Whats The Most Effective Network Topology

Published Date: 02 Nov 2017

Ans: The computers in networks can help to move information from one end to the other speedily and efficiently, without any human participation. It also helps the IT related users, to back up their information at some centralized location, thus ensuring less data loss (Chellis et al. 2000:11). WWW can present the information on huge no. of topics in a smart way (Price 2003:113), so the user may get information at just a click of a button (the Internet 1997: 58). Email (readers Digest 1999:195), Bulletin Boards (Crumlish 1996:16), chatting (Readers Digest 1999:261) and video conferencing (Quinn 2000:206) are the aids provided by networks to the users. Education, health, organization and other fields got aid for information transfer through networks.

You can place both TCP/IP clients and servers and IPX clients and servers on the same Ethernet network, and each client will talk to its server. How do you think this is possible? Support your answers from the literature. Discussion

Ans: It is very much possible to place both TCP/IP and IPX clients/servers, as Ethernet frames carry information packets within the limitations of data field, thus if you transport the packets to their corresponding destinations irrespective of the type of packet, and also that from where it is originated. The part of the message contains the address field within the header that ensures that the message received by the right client.

What is the most effective network topology and why? Be sure to support your answers. Discussion

Ans: I will prefer Mesh topology because it insures fully connected reliable connection with other nodes of the network. It is completely redundant and if one node of a network is down, it will not make any difference in connectivity of other nodes in a network. Star is also a reliable and cost effective solution if you want less cumbersome, low redundancy and easier to set up a network.

Most certainly you should not have any particular best topology. All networks are not the same, they have their own specifications and requirements. You should use a topology which is best suited to your network specifications.

(Ref, Lesson 3: Network Topology, Introduction to Computer Networks

By Instructor: C.Y. Hsieh)

Explain the data link layer switch operation. What is the practical importance of this? Support your answer. Discussion

Ans: The devices (switches and bridges) on layer 2 read all the frames on a particular network. Then they add the source MAC to filter table and keep listening on the port where the frame was arrived. Layer 2 devices also keep the logs of this information in a filter table. These devices always find a particular device and router always find a particular network.The filter tables maintained in switches are used to map individual devices. These tables then send frames to node with destination MAC address. If the destined node get the frame, switch or bridge will stop sending frame to any other segments. This processed is described as transparent bridging. If the frame is received by a layer 2 device it will send that frame to all connected nodes. When an unknown node receives the frame and responds to this frame, the switch or bridge will modify the filter table accordingly to the host’s position in the filter table. In the whole process, destination address was broadcast address and layer 2 devices forward all broadcasts to all the nodes of a network by default.

The advantage of using switches is it has a separate collision domain for all switch ports and the domain of broadcast is same for every port. Layer 2 switch is important as they are responsible for error checking too.

(Ref. Network Switching and Technology – Lesson 2 – Nortel Networks)

(Ref. Hubs vs. Switches vs. Routers v1. 31 – Aaron Balchunas)

Identify multiple wireless technologies. Compare them to one another and with Ethernet. Be sure to support your answer. Discussion

Ans: There are several wireless technologies available nowadays which are as follows:

Bluetooth

WI-Fi

3G (Third Generation)

Comparison:

In comparison with other wireless technologies, Bluetooth has low cost and low power consumption. It is a radio frequency cable for short distance communication. It has a range of approx 33 meters with a bandwidth of 2.4GHz. Its data transfer rate is approximately 1.5MB per seconds.

On the other hand, WI-Fi or wireless LAN is a network based on series of IEEE specifications named as 802.11. It supports longer communication range, ranging from 100 to 150 feet with a bandwidth of 2.4GHz. It can support data transfer from 11 to 54 MB per seconds.

3G or Third Generation has transformed the wireless communication into real time connectivity and online. 3G supports range all over the globe. It can support bandwidth ranging from 800Mhz to 1900Mhz which is lower as compared to other wireless devices and a data rate of 2 MB per seconds.

Ethernet or Wired LAN is a connection based on two or more computers connected directly via wire. Because of wired connectivity computer needed to be placed close or on same workplace which means less range. It can support 100 GHz bandwidth and data transfer in Giga bits per seconds.

