when En. Razak thought about this topic, i felt like " OMG!, this subject is really interesting. ;) "
sooooooo! i want to share with u guys about
TECHNOLOGY and TOPOLOGY ;D
NETWORK TOPOLOGY
-Think of a topology as a network's virtual shape or structure.
-It is divide to two type of network topology:
physical topology
logical topology
Physical topology
-The way that the workstations are connected to the network through the actual cables that transmit data
- the physical structure of the network
• Types/Classification of physical topologies
– Linear Bus
– Star
– Star-Wired Ring
– Tree
– FDDI
– Mesh
Linear bus
A linear bus topology consists of a main run of cable with a terminator at each end (See fig. 1). All nodes (file server, workstations, and peripherals) are connected to the linear cable.
Fig. 1. Linear Bus topology
Advantages of a Linear Bus Topology
Easy to connect a computer or peripheral to a linear bus.
Requires less cable length than a star topology.
Disadvantages of a Linear Bus Topology
Entire network shuts down if there is a break in the main cable.
Terminators are required at both ends of the backbone cable.
Difficult to identify the problem if the entire network shuts down.
Not meant to be used as a stand-alone solution in a large building.
STAR
A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub, switch, or concentrator (See fig. 2).
Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow. This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable.
Fig. 2. Star topology
Advantages of a Star Topology
Easy to install and wire.
No disruptions to the network when connecting or removing devices.
Easy to detect faults and to remove parts.
Disadvantages of a Star Topology
Requires more cable length than a linear topology.
If the hub, switch, or concentrator fails, nodes attached are disabled.
More expensive than linear bus topologies because of the cost of the hubs, etc.
STAR-WIRED RING
Uses physical layout of a star topology with ring topology data transmission method
Data is sent around the star in a circular fashion (dotted orange in figure)
This hybrid technology has the fault tolerance of star topology and, ...
in Token Ring networks, reliability of token passing
The advantage of star-wired ring
Easy Installation, Maintenance & Troubleshooting
Flexible Cable Support
Greater Fault Tolerance & Reliability
TREE
A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable (See fig. 3). Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.
Fig. 3. Tree topology
Advantages of a Tree Topology
Point-to-point wiring for individual segments.
Supported by several hardware and software venders.
Disadvantages of a Tree Topology
Overall length of each segment is limited by the type of cabling used.
If the backbone line breaks, the entire segment goes down.
More difficult to configure and wire than other topologies.
FDDI
In an FDDI LAN, the nodes that can be the source or destination of data frames are called stations. A station has a MAC layer, one or more MAC addresses, and one or more FDDI ports. The stations share the bandwidth provided by the ring.
As was the case for Token Ring, cabling management often is simplified by connecting stations to a concentrator (hub) unit. A concentrator can play its role invisibly. However, it will need a MAC layer and a MAC address if it is going to be configured or supervised via network management messages. In this case, it will have the status of a station, too.
FDDI Station Types
There are two main types of stations, class A which attach directly to dual rings; or class B which attach to a station acting as a concentrator.
A concentrator is a specialized workstation that attaches to the ring and has multiple ports that allow attachment of other devices in a physical star configuration. These may be cascaded.
HERE ARE ONE VIDEO THAT CAN EXPLAIN MORE ABOUT THIS TYPE OF TOPOLOGY ;)
LOGICAL TOPOLOGY
the mapping of the flow of data between the nodes in the network determines the logical topology of the network
the way that the signals act on the network media, or the way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices.
# This video explain about different between logical and physical topology.
LAN PROTOCOL
• Ethernet
• Token Ring
• FDDI
• Gigabit
Ethernet
ETHERNET
Ethernet is a family of computer networking technologies for local area networks (LANs) commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies.
Systems communicating over Ethernet divide a stream of data into individual packets called frames. Each frame contains source and destination addresses and error-checking data so that damaged data can be detected and re-transmitted.
WHAT IS ETHERNET??
TOKEN RING
)(1) A type of computernetwork in which all the computers are arranged (schematically) in a circle. A token, which is a special bit pattern, travels around the circle. To send a message, a computer catches the token, attaches a message to it, and then lets it continue to travel around the network.
(2) When capitalized, Token Ring refers to the PC network architecture developed by IBM. The IBM Token-Ring specification has been standardized by the IEEE as the IEEE 802.5standard.
I HAVE SPEND TIMES FOR ALMOST 3 HOURS TO FINISHED THIS NETWORKING ENTRY. WITH A HIGH PASSION I GIVE, AND THEN I CAN SMILE SEE MY TELECOMMUNICATION BLOG ;')
Networks are collections of computers, software, and hardware that are all connected to help their users work together.
Computer networks fall into two main types:
client/server networks = Uses one or more dedicated machines to share the files, printers, and applications.
and peer-to-peer networks= A peer-to-peer network allows any user to share files with any other user and doesn’t require a central, dedicated server.
The most common networks are Local Area Networks or LANs for short.
A LAN connects computers within a single geographical location, such as one office building, office suite, or home. By contrast, Wide Area Networks (WANs) span different cities or even countries, using phone lines or satellite links.
