Advantages
- It corrects the errors by itself
- Can find the problems easily
- Its faster than 10Mbps Ethernet
- Allows more workstations on network than Ethernet before performance decrease
- Its very reliable
- It is easy to expand
- Its has equal access for all the user
- Each workstation has full access speed to the ring
- No collision
- No terminators required
Disadvantages
- Failure of one computer can affect the whole network
- Adding and removing the nodes can disrupts network
- Costly Wiring
- Expensive Adaptor Cards
- Lost of token means cant communicate
Details of Token Ring Topology
Ethernet Cable Summary
Mesh
A computer that is directly connected to all other computers is known as mesh. A mesh is not common on LANs, it is most often used in WANs to interconnect LANs. Mesh is “Fault Tolerant”. There are two types of mesh; full mesh and partial mesh. Full mesh is usually each node is connected directly to others. In partial mesh some nodes are connected to all the others, but some nodes are connected to those nodes with which they want they exchange the most data. Example A mesh is used by Hospital, Soldiers etc.
Advantages
- Easy to expand
- Reliable
- Improves Faulty Tolerance
Disadvantages
- Its expensive because of the large number of cables and connections required
- Complicated
- Difficult to install
- Difficult to manage
- Difficult to troubleshoot
Details of Mesh Topology
Ethernet Cable Summary
Advantages of the Network
- Allows you to share hardware’s such as printers and scanners
- Allows you to share information
- Allows the user to save their work on server so they can access their work through any computer on the network.
- Allows the user to share the software’s
- It saves company money because with network the company only needs to buy 1 software and own multiple license.
- It is easier to upgrade from 1 computer to all the rest by using the network.
- It allows the users to communicate by sending electronic mail between them. Communication using the network is cheap and fast.
- It allows control over who has access to what data
- The work can be backed up through server this makes it easier because the company doesn’t have to back up every single computer individually. This process saves time.
- It allows the user to share high speed internet connection
- Allows the user to edit files that they have created
- It speeds up the business because more customers can join through world wide.
- It allows less duplication of the data
- Users can be monitored
Disadvantages of the Network
- If the server develops a faulty then users will be unable to run software’s
- If the network stops working the users might not be able to access hardware and software resources
- A badly managed network may operate less efficiently then stand alone computer.
- It is difficult to prevent the unauthorised access to data and software
- Printing can be slow if there are less printers and more computers because it will queue up
- Virus are more likely to spread quickly across the network to computers
- Security fears, hackers might hack into personal details of the company or unauthorised access.
- Setting up network is expensive because you need cables, interface cards, server etc
- If the cable or interface breaks the whole network will be effected or may not be able to use it unless its being repaired
- Increasing the Internet cost using broadband connections
TCP/IP
TCP/IP stands for “Transmission Control Protocol/Internet Protocol” is responsible for verifying the correct delivery of data from client to server. Data can be lost in the network. TCP adds support to identify errors or lost data and to activate retransmission until the data is correctly and completely received. TCP/IP is built into the and is used by the Internet. TCP/IP uses two transport protocols: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).
Advantages
- Good failure recovery
- Can add network without interrupting the existing services
- Independence Platform
- Low data operating cost
- Work on almost any processor
- Can operate without an OS
Disadvantages
- Limited functionality
- Limited security and encryption
- Performance limited by hardware
Circuit switching
Circuit switched is a type of network that is dedicated for a single connection. It creates an end-to-end circuit between the sending and receiving computers. It allows you to communicate one at a time because circuit switched is a single line connection. When is being used it is unavailable to others. An ordinary voice phone service is an example of circuit switched. Circuit switched is suited to voice and real-time videoconferencing.
Advantages
- Voice and real-time transmission
- No delivery delays
Disadvantages
- Costly
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Need to have direct electrical connection
Packet switching
Packet-switched is a type of network in which relatively small units of chunk of data called , routes through from one system to another.
How it Works
The message is being broken down into small packets, with a destination address on each one telling the network where to send them, when the recipient computer receives the packets, it reassembles them into the original data. The message is being sent to the destination through the help of routers. Routers examine the packets and send them to their destination.