(Ref. A Review of Wireless Technology Usage for Mobile Robot Controller - Saliyah Kahar, Riza Sulaiman, Anton Satria Prabuwono, Nahdatul Akma Ahmad, Mohammad Ashri Abu Hassan)

Telephone modems convert analog signals to digital signals and digital signals to analog signals. Codecs convert analog signals to digital signals and digital signals to analog signals. How are modems different from codecs? Support your answer. Discussion

Ans: Modem is an electronic device and used for transferring data from one place to another on a digital or analogue medium. Then information is encoded into analogue or digital signals based on the type of communication medium used and then transferred. At receiving end, the received information is decoded and then interpreted.

On the other hand, codecs are softwares that helps computer in understanding digital information in files and presenting it to the user. So codecs are the program that helps the user in understanding information and modems are device which listens and transfer information and interpret it.

(Ref. G.Clear, GSMFR, and G.726 Codecs and Modem and Fax Passthrough - Cisco)

Data Encoding Techniques

Several Internet access systems are asymmetric, with higher downstream speeds than upstream speeds. What are the benefits and disadvantages of such a system? How will you know whether this is good for your system? Support your answer. Discussion

Ans: Asymmetric systems have higher downstream than upstream speed, such type of connections is very much suitable for Internet consumers who need to download files rapidly, but they don't really need to upload files too often or faster.

Benefits:

ADSL is especially suited for gamers and streaming multimedia and downloading huge files.

ADSL is an "always on" service, means it automatically stays connected as long as your system is powered on, unless the connection is manually disconnected via software or hardware.

ADSL doesn’t require the use of a second phone line.

ADSL provides affordable broadband access.

Disadvantages of ADSL:

The location of the subscriber should remain within the boundaries of 5km from the telephone exchange, the greater the distance, the lesser will be the speed.

The user cannot upload the large file quickly.

Quality of Service (QoS) issues, and application output cannot always be measured.

Reason:

ADSL is much better because of the reasons;

It is cheaper than others.

 You can hold phone conversations without needing a separate line.

ADSL is ideal for most of the homes and middle level business firms, where they have to download much more data as compared to uploading.

(Ref, Page 6-10, Asymmetric or Symmetric?, white paper by Peter Murray )

For security reasons, many organizations do not allow error reply messages to leave their internal internets. How, specifically, could hackers use information in echo reply messages to learn about the firm's internal hosts? Does the same thing apply to ping requests? Support your answer. Discussion

Ans: Many organizations do not allow error reply messages to leave their internal internets because the hackers are always searching for vulnerabilities. When they found any, they exploit it and generate the error reports so that they can get the internal information of the system. It is better not displaying the echo messages, as due to these echo messages hacker could get to know that the system is being hacked or not. The errors are produced in special conditions such as:

The network is inaccessible: this error would help map the network.

The host is inaccessible: would show what hosts are online

Protocol inaccessible: shows what protocols are supported

Port inaccessible: some servers would indicate through this error message that no process is listening on that port

The datagram is too vast: would show what technology is used in the network

ICMP error messages are not usually involved in directly attacking the network but would help an attacker apprehend more about the network and know how and where to attack it. So this information should not leave the network because it should not be accessible to people outside the network. PING is an application of ICMP.

(Ref, Chapter 8: TCP/IP internetworking, Business Data Netwirks and Telecommunication, 7th Edition)

While there are many commercially available tools for managing your network, what are five (5) tools for network management that are available through open source/freeware/shareware that you would recommend. Provide a justification for why that tool was chosen and what purpose it would serve. (What information will you gain from each tool and what will you do with that information?) Essay 

Ans:

NetXMS

It’s an open source project runs on both windows and Linux. SNMP is used as well as Linus or windows agents. It also automatically discovers network nodes. The installation process is much easier as compare to other available softwares. It supports a broad range of databases like MySQL, MS SQL and SQLite etc and unified web based user interface.

OpenNMS

OpenNMS is also Open Source Solution build on Java, PostgreSQL and Tomcat. It is the oldest one available and is also free. It can be used for a large number of IP hosts. Basic network monitoring is quite easy. It also provides ICMP response time monitoring.

