Epic Learning, Inc.
TCP and UDP
• The two protocols that we are most
concerned with are TCP and UDP.
– TCP (Transport Control Protocol) -- a
connection-based protocol that guarantees
data transmission.
– UDP (User Datagram Protocol) -connectionless protocol that does not
guarantee data transmission
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
TCP
• TCP provides a point-to-point channel for applications
that require reliable communications. The Hypertext
Transfer Protocol (HTTP), File Transfer Protocol (FTP),
and Telnet are all examples of applications that require
a reliable communication channel. The order in which
the data is sent and received over the network is
critical to the success of these applications. When
HTTP is used to read from a URL, the data must be
received in the order in which it was sent. Otherwise,
you end up with a jumbled HTML file, a corrupt zip
file, or some other invalid information.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
UDP
• The UDP protocol provides for communication that is
not guaranteed between two applications on the
network. UDP is not connection-based like TCP. Rather,
it sends independent packets of data, called
datagrams, from one application to another.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
How does a network work?
• Diagram of two networks connected to the
Internet
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
How does a network work?
• In the diagram, there are two networks -- anyguy.com
and stooge.com -- that are connected to each other,
and the Internet, by a router. The router’s job is to
pass information (datagrams) to computers in different
subnets.
• For example, if moe.stooge.com and larry.stooge.com
want to speak to each other the datagrams never pass
through the router. If moe wanted to speak to
tom.anyguy.com, however, the router would have to
route that information to the proper network, using
information stored in its routing table.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
The TCP Frame
• Most Internet applications, including the web,
ftp and email, require a certain degree of
data integrity and a 100% transmission rate.
• To achieve 100% data integrity, TCP can be
used. Basically, TCP requires that the
destination computer acknowledge every
DATAGRAM that the source computer sends.
• This is much more reliable, but requires a lot
more bandwidth to achieve.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
What about the names?
• Names for machines,
(www.somecompany.com) don’t mean
anything in terms of networking.
• The machines only use the IP numbers (i.e.,
192.168.1.1). It is much more difficult for
humans to remember 207.25.71.25 than
www.cnn.com so the domain name schema
was invented.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
How does it work?
• Basically, whenever you use a computer
name, that name is sent to a DNS (domain
name service) and translated into the
corresponding IP address. This is called
resolving an IP address.
• The IP address of the DNS is specified in your
computer’s network settings.
• There are many DNS’s, and they work in a
hierarchy. In other words, not every DNS has
every computer on the Internet listed.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Choosing a Server
• When it comes to a server, there
are many points to consider:
– What tasks will this machine
perform?
– How long will we need to use this
server?
– How many people will access this
server?
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Some Tasks
• Your server typically performs the
following tasks:
– Web Server
– Email Server
– Database Server
– Application Server
– Office Backups
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Typical Choices
• The type of server you buy will depend
mostly on personal choices. Things to keep
in mind:
– What operating system are you familiar with?
– What OS does the office staff use?
– What programs does your office want to use, what
OS’s will they run on?
• You can mix systems, but only UNIX mixes
cross platform very well
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Typical Choices
• No matter what system you choose,
there are three main considerations:
– Get the fastest processor with the most
RAM your budget will allow.
– Size the Hard Drive to the tasks that the
server will perform.
– Make sure you have a way to back up the
server (tape backup, RAID controller, etc.)
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Practical Application: why is this
important to me?
• It is important to know how the webpages
you design are delivered.
• It is also possible that you may be asked to
do some simple networking in your office.
The following example will require you to do
just that; create a network in your office
using the skills you’ve learned in the
networking course.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
The Task
• Your boss wants to develop a web presence.
You are given a $8,000 budget to buy a
server, and upgrade the existing cabling and
equipment for a 100 Mbps network.
• You need to assess what equipment you need
to buy, obtain price quotes and compose a
one-page proposal outlining what needs to
be purchased.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
What you already have
• 2000 ft of Cat-3 Cable
• 10 Desktops running Win98
• 7 with 10/100 Ethernet cards, 3 with
10Mb cards
• 1 10 port, 10 Mb hub
• 48 port, Cat-5 capable patch panel
• A router
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Equipment You Need
•
•
•
•
•
Server
Cat-5 Cabling
100Mb bridge
Power Backup
Enough 100 Mb Ethernet cards
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Keep in mind
• You should take into account the existing
equipment and build off of that.
• Don’t forget about future expandability. You
may only need a 10 port hub for your 10
existing computers, but if you add one more
computer you will have outgrown your hub.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Resources
• Feel free to get quotes from any source you
like. You’ll need to include a copy of the
quotes with your proposal.
• If you’re unsure of where to get started, here
is an alphabetical list of online stores:
–
–
–
–
–
–
Apple (www.apple.com)
Compaq (www.compaq.com)
Dell Computer (www.dell.com)
Gateway 2000 (www.gateway.com)
IBM (commerce.www.ibm.com)
microWarehouse (www.warehouse.com)
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.
Final Thoughts
• It doesn’t matter what equipment you
choose, as long as you defend your choices
in your proposal. Brand reputation, past
experience and peer recommendations are all
good justifications.
Networking
Archimedes Performance, Inc.
Epic Learning, Inc.