A plus 220-1001 – Exam Objective 2.2
A+ Exam Objective 2.2
2.2 Compare and contrast common networking hardware
Welcome to CertBlaster ExamNotes! We will look at 220-1001 Sub-objective 2.2 Compare and contrast common networking hardware devices. We will look at the evolution of interconnectivity and the roles these devices play.
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The smallest network you can create is a one-to-one (Peer to
Peer) relationship between two computers or devices. A hub is designed to
distribute multiple signals to multiple hosts. Communications are managed by
CDMA (Carrier Sense –Multiple Access), where the host will check the cable to
see if it is clear before transmission is initiated. When a signal is
distributed by a hub, it is sent to all connected devices, causing a burst of
communications if left unchecked (CDMA).
Devices connect to hubs and switches either wirelessly or through
RJ-45 UTP cabling. The wired connection requires a Network interface card (NIC)
as shown below.
PCI Express 1X Ethernet
A switch determines whether or not a destination Hardware (MAC)
or network (IP) address is attached to the switch itself. A switch uses MAC or
IP addressing knowledge about the devices connected to it and the device
oriented environment it exists in. Switches utilize packet switching and the
information contained in each packet to determine if the destination for the
packet is connected locally or needs to be forwarded upstream. Unlike a hub, an
unmanaged switch uses the information gained to direct traffic to the correct
port. Switches operate as MAC Bridges.
The goal of a switch is to enable efficient traffic management.
A managed switch has features not found in an unmanaged switch such as VLAN
support and traffic prioritization. Managed switches can use the SNMP protocol
to enable remote management.
Cable management is always important. It is especially important
when there are a large number of users assigned and the cable closet is not
particularly roomy. The purpose of a patch panel is to connect and manage
inbound and outbound cables in a central area. Typically, the destination would
be labeled on the panel and lead to a wall jack. Presented below is a good
example of a well-organized patch panel. Take a good look. Notice the really
precise cable routing and management of four switches in a well-kept server
space. Most installations start out like this.
Here they all are rolled into one device! Most reputable ISPs
provide a device like the one shown. For this image, we took the most fully
featured non-ISP related modem available. My guess is that most of you have
seen a variation of this in your travels. This device is a Cable Modem, Router,
Firewall and Wireless Access Point as well as a Switch/Bridge.
Think of the Router as your network traffic cop. Ultimately, the
router and the firewall which has the final say, decides which traffic does and
does not get on to your network. The router is useful for finding the quickest
path for your data to take while finding its way through the maze of routers
and servers from point to point. Shown here is a combination Router/ Wireless
Access Point. It is responsible for routing and also access to the Wireless
Network among other functions.
Cloud resources and even entire virtual networks can be
accessible using Software Defined Networking (SDN). Network management can be
delegated to cloud resources to provide centralized management. This technique
can be used to create virtual WANs.
Here is a diagram explaining the function of a bridge. The
bridge takes the digital signal from the Wireless environment and converts it
for use with a wired entertainment component.
When one thinks of a modem, one thinks of the traditional digital
to analog phone modem, where the signal is converted from digital to analog on
the opposite end. The device can be internal.
Phone Modem RJ-11
Over the past few years, the term modem became synonymous with Cable Modems. Cable Modems, or Fiber modems, are at the most commonly used modems in use today. Most ISP provided modems today have port forwarding/ triggering functionality as well. This all-in-one feature bundling is part of the appeal of these devices. You no longer need a separate WAP, DHCP sever, and Modem. Depending on the modem itself, you may find a fully configurable Router and Firewall. Modems are trending towards having all services coming in on a single connection. (Show Router Access Point.jpg) Many readers have or have had this device in their homes. Cisco and Linksys are the most famous modem manufacturers.
Firewalls can be a hardware device, software, or both. Naturally,
you can address more threats with the combination approach by using your
hardware firewall as the first line of defense. Next, your software firewall
will provide additional protection and possibly even malware scans.
The hardware firewall device’s placement is important. It should
be between the external network, in most cases the internet, and your private
network or LAN.
Digital audio information is represented on a sine wave display
as a series of squared off steps, resembling a staircase. If displayed in the
analog format, it would represent the same information as a smooth vertical
line, a peak followed by decay back to zero. Here is the
simplest display of this process
Since the PC is transmitting information digitally, the signal
can be refreshed and restored to its original state using a repeater or
extender without distortion. Using this method with an analog signal would
boost the unwanted noise level along with the desired signal.
Ethernet over Power
We will talk about two conceptually similar but vastly different
technologies here. Your objectives call for The Ethernet over Power (EOP)
technology. This type of power distribution allows for energy and Ethernet to
share the same cabling. This allows for communication, command, and control
signals to be sent along with the main power supply.
The PoE (Power over Ethernet) system reverses this existing
technology using Ethernet cable as its primary carrier. This impacts the
effective Volt/Amp delivery as the RJ grade cable is not rated to carry the
higher voltages some devices require. It is however ideal for a low voltage
operation such as a security monitor or a baby monitor.
Phone over Ethernet – Upside down!
Injectors vs. PoE switch
A PoE injector provides data and power to a single device. A PoE
switch on the other hand is capable of distributing power and data to all
That will do it for Sub-objective 220-1001 2.2! Good Luck on the test!!
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