Groundwork Monitor

It is an open source network monitoring system built around PHP and Apache. Nagios and NMap are also wrapped up with it. It supports lots of agents, provides commercial support and active development.

Nagios

Free open source network solution implemented by the largest number of users. A Linux based solution which provides the much powerful agents as compare to others.

HP OpenView

It is a De-facto Standard. Usually, it is deployed in large heterogeneous IT infrastructures. It is very powerful with lots of available add-ons.

(Ref. Popular Network Management Software in Comparison - http://ipinfo.info/html/network_management_software.php)

What is the best form of authentication? Why? Support your answer from the literature. Discussion

Ans: Authentication is a process of verifying identity of users, networks etc. Several methods have been devised for handling user authentication. Plain password, are one of the most widely used and the easiest to implement method amongst all these. This method, as previously stated is easy to implement but generally weak in nature. Other methods include secure socket layers, digital signatures, IP Sec etc.

(Ref. An Overview of Different Authentication Methods and Protocols - SANS Institute Reading Room site)

The best authentication technique is the usage of biometric devices that require the verification of biological or behavioral actions. Biometric devices can analyze fingerprints, faces, hand figures, irises, retinas, handwriting and voice. The reason why biometric is the best form of authentication is that the biometric is difficult to replicate any other person’s retinal pattern or voice, as a result the information is protected from invaders. It is also easy to use, as there is no need to remember any passwords or personal identification numbers.

(Ref - A, Authentication gets personal with biometrics, Authors: Javier Ortega-Garcia, Josef Bigun, Douglas Reynolds, and Joaquin Gonzalez-Rodriguez)

( Ref - B, BIOMETRIC: CASE STUDY by Sushma Jaiswal, Dr. Sarita Singh Bhadauria and Dr.Rakesh Singh Jadon)

What role does strategic management play in network management? Why? How does one go about it? Support your answer. Discussion

Ans: Network management is a process that includes decision making services such planning, positioning, coordination, resource allocation and strategic development etc. Strategic management has in important part to play in network management at an organizational level. It will be necessary to provide conditions under which managers could implement organizational and partnership strategies. This particular strategy can help in finding out the flexibility of networks to be managed, the key roles of individuals in such management and ways of effective management. It helps to get an understanding of the difference between management and leadership skills for network environment and that for a single organization. (Managing Across Diverse Networks of Care: Lessons from Other Sectors, by Nick Goodwin, Perri 6 , Edward Peck, Tim Freeman & Rachel Posaner)

Strategic management guides that how, why and what technology product should be used or implemented in order to get a long term reliability and benefits. While designing the networks, one should know the aims of their organization like whether they want to gain the market share or whether they want to set the monopoly in the market etc. If the firm has a clear vision, aims and objectives then they can make a much more accurate strategies.

(Ref, NETWORK MANAGEMENT AS A WAY TO MANAGE INTELLECTUAL CAPITAL by Mag. (FH) Eva Eckenhofer)

What is cloud computing? How does that relate to Software as a Service (SaaS)? Service oriented architecture (SOA)? Simple Object Access Protocol (SOAP)? Support your answer. Discussion

Ans: Cloud computing are the services or applications which are available to users with an Internet connection. It has brought a change in how systems are developed, how the resources are organized and in the ways of delivering services.

(Ref. Introduction to Cloud Computing and Security- Securing the Cloud, 2011, Pages 1-27 - Vic (J.R.) Winkle)

Cloud computing is a subscription based services available over the internet. For example your email clients like Gmail, hotmail and yahoo, where these services available to take care of all your emails over the internet. You don’t have to have all those emails in your personal computers. The concept of software as a service is one in which the user is able to use the some required service provided at cloud infrastructure, through web browsers. E.g. web-based email, games etc. The user does not have the rights to control, manage or change the cloud infrastructure like the OS, servers, network settings/details, preferences etc.

Software as a service is a refinement, a hierarchical view of the cloud. It uses Service oriented architecture (SOA) to describe high level services provided on a cloud. SOA is encouraged to be used by organizations if they are moving toward cloud computing. SOAP is a protocol for communication between clients and cloud services.

