DanBurden's Interactive Blog

Thursday, 3 May 2012

Communication Protocols

Communication Protocols

Comprehensively explain protocols, devices and methods used in digital communication systems with elucidated examples and consistently using subject terminology correctly

Introduction

In this essay I will be explaining the uses of communication protocols as communication protocols act as the rules and restrictions for digital communication. A protocol is in charge of enabling devices to communicate with each other by agreeing on formats. There are several different types of networks which have their own features and technologies to enable them to establish a connection. Here is a list of some of the types of networks; PAN (Personal Area Network), LAN (Local Area Network), MAN (Metropolitan Area Network), (WAN) Wide Area Network. Each of these types of networks has their own advantages and disadvantages.

The Internet

The way in which people are able to communicate over the internet is by the implementation of several protocols. The protocols such as “IP” (Internet protocol) enable users to communicate with other users computers. IP is tasked with setting the correct destination for each packet. The creation of the internet by Tim Berners-Lee has given birth to several different ways in which we communicate in modern society. One of the most common used platforms in which to communicate these days are social networking sites such as Facebook and Twitter. The birth of these platforms has resulted in people all over the world being able to communicate with people the other side of the world very easily and free of charge. Social networking sites such as Facebook enable users to post all text messages, photos and videos to a digital personal space. Everything posted on Facebook would then be able to be viewed and commented on by yours friends. The popular social networking sites such as Facebook and Twitter can also be used on most new portable devices such as phones and also Internet TVs. As mobile phones use 3G this essentially enables a user to be connected to the internet all of the time.

How emails are sent

The way in which emails are sent is by sending an electronic message from one to another server. There are various protocols which handle various different tasks to complete the transport of a message. For example SMTP is a protocol which manages the layout of email an email while the protocol POP3 manages the authentication of usernames , email addresses and password. The MUA (Mail User Agent) is in charge of retreiving an email and manipulating the email so that is ready the read by the user.

Instant messaging

Instant messaging is a communication system which enables users to communicate with other people connected to the internet in real-time. The social networking site Facebook has an instant messaging service which enables Facebook users to speak with their friends. Instant messaging is free as you only really require a wired or Wi-Fi connection to communicate. The disadvantage of instant messaging is that because it’s so widely used it’s often used as a platform in which to send computer viruses or steal sensitive information which you have posted to someone. Before instant messaging people would spend lots of time on the telephone which would of cost a lot of money. Instant messaging acts as a cheaper and more effective way in which to communicate with friends and family.

Web 2.0

The internet has enabled the birth of various other platforms in which we use to communicate with other people

Popular communication services which can be found on the internet are forums which are basically a discussion board on various topics consisting of a community which have registered to the forum. An example of forum is “Empire Movie Magazine Forum” which consists of topics about movies and the community would likely be film fans.

One of the most popular uses of the internet is Social Networking and the most popular social networking sites currently are Facebook and Twitter which basically acts a digital place in which you can communicate and socialize with your friends. Facebook is also a platform in which companies can advertise their products to their target audience which is done by analysing the data which the user has inputted to their profile.

The internet also acts a platform in which to conduct business as online businesses such as Ebay and Amazon act as a popular choice for consumers to buy from as its most of the time cheaper and more convenient.

The World Wide Web acts a huge platform in which an individual can obtain information on pretty much anything. The World Wide Web isn't as restricted as the media that you see on TV so user-generated content can be uploaded onto sites such as YouTube which wouldn't be allowed on national TV. This platform acts as powerful way in which to relay information to the world.

CoIP

CoIP stands for conferencing over internet protocol and is a protocol which is used when more than two computers want to communicate using video and audio transmission at the same time. It’s a protocol which would be used when using software such as GoToMeeting which is video conferencing software.

3G is the 3^rd generation in network communication technology as this enables mobile devices users to reach speeds a lot higher than previous generations as well as broadened security. 3G essentially enables all users to reach speeds of 10 mbps and are pretty much guaranteed a connection 24/7. Popular websites are often design a mobile interface for their website to enable their website to be easy to navigate on weird screen resolutions.

One of the advantages of 3G over Wi-Fi is that it has a larger range than Wi-Fi as a Wi-Fi connection can only be established if the device is within 15 meters but one of the advantages of Wi-Fi has over 3G is that it can establish a faster connection speed in most cases. Wi-Fi is also a lot cheaper than 3G and it also consumes a lot less battery life than 3G.

