Network topology is the physical interconnections of the elements (links, nodes, etc.) of a computer network.A local area network (LAN) is one example of a network that exhibits both a physical topology and a logical topology.
2.Examples of Network Topology, their Definition and post example picture.
Star topology
Also known as a star network, a star topology is one of the most common network setups where each of the devices and computers on a network connect to a central hub. A major disadvantage of this type of network topology is that if the central hub fails, all computers connected to that hub would be disconnected. Below is a visual example of a simple computer setup on a network using the star topology.
Ring topology
Also known as a ring network, the ring topology is a type of computer network configuration where each network computer and device are connected to each other forming a large circle (or similar shape). Each packet is sent around the ring until it reaches its final destination. Today, the ring topology is seldom used. Below is a visual example of a simple computer setup on a network using a ring topology.
Mesh topology
A type of network setup where each of the computers and network devices are interconnected with one another, allowing for most transmissions to be distributed, even if one of the connections go down. This type of topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this type of topology is commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology.
Tree topology
Also known as a star bus topology, tree topology is one of the most common types of network setups that is similar to a bus topology and a star topology. A tree topology connects multiple star networks to other star networks. Below is a visual example of a simple computer setup on a network using the star topology.
A bus network topology is a network architecture in which a set of clients are connected via a shared communications line, called a bus. There are several common instances of the bus architecture, including one in the motherboard of most computers, and those in some versions of Ethernet networks.
Bus networks are the simplest way to connect multiple clients, but may have problems when two clients want to transmit at the same time on the same bus. Thus systems which use bus network architectures normally have some scheme of collision handling or collision avoidance for communication on the bus, quite often using Carrier Sense Multiple Access or the presence of a bus master which controls access to the shared bus resource.
A true bus network is passive – the computers on the bus simply listen for a signal; they are not responsible for moving the signal along. However, many active architectures can also be described as a "bus", as they provide the same logical functions as a passive bus; for example, switched Ethernet can still be regarded as a logical network, if not a physical one. Indeed, the hardware may be abstracted away completely in the case of a software bus.
With the dominance of switched Ethernet over passive Ethernet, passive bus networks are uncommon in wired networks. However, almost all current wireless networks can be viewed as examples of passive bus networks, with radio propagation serving as the shared passive medium.
The bus topology makes the addition of new devices straightforward. The term used to describe clients is station or workstation in this type of network. Bus network topology uses a broadcast channel which means that all attached stations can hear every transmission and all stations have equal priority in using the network to transmit[1] data.
The Ethernet bus topology works like a big telephone party line – before any device can send a packet, devices on the bus must first determine that no other device is sending a packet on the cable. When a device sends its packet out over the bus, every other network card on the bus sees and reads the packet. Ethernet’s scheme of having devices communicate like they were in chat room is called carrier access/ collision detection (CSMA/CD). Sometimes two cards talk (send packets) at the same time. This creates a collision, and the cards themselves arbitrate to decide which one will resend its packet first. Only one PC on a bus network share a common wire, which also means they share the data transfer capacity of that wire – or, in tech terms, they share its bandwidth.
This creates an interesting effect. Ten PCs chatting on a bus each get to use a much higher proportion of its total bandwidth than, for instance, 100 PCs on the same bus (in this case, one – tenth compared to one – hundredth). The more PCs on a bus, the more likely you’ll have a communication traffic jam. [2]
3. What is OSI Layer?
Short for Open System Interconnection, OSI is a network model developed by ISO in 1978 where peer-to-peer communications are divided into seven layers. Each layer performs a specific task or tasks, and builds upon the preceding layer until the communications are complete. Below are the purposes of each of the seven layers.
4. Examples of OSI Layer, their definition in order.
1 - Physical layer - responsible for the electrical, mechanical and timing across the link.
2 - Data link layer (also known as the link layer) - responsible for transmitting data across a link.
3 - Network layer - responsible for routing information through the network and allowing systems to communicate.
4 - Transport layer - responsible for transferring information between endpoints on the network and deals with errors such as lost or duplicate packets.
5 - Session layer - responsible for managing a session between two applications.
6 - Presentation layer - responsible for the data formatting and display, allowing for compatibility.
7 - Application layer - responsible for user interaction. An example of an OSI application is the FTAM.
5. What is Networking?
In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.
