1. Discuss the role of networks within different organizations and the resource implications of networks.
Of late, networks have become a principal mode of data transmission helping in collaboration, dissemination of knowledge, creative reproduction and gathering resources to undertake research. The networking system is integral to organizational function. Within different organizations, networks play the following roles:
- The network of an organization helps the employees increase their productivity by allowing them exchange ideas quickly.
- It keeps the employees connected all the time from anywhere by allowing them remote access.
- As there are several computers connected to a server of network, the storage capacity multiplies.
- It reduces the cost of communication by allowing employees communicate via cost effective modes of internet messenger and email in place of phones and fax machines.
2. Discuss the different distributed computing approaches of peer-to-peer, client-server networks and the advantages of client-server approaches particularly over centralized services.
P2P or peer-to-peer computing is a distributed application architecture performing the function of both server and client. All the computers connected to P2P networking are equally privileged and form a peer group by sharing the same network bandwidth, processing power without any need of servers centrally coordinating their actions. In the client server model the workloads and functions are divided between servers and clients. A server is a powerful host that coordinates with the subordinate workstations called clients.
3. Explain the functions of client and server computers on a network and give at least one example of the interactions between a client and server computer.
In this model client send requests to the server and the server acts upon the requests by sending resources and information. One single server can support several computers and many servers can grouped into a network to share the load of processing in case the number of clients increases. Both the client computer and server computer are separate entities entrusted with the responsibility of handling different tasks. For example, Outlook uses client server architecture. Outlook is configured in local machines with the IP address of the server. Every time an end user opens up the client software i.e. Outlook, it goes to the server mail application and extracts all the information related to the request made by the end user.
4. Draw and describe basic network topologies and define basic network components
Network topology is the arrangement of different components of a network. Physical topology defines the way actually the components are placed in the network and logical topology defines the data flows with that network structure regardless of physical connections, distances and transmission rates. Local area network (LAN) is typical example of physical and logical topology.
Physical topology defines where the actual components will be placed, how the connections will be made and how the cabling layout will turn out. Logical topology is closely associated with hardware methods and protocols and they can be dynamically configured and reconfigured using routers and switches. There are six basic topologies for networks.
Figure 1: Network Topologies (Abyss Computing, 2013)
- Extended Star
- Bus
- Star
- Ring or circular
- Mesh
- Tree/Hierarchical
Different types of topologies are used based on different needs. Bus topology is one of the most popular as it is very easily expandable. Star topology is good in terms of managing a connected system. If one computer is affected the central computer can take that out of the system without affecting others. The one problem of star topology is that if central computer is affected the whole network is affected. Apart from the above six there are other topologies like hybrid topology and daisy chain topology.
5. Discuss role of hardware, software, operating systems and network drivers.
The physical components of a computer are called hardware such as motherboard, CPU, RAM, video card, hard drive, optical drive and so on. The four major functions of hardware include produce output, accept input, process data and store data. Hardware and software share a symbiotic relationship with each other. Hardware would be meaningless without software and software won't function without hardware components. If the hardware is a brain of the computer, software is the body. Software helps run different hardware components coherently with the help of proper protocols.
Windows Server is the most popular of all the operating systems available in the market. It can be used as a domain controller with read/write/copy of active directories. Apart from Windows server other types of operating systems include UNIX and LINUX. There are several network drivers in the market. The selection of network driver depends on the type of operating system and hardware installed in a computer. VXMNET and VXMNET 2 are very robust network drivers but they are limited to certain operating systems. Windows operating system with 32 or 64 bit is compatible with VXMNET. E1000e is very good for both windows and Linux.
6. Explain different connection materials including their specifications and list the criteria you would use to choose such materials.
Networks components are the building blocks to a flexible and robust network. There are different types of network components which make up the network. Cable is the network component used in connecting different components within network. There are different types of cables available in the market. UTP-3 and UTP_5 cables are most commonly used. If price is not an issue then it is advisable to use UTP-5 cable as it can go up-to speed 100Mbps. If none of conventional cables can be used because of big length of the network and huge risk of data loss during transmission then fibre optic cable can be an alternative option. The rating of servers should be one of the highest as servers control network traffic and need to perform compatibly with Ethernet cards. Network adapter cards are changing with every passing year so in terms of network passing card its compatibility with operation system and speed should be considered. Routers are another important component. Router speed ratings are the primary thing to be considered during router selection.
7. Discuss the performance issues related to your selection of technology, software, network components, connection materials and configuration.
There are small things in the Windows Server operating system setting which may cause performance problem such as driver configuration, IP stacking and virtual memory. Therefore, CPU usage should be monitored and configured properly. There should be as less number of programs running as possible in the background all the time. Proper usage of task manager in the windows operating system will enhance system speed. Hard drive is the slowest component of the server as well as individual computers in the network. Using of RAIDs or high end drives may enhance speed significantly but the configuration of the same should be done properly. Firewalls sometimes considerably slow down the network as it checks every element going and out of the network. The best way to handle this is to exempt MTP/IP from the firewall only checking those data elements that are required. Also the slowness in the RAM and VPN settings should be taken care of to improve the performance of Windows server.