Bluetooth

Bluetooth is a close range wireless technology which has a high level of security meaning that a security code would need to be inputted before any communication can be inputted. Bluetooth can be found on devices such as mobile phones and wireless headsets. On my previous course I created a security robot which was programmed to relay a detection message to an external device and the way I did this was to establish a connection via Bluetooth. Bluetooth is more energy efficient than Wi-Fi because it require less bandwidth to establish a connection so it’s a perfect network to use on devices such as wireless mice and keyboards as it consumes less battery life than Wi-Fi would as these wireless devices would likely require rechargeable batteries.

GSM (Global System for Mobile Communications)

2G GSM is a technology which was created a replacement to 1G and has various advantages over 1G such as the network is a lot more stable than 1G as well as it uses digital signals instead of analogue which 1G uses. The quality of signals isn’t hindered that much inside buildings. GSM operates pretty much everywhere on the world so there aren’t any compatibility problems when travelling around the world apart from countries such as Japan. The disadvantages of GSM are that the signal can sometimes be disrupted by electronics. GSM is a shared network so in large populated areas you can experience a great deal of network lag as a result of lots of people using the network. GSM cannot be used on airplanes because the GSM signal can cause disruption to other electronics such as an airplanes radio. The advantages 3GSM have over 2G that it’s completely worldwide.

VoIP Protocols

Voice over internet protocol is a way in which people are able to communicate over the internet using a telephone which is free of charge. The type of data which transmitted when you talk on a phone is analogue audio signal which isn’t recognised on the internet so the VoIP converts the signal into a digital data which can be recognised. An analogue signal is a constant, always changing signal while a digital signal is a whole number value which can recognised by a computer.

The internet’s packet switching technology is used to establish a phone service between two computer systems. The transmission cost of an average phone call is only 128kbps which is hardly anything these days because of the growing implementation of fibre optic broadband.

The three most common services of VoIP currently are ATA (analogue telephone adaptor) which basically enables a normal telephone to use the VoIP service as ATA is basically an analogue to digital converter which enables it to work correctly.

Protocols

There are various rules that protocols that are put in place to manage the communication between computers on a network. These rules include guidelines that regulate the access method, topologies, types of cabling, and speed of data transfer. Different protocols offer different speeds and range so this reflects in the topology in which it is used in. For example longer ranged topology would use a fast Ethernet topology which uses a fibre optic cabling.

Protocols between networks are designed and illustrated and layered in the OSI model. Different network methods have their place in the OSI model The LAN protocols can be put under the physical and data link layers of communications over various LAN media such as Ethernet wires and wireless radio waves. The WAN protocol is for the lowest three layers and defines communication over various wide-area media, such as fibre optic and copper cables.

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Protocol	Cable	Speed	Topology
Ethernet	Twisted Pair, Coaxial, Fibre	10 Mbps	Linear Bus, Star, Tree
Fast Ethernet	Twisted Pair, Fibre	100 Mbps	Star
Local Talk	Twisted Pair	23 Mbps	Linear Bus or Star
Token Ring	Twisted Pair	4 Mbps - 16 Mbps	Star-Wired Ring
FDDI	Fibre	100 Mbps	Dual ring
ATM	Twisted Pair, Fibre	155-2488 Mbps	Linear Bus, Star, Tree

Importance of Network Protocols

Network Protocol is needed because the message or data sent by networks have to reach their destinations by going through different networks of different structure and different platform. Network protocols are performing the duty to make our sent data compatible to the new networks. They also help create a standard of communication, such as TCP/IP. This is used to enable different operating systems to talk to each other over a network. So the main significance of the network protocols is compatibility of networks over the internet.

Network Protocols and network topologies

http://dan-burden.blogspot.co.uk/2012/05/network-protocols.html

OSI Model

The OSI model is the standard architecture for modern Communication systems. More on blog:

http://dan-burden.blogspot.co.uk/2012/04/osi-model.html

Network Devices in Weymouth College

Wednesday, 2 May 2012

Network Protocols

Introduction

There are several different types of networks which have their own features and technologies to enable them to establish a connection. Here is a list of some of the types of networks; PAN (Personal Area Network), LAN (Local Area Network), MAN (Metropolitan Area Network), (WAN) Wide Area Network. Each of these types of networks has their own advantages and disadvantages.

