IT112(1:30-3:30)5110

Wednesday, February 29, 2012

Exam

Exam Printscreen and the codes..

Codes:
Exam part1

<html>
<title>Exam</title>
<head>
<body background="dragon age2.jpg">
<pre><marquee behavior="slide"><blink> The Story of my Life..</pre></blink></marquee>

</head>
<body>

<pre>

I am Gevy Abueva Jr.,20 years of age and A 2nd year Information Technology student
from University of Mindanao.I currently living at New Matina Gravahan,Davao City.
Im the 2nd of the four siblings of Mr.Gevy Abueva & Mrs.Caselda Abueva.
My friends usually call me "Exca" because of the name that
I complete my day by playing computer games.I read manga's,download movies,
reading articles related to science stuff(Discoveries,Inventions,Origins..
everything that is amazing to know).I loved hangging out with my friends,
meeting and knowing many friends.I believe that if you have many friends
you are good and everybody will respect you as whatyou respect your
friends.For me life is short.That's why i usually do what
makes me happy.I fond of playing computer games such as
Warcraft(dota),war games(strategic games),
COD(Call of Duty)series,flightsimulation games and
listening musics.

<a href="Exam part2.html">Images</a>
</left>

</pre>


</body>
</html>

Exam part2

<html>
<title>Exam</title>
<head>
<body background="green forest.jpg">
<pre><marquee direction="right" behavior="slide"> Images </marquee></pre></head>
<body>

<img src="aw1.jpg" align="left" width=250 hieght="250">&nbsp &nbsp &nbsp &nbsp
<img src="aw3.jpg" align="center" width=250 hieght="250"> &nbsp &nbsp
<img src="aw.jpg" align="center" width=250 hieght="250"> &nbsp &nbsp &nbsp <img src="aw2.jpg" align="center" width=250 hieght="250">
<pre>
<img src="gundam5.jpg" align="center" width=250 hieght="250"><img src="gundam6.jpg" align="center" width=250 hieght="250"><img src="gundam7.jpg" align="center" width=250 hieght="250"><img src="gundam8.jpg" align="center" width=250 hieght="250"><img src="gundam9.jpg" align="center" width=250 hieght="250">
</pre>
</body>
</html>

Tuesday, February 7, 2012

Communicating device in networking(Third Entry)

Network Communication Devices

NIC Adapter:

NIC is Network Interface Card; this is the most important device in building network.These adapters are the most common part of computers which are used in our homes and offices.Nic is also referred to LAN, i.e. is Local area network card. Communication mediums (cables) are attached to this card to build network. This device has unique Mac address. To build network unique IP address is assign to this LAN card to begun communication.In case of developing WLAN, instead of LAN card we use Wireless card. Its functionality is same as simple LAN card; it is just wireless communication device which connects to router for communication.

Routers:

Router is intelligent device which routes data to destination computers. It helps in connecting two different logical and physical networks together. In small network server is connected to router along with clients for communication. With routers network communication is not possible; it is soul of network without which distribution if internet and other network data to entire network is impossible. It works very same when it comes to use wireless network using wireless network router. It performs all functions similarly without using any medium like cables etc.Router uses software known as routing table. Routing table is used to store source and destination address. Major companies which know for manufacturing routers and wireless routers are Tp Link, Cisco systems, Nortel, D link etc.

Hubs:

If we talk about networks on larger scale hub(s) are required to build network. All computers are connected directly to the hub as hub performs as centralized device the network. When data is sent to the hub it broadcasts the data to all the ports of the hub and then it is sent to destination computer on the network. If hubs fails to perform its routine functions it will halt the working of the entire network until it is put back in normal condition.

Switches:

Switch is another important device when we talk about computer network on broader spectrum.It is used at the same place as hub is but the only difference between the two is that switch possess switching table with in it. Switching tables store the MAC addresses of every computer it is connected to and send the data to only requested address unlike hub which broadcasts the data too all the ports. Switches can be considered advance form of hubs.

Gateways:

As name suggests it some kind of passing through to some thing. Interestingly gateways can be software or it can also be device. Gateway device connects LAN with internet. Its basic functionality is to provide security to the network. By using gateways incoming/out going traffic can be monitored for any malicious activity within the network which can be harmful to network integrity.

Modems:

Modems can be of two types. One modem is very common in every computer which we use to connect to internet using our telephone line by dialing to our ISP and the other one is used to connect to DSL. Functions however are same for both types of modems; they are used for modulation and demodulation, they are used to convert analog signals into digital and digital signals into analog so that signals can be travelled on telephone lines.

Cables:

Cables are obviously used to connect communication devices with each other to form network. There different types of cables, commonly used cables are 10baseT/CAT5 , coaxial cable, Ethernet and fiber optical cable. Fiber optical is the most expensive as it enables the data transfer at speed of light. It is costly solution which is mostly get adopted by corporate sector. However in recent developments optical fiber cable is now being used in home networking and also used as medium to connect to internet.

