UK Essays Services:

Free Help:

Free Essays - Essays

Peer Network Architecture

Section 1 P2P versus Client server networks

1 a The motivating factors for the development of Peer-to-Peer network architecture

Before discussing the motivating factors for develop the Peer-to-Peer network architecture, let's talk about what is Peer-to-Peer network. The Peer-to-Peer network architecture has been developed for a very long time. The first concept appeared at the year of 1969.

P2P World (2006) defines Peer-to-Peer network is an online community where member is available to share, search and download different types of data/files which are storing in their computers. Every members for the community have their own collection of data/files which it available share to each others in the community. It is no centralized server where files being stored.

The motivating factor for develop the Peer-to-Peer network architecture is because of its advantages. P2P World (2006) states an important target in Peer-to-Peer networks is all clients is available to provide resources which including bandwidth, storage space, and computing power.

Which means as nodes demand and arrive in the system are increased, it will also increase the total capacity for the system. Compare with traditional client-server network architecture, the Peer-to-Peer network architecture without a fixed set of servers. A client-server network when add more clients could result slower data transfer for all connected users.

Another advantage of the Peer-to-Peer networks is it increases robustness and stability. In case of failures by replicating data through over the multiple peers. It also enable peers to search data/files without relied on an centralized index server. Again, compare with traditional client-server network architecture, it without single point of failure in the whole system.

Therefore, with such advantages, Peer-to-Peer networking has becoming a very common architecture and its application are popular use for people around the world.

1 b THREE major types of P2P networks

Hassan1 (2007) defines three major types of Peer-to-Peer networks. This three types of Peer-to-peer networks are classified based on network and application: Collaborative Computing Collaborative Computing also known as distributed computing. Collaborative Computing combines together the idle or maybe unused processing power of the CPU and/or also the free disk space for many computers on the network to process a specific task.

Collaborative computing is popular use in science and biotech organizations where intensive computer processing power is required. One of the examples of distributed computing can be found from the GRID.ORG. On the Grid MP platform, the United Devices hosting a virtual screening for cancer research. It is the biggest computational chemistry project in the history. The United Devices harnessed power of over 2 million PCs around the world and generated over 100 teraflops of power.

Most of the collaborative computing networks are formed by users which they volunteering their idle or unused computing resources to collaborate to the public interest research projects. Instant Messaging It is a very common software using Peer-to-Peer networking architecture. For example ICQ, Skype, MSN Messenger or Yahoo Messenger. Which those applications allow users chat via text messages in real-time and sending date/files. Many software vendors offer a free version of their Instant Messaging software to download and used.

Nowadays, many business organization and corporative have begin to develop their own Instant Messaging software as their standard communications tools for business used. Affinity Communities It is the group of Peer-to-Peer networks which based on file-sharing It is based on users collaborating which allow search other user's computers for data, files and information. It becomes widely known due to the public legal controversy surrounding Napster, which provide online music file sharing service through the Internet.

1 c THREE vulnerabilities particularly linked with P2P technologies

Dubin (2005) shows the three vulnerabilities that particularly linked with Peer-to-Peer technologies are availability, confidentiality and authentication:

Find out how our expert essay writers can help you with your work...

Availability

Unlike traditional client-server network with a centralized dedicated server to handle the heavy traffic, Peer-to-Peer network might suffer from availability issues. Since Peer-to-Peer networks might got a mix of clients with different hardware, not every clients have sufficient CPU processing power and/or sufficient disk space to handle the heavy traffic.

Confidentiality

The traffic between the peers is better protect by encryption once they have authenticate each others. One of the Peer-to-Peer file transfer program which published in Hong Kong, Mainland China and Taiwan named Foxy. Which has many case of disclose confidential information to the public from the government department.

Authentication

For another security issue authentication requires to set up, therefore, only trusted clients can communicate each others. It is because multiple clients are available to access each other and there's no centralized authentication server, therefore, the system should have a method for two clients authentication each other when doing the communication. For example, this can be solved by using key exchanges or a certificates.