Networks are often categorized in other ways, too. You can refer to a network by what sort of circuit boards the computers use to link to each other – Ethernet and Token-Ring are the most popular choices. You can also refer to a network by how it packages data for transmission across the cable, with terms such as TCP/IP (Transmission Control Protocol/Internet Protocol) andIPX/SPX (Internet Package eXchnage/Sequenced Package eXchange).
TYPE OF NETWORK :
Personal Area Network (PAN)
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
# this video are very useful to understanding the type of network communication. I've also understand more about this chapter from this video ;D
Bluetooth uses short-range radio waves over distances up to approximately 10 metres. For example, Bluetooth devices such as a keyboards, pointing devices, audio head sets, printers may connect to Personal digitalassistants (PDAs), cell phones, or computers wirelessly.
Infrared Data Association
Infrared Data Association uses infrared light, which has a frequency below the human eye's sensitivity. It is used, for instance, in cell phones, TV remotes and ps3 controllers. Typical WPAN devices that use IrDA include printers, keyboards, and other serial data interfaces.
WiFi
WiFi uses radio waves for connection over distances up to around 91 metres, usually in a local area network(LAN) environment. Wifi can be used to connect local area networks, to connect cellphones to the Internet to download music and other multimedia, to allow PC multimedia content to be stream to the TV (Wireless Multimedia Adapter), and to connect video game consoles to their networks.
# one type of PAN
Local Area Network
LAN stands for Local Area Network (as opposed to WAN, or Wide Area Network), which commonly refers to how a connection to the Internet is made. LANs are used to connect computers that are geographically close together, whether inside a room or inside a building. This allows people to share files and printers, play computer games together and even send music to a stereo system or videos to a television
The Basic LAN
The basic type of LAN is connected by Ethernet cables to a router or hub (modern routers usually integrate hubs). A router allows all computers connected to it to access a high-speed modem connected to the router. Each computer has an IP (Internet Protocol) address, but a computer on the other side of the Internet will only see the router's IP address. This, and a router's built-in firewall, creates a safer environment for accessing the Internet. (Firewalls are used to filter out unauthorized access to the network.)
#one type of LAN
Metropolitan Area Network
A metropolitan area network (MAN) is a computer network that usually spans a city or a large campus. A MAN usually interconnects a number of local area networks (LANs) using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks (or WAN) and the Internet.
Type of Metropolitan Area Network ( MAN )
Wide Area Network ( WAN )
Definition: A WAN spans a large geographic area, such as a state, province or country. WANs often connect multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs).
TYPE OF WAN
Networking Guide : Network Components
Besides a physical medium, a network operation needs devices that are designed to handle certain network functions. The devices are often called networking devices or equipment and specifically referred to as network components in this guide. Each network component has a name that is related to its functions. For example, a network adapter works to "adapt" a computer message that is going to be sent to a network, to a format that is defined by the network.
Picture: Networking Hardware
Terminal and Workstation
Transmission Media
Network Electronic Device
Software
1. Terminal and Workstation
what is terminal and workstation in networking?
Terminal as it relates to a workstation is usually a user interface [keyboard/mouse/video] that has enough stuff to get connected to a main frame/VAX/terminal server. A terminal does minimal processing.
A workstation on the other hand has all the stuff it needs and does all of the processing. It does not need to connect to a server to do its stuff.
example:
#lowest workstation terminal
# Network terminal
2. Transmission Media
The means through which data is transformed from one place to another is called transmission or communication media. There are two categories of transmission media used in computer communications.
1. BOUNDED MEDIA:
Bounded media are the physical links through which signals are confined to narrow path. These are also called guide media. Bounded media are made up o a external conductor (Usually Copper) bounded by jacket material. Bounded media are great for LABS because they offer high speed, good security and low cast. However, some time they cannot be used due distance communication. Three common types of bounded media are used of the data transmission. These are
Coaxial Cable
Twisted Pairs Cable
Fiber Optics Cable
COAXIAL CABLE:
Coaxial cable is very common & widely used commutation media. For example TV wire is usually coaxial.
CHARACTERISTICS OF COAXIAL CABLE
Low cost
Easy to install
Up to 10Mbps capacity
Medium immunity form EMI
Medium of attenuation
ADVANTAGES COAXIAL CABLE
Inexpensive
Easy to wire
Easy to expand
Moderate level of EMI immunity
DISADVANTAGE COAXIAL CABLE
Single cable failure can take down an entire network
Twisted Pair Cable
The most popular network cabling is Twisted pair. It is light weight, easy to install, inexpensive and support many different types of network. It also supports the speed of 100 mps.Twisted pair cabling is made of pairs of solid or stranded copper twisted along each other. The twists are done to reduce vulnerably to EMI and cross talk. The number of pairs in the cable depends on the type. The copper core is usually 22-AWG or 24-AWG, as measured on the American wire gauge standard. There are two types of twisted pairs cabling
1. Unshielded twisted pair (UTP)
2. Shielded twisted pair (STP)
1. Unshielded twisted pair (UTP)
Characteristics of UTP
low cost
easy to install
High speed capacity
High attenuation
Effective to EMI
100 meter limit
Advantages of UTP
Easy installation
Capable of high speed for LAN
Low cost
Disadvantages of UTP
Short distance due to attenuation
2.Shielded twisted pair (STP)
It is similar to UTP but has a mesh shielding that’s protects it from EMI which allows for higher transmission rate.