Advantages
- Efficient, less expensive, reliable
- If the network part is down it will still function
Disadvantages
- It can delays in receiving packets
- Its not suitable for real-time voice communication
IP
Every computer connected to the Internet is assigned a unique number known as an Internet Protocol (IP) address. The format of an IP address is a 32 bit numeric address written as four numbers separated by periods. Each number can be zero to 255. The four numbers in an IP address are called octets, because they each have eight positions when viewed in binary form. An example of how an IP address looks like;
216.239.63.255
The above address translates to . This address breaks down as follows;
216 – This shows geographical region number
239 – A division or country number
63 – LAN number
255 – Individual Machine Number
IP addressing is based on the idea of hosts and networks.
The hosts are connected of multiple networks. The IP address of any host consists of its network address plus its own host address on the network.
There are different classes of IP address. The three most known are; Class A, Class B and Class C IP addresses.
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Class A addresses are for large networks for international companies. It has 1 network and 3 hosts.
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Class B addresses are for medium-sized networks for large college campus. It has 2 networks and 2 hosts.
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Class C addresses are for small networks for small business. It has 3 networks and 1 host.
Purpose of the Internet Protocol (IP)
- The IP protocol transfers the data used throughout a TCP/IP Internet.
- IP software carry’s out the routing function.
- How hosts and routers should process packets.
- How and when error messages should be created.
Advantages of IP Address
- It is currently used on Internet
- It is supported by current stacks
- It works with current DNS and DHCP servers
Disadvantages of IP Address
- Less space because running out of addresses only 32-bit
- Lack of auto configuration
- Lack of security support
MAC Address
MAC (Media Access Control) is an address given to device in a network. It consists of a 48-bit hexadecimal number (12 characters). The address is normally assigned to a device, such as a network card, when it is manufactured.
Advantages of MAC Address
- It contain broadcasts
- It filters when needed by protocol
Disadvantages of MAC Address
- It’s slow because each packet intensively processed
- It’s complex
- It’s expensive especially for higher bits 100Mbps and 1Gbps
Network Cabling
Cable is a piece of wire where information usually flows through from one computer to others. There are several types of cable which are commonly used with LANs. Some network utilize only one type of cable, other network uses a variety of cable types. The type of cable is depending on network topology, protocol and size.
Unshielded Twisted Pair (UTP) Cable
There are two different types of Twisted Pair: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks
The cable has four pairs of wires inside the covering. Each pair is twisted with a different number of twists per inch to help reduce interference from next pairs and other electrical devices. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot.
Unshielded Twisted Pair Connector (RJ45 and RJ12)
RJ-45 is the standard connecter for unshielded twisted pair. It’s a plastic connecter that looks like a telephone-style connecter. RJ stands for Registered Jack, an eight-wire (8pin) connector used commonly to connect computers onto a LAN, especially Ethernets. RJ12 is similar to RJ45 but in this case it has four-wire (4pin) connector.
Shielded Twisted Pair (STP) Cable
A type of copper telephone wiring in which each of the two copper wires that are twisted together are coated with an insulating coating that functions as a ground for the wires. The extra covering in shielded twisted pair wiring protects the transmission line from electromagnetic interference leaking into or out of the cable. STP cabling often is used in Ethernet networks such as Token Ring, especially fast data rate Ethernets.
Coaxial Cable
There are two types of coaxial cable thick and thin.
Thick Ethernet
Uses single length of coaxial cable to connect the nodes using smaller individual cables called transceiver cables. A thicknet uses a 10Base5 or 3 Ethernet cable.
Thin Ethernet
A single wire that uses separate lengths of a narrower type of coaxial cable, and each length of cable connects one node to the next. A thinnet uses a 10Base2 Ethernet cable.
Coaxial cable
It’s a single copper conductor in center with insulation and braided metal shield with plastic cover on top to cover. Braided metal shield helps to prevent the interference from other computers.
Coaxial cable is difficult to install but it is highly resistant to signal interference. It is better than twisted pair because coaxial cable supports greater cable lengths between network devices.
Coaxial Cable Connectors (BNC)
A push-and-twist connector for connecting thin coaxial cable. It is commonly used on 10base2 thin Ethernet networks, both on cable interconnections and network cards. There are different types of adapters are available for BNC connectors, including a T-Connector, barrel connector and terminator. BNC connectors are best for network instead others which has to screw rather than crimp. BNC stands for Bayone-Neill-Concelman.
