Section 1 - M1

Unit 9 - Computer Networks                                                                          Elmi Awil

Peer-To-Peer Network

 

 

 

 

 

 

 

 

 

 

 

 

 

Peer to peer network is an infrastructure which ensures that all devices on the system are treated as equals sharing a wide range of network services between each other. There is no centre to peer system, but some devices may offer greater services than others. This ensures that users of many different computers systems can join a simple network infrastructure.

Peer networks are found in many situations. Four common examples:

·        A private networks created at home to share an internet connection

·        Some network gaming clans (teams who play networks games together)

·        A small network in a company with fewer than ten computers

·        File- and resource-sharing like BitTorrent, which are applications designed to ensure that file sharing occurs.

 

The advantage of peer-to-peer system is their technological simplicity – they are easy to install, operate and manage. But their ability to scale (expand growth) is restricted – it is accepted in the in the networking industry that 20 workstations is the reasonable maximum.

 

File sharing systems overcome the issues of scale by providing your computer with a client which reports your files to a server which manages the peer connections.

All operating systems since the early 90’s have offered a peer-based element. It is now possible to create peer connections with all operating.

 

The advantages of peer-to-peer over client-server include:

• No need for a network administrator
• Network is fast/inexpensive to setup & maintain
• Each PC can make backup copies of its data to other PCs for security. 
• Easiest type of network to build, peer-to-peer is perfect for both home and office use.

But the disadvantage for peer to peer is Another disadvantage to end users can be that viruses are available on the majority of peer to peer programs and usually the virus is masked as a music or video file this in turn can severely damage computers and in some cases the computer will not turn on.

Client-Server Network

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

As opposed to the peer-to-peer system, a client-server system has central control and management, which allows a considerably larger number of devices to become part of the system.

 

Examples of client-server systems are wide-ranging and diverse. Some examples include:

·        Web server being accessed by many clients (the client being the web browser)

·        Many online gaming systems

·        The file server at work or your centre of learning which is accessed via Windows Explorer.

·        MSM, Skype and other communication systems.

 

To operate, a client-server system must have different operating systems and computers for the client and the server. The client can be implemented on most standard operating systems. It can be very small in software terms but must allow network or internet access. It can run on a lower-specification computer system.

 

The server must run on a network operating system (or one which supports multiple connections and processes). It may need a system with a higher-specification computer (multiple processors, more memory, and larger hard drives) and it needs a better quality network/internet connection as it will be busier.

 

Client-server allows the installation of anti-virus on a dedicated server, this means that all stations that are connected to that server are protected against viruses. In peer to peer, each station has to be installed with the anti-virus. Because peer to peer allows the sharing of files it is possible that some files are infected and because anti-virus is not as effective on peer to peer, the virus would get in and disrupt the network.

The disadvantages for client-server network are that one, server can get overloaded, generally more expensive than the peer to peer and that its more difficult to set up than the peer to peer.

 

 

 

 

 

 

 

 

 

Mr Udeafor 

Section 1 - P2

Unit 9 - Computer Networks                                                                                               Elmi Awil

Section 1: P2 – Add separate information sheets/leaflets/web page that describes why different network standards and protocols are necessary. Your examples should be realistic.

Different protocols and network standards are necessary for different systems to interact with each other. Protocols are used to communicate, authenticate and used for error detection and recovery.

The protocol allows computers to communicate with each other by setting the "ground rules". It allows for data to be retrieved back and fourth from computers.

TCP/IP (Transmission control protocol/internet protocol) is the most common protocol, and is actually two distinguished protocols, joined together (TCP (Transmission Control Protocol) and IP (Internet Protocol). Every protocol does a various "job". Others, such as FTP (File transfer protocol) are used for particular duties to be performed.

Network Standards are entirely separate, although related to each other. The network standard is the fundamental rules and regulation networks need to be abide by in order to run such as the types of certain cables, the amount of data they can transfer in order for the network to run efficiently.

This is usually done to ensure backwards compatibility and compatibility from vendor to vendor. If each company made its own "protocol standard" and didn’t allow it to talk with another’s "protocol standard". That company would become very rich by being the sole provider, or out of business because nobody would buy it because of its uniqueness.

To conclude standards and protocols are what allow different computers, from different companies, running different software to communicate with each other.

