# data[].attributes.body
Allows the network to centralize functions and applications in one or more dedicated file servers.  The file servers become the heart of the system, providing access to resources and providing security. UNIX/Linux and Microsoft family of Windows Servers are examples.
Advantages: centralized-resources and data security are controlled through the server, scalability- any or all elements can be replaced individually as needs increase, flexibility- new technology can be easily integrated into system, interoperability-all components work together, accessibility- server can be accessed remotely and across multiple platforms.
Disadvantages: Expense- investment in dedicated server; maintenance- large networks will require a staff to ensure efficient operation, dependence- when servers go down operations will cease across the network.

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It allows users to share resources and files located on their computers and to access shared resources found on other computers. In this kink of network, all computers are considered equal; they all have the same abilities to use the resources available on the network.
Advantages: less initial expense (no need for a dedicated server), set up-an operating system like Windows XP already is in place and may only need to be reconfigured.
Disadvantages: decentralized-no central repository for files and applications, security-does not provide the security available on a client/server network.

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NOS coordinate the activities of multiple computers across a network.  It acts as a director to keep the network running smoothly.
Two major types: Peer-to-peer and client/server

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-money: A linear bus network may be the least expensive way to install a network ( no need to purchase concentrators)
-length of cable needed: The linear bus network uses shorter lengths of cable.
-future growth: With a star topology, expanding a network is easily done by adding another concentrator.
-cable type: The most common cable in schools is unshielded twisted pair, which is most often used with star topologies.

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Between any two nodes on the network, there can only be a maximum of 5 segments, connected through 4 repeaters/concentrators, and only 3 segments may be populated (trunk) segments if they are made of coaxial cable.
This rule DOES NOT apply to other network protocols or Ethernet networks where all fiber optic cabling or a combination of a fiber backbone with UTP cabling is used. In this instance, the rule would translate to a 7-6-5 rule.

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Combines characteristics of linear bus and star topologies.
It consists of groups of star-configured workstations connected to a linear bus backbone cable.
Advantages: point-to-point wiring for individual segments, supported by several hardwired and software vendors.
Disadvantages: overall length of each segment is limited by the type of cabling used, if the backbone line breaks, the entire segment goes down, more difficult to configure and wire.

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designed with each node (file server, workstations and peripherals) connected directly to a central network hub, switch or concentrator.
Advantages: easy to install and wire, no disruptions to the network when connecting or removing devices, easy to detect faults and to remove parts
Disadvantages: requires more cable length than a linear topology, if the hub, switch, or concentrator fails, nodes attached are disabled, more expensive than linear bus topologies because of the cost of the bubs, etc.

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consists of a main run of cable with a terminator at each end
file server, workstations, and peripherals are all connected to the linear cable.
Advantages: easy to connect a computer or peripheral; requires less cable
Disadvantages: entire network shuts down if break in main cable, terminators are required at both ends of backbone cable, difficult to identify the problem if the entire network shuts down, not meant to be used as a stand-alone solution in a large building

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The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Types of topology: linear bus, star, tree (expanded star)

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-wireless much more susceptible to unauthorized use because devices use radio waves to communicate
Three techniques used to protect networks:
encryption, isolation and hidden SSID

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-Wi-Fi Alliance is a global, non-profit that helps insure standards and interoperability for wireless networks
-Wi-Fi networks use Ethernet protocol

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-operates without cables (wireless mode)
-wireless LANs use high frequency radio signals, infrared light beams, or lasers to communicate between the workstations, servers, or hubs
-information is relayed between transceivers for close distance
-for longer distances, wireless communications can take place through cellular telephone technology, microwave transmission, or by satellite.

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-consists of a center glass core surrounded by several layers of protective materials
-transfers light instead of electronic signals
-has the ability to transmit signals over much longer distances
-carries information much faster
-two types: single mode (more distance, more expensive); multimode (larger diameter)

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-most common is Bayone-Neill-Concelman (BNC) connector
-different types of adaptors available such as T-connector, barrel connector and terminator
-weakest point in any network

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-also referred to as thicknet
- 10Base5 refers to specifications for carrying Ethernet signals
-maximum segment length is 500 meters

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-also referred to as thinnet
-10Base2 refers to specifications for carrying Ethernet signals
-maximum segment length is 485 meters

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-has a single copper conductor at its center
-a plastic layer provides insulation between the center conductor and the braided metal shield
-highly resistant to signal interference
-two types: thick coaxial and thin coaxial

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good for environments with lots of potential interference
Three different configurations:
-each pair of wires is individually      shielded in foil
-there is a foil or braid shield inside the jacket covering all wires (as a group)
-There is a shield around each individual pair, as well as around the entire group of wires (referred to as double shield twisted pair)

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RJ-45 connector (looks like a large telephone-style connector)

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Category  Speed      Use
1                 1 Mbps     Voice Only (telephone)
2                 4 Mbps     Local Talk & Phone
3                16 Mbps     10 Base T Ethernet
4                 20Mbps    Token Ring
5                 100Mbp    100Base T Ethernet
1000Mbp  Gigabit Ethernet
5e               1000Mbps  Gigabit Ethernet
6                 10,000Mbps  Gigabit Ethernet

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-two varieties: shielded and unshielded

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-the medium through which information usually moves from one network device to another.
-type of cable used in a network is related to the network's topology, protocol and size.