Personal Area Network

A personal area network normally uses equipment and technologies which are used by one person and enable other systems to use the devices on the network an example of the type of devices which would commonly be used on this network are printers.

Local Area Network

A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. Local area networks are mostly made up of cheap hardware such as Ethernet cables and network adaptors. A local area network can be made up of a minimum of two computers while large LAN’s can include thousands of computers and then they can be divided into separate logical groups called subnets. The internet protocol called “Class A" LAN can in theory accommodate more than 16 million devices organized into subnets.

Wide Area Network

A wide area network typically consists of two or more local area networks. Computers connected to a wide-area network are often connected through public networks, such as the telephone line system or satellites.

Protocols

Protocol	Cable	Speed	Topology
Ethernet	Twisted Pair, Coaxial, Fiber	10 Mbps	Linear Bus, Star, Tree
Fast Ethernet	Twisted Pair, Fiber	100 Mbps	Star
LocalTalk	Twisted Pair	23 Mbps	Linear Bus or Star
Token Ring	Twisted Pair	4 Mbps - 16 Mbps	Star-Wired Ring
FDDI	Fiber	100 Mbps	Dual ring
ATM	Twisted Pair, Fiber	155-2488 Mbps	Linear Bus, Star, Tree

Importance of Network Protocols

WAN wide area networks connect to organisations which are located nationwide. A wide are network would likely be used to connect smaller local area networks to other Local area networks which may be located further away for example in another country.

MAN metropolitan area network. Authorities and finance would use this type of network. This type of network would typically be used to connect separate offices around a city with extremely fast transfer speed.

PAN personal area network would use network medians such as Bluetooth. Personal area networks typically involve a portable device which has internet connectivity such as a PDA. You can use these networks to transfer files including email and calendar appointments, digital photos and music. The range of a PAN network would typically only over the distance of 10 metres.

There are many useful services that are featured in networks which include enable schools and businesses to share resources with all the computers connected to the network. This is perfect for businesses which want to relay important files and documents to all the employees with ease. The way in which this is done is simply by uploading files to a central server which can then be accessed by everyone on the network. Without this feature it would be considerably harder and take considerably longer for businesses to get files to employees. This feature is also perfect for businesses which are looking to save money by using fewer resources such as paper because files can simply be completed on a computer then saved and sent through the network without needing to print the documents.

Networks also have the capacity to provide their own private email service. This is perfect for businesses and schools as it enables an email system to be created in the internal network which ultimately enables you to send emails to users in the network. An example would be to have a boss of a business send a mass message to all employees without needing to stage a meeting or print out loads of pages. This saves money, easier and consumes considerably less resources.

Telecommunication services are useful in networks as it enables businesses to implement other connection mediums such as wireless technology so that employees can access the network in a remote or mobile location as long as they are in the network range. For example they can use laptops anywhere in the building without being hindered by the length of their network cable. Wireless computers can also be linked together which is useful if a computer needs to be controlled remotely by another computer for maintenance needs.

This way of connecting the business together makes the network pretty secure from external intrusions as well as enabling the business to safely relay information and communicate at a considerably lower cost that if it was done other ways.

Thursday, 19 April 2012

Network Devices

The Weymouth college network is mainly in the format of a local area network but is divided into three separate locations. These networks can be found in Weymouth and Dorchester. They all have different methods of transferring data for example one method Weymouth college utilizes is by transferring microwaves. The tool it uses to enable the transferring of data is simply by using wireless mediums which are located all over Weymouth College in the form of Hubs or switches.

The layout of the Weymouth College would classify it in the category of being in the star topology. Different places in the college use different mediums for example as the primary Hub is located in the Holworth building it then enables physical wires such as fibre optic cables or Ethernet cables to be connected to the desktops in that building this would ultimately result in a vastly higher connection speed in the holworth building than any other building around the college which have to be connected via wireless mecum. For example the fibre optic cable has the capacity to transfer up to 1GB speed per second, while the wireless medium is restricted to 54mbps.

The fibre switch backbone which is the main server for Weymouth College divides its speed evenly throughout all the buildings. Each building of the college has a node in it which collects the data and then passes it onto the main node. The reason it odes this and doesn’t go straight to the main node is that it stops the network form receiving too much traffic which may crash it. `Peripheral devices such as printers are connected via Ethernet cable. In the learning gateway the computers are positioned in circles around many tables around the room. The desktops are all located to the closest printer. There are locations in the college which are remote and are unable to receive a wired connection to the main server therefore they use the following mediums Microwave, ADSL Broadband and Leased Lines.

