The main problem with many p2p is that storage and transfer of data can take an alarming amount of time. Because all the local computers within the network have their own database they spend most of their time operating, communication with other computers is constantly moving and therefore most of the time the cables are packed with information. The p2p would have to wait till a suitable space within the cable, etc. appears to send the file. Not good, especially when a music or picture file could be 50MB to 300MB or more, collision is most likely.
WAN
WAN is the second most important form of Network, it stands for Wide Area Network and is used mainly used by multinationals to transfer and acquire data from other parts of the company from aboard. This is good as it saves time and money that would otherwise be wasted on international mail and/or transport to and from the different countries.
A wide area network operates over a system of personal computers (hosts) which link to a communication subnet, which is basically a telephone company, and send messages to and from each other. The messages travel over Transmission Lines (wires or radio waves) and meet at Switching Elements/Router’s (a central computer that will connect a group of the transmission lines) where it is decided which Transmission Line the Data must travel out on. The series of Switching Elements are what form the communication subnet.
A common Misconception is that the Internet is a WAN. The internet is not owned by a single identity, it is a means to connect one network with another. A WAN is owned by a single company and can therefore only be accessed by employees/owners of that company, where as the internet is a connection of all the LAN’s, MAN’s and WAN’s surrounding the world.
Many of the problems associated with WAN is similar to LAN, infection of a virus, the system becoming corrupted or going down, transmissions could not send, hackers interfering and/or stealing vital information. These are just a small list of the problems that can arise.
MAN
Now we have a MAN, or Metropolitan Area Network, designed to cover a city or specific geographical area. This network is more based on company use, designed to join a number of different LAN’s either for a private owned company, or for the public access, owned and run by a telephone company for example. MAN’s are useful for government’s or government agencies. A MAN acts in the same way as a really large LAN, it has the data base of a WAN but is restricted to a specific area.
Many of the problems associated with a MAN tend to also be associated with a WAN, spreading of Virus’, hackers, system going down or being corrupted, etc.
NIC
The Network Interface Card is basically an expansion board (a circuit board which gives added features) that allows a computer to connect to a network. NIC’s come in different formats depending on the type of network needed. They are developed in half size (8bit transmission) or Full size (16bit transmission) which means the can send a small or large amount of communication data.
Topologies
LAN networks are created under different topologies. Topology is how the network has been shaped, since this will affect the amount of Data that can be transferred and the speed at which it will run. There are 4 main topologies – Bus, Star, Ring and Tree.
Bus topology – A single central line in which all the computers connect, this is known as the backbone. Mainly used in small networks due to their ease of installation. Bus networks rely on Ethernet connections, where information is passed down a cable (usually Coaxial or Twisted-pair). Usually information will collide when two or more computers are interlinking at the same time, however Ethernet relies on Carrier Sense Multiple Access/Collision Detection, which is a system that waits for an empty frame within the line to send the information.
Ring topology – where one computer is connected to two other computers either side of it, these also connect to one on either side of them, and so on until all the systems are grouped together. Ring networks are difficult to install and are quite expensive but do offer a larger and faster Data transfer rate, they can also span over a large area. These kinds of network rely on a system known as Token Ring; in the ring of computers empty information frames travel around the ring. When one computer, for example PC1, wants to send information to another, PC7, it will wait for the ring to provide a free frame. Once an empty frame appears, PC1 will write the destination, PC7, then the message (changing the 0’s to 1’s and vice-versa) and then who its from. The message will then be sent through each individual PC until the message arrives at PC7, where the message will be copied and changed to 0’s again, the frame will then continue around the ring until the empty frame appears at PC1 which notes that the message has been received and deletes the information leaving the frame empty for another user.
Star topology – here we have a central computer, known as the Hub, where all information can pass through. Similar to the Ring network, a Computer will wait for an empty frame to send information, however instead of going through all of the PC’s the frame meets in the Hub, and this will decide where to send the frame. A common problem with a Star topology is that the Hub can sometimes become bottlenecked due to data overflow, which slows the network down. Star networks also use Token Ring technology. A Star network is relatively simple to install and run.
Tree Topology – this is a combination of Star and Bus networks, where a group of Star networks interlink on Bus connections. This provides two relatively simple networks to combine creating a bigger data interface. However similar problems can arise with data transfer, due to the lower level transfer involved in a Bus network, and the bottleneck problem found in Star networks.
List of common Topologies =
Protocols
Networks cannot exist without these, one computer would need to understand the format that another computer was using to send and receive information, this is known as the networks protocol. Protocols are defined under 3 elements: Syntax, Semantics and Timing.
Syntax – the way the data is presented, e.g.: the binary data (which runs in 8bits of 0’s or 1’s) will start with the address of the other computer, then with the address of the sender and finally with the information/data that is being streamed out.
Semantics – this basically decides how the binary data should be interpreted, e.g.: does the address mean the route that the data will take, or the final destination where it will be received.
Timing – this has 2 characteristics, when data is sent and how fast it should be sent. Meaning if PC1 can send 100 Mbps (Megabits per second) but PC7 can only receive 10 Mbps then the receivers transmitter will overload and most of the information will be lost.