8. Network Architecture Diagram
Figure 2: Network Architecture Diagram (World of Network, 2010)
Network architecture is where the whole configuration of the actual network starts. A robust design of the network goes a long way to create an equally robust actual network. Open System Interconnection architectures are not owned by any particular vendor and one can design it as per his wish. If it is difficult to design a new architecture then the standard ones by IBM or Apple, Novell or Cisco can be used. A typical Cisco network architecture is shown below.
Figure 3: Cisco Network Architecture (Edrawsoft, 2012)
9. Describe basic signalling methods and their characteristics.
Figure 4: Baseband and Broadband Signals (Technow,2013)
Computers networks and systems use digital signals for transmission and receiving. Two types of signals are used in computer communications, baseband and broadband. Baseband signals are single digital signal sent or received at a single point in time. It uses a single wire. Baseband signals are bi-directional and it can be achieved using time division multiplexing. Broadband on the other hand use optical or electromagnetic wave to transmit data using more than one frequency.
10. A discussion of the OSI 7-layer model; the role of protocols at different layers of OSI model describing the function of specific protocols. Describe how they are set on a host computer.
OSI model is a model of the communication system inside a network. It defines the protocols for communication using layered configuration. There are seven layers to this model:
- Application layer
- Presentation Layer
- Session layer
- Transport layer
- Network layer
- Data link Layer
- Physical layer
Physical layer consists of network components like routers, switches etc. Data Link layer which is used for network error detection provides the procedural structures to transfer data between network entities. Network Layer defines the IP protocols (IPV4 or IPV6 etc.). Transport layer gives direction about TCP/UDP protocols. It defines how two machines in a system will transfer or exchange data between each other.
OSI defines different classes of transport protocols. Class zero protocol cannot recover error data but Class 4 is very close to TCP in terms of connection methods. Session Layer controls the connections between computers. It helps establish, manage and disconnect connections as per the defined applications rules. Presentation Layer defines the syntax, semantics and rules for the application layer. Application layer is the first layer and it is encountered by the end users. It interacts with the system software and communicates how software should run.
11. Discuss the role of packets and how they are built up from their various components. Explain how data packets are transmitted through the layers of the OSI model.
A data packet is the base unit of communication over a digital network. Data packets are always digital in nature. Large data packets are broken down into smaller packets and then transmitted. Once all packets reach destination they are again reassembled and processed. Data packets differ in structure depending on the protocol they follow. Typical data packets have a header that stores the information about source and destination IP address, sequence of the packet etc.
12. Explain the role of the network interface card (NIC), installation and configuration of a network interface card using NOS tools.
If Microsoft server is used as the administrator operating system then the configuration of the network interface card can be done automatically using Windows PowerShell. In case of UNIX systems the Ethernet interfaces which are generally stored in files /etc/sysconfig/network-scripts/ifcfg-eth0 need to be found out. There may be lot of NIC in the system as each system requires its own NIC configuration. The configuration can be done using fixed or dynamic protocol. In systems where DHCP is enabled there the IP address is provided by DHCP so no need to configure that. In atypical NIC things like Boot Protocol, Broadcasting Protocol, Device Naming protocol, DNS Address, MAC address, IP Address etc. need to be configured. The recommendation will be to use some kind of network manager tool for managing all the NICs configurations. Network Manager is one such tool that can be used (Redhat).
13. Discuss how network drivers are selected and implemented. Describe the installation and removal of a driver.
Network drivers are hardware components attached with the server or the end user computers and machines. Most of the hardware comes with compatibility in windows and UNIX systems. Before buying a network adapter just ensure its compatibility with the operating system. Then once that network driver is connected to the computer slot and the system is started, automatically the new hardware will get installed. If that is not done then one can find the driver from device manager in MS Windows and then manually install the driver. To uninstall an old driver you can use device manager to uninstall it. For UNIX systems the installation can be done using command /usr/sbin/swinstall.
14. Explain the operation of IEEE 802.N network configurations.
802.11N is an amendment to the earlier standards for wireless networks. The new wireless standard allows speeds up-to 600Mbps which is significantly higher than 801.11G which only can handle up-to 54Mbps. This is a new wireless protocol that improves two aspects of network connectivity – speed and security features. This technology also can comprehend data input and output from multiple antennas and channels. This technology is called spatial division multiplexing. This protocol can achieve the speed of 600 Mbps using 40MHZ channel. This technology is in most part backward compatible.
15. Define network architecture. Explain how architecture influences access and control of the network. Describe scenarios where one architecture might be favoured over another.
Network architecture refers to the framework of the computer network that consists of hardware components, software, topologies, communication protocols, physical and wireless routers, cabling and device plans and so on (Cory Janssen). Network Architecture has a huge role to play in the administration and flexibility of any network. For example, if some network is using star topography then it is easier for the network administrator to isolate any computer from the network without affecting others. BUS topology is easy to expand. Similarly, if using Windows server as software then it is easy to operate and maintain on the other hand UNIX is more robust and secure.
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