In this task we will investigate and discuss about the Network Topologies and media required for building a LAN for the Fire Department in Townsville. Network Topologies are the physical or logical arrangement of the elements in the network. There are four main types of network topology. They are:
Other topologies like Mesh Topology and Hybrid Topology can be derived by interconnecting two or more topologies. Each of the end points or the workstations can be called as nodes.
We will now know how this topologies work.
Task 1 (a)
Star Topology: It is a network in which all of the workstations are connected to a central base station like hub, switch or computer. This central base station rebroadcast the incoming frame from any workstation to all of the nodes sometimes including the original node. Thus it reduces the chances of network failure. All peripheral nodes may thus communicate with all others by transmitting to, and receiving from, the central node only. The failure of a transmission line linking any peripheral node to the central node will result in the isolation of that peripheral node from all others, but the rest of the systems will be unaffected. Star topology uses Ethernet protocol. (IEEE 802.3)
Fig: Star Topology
Bus topology: In this network, all of the nodes or devices are connected to a shared central cable called bus. When a node sends a packet the device needs to check if any other device is sending any packet on the cable. Once a packet is sent on the cable the other devices on the network can see and read the packet. Sometimes two devices send packet over the bus at the same time and thus the packet collides and the devices themselves need to decide which packet be send first. The more the number of nodes on the bus, the more is the chances of collision. This topology also uses Ethernet protocol (IEEE 802.3).
Fig: Bus topology
Ring Topology: All the nodes or devices in this network are connected to two other nodes within a loop. Thus it forms ring like structure without any start or end. Each signal will repeat over the network regardless any destination. The whole network might fail by da failure of any single node. Thus FDDI (IEEE 802.6) network is used where the data is sent in a clockwise and a counterclockwise manner i.e. the data is wrapped into a complementary ring forming a C-Ring before reaching to the broken cable. This type of network is called as the IBM Token Ring network.
Fig: Ring Topology
Tree Topology: The combination of bus and star topology results in Tree topology. Many servers can be placed along the network and the network can be branched out like the tree branches. The nodes in the network can be spread in a hierarchy manner where each of the nodes will have a fixed number of nodes connected to it. It should have at least three hierarchical levels and the higher hierarchical levels are expected to have more functionality than the lower level nodes. Tree topology is best used for large networks rather than small network.
Fig: Tree Topology
Task 1(b)
Several types of media are available for networking. For example:
There are several kinds of mediums in network. Such as-
Modem
Hub
NIC
cables
Switch
Router
Modem:
Fig: ADSL USB modem
Advantages:
A modem transfigures the data from analog to digital and digital to analog.
Good for broadband connetion.
Disadvantages:
Modem increases the downloading time.
There is no traffic maintenance.
Hub:
Fig: Hub
Advantages:
Any packet received by the hub is copied and sent to all of the ports in a LAN so that everyone can see it.
Easy and inexpensive to monitor.
Disadvantages:
The total bandwidth is shared between multiple port, thus every computer in a network get very limited speed.
A hub is not wise for large networks.
NIC: Network Interface Card :
Fig: NIC
Advantages:
This type of cards provides a consistent connection with the internet.
NIC maintains the data flow within the network.
Disadvantages:
NIC connection cannot secure data.
Cable: (Twisted pair cable for internal connections and Fibre optics for External connection):
Fig: Twisted Pair Cable and Fiber Optic Cable
Advantages:
A cable ensures a continuous connection with the Internet.
Cables offer more secure communications, very less data loss possibility as they are highly resistant to tapping, radio frequency interference and jamming.
Disadvantages:
Very expensive almost double than any other electrical wiring.
Not available in all areas.
Switch:
Fig: Switch
Advantages:
Compared to hub, switch is more inexpensive and supports more number of ports.
Switch supports Virtual LAN.
Disadvantages:
May prove dangerous if not designed or configured properly.
A switch cannot establish communication between two networks.
Router:
Fig: Router
Advantages:
Router can filter the packets passing over the network.