(Ref. A reference model for developing cloud Applications - Mohammad Hamdaqa, Tassos Livogiannis and Ladan Tahvildari )

Is Software as a Service a secure mechanism for software acquisition? Why or why not? Be thorough in your answer and provide substantive support. It might help to think of this in terms of a specific company or class of companies. Essay

Ans: The development of SaaS as a software delivery mechanism is very useful, it produces a chance for Information Technology (IT) departments to change their attention from supporting and deploying applications for handling the services that is provided by those applications.

Key Outcomes

In SaaS market, Trustability factor is a competitive differentiator.

Some SaaS assistances include higher levels of security and flexibility than most organizations can provide in house.

The industry is progressing and analysising a risk assessment model that will make significant use of

Neutral third parties and standardized certifications.

The level of transparency provided today, even by leading vendors in this space, is

Immature compared

Understanding SaaS

Simply put, SaaS can be defined as "software deployed as a hosted service and accessed over the Internet." SaaS as a concept is often associated with the application service providers (ASPs) of the 1990s, which provided "shrink-wrap" applications to business users over the Internet. These early attempts at Internet-delivered software had more in common with traditional on-premise applications than with modern SaaS applications in some ways, such as licensing and architecture. Because these applications were originally built as single-tenant applications, their ability to share data and processes with other applications was limited, and they tended to offer few economic benefits over their locally installed counterparts.

Today, SaaS applications are expected to take advantage of the benefits of centralization through a single-instance, multi-tenant architecture, and to provide a feature-rich experience competitive with comparable on-premise applications. A typical SaaS application is offered either directly by the vendor or by an intermediary party called an aggregator, which bundles SaaS offerings from different vendors and offers them as part of a unified application platform.

In contrast to the one-time licensing model commonly used for on-premise software, SaaS application access is frequently sold using a subscription model, with customers paying an ongoing fee to use the application. Fee structures vary from application to application; some providers charge a flat rate for unlimited access to some or all of the application's features, while others charge variable rates that are based on usage.

On the technical side, the SaaS provider hosts the application and data centrally—deploying patches and upgrades to the application transparently, and delivering access to end users over the Internet through a browser or smart-client application. Many vendors provide application programming interfaces (API) that expose the applications data and functionality to developers for use in creating composite applications. A variety of security mechanisms can be used to keep sensitive data safe in transmission and storage. Application providers might provide tools that allow customers to modify the data schema, workflow, and other aspects of the application's operation for their user.

Benefits of Consuming SaaS

Of course, just because you can add SaaS to your IT infrastructure is not by itself a reason to do it; there has to be a viable business reason, too. SaaS offers substantial opportunities for organizations of all sizes to shift the risks of software acquisition, and to move IT from a reactive cost center to being a proactive, value-producing part of the enterprise.

Managing the Risks of Software Acquisition

Traditionally, deploying large-scale business-critical software systems, such as ERP and CRM application suites, has been a major undertaking. Deploying these systems across a large enterprise can cost hundreds of thousands of dollars in upfront licensing cost, and usually requires an army of IT personnel and consultants to customize and integrate it with the organization's other systems and data. The time, staff, and budget requirements of a deployment of this magnitude represent a significant risk for an organization of any size, and often puts such software out of the reach of smaller organizations that would otherwise be able to derive from it a great deal of utility.

The on-demand delivery model changes some of these. SaaS applications don't require the deployment of a large infrastructure at the client's location, which eliminates or drastically reduces the upfront commitment of resources. With no significant initial investment to amortize, an enterprise that deploys a SaaS application that turns out to produce disappointing results can walk away and pursue a different direction, without having to abandon an expensive on-premise infrastructure.

Additionally, if custom integration is not required, SaaS applications can be planned and executed with minimal effort and roll-out activities, creating one of the shortest time-to-value intervals possible for a major IT investment. This has also made it possible for a number of SaaS vendors to offer risk-free (and often literally free) "test drives" of their software for a limited period, such as 30 days. Giving prospective customers a chance to try the software before they buy it helps eliminate much of the risk surrounding software purchase.