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Our LAN
network is set up as follows:
·
All connections are made with fiber
optics. This is the standard for all the servers and to the switches and
router and bridges.
·
The layouts shown in the
TOPOLOGY link are the type dependent on
floors and building.
·
The switches/routers are from Cisco
systems. They can support the network activity of 20 Meg connections for
workstations and the 100 Meg for the database servers.
·
For the connection between buildings, we
are using fiber optics again.
·
Connecting to the outside network, we use
a T1 line.
·
We have both a software and hardware
firewall to protect our internal network. The firewall is made by Cisco
and there are a number of different software firewalls.
·
The number of workstations and the number
of floors per building will determine the number of routers needed.
The main
office in Houston is where the data center/main server room is located.
All the other workstations and servers are backed up to this location,
using the netback tool.
(See Figure 6 and 7 in FUTURE VIEW)
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Linear bus topology consists
of a main run of cable with a
terminator at each end (See Figure 1). All
nodes (file server, workstations, and peripherals) are connected to
the linear cable.
Ethernet and
LocalTalk networks use a linear bus topology.

(Figure 1)
A star topology is designed
with each
node (file server, workstations, and peripherals) connected directly
to a central network
hub or
concentrator (See Figure 2).
Data on a star network passes
through the hub or concentrator before continuing to its destination.
The hub or concentrator manages and controls all functions of the
network. It also acts as a
repeater for the data flow. This configuration is common with
twisted pair cable; however, it can also be used with
coaxial cable or
fiber optic cable.

(Figure 2)
A tree topology combines
characteristics of linear bus and star topologies. It consists of groups
of star-configured workstations connected to a linear bus backbone cable
(See Figure 3). Tree topologies allow for the expansion of an existing
network and enable schools to configure a network to meet their needs.

(Figure 3)
Peer-to-peer network
operating systems allow users to share resources and files located on
their computers and to access shared resources found on other computers.
However, they do not have a file server or a centralized management
source (See Figure 4). In a peer-to-peer network, all computers are
considered equal; they all have the same abilities to use the resources
available on the network. Peer-to-peer networks are designed primarily
for small to medium local area networks. AppleShare and Windows for
Workgroups are examples of programs that can function as peer-to-peer
network operating systems.

(Figure 4)
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DMC Future View for the
Wireless LAN Network:
Wireless, if wisely applied, offers extraordinary opportunities. The
opportunities are only going to be realized by building the
communications infrastructure to support the wireless LANs.
Bluetooth started out as a
consortium and still remains an active consortium of companies with an
interest in cable replacement technologies with a range of 30 feet. The
small chipset size and very low cost ($3-$20 chipset cost) is the design
criteria. The Bluetooth consortium specification used 2.4GHz fast
frequency hoping in its deployment IEEE 802.11b standard, an 11Mbps
Direct Sequence version, and is the most popular.
Security & Recommendations
The goal of any
comprehensive WLAN security plan should be to protect the network from
attack from within, as well as from the outside.
Maintaining a secure wireless
network and associated devices requires significant effort, resources,
and vigilance and involves the following steps:
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Managed Security Services
to offer comprehensive solutions for real-time security management
including system monitoring, emergency response and 24/7 guaranteed
protection
-
Stop the unwanted material
DMC employees receive in e-mail. Managed Security Services for e-mail
security can provide a variety of solutions to enhance existing
security posture that will help to prevent viruses, spam and control
unwanted content in e-mail.
-
Managed Security Services
for Web security to protect DMS from Internet threats with 24/7
scanning that helps stop viruses and spy ware before they can
compromise the network. Simple to deploy and easy to manage, with
robust antivirus, anti spy ware and URL-filtering technologies
-
Prepare ahead for
information security breaches or stop attacks in progress with
Emergency Response Services from Internet Security Systems
-
Work with expert security
consultants to help bring DMS systems into compliance with industry
and government regulations for information security.
-
Maintaining a full
understanding of the topology of the wireless network
-
Performing periodic
security testing and assessment of the wireless network
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Applying patches and
security enhancements
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Creating backups of data
frequently
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Labeling and keeping
inventories of the fielded wireless and handheld devices
-
Labeling and keeping
inventories of the fielded wireless and handheld devices
-
Performing ongoing,
randomly timed security audits to monitor and track wireless and
handheld devices
Risks and Mitigation
Because it is much more
difficult to address security once deployment and implementation have
occurred, security should be considered from the initial planning stage.
The risks related to the use
of wireless technologies are considerable. Many
current communications
protocols and commercial products provide inadequate protection and thus
present unacceptable risks to agency operations. DMC must actively
address such risks to protect their ability to support essential
operations, before deployment of wireless technologies.
Wireless LANs Access points
being considered:
Each access point typically
supports up to 255 client computers. By connecting access points to each
other, local networks having thousands of access points can be created.
Client computers may move or "roam" between each of these access points
as needed:
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Houston, TX - 20 access
points,
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Los Angeles, CA - 10 access
points,
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Jacksonville, Florida - 10
access points,
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Phoenix, AZ - TBD
Benefits:
WLANs offer four primary
benefits:
-
User
Mobility—Users
can access files, network resources, and the Internet without having
to physically connect to the network with wires. Users can be mobile
yet retain high-speed, real-time access to the enterprise LAN.
-
Rapid
Installation—The
time required for installation is reduced because network connections
can be made without moving or adding wires, or pulling them through
walls or ceilings, or making modifications to the infrastructure cable
plant. For example, WLANs are often cited as making LAN installations
possible in buildings that are subject to historic preservation rules.
-
Flexibility—Enterprises
can also enjoy the flexibility of installing and taking down WLANs in
locations as necessary. Users can quickly install a small WLAN for
temporary needs such as a conference, trade show, or standards
meeting.
-
Scalability—WLAN
network topologies can easily be configured to meet specific
application and installation needs and to scale to very large
enterprise networks that enable roaming over a broad area.
VOIP
DMC will
use VOIP to prevent network phone drops. Voice over IP (VoIP) is the
transfer of voice conversations as data over an Internet Protocol (IP)
based network. (See Figure 5). Advantages
to this new technology are that VoIP service allows phone numbers to no
longer have any direct relationship to where in the world someone is
located. A phone can work anywhere in the world where there is a
broadband internet connection, and any area code can be used. For
example, a military family living in Germany could have a Chicago phone
number and could make and receive calls to and from the US.


(Figure 7)
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