Fiber Optic Cable
Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials. It transmits the information through light signals. Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds.
Fiber Optic Connector (ST)
Fiber Optic uses an ST connector. It is barrel shaped, similar to BNC connector.
Fiber Optic Connector (SC)
SC connector is more popular. It has a squared face and is easier to connect in a small space. It has a push pull locking system.
Fiber Optic Connector (FDDI)
A FDDI push/pull type dual connector. It’s used in FDDI network, this is a duplex connector using two 2.5mm ferrules.
What is Networking Hardware?
Networking hardware includes all the nodes, devices, interface cards and other equipment needed to perform data-processing and communications within the network.
File Servers
File server controls the communication of the information between the computers on a network. A file sever has massive storage space because it shares software, hardware etc to the users. File servers should have at least the following requirements:
- 166 megahertz or faster microprocessor (Pentium, PowerPC)
- A fast hard drive with at least nine gigabytes of storage
- A RAID (Redundant Array of Inexpensive Disks) to preserve data after a disk casualty
- A tape back-up unit (i.e. DAT, JAZ, Zip, or CD-RW drive)
- Numerous expansion slots
- Fast network interface card
- At least of 32 MB of RAM
Workstations
All of the nodes connected to the file server on a network are called workstations. A normal workstation is a node that has NIC card, network software and appropriate cables. All the work can be saved on file server so there is no need for floppy drive. All the computers that are connected to the network can serve as workstations.
Network Interface Cards
A network interface card (NIC) is a computer circuit board or card that is installed in a computer so that it can be connected to a network and computer workstation. NIC can be in different types the better NIC gives fastest speed and better performance of network. NIC also depends on the type of workstation you are using.
The three most common network interface connections are Ethernet cards, LocalTalk connectors, and Token Ring cards.
Ethernet Cards
Ethernet cards can be in two types either coaxial or twisted pair cables or both. If it’s designed for coaxial cable then it uses BNC connector. If it’s designed for twisted pair then it uses RJ-45 connection. Some Ethernet cards also use an AUI connector. AUI is used for coaxial, twisted pair or fiber optics cable. When AUI connector is used there is always an external transceiver attached to the workstation.
LocalTalk Connectors
LocalTalk is invented by Apple's for networking Macintosh computers. It operates with special adapter box and a cable that plugs into the printer port of a Macintosh. LocalTalk is slow then Ethernet because Ethernet connection operates 10Mbps where LocalTalk operates at only 230 Kbps.
Token Ring Cards
A token Ring cards has a nine pin DIN type connector to attach the card to the network cable. A token Ring cards is similar to Ethernet cards the only difference is that the connector is different.
Switch
A network switch is a small device that joins several nodes together at a low-level network protocol layer. Network switches operate at layer two (Data Link Layer) of the OSI model.
Switches are similar to hubs, but a switch normally contains more intelligence than a hub. Switches are capable of checking the data packets as they are received, checking the source and destination device of that packet, and forwarding that packet appropriately. By delivering messages only to the connected device that it was intended for, network switches protect network bandwidth and offer generally better performance than hubs.
Hub
A Hub provides a common connection point for nodes, printers, and other network devices in a star network. It allows network to be managed from a central location. Hub allows you to connect and disconnect individual nodes and devices without disrupting the network. Hubs operate at the physical layer of the OSI Model. Hubs usually contain ports for 8 – 12 computers and other devices.
Hub can be in three different types they are; passive, active and intelligent.
Passive hubs do not increase the electrical signal of incoming packets before broadcasting them out to the network.
Active hubs, regenerate and retransmit the data signal, because they repeat the signal they can, increase the distance of the network.
Intelligent hubs are similar to active hub but this hub has extra features. An intelligent hub is built in multiple units that can be placed one on top of the other to save space.
Repeaters
Repeater is a device that boosts the signal when the cable loses the strength. The repeater electrically increases the signal it receives and rebroadcasts it. Repeaters can be separate devices or they can be built-in into a concentrator. They are used when the total length of your network cable exceeds.
