Transcript 109.02 Presentation File

Select appropriate hardware for building networks.
Objective 109.02 Course Weight 2%
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Essential Components
Computer networks consist of three essential
components:
End Devices – User connection to the network.
Intermediary Devices – The devices that handle the
information exchange in between the end devices.
Media – The various connecting wires and signals
that allow the devices to communicate.
The focus of this section will be on the intermediary
devices and media components.
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End Devices
These are the user’s interface to the network. They
include, but are not limited to:
Desktops
Laptops
Tablets
Mobile Phones
IP Phones
Printers
Servers
Smart Devices (TVs, Refrigerators, etc.)
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End Devices on the Network
Connecting desktops, laptops, and servers to a
network depends on the Operating System (OS) that
the device is running.
All of the other end devices can be connected to a
network by following manufacturer specific
instructions that can usually be found on the
manufacturer’s support web site.
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Intermediary Devices
These handle the flow of information to and from end
devices. They include, but are not limited to:
Switches (Layer 2 and Layer 3)
Routers
Firewalls
Wireless Access Points (WAPs)
Hubs (deprecated due to the advent of switches)
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Intermediary Devices
This section focuses on the first two devices in this list
Switches (Layer 2 and Layer 3)
Routers
Firewalls
Wireless Access Points (WAPs)
Hubs (deprecated due to the advent of switches)
Firewalls and WAPs are critical components in the
modern network, and are covered in Security unit 207.
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Switches
They are used to connect multiple computers in a
LAN setting.
Replaced hubs.
OSI model: Layer 2
Delivers data based on MAC addresses.
Keep a table of connected MAC addresses to support
quick communication.
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Switches
Switches have a wide variety of features.
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Unmanaged vs. Managed (VLANs)
Fast Ethernet vs. Gigabit Ethernet
Copper Uplink vs. Fiber Uplink
Layer 2 vs. Layer 3
Non-Power over Ethernet (PoE) vs. PoE
In the above list, the second option is generally more
expensive, more advanced, and preferred for a more
robust network.
Come in a variety of port configurations.
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Usually multiples of 2.
5, 8, 16, 24, and 48 are common.
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Routers
Used to interconnect networks.
OSI model: Layer 3
Delivers data based on IP addresses.
Gateway routers connect LAN to WAN.
Bridge routers connect LAN segments together.
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Routers
Routers are usually thought of as a stand alone
hardware device, but Windows Servers can operate
as software-based routers as well.
Like switches and their MAC address tables, routers
maintain tables called route tables that keep track of
other nearby routers.
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Routers
Static Routes versus Dynamic Routes
When route tables are maintained manually by an
administrator they are referred to as static route
tables.
 These are rarely used today due to the
complexity of modern IP networks.
Most route tables today are maintained by different
routing protocols in which routers automatically
figure out how to handle traffic.
 This is called dynamic routing.
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Routers
Dynamic Routing Protocols
 RIP – Router Information Protocol
 Distance-vector based protocol that uses an algorithm to
determine how to send traffic.
 OSPF – Open Shortest Path First
 Link-state protocol that monitors if a link is on/off to
determine the best way to route traffic.
 IGRP – Interior Gateway Routing Protocol
 Cisco-owned and developed protocol that is an improved
version of RIP.
 BGP – Border Gateway Protocol
 Exterior gateway protocol used to determine best routes
across the Internet.
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Media
These are the channels that data travels through. They
include, but are not limited to:
Fiber Optic Cable
Twisted Pair Cable
Coaxial Cable
Wireless Channels
Each of these media types are common in today’s
networks. Coaxial is less common inside the LAN.
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Fiber Optic Cable
 Fiber optic cable should be used when the highest bandwidth
is desired, and money is not an issue.
 Multimode fiber is generally used inside the LAN.
 The longer a multimode run is stretched the slower the
bandwidth .
 Single mode fiber is used for long-haul WAN connectivity.
 Single mode fiber is quite incredible. It can maintain
throughput of ~40Gbps at distances exceeding 100km.
 Fibers are usually run in pairs because a single fiber is
unidirectional.
 Two fibers are required for duplex transferring.
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Twisted Pair Cable
Twisted pair is the most commonly used network
media because of its transmission speeds and value.
It is less expensive than coaxial and fiber.
It can transmit data at gigabit speeds.
It comes in shielded and unshielded varieties in case
there is an area where the network may experience
interference.
It also comes with plenum and non-plenum ratings
in case the wire is run through plenum space.
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Coaxial Cable
Coaxial cable is a very rugged cable type that is
designed to resist interference.
This cable type is commonly used by cable TV and
satellite TV providers.
It is recommended for installations where the cable
may experience a wide variety of environmental
conditions.
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Wireless Channels
Radio frequency media is becoming more popular
each year.
The increase in popularity of this media type is
driven by the rise in the use of mobile end devices.
It is great to use when a device needs to be free and
mobile for purposes such as presentation.
The largest drawback of wireless media is the
possibility of Radio Frequency Interference (RFI).
Another obstacle to the use of wireless media are
dense, solid walls which prevent the signal from
broadcasting.
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Putting It All Together
Gateway Routers connect to the Internet.
Bridge routers connect one network to another
network.
Switches and WAPs connect end devices to the
network.
Different media is used to connect the end and
intermediary devices together based on the
requirements of the network.
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Putting It All Together
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