In a star topology, each device on the network connects to one central device known as a hub or a switch. Every workstation has a cable which goes from the network card to the hub device, because of that, a star topology requires far more cables than other topologies. Multiple star can be combined into a tree-like structure known as hierarchical star. The hierarchical star allows for high levels of flexibility and expandability.
On of the major advantages of the star topology is that computer can be connected and disconnected from the network without affecting any other system. As a result, it's very easy to add system to or remove system from the network. Another benefit is the fact that, if there is a break in the cable it affects only the system which is connected to that cable, not the entire network. On the other hand there are some disadvantages, for example, if the central device fails, the whole network fails to operate. It can be said, the cables could be a disadvantage, because each devise requires its own cable. In hierarchical network installation and configurations is difficult. However, the star topology is the most wildly implemented network design in use today.
On the other hand, the mesh topology is unique: it requires each computer on the network to be individually connected to every other, creating point-to-point connection between every device on the network. The purpose of the mesh design is to provide a high level of redundancy. If one cable or link fails, data always has an alternative path to get to its destination. The wiring for a mesh topology can be very complicated, as a result mesh networks are not practical in a LAN setting. For example, to connect eight computers in a mesh topology, each computer would have to have seven network interface card, and 28 cables would be required to connect each computer to the seven other computers in the network. Obviously, this scheme isn't very scalable.
Advantages of mesh topology:
Better privacy and security
Mesh topology is robust
Failure of any link will not cause failure of entire network
Point-to-point links make fault identification and fault isolation easy
Dedicated link between nodes ensure optimum data rate and eliminates traffic problem.
Disadvantages of mesh topology:
Large amount of cabling and I/O ports are required
Hard-ware required for each link (I/Q ports) and redundant link increases cost
Difficulty in installation
Difficult to reconfigure
Ring topology
In a ring topology, packet are sent around the circle form one computer. Every computer looks at each packet to decide whatever packet was proposed for it. If not, the packet is going to be passed to another computer in the ring. The installation and configuration of the ring topology is more difficult than other topologies, because if the loop is broken, it would disrupt the entire network. Even if network devices are used to create the ring, the ring must still be broken if a fault occurs or the network needs to be expanded.
Advantages of ring topology:
Lin failure can be easily found as each devise is connected to its immediate neighbour only.
Because every node is given equal access to the token no one node can monopolize the network
Disadvantages of ring topology:
Maximum ring length and the number of devises is limited
Failure of one node on the ring can affect the entire network.
Adding or removing nodes disrupts the network.
Bus topology
A bus topology uses one cable as a main trunk to connect all of the systems together. To set up a bus topology is very easy and it doesn't require additional hardware such as a hub. The cable is also called a trunk, a backbone or a segment. With a bus topology, when signal is sent by a computer, the signal travels in the both directions of the cable length from the sending computer. When the signal reaches at the end of the length cable it bounces back and returns in direction it came from. This is known as a signal bounce. Signal bounce is a problem, because if another single is sent on the cable length at the same time, the two signals will crash and be destroyed and then must be retransmitted. Because of this,at the ends of the cable, there is a terminator.
Advantages of bust topology:
Bus topology is easy to install
Because of backbone, less cable is required
Number of I/O port required is less. Also hardware is reduce
The backbone can be extended by using a repeater
Cost of the network is low
Disadvantages of bus topology:
Heavy network traffic can slow a bus considerably
Difficult reconnection and fault isolation
Difficult to add new node/devise
Signal reflections at the tabs can cause degradation in quality
Failure of backbone affects failure of all devices on the network
NAPISATI CONCLUSION
Part B
NAPISATI INDRODUCTION
Firstly, as it shown on the diagram, there should be a central stock, which will keep the all products, such as food for the restaurant and the shops. In each shop, there will be installed one computer, also restaurant will have one as well. In the central stock, will be installed 3 computers and every computer will be connected with each other. Those computers will be desktop PC's; about them we can see more information in the spreadsheet.