Bridges
A bridge is used to join two LAN network together, it allows computers on either network to access resources on the other. Bridges are also used to divide large networks into smaller. Bridges is similar to repeaters, but bridge can have more nodes, and since the network is divided, there are less computers competing for resources on each segment thus improving network performance. Bridges can also connect networks that run at different speeds, different topologies, or different protocols. Bridges cannot, join with an Ethernet segment with a Token Ring segment, because it uses different networking standards. Bridges operates at both the Physical Layer and the MAC sublayer of the Data Link layer.
Routers
Routers are used to connect different types of networks together such as those using different topologies and protocols. It operates at the first three layers of the OSI Model. This means they can switch and route packets across multiple networks. Routers decide the best path for sending data. Routers can also be used to connect LAN's to a WAN's. Routers can:
- Direct signal traffic efficiently
- Route messages between any two protocols
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Route messages between bus, star, and topologies
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Route messages across , , and cabling
Brouters
Brouters are a combination of bridge, and router in one device. Brouters are more cost effective as both the bridge and router are combined together.
Gateways
A gateway is used to connect networks using different protocols. Gateways operate at the network layer of the OSI model.
A gateway receives data from a network using one type of protocol, removes that protocol and repackages it with the protocol that the other network can use.
What is a Network Operating System?
Network requires special software to control the flow of information between users. A Network Operating System, or NOS, is installed onto each PC that requires network access. The NOS is like a traffic that monitors the exchange and flow of files, electronic mail, and other network information.
The two major types of network operating systems are:
- Peer-to-Peer
- Client/Server
Peer-to-Peer
A peer-to-peer network is a simple, low-cost network. All computers in a peer-to-peer network have equal status; no one is in control. Peer to peer network allows the users to share the hardware, data, or programs located on any other computer in the network. It stores files on its own storage devices. Each computer in the network must have network operating system and application software. However, only one computer in the network needs to connect to resources, the other computers in the network can share these resources. Peer to peer network is mostly used in small business and organizations. AppleShare and Windows for Workgroups are examples of programs that can function as peer-to-peer network operating systems. A peer-to-peer network can be built with either 10BaseT cabling and a hub or with a thin coax backbone.
Advantages of a peer-to-peer network:
- 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.
- No requirement for server hardware/software
- Users can mange their own resources
Disadvantages of a peer-to-peer network:
- Typically do not offer email or videoconferencing capabilities slow down in communication
Provide a limited number of connections
May slow performance of nodes
Do not allow central management
Do not have a central store of files
Users responsible for managing own resources
Offers very poor security
Client/Server
Each computer or resources in the network is either client or server. Servers are powerful computers because it manages internal and external resources such as disk drives (file servers), printers (print servers), or network traffic (network servers). A server controls the access limit of the clients. Clients are nodes or workstations on which users run the applications. Clients rely on the servers for resources such as files, devices and processing power. Most client/server networks have a network administrator, who is the operations person in charge of the network.
Novell Netware and Windows 2000 Server are examples of client/server network operating systems.
Advantages
- Inexpensive but powerful array of processors
- Easily expandable
- Server controls the resources and data security
- Improves performance due to less traffic on network
- Makes saving on the hardware upgrading
Disadvantages
- Requires initial investment in server
- Retraining required
- Large network will require a staff to ensure efficient operation
- If server goes down then it will stop communicating with each other and stop sharing resources
- Software costs for both server and client
Examples of network operating systems
Below list are some of the popular peer-to-peer and client/server network operating systems;
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- It includes both server and workstation software.
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- A better version of Windows 2000 that provides a powerful client/server network operating system.
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- Most popular client/server network operating program. Netware can handle any size of network.
Which network will be appropriate for Animal World and why?
Star
A Star topology connects the computers by single cables to a central unit, usually a hub.
Star is most popular nowadays for businesses. Animal World only has 10 computers and I think that star will be better for them because they can communicate with each other directly without waiting unlike token ring. They can also share resources such as printers, scanners etc in star network through Hub. Animal World can expand their network without disrupting other computers.
Cables and Connector
CAT5 and RJ45 are the cable and connector used in Star network.
Hardware
Hub is the hardware that is used in star network. It is essential that hub is needed to connect the computers together in star network.
Software
Client- Server is the software that is used star network.
Protocol
Ethernet is the protocol used in star network.
Drawbacks
Single point failure hub can shutdown the network from communicating and sharing.
Star network is expensive because cables are connected from each node back to hub.
