Transcript Assignment 3 - Network Components

Networking Components
Chad Benedict – LTEC 4550
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What is a Network HUB?
A Network HUB is a common connection point for devices in a network.
HUBs are commonly used as the easiest and least expensive way to connect segments of a
LAN by using multiple ports. When a packet arrives at one port, it is copied to the other ports
so that all segments of the LAN can see all packets.
Unlike a network switch or router, a network hub has no routing tables or intelligence on
where to send information and broadcasts all network data across each connection.
When computer “A”
responds, its response
also goes out to every
other port on the hub
If a message comes in for
computer “A”, that
message is sent out all the
other ports, regardless of
which one computer “A” is
on.
Prices range depending on the number of ports on the HUB. Example. 5 Port HUB = $10-30
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What is a Network Switch?
A network switch (also called switching hub,
bridging hub, officially MAC bridge) is a
computer networking device that connects
devices together on a computer network, by
using packet switching to receive, process and
forward data to the destination device.
Initially, a switch knows
nothing and simply sends
on incoming messages to
all ports.
A switch does essentially what a hub does, but
more efficiently. By paying attention to the
traffic that comes across it, it can “learn” where
particular addresses are.
Even accepting that first
message, however, the switch
has learned something – it
knows on which connection
the sender of the message is
located. Thus, when machine
“A” responds to the message,
the switches only need to send
that message out to the one
connection.
People tend to benefit from a switch over a
hub if their home network has four or more
computers, or if they want to use their home
network for applications that generate
significant amounts of network traffic, like
multiplayer games or heavy music file sharing.
Prices range depending on the number of ports on the
Switch.
5-8 Port Switch = $10-30
16-24 Port Switch = $100-200
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In addition to sending the
response through to the
originator, the switch has now
learned something else – it
now knows on which
connection machine “A” is
located. That means that
subsequent messages
destined for machine “A” need
only be sent to that one port.
What is a Network Router?
Routers come in all shapes and sizes – from
the small, four-port broadband routers that are
very popular right now to the large industrial
strength devices that drive the internet itself.
Routers should be used when the network
needs to connect to the internet.
DHCP – Dynamic Host Configuration Protocol – is the way dynamic
IP addresses are assigned. A device asks for an IP address to be
assigned to it from “upstream” and a DHCP server responds with
an IP address assignment. A router connected to your ISP-provided
internet connection will typically ask your ISP’s server for an IP
address; this will be your IP address on the internet. Your local
computers, on the other hand, will ask the router for an IP address
and these addresses are local to your network
A simple way to think of a router is as a
computer that can be programmed to
understand, possibly manipulate, and route the
data that it’s being asked to handle. Many
routers today are, in fact, little computers
dedicated to the task of routing network traffic.
As far as simple traffic routing is concerned, a
router operates exactly as a switch, learning
the location of the computers on its
connections and routing traffic only to those
computers.
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Prices range depending on the number of ports on the Switch.
5-8 Port HUB = $10-75
16-24 Port Switch = $60-200
What is a Network Bridge?
A network bridge is a network device that
connects multiple network segments or two
segments of the same LAN that use the same
protocol, such as Ethernet or Token-Ring.
Bridges only forward packets between
networks that are destined for the other
network. Bridges are important in some
networks because the networks are divided
into many parts geographically remote from
one another or the networks have different
types of systems or devices. Something is
required to join these networks so that they
can become part of the whole network.
A bridge may be used to connect a wireless
network with a wired network.
There are four types of network bridging
technologies: simple bridging, multiport
bridging, learning or transparent bridging, and
source route bridging.
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Prices range depending on the number of ports, the bandwidth, and
whether it is wireless or wired. $20-500
What is a Network Gateway?
A network gateway is an internetworking
system capable of joining together two
networks that use different base protocols. A
network gateway can be implemented
completely in software, completely in
hardware, or as a combination of both.
Depending on the types of protocols they
support, network gateways can operate at any
level of the OSI model.
Because a network gateway, by definition,
appears at the edge of a network, related
capabilities like firewalls tend to be integrated
with it. On home networks, a broadband router
typically serves as the network gateway
although ordinary computers can also be
configured to perform equivalent functions.
Prices range depending on the number of ports, the bandwidth, and
whether it is wireless or wired. $100-500
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What is a Firewall?
A firewall is a network security system that
controls the incoming and outgoing network
traffic based on an applied rule set. Firewalls
can be implemented in both hardware and
software, or a combination of both. The
firewall establishes a barrier between a
trusted, secure internal network and another
network (e.g., the Internet) that is assumed not
to be secure and trusted.
A network may be configured to use NAT – Network Address
Translation in order to act as a firewall. The router translates the
IP addresses of packets that cross the internet/local network
boundary. When computer “A” sends a packet out, the IP address
that it’s “from” is that of computer “A” – 192.168.1.2 in the
example above. When the router passes that on to the internet, it
replaces the local IP address with the internet IP address
assigned by the ISP. It also keeps track, so that if a response
comes back from somewhere on the internet, the router knows to
do the translation in reverse – replace the internet IP address with
the local IP address for machine “A” and then send that response
packet on to machine “A”.
All messages entering or leaving the intranet
pass through the firewall, which examines
each message and blocks those that do not
meet the specified security criteria.
Router used as a
Firewall
The Firewall may be a computer or server with
firewall software, a network router, or a
gateway.
Computer or Server
used as a Firewall
Prices range vary greatly depending on the configuration of the
network.
Routers with built in Firewall range from $60-200
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What is a Wireless Access Point?
In a wireless local area network (WLAN), an
access point is a station that transmits and
receives data (sometimes referred to as a
transceiver). An access point connects users
to other users within the network and also can
serve as the point of interconnection between
the WLAN and a fixed wire network. Each
access point can serve multiple users within a
defined network area; as people move beyond
the range of one access point, they are
automatically handed over to the next one. A
small WLAN may only require a single access
point; the number required increases as a
function of the number of network users and
the physical size of the network.
Access points don't have built-in technology for
sharing Internet connections. To share an
Internet connection, you must plug an access
point into a router or a modem with a built-in
router.
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Prices range vary greatly depending on the configuration of the
network.
Wireless Access Points $20-200
Network Diagram with all components
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Q&A
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