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-installed at the entrance to a LAN when connecting networks together, particularly connecting a private to a public network
-uses rules to filter traffic into and out of the private network, to protect remote network users and data from malevolent hackers.
-either hardware or software

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-traffic directors of the global internet
-communicate with each other and forward network packages out of or into a network

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-allows you to segment a large network into two smaller networks
-connects old and new networks
-maintains the traffic on both sides of the network to maintain optimum performance

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-boost the signal as it passes along a cable
-good for cables that exceed 100 meters in length

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-provide a central connection point for cables from workstations, servers and peripherals.
-usually configured with 8, 12, or 24 RJ-45 ports
-often used in a star or tree topology
available as "managed" or "unmanaged"
-direct replacements for hubs, immediately reducing network traffic
-usually installed in a standardized metal rack

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-found in most portable devices

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-can contain connections for either coaxial and/or twisted pair cables
coaxial >connection will be BNC
twisted pair>connection will be RJ-45
-some contain AUI connector

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provides a physical connection between the network and the computer work station. Most are internal. Major factor determining speed and performance of a network. Most common are Ethernet cards and wireless adaptors.

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Have modest internal storage, but enough power to to be a workstation. Usually has a wireless adapter.

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typically a computer that is configured with a network interface card, networking software, and the appropriate cables.

# data[].attributes.headline
Guidelines for configuring a network server

# data[].attributes.subject
Guidelines for configuring a network server

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-fast processor(s)
-large amount of RAM
-multiple large, fast hard drives
-extra expansion slots
-fast network interface card(s)
Optionally (if no other such devices are available on the network:
-a RAID to preserve large amounts of data
-a back-up unit

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Part of nearly every local area network. These are very fast computers with a large amount of RAM and storage space as well as one or more fast network interface card(s).

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Networking HARDWARE includes all computers, peripherals, interface cards and other equipment needed to perform data-processing and communications within the network.

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HTTP, FTP, SMTP and DNS (Session/Presentation/Application Layers)

# data[].attributes.subject
HTTP, FTP, SMTP and DNS (Session/Presentation/Application Layers)

# data[].attributes.body
Several protocols overlap the session, presentation and application layers of networks.
DNS, DHCP., FTP, HTTP, IMAP, IRC, POP3, SMTP

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concerned with efficient and reliable transportation of the data packets from one network to another.

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paired with SPX at the transport layer for some older Macintosh, Linus, UNIX, Novell and Windows networks

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paired with TCP at the transport layer for Internet work

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Is in charge of routing network messages (data) from one computer to another.

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1000 Mbps

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supports speeds up to 100 Mbps

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max speed of 10 Mbps

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-Focuses on hardware elements such as cables, repeaters and network interface cards.
-most common protocol used
-uses access method CSMA/CD (a system where each computer listens to the cable before sending anything through the network)

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HTTP/FTP/SMTP/DNS/Telnet

TCP/SPX
IP/IPX
Ethernet

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OSI Layer      Name
7                  Application
6                  Presentation
5                  Session
4                  Transport
3                  Network
2                   Data Link
1                    Physical

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PROTOCOL is a set of rules that governs the communications between computers on a network.

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A WIDE AREA NETWORK (WAN) connects networks in larger geographic areas, such as a state, country or the world.

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Workstations can be wired or wireless.

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Nearly all servers will be connected to a network by cables because it is still the fastest connection.

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Devices on a network that provide a bridge between computers and networks.

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on a single LAN, computers and servers may be connected with a cable or wirelessly.

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typically have a human user which interacts with the network through them. Usually a desktop or a laptop, tablet or phone.

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are generally not used by humans directly, but rather run continuously to provide "services" to the other computers on the network.

# data[].attributes.headline
Computers connected to a network are either servers or workstations

# data[].attributes.subject
Computers connected to a network are either servers or workstations

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a LOCAL AREA NETWORK (LAN) is a network that is confined to a relatively small area like a writing lab, school or building.

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a NETWORK consists of two or more computers that are linked in order to share resources (printers, scanners, etc), exchange files, or allow electronic communications.