Monday, February 6, 2012

IT 112(Network Topology & Types of Networks)

Network Topology

Network topology is the layout pattern of interconnections of the various elements (links, nodes, etc.) of a computer or biological network.

Network topologies may be physical or logical. Physical topology refers to the physical design of a network including the devices, location and cable installation. Logical topology refers to how data is actually transferred in a network as opposed to its physical design. In general physical topology relates to a core network whereas logical topology relates to basic network.Topology can be understood as the shape or structure of a network. This shape does not necessarily correspond to the actual physical design of the devices on the computer network.

Types of Topology:

Bus Network Topology

LANs that make use of bus topology connects each node to a single cable. Some connector connects each computer or server to the bus cable. For avoiding the bouncing of signal a terminator is used at each end of the bus cable. The source transmits a signal that travels in both directions and passes all machines unless it finds the system with IP address, the intended recipient. The data is ignored in case the address is unmatched. The installation of one cable makes bus topology an inexpensive solution as compared to other topologies; however the maintenance cost is high. If the cable is broken all systems would collapse.

Star Network Topology

The topology when each network host is connected to a central hub in LAN is called Star. Each node is connected to the hub with a point-to-point connection. All traffic passes through the hub that serves as a repeater or signal booster. The easiest topology to install is hailed for its simplicity to add more nodes but criticized for making hub the single point of failure. The network could be BMA (broadcast multi-access) or NBMA (non-broadcast multi-access) depending on whether the signal is automatically propagated at the hub to all spokes or individually spokes with those who are address. In local area networks with a star topology, each network host is connected to a central hub with a point-to-point connection. The network does not necessarily have to resemble a star to be classified as a star network, but all of the nodes on the network must be connected to one central device. All traffic that traverses the network passes through the central hub. The hub acts as a signal repeater. The star topology is considered the easiest topology to design and implement. An advantage of the star topology is the simplicity of adding additional nodes. The primary disadvantage of the star topology is that the hub represents a single point of failure.

Ring Network Topology

Ring topology is one of the old ways of building computer network design and it is pretty much obsolete. FDDI, SONET or Token Ring technologies are used to build ring technology. It is not widely popular in terms of usability but incase if you find it any where it will mostly be in schools or office buildings.
Such physical setting sets up nodes in a circular manner where the data could travel in one direction where each device on the right serves as a repeater to strengthen the signal as it moves ahead.

Mesh Topology

A 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 topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this topology is commonly used for wireless networks.

Tree Topology

Tree Topology is a combination of the bus and the Star Topology. The tree like structure allows you to have many servers on the network and you can branch out the network in many ways. This is particularly helpful for colleges, universities and schools so that each of the branches can identify the relevant systems in their own network and yet connect to the big network in some way.
A Tree Structure suits best when the network is widely spread and vastly divided into many branches. Like any other topologies, the Tree Topology has its advantages and disadvantages. A Tree Network may not suit small networks and it may be a waste of cable to use it for small networks. Tree Topology has some limitations and the configuration should suit those limitations.

-----------------------------------------------------------------

Network Types:

LAN - Local Area Network
-A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet.

WLAN - Wireless Local Area Network
- A LAN based on WiFi wireless network technology

WAN - Wide Area Network
- As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the earth. A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

MAN - Metropolitan Area Network
- A network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN is typically owned an operated by a single entity such as a government body or large corporation.

SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network
- Connects servers to data storage devices through a technology like Fibre Channel.

CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
- A network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus.

PAN - Personal Area Network
- A computer network used for communication among computerized devices, including telephones and personal digital assistants. PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink).

DAN – Desk Area Network
- Is a multimedia workstation based around an ATM interconnect (as shown in the above diagram). All communication between peripherals and even between the CPU and its main memory is achieved by sending ATM cells through a switch fabric.

Tuesday, January 31, 2012

"The Net"

The movie was great and I think of what an Internet can cause to the lives of many people.Like Angela Bennett.. Because of her work and expertise she receive an important file from the commonly used computer security system called "Gatekeeper" sold by Gregg Microsystems.The file was send by her coworker name "Dale" who died because of a navigation error that cause the plane crash. Because of that Jack Devlin ruined the identity of Angela her fingerprints, Social Security number and picture I.D. are vanished and named Angela as "Ruth Marx" who has an arrest record.Angela fights to bring back her identity.She fights and due to his courage and intellectual basis she win by exposing the conspiracy and take her identity back.The films ends where Angela reunited with her mother and the conspiracy exposed..Thrilling..exciting..what can I say..>_<

The movie tells me that don't exposed yourself,your identity,your information in the internet...Remember "Hackers" is one of the many bad guys in the internet society.