 |
| Image Source: https://5.imimg.com/data5/WM/DX/GLADMIN-15632470/networking-and-security-solutions-for-corporates-500x500.png |
The Fundamental Principles of Networks
Network fundamentals are the building blocks of network design. It s a way for two or more computers to be connected or linked together in order for them to exchange data. It could be linking computers within an office or home, or linked over the internet. They can be connected by a wired connection or wireless connection.
- Local-area network (LAN): The computers are geographically close together (that is, in the same building).
- Wide-area network (WAN): The computers are farther apart and are connected by telephone lines or radio waves.
- Metropolitan-area network (MAN): A data network designed for a town or city.
- Home-area network (HAN): A network contained within a user's home that connects a person's digital devices.
- Virtual private network (VPN): A network that is constructed by using public wires — usually the Internet — to connect to a private network, such as a company's internal network.
- Storage area network (SAN): A high-speed network of storage devices that also connects those storage devices with servers.
Server:
A computer or device on a network that manages network resources.
Servers are often dedicated, meaning that they perform no other tasks
besides their server tasks.
Client: A client is an application that runs on a personal computer or workstation and relies on a server to perform some operations.
Devices:
Computer devices, such as a CD-ROM drive or printer, that is not part
of the essential computer. Examples of devices include disk drives,
printers, and modems.
Transmission Media:
the type of physical system used to carry a communication signal from
one system to another. Examples of transmission media include
twisted-pair cable, coaxial cable, and fiber optic cable.
Network Operating System (NOS):
A network operating system includes special functions for connecting
computers and devices into a local-area network (LAN). The term network
operating system is generally reserved for software that enhances a
basic operating system by adding networking features.
Operating System:
Operating systems provide a software platform on top of which other
programs, called application programs, can run. Operating systems
perform basic tasks, such as recognizing input from the keyboard,
sending output to the display screen, keeping track of files and
directories on the disk, and controlling peripheral devices such as disk
drives and printers.
Network Interface Card (NIC):
An expansion board you insert into a computer so the computer can be
connected to a network. Most NICs are designed for a particular type of
network, protocol, and media, although some can serve multiple networks.
Hub:
A common connection point for devices in a network. A hub contains
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.
Switch:
A device that filters and forwards packets between LAN segments.
Switches operate at the data link layer (layer 2) and sometimes the
network layer (layer 3) of the OSI Reference Model.
Router:
A router is a device that forwards data packets along networks. A
router is connected to at least two networks and is located at gateways,
the places where two or more networks connect.
Gateway: A node on a network that serves as an entrance to another network.
Bridge: A device that connects two local-area networks (LANs), or two segments of the same LAN that use the same protocol
Channel Service Unit/Digital Service Unit (CSU/DSU): The CSU is a device that connects a terminal to a digital line. Typically, the two devices are packaged as a single unit.
Terminal Adapter
(ISDN Adapter): A device that connects a computer to an external
digital communications line, such as an ISDN line. A terminal adapter is
a bit like a modem but only needs to pass along digital signals.
Access Point:
A hardware device or a computer's software that acts as a communication
hub for users of a wireless device to connect to a wired LAN.
Modem
(modulator-demodulator): A modem is a device or program that enables a
computer to transmit data over, for example, telephone or cable lines.
Firewall:
A system designed to prevent unauthorized access to or from a private
network. Firewalls can be implemented in both hardware and software, or a
combination of both.
MAC Address:
A MAC (Media Access Control) address, sometimes referred to as a
hardware address or physical address, is an ID code that's assigned to a
network adapter or any device with built-in networking capability.
OSI Model
OSI Image Source:
https://www.digikey.co.il/he/articles/techzone/2012/apr/~/media/Images/Article%20Library/TechZone%20Articles/2012/April/Communication%20in%20Industrial%20Networks/article-2012march-communications-in-fig1.jpg
To help simply the different stages or "layers" of a model, they are divided into either the 7 layer model or the OSI model. Each layer handles specific stages and is independent of the other layers.
The layers are as follows: (Beal)
Physical Layer
This layer conveys the bit stream -
electrical impulse, light or radio signal -- through the network at the
electrical and mechanical level. It provides the hardware means of
sending and receiving data on a carrier, including defining cables,
cards and physical aspects. Examples include Ethernet, FDDI, B8ZS, V.35,
V.24, RJ45.
2. Data Link Layer
At this layer, data packets are encoded
and decoded into bits. It furnishes transmission protocol knowledge and
management and handles errors in the physical layer, flow control and
frame synchronization. The data link layer is divided into two sub
layers: The Media Access Control (MAC) layer and the Logical Link
Control (LLC) layer. Examples include PPP, FDDI, ATM, IEEE 802.5/ 802.2,
IEEE 802.3/802.2, HDLC, Frame Relay.
3. Network Layer
This layer provides switching and routing
technologies, creating logical paths, known as virtual circuits, for
transmitting data from node to node. Routing and forwarding are
functions of this layer, as well as addressing, internetworking, error
handling, congestion control and packet sequencing. Examples include
AppleTalk DDP, IP, IPX.
4. Transport Layer
This layer provides transparent transfer
of data between end systems, or hosts, and is responsible for end-to-end
error recovery and flow control. It ensures complete data
transfer.Examples include SPX, TCP, UDP.
5. Session Layer
This layer establishes, manages and
terminates connections between applications. The session layer sets up,
coordinates, and terminates conversations, exchanges, and dialogues
between the applications at each end. Examples include NFS, NetBios
names, RPC, SQL.
6. Presentation Layer
This layer provides independence from
differences in data representation (e.g., encryption) by translating
from application to network format, and vice versa. This layer formats
and encrypts data to be sent across a network, providing freedom from
compatibility problems. Examples include encryption, ASCII, EBCDIC,
TIFF, GIF, PICT, JPEG, MPEG, MIDI.
7. Application Layer
This layer supports application and
end-user processes. Communication partners are identified, quality of
service is identified, user authentication and privacy are considered,
and any constraints on data syntax are identified. Everything at this
layer is application-specific. This layer provides application services
for file transfers, e-mail, and other network software services.
Examples include WWW browsers, NFS, SNMP, Telnet, HTTP, FTP
Network topologies is the diagram of the different ways that the computers can be linked together. It also contains the way that they communicate. These 4 types of topologies are listed below: (Beal) These topologies can also be mixed and matched to fit the needs of the way that they network needs to be set up in order to function the way needed.
 |
| Image Source: https://hi-static.z-dn.net/files/dca/640c464fa5c89a5ec18cc660170eb8fa.jpg |
Bus Topology
All devices are connected to a central
cable, called the bus or backbone. Bus networks are relatively
inexpensive and easy to install for small networks.
Ring Topology
All devices are connected to one another
in the shape of a closed loop, so that each device is connected directly
to two other devices, one on either side of it.
Star Topology
All devices are connected to a central
hub. Star networks are relatively easy to install and manage, but
bottlenecks can occur because all data must pass through the hub.
Tree Topology
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.
Works Cited:
Beal, V. (2015, September 6). Network Fundamentals
Study Guide. Retrieved from Webopedia:
https://www.webopedia.com/quick_ref/network-fundamentals-study-guide.html#terms
Comments
Post a Comment