Router can connect computer and other devices within the network.
Disadvantage:
Router is more expensive than any other device.
Only routing protocols can communicate with router.
Task 1 (c)
Recommendation:
We have already discussed about the several networking topologies and the media used to build the in house LAN.
My recommendation about the topology and media to build an in house LAN would be:
Star Hybrid Topology for LAN, it is made by connecting several Star Topology with a bus. Because Star Topology is the ideal network topology. If anything goes wrong with a workstation in the network, the whole network remains unaffected. Everyone in the network can intercommunicate with each other.
And as media I would recommend to use:
NIC (Network Interface Card): For consistent connectivity with the Internet.
Switch: For connecting to the Internet.
Fiber Optic Cable: For secured and fast data transfer.
Router: To connect the several switches in the network.
Task 2
Task 2(a)
World Wide Web: Also known as WWW and W3. It is a system of Internet Server that support hypertext document known as HTML. Hypertext refers to text that links to other documents like video, graphics, audio pictures. We can just move to the references by just a single click with mouse.
Electronic Mail (e-mail): Electronic mail has become the most common form of communication since it has been introduced. It is like formal or informal letter sent over the internet. All we need to have is connection with the internet, an e-mail account and a anyone else with an e-mail account.
FTP: It stands for File Transfer Protocol. This protocol is to copy files from one computer to another. FTP uses Internet's TCP/IP protocols to transfer data. FTP is used either download files from a server or to upload files to the server. FTP usually requires a user account in the server machine to copy files. It is usual to allow Anonymous FTP so that no user account needs to be created and requires no password.
VPN service: VPN means Virtual Private Network. This is a computer network. VPN accommodate the needs of remote LANs and distant offices. A VPN is a private network that uses the Internet to connect remote sites or users together. Instead of using a dedicated, real-world connection such as leased line, a VPN uses "virtual" connections routed through the Internet from the a private network to the remote site.
Task 2(b)
The Connection speed to meet the above mentioned services should be at least 1Mbps for both uploading and downloading.
Task 2(c)
There are many ISPs in our country that can provide the services above. Some of the examples are given below:
Aftab IT Limited
Access Telecom Limited.
Bangladesh Online Ltd.
Bangladesh T&T Board
Grameen Cybernet Ltd.
Bijoy Online Limited.
Task 2(d)
I would recommend Bijoy Online Limited as the ISP. Because they provide support with all of the services (including VPN service) mentioned above.
The charges according to their services are:
Name of Services
Amount
Installation charge for each PC
BDT 1200.
Web Page Development
BDT 7,000.
Per year payment for web hosting and mail
BDT 5,000
Internet connection for 1Mb speed per month
BDT 3,800.
Task 3
Task 3(a)
Half Duplexing: It refers to the transmission of data in just one direction at a time. For example, a walkie-talkie is a half-duplex device because only one party can talk at a time. Some modems contain a switch that lets us to select between half-duplex and full-duplex modes. In full duplex mode, every character is echoed by the local device and thus the words displays on the screen. Half duplex uses a single frequency to communicate but one user at a time and then the second user. In half duplex communication takes place with same signal, one message sends a message then the second user receives it and replies via same signal, and there is traffic monitor at each end, therefore there is no chance of signal jamming.
The half duplexing devices can communicate with another device within only 25 km radius at max.
Fig: Half Duplexing
Duplexing or Full Duplexing: Also known as full-duplex. It refers to the transmission of data in two directions at a time. E.g. Telephone communication is a two way communication. In full-duplex mode, data we transmit does not appear on our screen until it has been received and sent back by the other party. This enables us to validate that the data has been accurately transmitted.
In full duplexing two devices use two separate signals for communicating. So both parties can send and receive signals at the same time. Thus there is no possibility of collision.
Full duplexing frequency covers large area nowadays the devices catch frequencies nationwide.
Sometimes some packets are lost while the transmissions are carried out in peak usage. If many packets are lost in this way it may also result in disconnection with the server.