Secondly, the internet provider should be found, who will give the fix IP address, which will be used by people who work in that company. Presentation of the company should be attached on the internet (on the server of provider) and it should be seen 24 hours per day and 365 days in a year. Also it should be guaranteed by Internet provider, that the application will be protected with some programs from the hackers. What's more, the Internet provider must offer the certain speed. This package is called the web hosting. This way is better than to try everything on your own, because nobody can guarantee that you will be able to have internet 24 hours in the central stock where would be installed the main computer and that your presentation will be protected. So like this, with internet provider you do not need to worry about anything, they are there to take care of everything.
In the presentation, one part will be assigned to the people who will be working it the central stock, the shops and the restaurant. That part of the presentation will be protected, what means the each worker will be given a username and password and just with that information they will be able to go to that part. Now, depends of you, the usernames and the password could be given to the other shops which would like to buy some products from you.
The software which would be great for this job must be able to cover the all request from the needed of the company. That means, the computer in the central stock should have application, which can give the balance in the central stock, the balance in the restaurant and the shops at any time. You have to make sure, that at least one till from the shop is connected with the computer in the shop. So, every time when costumer buys something and when the worker scans the bar code, it should immediately be moved from the balance in the stock. Also, when the balance in the shops and the restaurant is going down or when it is under the certain point, the application would send something like the warning message to the computer in the stock and the computer in the central stock to inform them. As a result, the workers from the restaurant or the shop would order some products which they need, so when the computer in the central stock get the orders from them and when is it prepared it would be passed to the drivers who would drive it to the already known places.
The person, who would be using the main computer in the central stock, would be someone who uses the most that application. That user would know about balance in the shops, restaurants and central stock, as well he would be the one who will always update the balance in the application, which is as I already said on the server of the internet provider. On the other hand, the workers in the restaurant and the shops would just be interested in their balances and the balance of the central stock. In some case, they could know about the balance in the other shops, so if they need to get something immediately, they could order something from them or send the customer to other shop, but in my opinion that's not too much important. Finally, the connection between the she restaurant or shops and the server doesn't need to be strong, because they would not share big information, it would be more like textual. The software should be optimal not too good and expensive, but also not too bad and cheap.
Software
In this part of the assignment, I would like to give description about the software, which would be suitable for the job. The name of the software is DataLab PANTHEON-Goods.
Receivables
Different types of invoicing(ability of retail and wholesale in various currency)
The program gives possibility that, each time when some of the product is sold, it has been automatically removed from the central stock. That means, every time when the bar code is scanned on the till, it has immediately been moved from the status in the local stock or wherever it is bought.
Handling all necessary prints out connected with the goods from the central stock
In case if some other company or the shop would like to buy some of products from the central stock, it would not be necessary to give invoice every single time when they get it. So, the program the program has an option to keep the history of their orders and at the end of every month, invoice would be sent to them based on that history.
In case that some of the items have been sold in some of the local stores, receipts would be made automatically on the till.
Option to follow up purchases from the certain location (store) or the certain customer, during certain time period. On the other words, to create statistics of the payment and the purchases from the certain customer.
There is an option to handle the documents on the levels of departments and the level of the cost centres.
Possibility of paying the orders at different times until the total is reached or better said, given opportunity to costumers to pay their order in a few months. So, amount of money which they owe could be divided.
Rebottling monitoring status of local stocks-person who is working in the central stock has possibility of continues monitoring of the status of the local stocks .That way we have opportunity to react immediately when there is a shortage of the goods on the local stock and need to be delivered from the central stock it is necessary to fill up and need of the local shops.
Inventory Count and Price Changes
The program gives an option that in every moment, at any time, the status of the supplies in the central stock could be monitored and printed in proper format.
After income of new items in central stock or stocks in local shops it is very easy to update status of those items in program.
There is an option which gives opportunity to a worker in the central stock to help him to know about deficiency and excess of inventory.
Reports
Report of central stoke flow and its current status-the program can inform the workers about central stock flow and current program
At the end of certain time period, workers in the central stock could get a report which informs them about goods those are sold and remaining goods on the stock.
Gives opportunity to people who work in central stock to know at any time about current status of the goods, the goods which are available to be sent to the local stock or restaurant and the minimum status in the central stock.
Report based on different categories.