6. Example of Networking, Post at least 5 examples with picture.
Local area network
A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Current wired LANs are most likely to be based on Ethernet technology, although new standards like ITU-T G.hn also provide a way to create a wired LAN using existing home wires (coaxial cables, phone lines and power lines)
Home area network
A home area network (HAN) or home hetwork is a residential local area network. It is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices. An important function is the sharing of Internet access, often a broadband service through a CATV or Digital Subscriber Line (DSL) provider.
Storage area network
A storage area network is an network architecture to attach remote computer storage devices (such as disk arrays, tape libraries, and optical jukeboxes) to servers in such a way that the devices appear as locally attached to the operating system. A SAN typically is its own network of storage devices that are generally not accessible through the regular network by regular devices. The cost and complexity of SANs has dropped in recent years, resulting in much wider adoption across both enterprise and small to medium sized business environments.
Campus area network
A campus area network (CAN) is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. It can be considered one form of a metropolitan area network, specific to an academic setting.
In the case of a university campus-based campus area network, the network is likely to link a variety of campus buildings including; academic departments, the university library and student residence halls. A campus area network is larger than a local area network but smaller than a wide area network (WAN) (in some cases).\
Metropolitan area network
A metropolitan area network (MAN) is a network that connects two or more local area networks or campus area networks together but does not extend beyond the boundaries of the immediate town/city. Routers, switches and hubs are connected to create a metropolitan area network.
NIC Cards
The Network Interface Card (NIC) is a circuit board that is physically installed within an active network node, such as a computer, server, or printer. The NIC is an adapter that controls the exchange of information between the network and the user. Newer NICs are increasingly pre-installed and have the ability to automatically configure to match the speed of the network to which they are connected. For example, if a workstation is attached to a switch on a dedicated connection, the adapter may configure itself to run full-duplex (both talking and listening at the same time) without fear of collisions.
A hub is a box that is used to gather groups of PCs together at a central location with 10BaseT cabling. If you're networking a small group of computers together, you may be able to get 
by with a hub, some 10BaseT cables, and a handful of network adapters. Larger networks often use a thin coax "backbone" that connects a row of 10BaseT hubs together. Each hub, in turn, may connect a handful of computer together using 10BaseT cabling, which allows you to build networks of tens, hundreds, or thousands of nodes.
It is very common to see classrooms operating on this type. It is also slow and transfers 10 Megabits (not Megabytes) per second. The category 3 unshielded twisted pair can be used here but if you are just setting up "CAT5" is recommended to save time and money in the future. This is the most common type used in the school system today and uses unshielded twisted pair (UTP) and RJ-45 connectors (low cost phone wire and jacks) to connect users to a hub. The most common type of topology used is a star pattern, so that each node has its own separate segment. This type is very easy to trouble shoot thus lends itself to the school system where technicians are sometimes few and far between.
| Cable/DSL |
Typically DSL and Cable Modems connect to the carrier on one side and a modem on the other. Essentially you must discover the type of system your school uses to decide how to hook-up from there. This is the only type of system going into the home and thus will be of interest to you for that reason. The cable and the DSL lines are probably going to be 10Megabit since that is faster than any of the providers of this service are at this time.
The college and large school divisions are on optic lines which much improves there speed etc. but will not affect us for our discussions. We will leave this until another time.
| Firewalls Basic security to control the flow of data in and out of a network. For our purposes this is controlled by the server that brings all connectivity to computers outside of the classroom. If this were a home cable or DSL line then you would want to install a firewall (software) that would control what other people on the internet can see in your personal computer. |
Bridges
A bridge device filters data traffic at a network boundary.Bridges have a single input and a single output port.They differ from repeaters in that they can interpret the data they retransmit.
Gateways
A network gateway is an internetworking system, a system that joins two networks together. A network gateway can be implemented completely in software, completely in hardware, or as a combination of the two. Depending on their implementation, network gateways can operate at any level of the OSI model from application protocols to low-level signaling.
Routers
A router is a multiport connectivity device that can integrate LANs and WANs running at different transmission speeds and using a variety of protocols. Routers operate at the Network layer (Layer 3) of the OSI Model. Routers have been slower than switches or bridges because they pay attention to information in Layers 3 and higher, such as protocols and logical addresses. Consequently, unlike bridges and Layer 2 switches, routers are protocol-dependent.They must be designed or configured to recognize a certain protocol before they can forward data transmitted using that protocol.