Fig: Full Duplexing
Task 3(b)
The following are the principal legal statutes governing the telecommunication industry in Bangladesh:
a. The Bangladesh Telecommunication Act, 2001 (as amended).
b. The Wireless Telegraphy Act, 1933 and The Telegraph Act, 1885, for matters that are not covered by the Bangladesh Telecommunication Act, 2001 (as amended).
c. Licensing Procedure Regulations, 2004 as amended.
The Licensee shall provide necessary connections including necessary equipment and software to
the Commission for online and offline monitoring and analyzing of Call Detail Record (CDR), Call Accounting, Signaling, QoS and or any other system as may be required by the Commission. User licenses for the software will be at least 5 (five) in number.
The Licensee will not be eligible for any other License(s) from the Commission. No shareholder and/or his family of the company that is awarded the License in the capacity of an owner, shareholder, director, officer or partner of any other company can hold or will hold any other License from the Commission.
One entity will be allowed to get ONLY one ICX License.
The Licenses will be awarded by open auction subject to fulfillment
Reference: http://www.btrc.gov.bd/licensing/guidelines/icx_guidelines.pdf
Task 3(c)
Every country has the licensing cost rate varying according to their economy and the government policies. The installation cost, operating cost and the set up cost also different for different countries.
Licensing cost in our country may range from BDT 5lakh to BDT10lakh according to the services under the license.
The Operating cost in our country may require around BDT 1Lakh depending on the human resources involved in operating the system.
The set up cost depends on the equipment used in the system. There are equipment of several rates varying according to the features and manufacturing differences. But for an average set up type it may need near BTD1 crore.
Task 3(d)
Every method has their strengths and weaknesses. We have already discussed their features above. The limitations of the methods are as follows:
Half Duplex Limitations:
Only one person can talk at a time.
There is no privacy in communication because anyone with a suitable device can hear the communication.
Half duplexing device covers only a limited area.
Duplexing or Full Duplexing Limitations:
Duplexing systems are expensive to set up.
During communication in peak hours, some packets may be lost and if many packets are lost it may result in communication break.
If the radio device cannot reach the repeater the communication cannot be established.
Task 3(e)
Recommendation:
Townsville Fire Department should use a communication method that serves the requirement of their communication at the same time keeping in mind the consistent connectivity and cost effectiveness of the system.
According to above mentioned features I would recommend half duplexing method for the Fire communication.
Reasons for recommendations are:
While a message is passed from one device other devices in the network within the frequency range can be aware about it and may help.
As one signal is sent at a time thus there is less possibility of network traffic jamming.
And the equipment and system installation cost are also reasonable.
Task 4
In this task we have been asked to investigate the telephone systems available in our country for single site organizations like Fire Department. For telephone communication in a single site we can establish a PBX (Private Branch Exchange) system using the local telephone connection.
Users of the PBX share a certain number of outside lines for making telephone calls external to the PBX.
Most medium-sized and larger companies use a PBX because it's much less expensive than connecting an external telephone line to every telephone in the organization. In addition, it is easier to call someone within a PBX because the number we need to dial is just the extension number.
Task 4(a)
Equipment to be installed:
Telephone instruments.
Private Branch Exchanges(PBXs)
Key Telephone Systems(KTSs)
Automatic Call Distribution (ACD) systems
Voice Processing Systems.
Telephone Call Information Loggers (CIL).
Telephone Answering Machines
Facsimile Machines.
Modems
Local Area Network (LAN) Bridges.
Local Area Network Routers
Multiplexers.
Task 4(b)
There are two types of telephone service:
ISDN- Integrated Services Digital Network. It is an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires.
PSTN- Public Switched Telephone Network. It refers to the international telephone system based on copper wires carrying analog voice data.
Features of ISDN PBX:
Analogue Extensions: The INPBX provides us with 2, 4or 6 extensions (depending on model). Connect standard telephones, fax machines, Modems, etc. It supports internal communication while both B channels are in use.