The Star topology is perfect for the college as its very error tolerant. For example if a building has an error this wouldn’t affect the other buildings. The only possible way the all systems could go down would be if the primary switch goes down. The star topology also has many other advantages such as if there is a fault it is quite easy to troubleshoot because the topology’s layout isolated and centralises all the devices. An error which occurs quite a lot on the Weymouth College network is when there’s a lot of traffic from one area using a large quantity of bandwidth this can cause significant slow down to other areas demanding the bandwidth. A simple occurrence of this would be everyone tried signing in on a machine at the same time this would cause significant slow down for everyone therefore possible causing it to take 5 times as long to log on that it normally would, another disadvantage of this topology is that settings up all the complex wiring can be very costly, significantly more than other topologies. The star topology is the best topology to use in a college or school environment as other topologies such as the ring topology has many disadvantages such as errors are very hard to identify and also if there’s a break in the main cable then it would cause the shut down of the whole system. Adding these both disadvantages together would result in the network being down quite often and being down for a long duration. Another advantage of why to use the star topology for a college environment is that it’s very east to expand so if the college wants to construct new buildings or facilities which they want to have network access, it would be done with little stress and with no danger or damaging the system.

Weymouth College uses a Cisco Firewall to enable the college to keep all of the internal resources from being accessed by external intruders. Most of the ports on the Weymouth College server are blocked excluding port 80 which enables users to access the Weymouth college webpage. Which a user can sign into which then enables users to have access to resources for their course.

Students who are connected to college network would be able to browse the internet although there is software which blocks certain sites which the college deems to be inappropriate for a learning environment. This is also to stop the college network to be hit with a virus.

There is also another function on the college network called “Packeteer” which enables the network admin to control the whole network traffic as this would enable faster speeds on the network and it stops people using the whole network to themselves for example if two students were downloading lots of files this would normally cause slow down for the whole network but on this network it wouldn’t cause slow down. This is because that user would only be given about 1% of the total bandwidth.

The Star topology uses the regular LAN Ethernet protocols which consists of the some Wide area network applications and manages the maximum packet size. The college network uses Microsoft Outlook but has been customised to the WAN so that you can send emails to other students or lectures the network identifies the students email by a student id which is given to all the students. The College email system works in a way which only enables traffic to flow into the server and back out again so if a user hacked the E-mail they wouldn’t be able to access the main internal servers. So the only people who can obtain information from the internal server would be people who are on a machine within the network. The computers on the internal server start lower on in the network topology while external computers start a lot higher for example. Computers on the internal network have do go through the web proxy and many of the hubs and switches. As a result this takes the external users through a different path in this case a path which restricts the access to the network.

OSI Model

OSI Layers Protocols

The OSI model acts as the standard architecture for communication systems in modern society. The OSI model standardises the whole inter-communication process by dividing it into the seven layers each layer in the OSI model has their own individual tasks to complete.

The main aim of network layers is to solve a complex problem into smaller pieces and hiding information as it may be easy to hack data which is stashed in a single place. The OSI model is also very important because the OSI model provides a universal set of rules that make it possible for various manufacturers and developers to create software and hardware that is compatible with each other.

Layer 1: Is the physical layer which manages the electrical impulses and conveys light or radio waves through the network at mechanical and electrical levels. So it basically manages the physical hardware such as defining components such as cables and cards. The first layer of the OSI model is primarily concerned with media, the actual physical wiring that connects a network; and with the standards for a particular media the physical later is concerned with transmitting raw bits over the media. This layer is important because it is the only layer which actually operates physically. Although as a result this layer doesn’t have any idea on the actual contents of the messages. This layer is closely linked to the 2^nd because physical components such as an Ethernet cable but the actual maximum length are closely linked to the message format which is managed by the data link layer. At this layer data is transmitted using types of signaling such as electric voltages and pulses of infrared. This layer uses network devices such as repeaters which basically repeat a signal to a port from another port. The repeater which is located in this layer is then able to expand a network way past the distance limitations. That’s one factor which makes this layer so important. This is also an important layer because this is where the formatted data exits the network cable.