Switches
A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at layer two (Data Link Layer) of the OSI model.
8. Example of networking cables and their functions, post at least 10 w/ picture.
Twisted pair cabling-is a type of wiring in which two conductors (the forward and
return conductors of a single circuit) are twisted together for the purposes of canceling
out electromagnetic interference (EMI) from external sources; for instance,
electromagnetic radiation from Unshielded Twisted Pair (UTP) cables, and crosstalk
between neighboring pairs.
Coaxial cable-or coax, is an electrical cable with an inner conductor surrounded by a
tubular insulating layer typically of a flexible material with a high dielectric constant,
all of which are surrounded by a conductive layer called the shield (typically of fine
woven wire for flexibility, or of a thin metallic foil), and finally covered with a thin
insulating layer on the outside. The term coaxial comes from the inner conductor and the
outer shield sharing the same geometric axis.
Fiber-optic-communication is a method of transmitting information from one place to
another by sending pulses of light through an optical fiber. The light forms an
electromagnetic carrier wave that is modulated to carry information. First developed
in the 1970s, fiber-optic communication systems have revolutionized the telecommunications
industry and have played a major role in the advent of the Information Age. Because of its
advantages over electrical transmission, optical fibers have largely replaced copper wire
communications in core networks in the developed world.
Unshielded Twisted Pair (UTP)
UTP cable is a medium that is composed of pairs of wires (see Figure 8-1). UTP cable is used in a variety of networks. Each of the eight individual copper wires in UTP cable \is covered by an insulating material. In addition, the wires in each pair are twisted around each other. UTP cable relies solely on the cancellation effect produced by the twisted wire pairs to limit signal degradation caused by electromagnetic interference (EMI) and radio frequency interference (RFI). To further reduce crosstalk between the pairs in UTP cable, the number of twists in the wire pairs varies. UTP cable must follow precise specifications governing how many twists or braids are permitted per meter (3.28 feet) of cable.
5.) Shielded Twisted-Pair Cable
Shielded twisted-pair (STP) cable combines the techniques of shielding, cancellation, and wire twisting. Each pair of wires is wrapped in a metallic foil. The four pairs of wires then are wrapped in an overall metallic braid or foil, usually 150-ohm cable. As specified for use in Ethernet network installations, STP reduces electrical noise both within the cable (pair-to-pair coupling, or crosstalk) and from outside the cable (EMI and RFI). STP usually is installed with STP data connector, which is created especially for the STP cable. However, STP cabling also can use the same RJ connectors that UTP uses.
Patch cable-
A patch cable is an electrical or optical cable, used to connect one electronic or optical device to another for signal routing. Devices of different types (ie: a switch connected to a computer, or switch to router) are connected with patch cords. It is a very fast connection speed. Patch cords are usually produced in many different colors so as to be easily distinguishable[2], and are relatively short, perhaps no longer than two Ethernet crossover cable.
Ethernet crossover cable
is a type of Ethernet cable used to connect computing devices together directly where they would normally be connected via a network switch, hub or router, such as directly connecting two personal computers via their network adapters.
Power lines
Although power wires are not designed for networking applications, new technologies like Power line communication allows these wires to also be used to interconnect home computers, peripherals or other networked consumer products. On December 2008, the ITU-T adopted Recommendation G.hn/G.9960 as the first worldwide standard for high-speed powerline communications[3]. G.hn also specifies communications over phonelines and coaxial wiring.
Plenum cable
is cable that is laid in the plenum spaces of buildings. The plenum (pronounced /ˈplɛnəm/) is the space that can facilitate air circulation for heating and air conditioning systems, by providing pathways for either heated/conditioned or return airflows. Space between the structural ceiling and the dropped ceiling or under a raised floor is typically considered plenum; however, some drop ceiling designs create a tight seal that does not allow for airflow and therefore may not be considered a plenum air-handling space.
Audio multi-core cable
A multicore cable "snake" helps sound engineers to route a number of signals without having to have a tangled mess of individual cables
Used in the audio recording and sound reinforcement fields, an audio multicore cable (most commonly known as a snake cable or just a snake) is a compact cable, typically about the diameter of a coin, which contains from 4 to 56 individual shielded pair microphone cables all housed by one rugged, heavy-duty common outer jacket. Each end of the multicore cable terminates in a "tail", which contains either a patchbay for female XLR or 1/4" jacks or male plugs.