Characteristics of STP
Medium cost
Easy to install
Higher capacity than UTP
Higher attenuation, but same as UTP
Medium immunity from EMI
100 meter limit
Advantages of STP:
Shielded
Faster than UTP and coaxial
Disadvantages of STP:
More expensive than UTP and coaxial
More difficult installation
High attenuation rate
Fiber Optics
Fiber optic cable uses electrical signals to transmit data. It uses light. In fiber optic cable light only moves in one direction for two way communication to take place a second connection must be made between the two devices. It is actually two stands of cable. Each stand is responsible for one direction of communication. A laser at one device sends pulse of light through this cable to other device. These pulses translated into “1’s” and “0’s” at the other end.
In the center of fiber cable is a glass stand or core. The light from the laser moves through this glass to the other device around the internal core is a reflective material known as CLADDING. No light escapes the glass core because of this reflective cladding.
Fiber optic cable has bandwidth more than 2 gbps (Gigabytes per Second)
Characteristics Of Fiber Optic Cable:
Expensive
Very hard to install
Capable of extremely high speed
Extremely low attenuation
No EMI interference
Advantages Of Fiber Optic Cable:
Fast
Low attenuation
No EMI interference
Disadvantages Fiber Optics:
Very costly
Hard to install
3. NETWORK ELECTRONIC DEVICE
Network devices are components used to connect computers or other electronic devices together so that they can share files or resources like printers or fax machines. Devices used to setup a Local Area Network (LAN) are the most common type of network devices used by the public. A LAN requires a hub, router, cabling or radio technology, network cards, and if online access is desired, a high-speed modem. Happily this is much less complicated than it might sound to someone new to networking.
HUB
A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When apacket arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.
A passive hub serves simply as a conduit for the data, enabling it to go from one device (or segment) to another. So-called intelligent hubs include additional features that enables an administrator to monitor the traffic passing through the hub and to configure each port in the hub. Intelligent hubs are also called manageable hubs.
A third type of hub, called a switching hub, actually reads the destination address of each packet and then forwards the packet to the correct port.
ROUTER
Definition: Routers are physical devices that join multiple wired or wireless networks together. Technically, a wired or wireless router is a Layer 3 gateway, meaning that the wired/wireless router connects networks (as gateways do), and that the router operates at the network layer of the OSI model.
Definition: A bridge device filters data traffic at a network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two segments.
Bridges operate at the data link layer (Layer 2) of the OSI model. Bridges inspect incoming traffic and decide whether to forward or discard it. An Ethernet bridge, for example, inspects each incoming Ethernet frame - including the source and destination MAC addresses, and sometimes the frame size - in making individual forwarding decisions.
Bridges serve a similar function as switches, that also operate at Layer 2. Traditional bridges, though, support one network boundary, whereas switches usually offer four or more hardware ports. Switches are sometimes called "multi-port bridges" for this reason.
GATEWAY
Definition: A network gateway is an internetworking system capable of joining together two networks that use different base protocols. A network gateway can be implemented completely in software, completely in hardware, or as a combination of both. Depending on the types of protocols they support, network gateways can operate at any level of the OSI model.
What is gateway & how it works?
Gateways work on all seven OSI layers. The main job of a gateway is to convert protocols among communications networks. A router by itself transfers, accepts and relays packets only across networks using similar protocols. A gateway on the other hand can accept a packet formatted for one protocol (e.g. AppleTalk) and convert it to a packet formatted for another protocol (e.g. TCP/IP) before forwarding it. A gateway can be implemented in hardware, software or both, but they are usually implemented by software installed within a router. A gateway must understand the protocols used by each network linked into the router. Gateways are slower than bridges, switches and (non-gateway) routers.
A gateway is a network point that acts as an entrance to another network. On the Internet, a node or stopping point can be either a gateway node or a host (end-point) node. Both the computers of Internet users and the computers that serve pages to users are host nodes, while the nodes that connect the networks in between are gateways. For example, the computers that control traffic between company networks or the computers used by internet service providers (ISPs) to connect users to the internet are gateway nodes.
# ENJOY WATCHing DIS VIDEO !! ;D
SOFTWARE
A network (=server) operating system (NOS)
– a piece of software that controls a network and its message traffic and queues, controls
Page‐ 14
access by multiple users to network resources such as files, and provides for certain administrative functions, including security.
– Installed on the server
client software – Installed on the PC/cmputers to access the network and to issue requests to the Page‐ 15 network
Assalamualaikum dan hai.
saya rasa mesti anda2 sesat kat sini kan? SELAMAT DATANG saya ucapkan kepada yang telah tersesat. Bacalah blog saya dan harap jumpa jalan keluar. Salam sayang dari saya, aisyahsitinggilampai, thehehehe ;D
TECHNOLOGY AND TOPOLOGY
Fig. 1. Linear Bus topology
Fig. 2. Star topology
Fig. 3. Tree topology