Section 1 - P1

Unit 9 - Computer Network                                                                                             Elmi Awil

Section 1: Networks

P1

Produce a series of information sheets or leaflets or small set of linked web pages that describe each of the different types of networks available and how they relate to particular network standards and protocols.

 

Area networks all cover different boundaries of network topologies, the difference between them are that they have other terminologies from each other. These Area Networks are WAN, LAN, WLAN, PAN, ATM, MPLS. The protocols which are used by the above area network are TCP/IP, AppleTalk, UDP, 802.2, 802.3

 

BUS Network

 

How does it work?

BUS network 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. The Bus Network uses a very common network protocol which is called Ethernet. The bus network topology uses the Ethernet protocol.

 

Advantages        

      Easy to install

      Cheap to set-up

      Easy to manage and extend

      Less expensive than the other topologies

      Easy to spot the failures in the network.

 

Disadvantages

      Both ends of the BUS need to be connected to a PC or machine to work.

      If there is a problem with the cables, the entire network breaks down.

      It works more efficient with fewer nodes.

 

 

STAR Network

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

How does it work?

In star network each node is connected to a central main hub by one single cable, so the internet access is quite fast given the fact that the signal input doesn’t have to go through other nodes, which means the signal is direct from the hub to the node. The star network uses the Fast Ethernet, ATM and Local Talk protocol.

 

Advantages

      Star topology prevents the bundle of data packets through an excessive number of nodes.

      Each device is naturally isolated by the link that connects it to the hub. This makes the isolation of the individual devices uncomplicated and amounts to disconnecting each device from the others.

      Easy to detect faults and to remove parts.

      No disruptions to the network when connecting or removing devices.

 

 Disadvantages

            If the central hub breaks down the whole network collapses.

            High dependence of the system on the functioning of the central hub.

 

Extended Star Network

 

 

 

 

 

 

 

 

 

 

 

 

 

How does it work?

Instead of connecting all devices to a central unit, we have sub central devices to a central unit; we have sub central devices added to the mix. This allows more functionality for organisation and subletting yet. The extended star network uses the fast Ethernet protocols.

Advantages

            Better for larger and more complex places or environments.

 

Disadvantages

      Can be useless if used for an entire building.

      If one sub central device breaks down all the devices connected to it breaks down as well.

 

 

 

 

 

Hierarchical/Tree Network

 

 

 

 

 

 

 

 

 

 

How does it work?

Similar to a ‘Star Network’, except it doesn’t use a central node. The hierarchical or tree network also uses Ethernet and ATM.

Advantages

      Popular

      Easy to set up

      Cheap

      Creates more redundancy than a BUS Network.

      Better suited for small networks.

Disadvantages

      If the device that is on top of the chain fails, considers the entire network down.

 

 

 

 

 

MESH Network (Full)

How does it work?

The full-mesh topology connects every single node together.

This will creates the most redundant and reliable network around- especially for large networks. It any link fail, we (should) always have another link to send data through. The mesh network uses is Ethernet as well.

Advantages

·   Secure and (should) always work

 

Disadvantages

·   Highly expense

·   Impractical

·   Cannot work over a number of sites

 

 

 

 

 

Ring Network

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

How does it work?

A ring network is a network topology in which each node connects to exactly two other nodes, forming a single continues pathway for signal through each node – a ring. Data travels from node to node, with each node along the way handling every packet. The protocol that ring network uses FDDI (Fiber Distributed Data Interface). Ring network also uses token ring network protocol which uses twisted pair cabling. The advantage is that it is a cheap protocol to purchase and set up.

 

 

 Advantages

-          Since there is no end on a ring topology, nolerminators are necessary

-          Does not require a central node to manage the connectivity between the computers.

Disadvantages

-          One malfunctioning workstation can create problems for the entire network.

-          Communication delay is directly proportional to number of nodes in the network.

 

 

Mesh (Particle) Networks

 

 

 

 

 

 

 

 

 

 

 

 

 

How does it work?

Like the full mesh, only we don’t connect each devise to every other devise on the network. Instead we only implement a few alternate routes. A mesh network in which every devise connects to every other is called a full mesh. A partical mesh network also exists in which some devises connect only indirectly to others. The protocol that the mesh (particle) uses is Ethernet and ATM as well.

 

Advantages

-          secure and (should) always work

 

Disadvantages

-          highly expensive

-          impractical

-          cannot work over a number of sites

 

 

 

Mr Udeafor