Non-Blocking: The PBX switch is non-blocking and there are no simultaneous extensions to extension calls.
Configuration setting: The Configuration setting can be done by the user using the standard phone connected to the T1 port of the PBX extensions.
Direct Inward Dialing: Each extension can have its own direct inward dial phone no.
Call pick up: Any extensions can be used to answer incoming call on another extension, or calls can be routed to operator extensions.
Call Transfer: Call can be transferred to any extensions with or without announcing via beeps, while first call is in progress.
Call Waiting: Second incoming call is announced via beeps, while first call is in progress.
Caller ID Presentation: Caller ID is presented on all the extensions wherever the coming calls ring.
Busy call complete: A user can get access to a busy extensions or external line the moment it gets free.
Call Conferencing: It can conduct a 3 way conference call with either two external callers and one external caller and two internal extensions.
Call Hold: An external call can be put on Hold on any of the extensions while a second call I to be made or answered. Multiple Hold support if enabled in CO Switch.
Toll Restriction: We can prevent dialing of STD/ISD calls.
Distinctive Ringing: A distinctive ringing pattern intimates the type of call, such as outside calls, intercom calls, etc.
Global Call Receive: Calls having no numbering info will be routed to all ports.
Reference: http://www.teletechsystem.com/new.htm
Features of PSTN-PBX:
As we know, PSTN is the analog telephone system thus a PSTN-PBX can carry out all the basic PBX functions but in analog form.
The basic features are:
To dial other extensions.
To dial outside lines.
To make an enquiry call to another extension whist connected to an external call.
To transfer the external call to the extension where an enquiry call had just been made.
Task 4(c)
As mentioned in the tasks earlier, we know the equipment cost may vary according to the vendors supplying the equipment and the negotiation capability.
Thus the equipment cost according to quality of workstation may range up to BDT 2lakhs for the whole Fire department as per bought from the whole-selling vendors negotiating accordingly.
And the Installation charge for ISDN PBX may range upto BDT 60,000 to 70,000.
Task 4(d)
The operating cost again depends on the number of user and manpower maintaining the system. In average the operating cost may result in BDT 2 to 3 lakhs per year. And for ISDN PBX system also have a Operator.
Task 4(e)
Recommendation:
Recommending a telephone system for the Fire Department of Townsville depends on several factors like, requirements from the system, features available with each system and the budgets of operating the system.
Keeping in mind the above factors and the things investigated during the task, in the point of view of a network administrator, I would recommend ISDN-PBX for a single site telephone system.
ISDN-PBX is recently mostly used and provides a variety of functionality. According to the communication requirement of the Fire Department of Townsville, ISDN-PBX will full fill the best needs. ISDN-PBX also provides the facility of using facsimile (fax) service and also can carry out several Internet services including Voice over IP (VoIP).
Task - 5
Backup system for Electronic Power:
There are many electronic Power backup systems if electricity failure. Such as
Generator.
IPS (Instant Power Supply).
If the electrical power system failure In Fire department I allow Generator for electronic backup.
Electrical Generator:
An electric generator is a device that converts mechanical energy to electrical energy. The reverse conversion of electrical energy into mechanical energy is done by a motor; motors and generators have many similarities. A generator forces electrons in the windings to flow through the external electrical circuit. It is somewhat analogous to a water pump, which creates a flow of water but does not create the water inside. The source of mechanical energy may be a reciprocating or turbine steam engine, water falling through a turbine or waterwheel, an internal combustion engine, a wind turbine, a hand crank, compressed air or any other source of mechanical energy.
Backup System for telephone line:
If telephone lines are being broken I allow Radio system for emergency work. Walkie-talkie is half-duplex radio telephone system which is allow for alternative telephone system.