Layer 2: Manages the data link where data packets are encoded into bits. This layer also cleans up transmission protocols and also handles errors in the physical layer. It also manages the data flow. This layer although is divided into two layers which are the media access control and the logical link control. The media access manages how a computer on the network gains access to the data stored there and the gives permission for it to be transmitted. The error checking layer 2 uses is Frame checking sequence. The data is then taken up to layer if it passes the (FCS). This is an important layer because it ensures the data is error free by the time it reaches the network layer.

Layer 3: This layer manages the network part of the OSI model. So it primarily manages switching and routing technologies, but also handles error handling, congestion control and packet sequencing. So this layer is very important when it comes to transferring data to external sources. Layer 3 protocols include IP which stands for internet protocol. This layer is also responsible for compressing larger packets into smaller packets where it is then moved onto layer 4. This layer is important because it allocates unique addresses to nodes. An example of a piece of a hardware which uses the IP protocol is a router which allows Local area connection to connect to WAN. This layer uses the IP information to then determine the best possible transmission path between the source and target. This layer is important because it obtains an IP header

Layer 4: This layer is the transport layer which provides transparent transfer to end systems and hosts. This layer is crucial because it ensures complete data transfer. This is the middle layer but does have much in common with the higher layers such as 5, 6 and 7 it relies on the lower layers to manage the process of transferring data. This layer has to be modernizes because as computers now mostly multitask so has to handle a number of different software applications which are both sending and receiving data. The transport layer must keep track of what data comes from each application. So that is can be sent in one flow to the lower levels. Another protocol this layer has to undergo is the reassembly of broken packets which may have been corrupt as a result of the editing and movement in layers in which it had to go through. This layer is important because it ensures all the data is in the right sequence and error free. It uses flow control to enable that the information is sent with the correct properties. This layer obtains information linking with the TCP header which stands for transmission control protocol.

Layer 5: This layer which is called the session layer has important protocols such as managing and terminating connections. So this layer basically sets up conversations between applications at each end. This layer manages the transaction sequencing. This layer also keeps a log and notification if a message fails. A completed conversation will then enable the data to be moved up to layer 6. The layer is used to ensure the connection between two nodes and to make sure it remains maintained until it is disconnected. This layer is important because it manages the security of the session. Checksums will be used during data synchronization to ensure all the data reaches its destination without error. This layer is important because it sets up conversations between applications and then enables it to be sent to layer 6.

Layer 6: The presentation layer is unique from the others because it translates data into a network format but also has the capability of doing the opposite. It transforms data into a form the above layer which is the application can accept. It formats layers so that it can be sent over a network so you don’t have to worry about compatibility errors. Here is an example of some formats which would be converted. GIF,HTML and JPEG. This is important because the data needs to be in a form of information which is presentable for the application layer. The presentation layer is also in charge of the security of the data and the way it does this it encrypts data. Encryption is when data is locked in a sequence which can only be known by the user as it could have millions of possible combinations. All data stored here is either in graphical, video or sound format.

Layer 7: The top layer known as the application layer manages end user processes. It identifies several factors such as which you are communicating to and the quality of service. It keeps in mind privacy and any constraints on the data. Everything here is application specific so also provides services such as file transfer and e-mail. This is an important layer because it enables application to access the network, which is needed because it’s not executed by any of the other layers. The application layer also has to manage syntax rules. The application although isn’t the actually application but it’s the layer which provides the services. This player is also responsible in finding what resources are required. This layer will also enable your computer to communicate with other computers at a high level. When this layer has executed its tasks correctly it will then be able to present the data in a browser.

Wednesday, 18 April 2012

Gl Basic Progress

During the easter holidays I implemented a scrolling background. I believe this change improved the presentation of the game massively. My next step would be to try and put my game on an android phone so I can see how well it plays on a touchscreen and I will then adapt my game to any problems I see.

Action Script Platform Game

During the easter holidays I began work on my action script 3 platform game. I was able to create a moving character with animations. I was also able to create platforms which the character can jump onto. The next step would be to create enemies and a background. I will also try and implement sound effects and music.

Friday, 23 March 2012

Adobe Flash As2 Screen Scaling

Today I used flash to scale a website to fullscreen I also implemented some buttons which would enable me to create a user interface in any future projects I create. I learnt that I will initially need to crop an image in photoshop before using it as a flash background because an image can become strectched is not sized correctly.