Protocols also rely on Standards, which means that all of the components must be able to understand each other. The increasing number of computer manufacturing companies produce many of their own parts, some of which may be excellent and some not as much. Where as another company may create this part much better. However, if standards did not exist then chances are that these parts would not work together, because they would not understand each other. Standards make all computer components compatible, which is vital for a network.
The World Wide Web works on a protocol called TCP/IP (TCP = Transmission Control Protocol, IP = Internet Protocol). This basically keeps an eye on what is being communicated between computers (with regard to size and speed, etc) and allows for connection be created through many different machines.
Smaller networks use either NetBEUI (NETBios Enhanced User Interface or IPX/SPX. NetBEUI is designed for small networks that do not need to be routed, used in LAN. IPX/SPX is mainly focused on larger LAN’s like the ones used within a University or Company.
Internet
As previously mentioned the Internet is not strictly a network, but a network of networks. People make their information available to download from the internet in order that other people learn from it. The internet is the perfect file transportation system with regards to speed, however internet data transfer will very much depend on what size modem the computer has. They come in 33.6 kbps (killer bytes per second), 56 kbps and even up into the 100’s (digital modem/Broadband). The 33.6 kbps is very slow, and large data files could take a very long time so send. Meaning that Real Time video streaming would be virtually impossible. However, now internet connection can be digital, which prevents interference with the phone line and provides larger file transfer at quicker speeds, in this situation Real Time is a possibility, but a difficult one. Audio being streamed across the internet works in a similar way to the binary code, the audio is turned into a list of packets, which are sent across the internet to the other computer, which decodes the packets as they come in. As it reads the packets, the audio begins to build up because they are sent faster than they are decoded and this can create a diminished sound, with pops and crackling sounds. However it is possible to create real time, depending on the type of network connection (speed and size) and the size of the RAM within the computer. Real Time could be vital to a musician working abroad, since creativity can strike at any time, Real Time jamming would aid an artist in contacting other members of the/a band and place down all new material and would even manage recording it.
The internet is susceptible to all kinds of problems, hackers would be a music production companies main problem, breaking in through the cable or wireless connection that we use for access to the internet and viewing the hard drive for useful information without permission. Or internet viruses that can delete an entire hard drive can invade simply through an email.
Data Transfer
Stated earlier, computers work in binary, which is what data is. This binary data comes under many different categories (text, colour, speed, photo, etc.), the main ones we are interested in however are Audio and Video. Audio files can be up to 70MB in size, which can cause massive delays in networks such as Linear or Bus, and if a video were to be streamed at the same time the network would effectively lock up. This is where different network topologies would need to be considered. The network computers would also have to manage a large level of data, as mentioned above the possibility of losing vital information between computers is possible if both do not handle the same levels of data in data transfer. A major factor also included in Data Transfer would be the cabling used. Of which there are 5 types:
and all of these cables carry data at different speeds:
For music to be transferred effectively within a Real Time session the best kind of cable would be Fibre Optic, the fastest but also the most expensive.
Evaluation
In my opinion the most obvious choice of network would have to be the Peer-To-Peer, due to its capacity for holding a larger amount of data within each computer. A client-server network working with music files will restrict how many of the files that can be stored within the system. The system would be much slower, however it would be far more reliable and would have a greater list of resources. The best kind of topology would most likely be the Ring topology, because is has a high transmission rate, it would be directly linked to every other computer and could be extended. However, it would be difficult to install, requiring an expert to maintain the system and is expensive to set up. A Star network would probably be better with regards to ease, but the size of the files being used could lock up the central Hub each time more than one computer wanted to stream a conference or send some audio files at the same time. A better idea would be to possibly create a Tree topology with a Ring system instead of a Star, this way all of the computers would be interconnected without the fear of bottleneck and could be lined out via a Linear/Bus connection to another Ring network. Fibre Optic cables would be the best line of media to use due to its capacity to carry 1Gbps of information, more than enough for an audio file and video streaming, also it can be spread across a great area, so networking from two buildings should be no problem, and internet conferencing should also be no problem, provided that Digital modems are used since they have a faster transfer rate.
Conclusion
In conclusion the final draft of my Networking Report could have been much better. With regards to research I found many useful definitions for all of the areas covered, such as LAN, WAN, Topology, etc. However I wish that my research into Real Time innovation could have been more in-depth. My lack of complete technical knowledge meant that much of my research time was spend reviewing how networks worked instead of how they could benefit the user. My research on actual networking, however, was more extensive and has a clear approach for those not familiar with networking.
Further development would involve a videoed experiment with a home network to see how well a Real Time session would react under different circumstances and topologies and I would also research into different projects and peoples opinions with regard to how other people approached it.
I produced my assignment in report format, since this allowed me to almost pin-point the information under headings for each part. This way confusion would not arise with regard to other aspects of the report whilst reading it.
Bibliography
Computer networks, 4th edition – Andrew S. Tanenbaum
Data Communications and Networking, 2nd edition – Behrouz A. Forouzan
Networking for Dummies, 4th edition – Doug Lowe
The Internet Book, 3rd edition – Douglas E. Comer
World's First Low-Latency Videoconferencing System -
Middlesbrough HND Music Technology Networking Aid -
Internet definitions encyclopaedia -
Networking Definitions - and