Walkie-talkie:
A walkie-talkie, or handie talkie, (more formally known as a handheld transceiver) is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald L. Hings, radio engineer Alfred J. Gross, and engineering teams at Motorola. Similar designs were created for other armed forces, and after the war, walkie-talkies spread to public safety and eventually commercial and jobsite work. Major characteristics include a half-duplex channel (only one radio transmits at a time, though any number can listen) and a "push-to-talk" (P.T.T) switch that starts transmission. Typical walkie-talkies resemble a telephone handset, possibly slightly larger but still a single unit, with an antenna sticking out of the top. Where a phone's earpiece is only loud enough to be heard by the user, a walkie-talkie's built-in speaker can be heard by the user and those in the user's immediate vicinity. Hand-held transceivers may be used to communicate between each other, or to vehicle-mounted or base stations.
Task 6
REPORT ON: ENTERPRISE NETWORK
Assignment Title: Fire Department
Prepared By: Abdur Rahman Mamun
Submitted To: Khandaker Reza-e Rabbi
Lecturer of Bhuiyan Institute of Technology
Executive Summary:
Keeping in mind the scenario of Townsville Fire Department, we carried out investigation on the following key points:
Networking topologies: Different types of topology and their advantages and disadvantages.
Media used in networking: Different types of media that needs to be used to make the network effective and their advantages and disadvantages.
Internet services: The various Internet services that may be required by the Fire Department for communication.
Internet Service Providers: The ISPs in our country who can provide this services and their charges for the services.
Charges for the servies in our country: Each of the services has so charge to be paid to the Internet Service Providers.
Methods for Two-way Communication: Two-way communications like Half-duplex and Full-duplex. Their advantages and disadvantages. How each method works? Legal requirements for establishing these methods. The cost of licensing, installation and operating the methods.
Details of legal requirements: allocation of frequencieslicensing requirements, etc in our country.
Limitations of Two way communication methods: Limitaions in capturing the frequency range and interference of the communication.
Telephony systems: For single site organizations which telephone systems can be used e.g. Private Branch Extension. Features and equipment of the telephony systems. And cost of installing and operating the systems.
Main equipment to be installed in the Telephony system: The list of each of the hardware and system complementary equipments for the Telephony System.
Features fo the Telephony System: Features of the systems like ISDN-PBX and PSTN-PBX.
Cost of equipment installation: Charges for installing the equipment.
Cost of operating the system: Cost to be evaluated per year for operating the telephone system.
Backup System: Backup of power and network system is also included.
Final Recommendation: Final recommendation of the whole network for the Townsville Fire department.
Terms of Reference:
The above mentioned investigations have been carried out using different source of media text book and also with the help of our Lecturer.
The mission of carrying out this investigation was to find out the several procedures of communication and legalization over Enterprise Networking. I hope this assignment will fulfill the networking requirements of the Fire Department of Townsville.
There were several assumptions made to investigate the requirements, like the equipment and services to be used by the Fire Department of Townsville. The cost of the equipment and the licensing requirements has also been assumed. Different alias has also been used.
All of the work has been done from the point of view of a network administrator.
Appendix:
Task 1:
Network Topology……………………………………..
Description of each topology
Advantages and Disadvantages of each Topology.
Media used in the network……………………………
Advantages and Disadvantages of each medium
Fig: Star topology
Fig: Bus topology
Fig: Ring Topology
Fig: ADSL USB modem
Fig: Hub
Fig: NIC
Fig: Twisted Pair Cable and Fiber Optic Cable
Fig: Switch
Fig: Router
Task 2:
Internet Services………………………….
Examples of Internet Service Provider in our Country……………
Charges of services in our country……………………
Recommendation………………………………….
Task 3:
Methods of two way communication……………………….
How each method works…………………………….
Legal requirements for licensing……………………….
Cost of setting up the method……………………………….
Limtations of each method………………………………..
Recommendation ………………………………………
Task 4:
Telephone Systems in our country……………………………….
Equipment to be installed………………………..
Features of each System………………………
Cost of Equipment and Installation……………….
Cost of operating the System…………………..
Recommendation…………………………..
Task 5:
Backup System for electronic Power……………………….
Backup system for telephone system………………………………
Task 6:
Executive Summary………………………………………………….
Final Recommendation………………………………………………..