1 d Common approaches for building trust relationship between entities on a network

A common approaches for building a trust relationship between the entities on a network, Berket, K., Essiari, A. & Thompson, M. R. (2005) introduce the use of pseudo-certificates. This pseudo-certificates allowed user join a collaborative application easily. Their model enforced an authenticated access to the public resources and allowed user meets each other and facilitates the building of the trust relationships. The use of the resource sensitivity levels allowed a casual collaboration to be secure do not require all users have X.509 public key certificates from the trusted CAs.

1 e Software tools employed to develop trust for a client, a server and the client server network

In client server network, especially in e-commerce, the digitally signed credentials has pass between the client and the server then develop a trust between them. This requires one of them to disclose their credentials to the others before the disclosing one know anything about the one who are receiving.

In order to solve this, the invention implement an negotiation for the credential disclosure named automatic incremental credential disclosure. Every credential which held at the local site is associate with a access policy which base on the opposing site's credentials. The incoming request from the credential is then logically combine with the access policy to derive further negotiation responses.

1 f Software tools employed to develop trust for peers and also, the P2P network

Tranche is the software tool use Peer-to-Peer concept and it mix modern encryption to create a secure distributed file system. It is compatible with any programming language and any operating system and it is independent for any particular centralized authority and suitable for any size of data.

On security, it have the following characteristics:

It's encryption allows people knows which person published data to the network exactly

o It allows the network to prevent illicit data shared across the network and from ever getting published

It simply share the pre-publication data securely with the collaborator and some of the others be able to access it

It have the option to lock or unlock data

It can from any time revoke posted data from network

Section 2 XML based technologies

2 a The differences between the server side development and service centric development

You can get expert help with your essays right now. Find out more...

Server side development

Wikipedia (2008) defines it is a web server technology which user request is satisfied by web server directly performing or running a script to generate dynamic HTML pages. Which usually use for providing an interactive web site interact to a database or store other data.

When server serves data in a common and well known use manner, e.g., according HTTP or FTP protocols, the users may have their own choice for a number of client applications like web browsers. In more specialized applications, the programmers could write their own client, server and communications protocol which only be use either one of them. The operations of such applications would not be considered client-side operations.

Service centric development

Chatarji (2004) states which is a collection of services and those services can be communicate with each others. That communication can involve simple data passing or two or more service coordinating with some activities. The internal and external to an organization and combination of services create a service centric development.

Web Services is a connection technology for service centric development. Web services use XML to create a connection, i.e. exchange messages between server and caller to provide services

Difference

Server-side development is a method to put software components that can serve the visitors visiting a particular website, but in service centric development, services developed can invoke anywhere within a network and can put into distributed server.

2 b The differences between the deployment objectives of XML and HTML

Simply, XML deals with data which is for data storing and denote data element and HTML deals with presentation. However, XML can defines HTML.

W3Schools (2008) defines XML does not do anything since it's for storing data as mentioned above. Moreover, XML with redefined tags, so you have to invent it by your own. By the way, XML is not a replacement for HTML. In many web programs or applications, XML is use for storing data and HTML is use for present the data.

2 c Why a well formed XML document may, or may not, be a valid document

For XML document, Wikipedia (2008) defines there are 2 levels according to their correctness:

Well formed

It is a syntactically correct document and it follows all syntax rules of XML. When a start-tag without a corresponding end-tag then it is not well formed. A document which is not well formed should not be consider as XML. A conforming parser shouldn't allow process it.

Valid

It is a document which is both well formed and follows some semantic rules. Those rules are defined by DTD or XML schema. When a document which contain some undefined element, then it shouldn't valid. A validating parser shouldn't allow process it.

First of all, we use English sentence as an example.

I ABC you

Which the ABC is a verb and the whole sentence is syntactically correct. So this sentence is well formed. Then in order to make meaningful for this sentence, we require to provide the complete meaning of word ABC. Otherwise this sentence is invalid.

"I ABC you" which is well formed but it is invalid.

"I love you" which is well formed and valid.

Therefore, not just grammar, the meaning should also be valid.

So we use real XML document as example:

<?xml version='1.0' encoding='UTF-8' standalone='no'?>

<!DOCTYPE Staff SYSTEM "staff.dtd" >

<Staff>

<Name>

</Name>

<Project>JumboProject</Project>

<Project>TinyProject</Project>

<Project>others</Project>

</Projects>

<Email>YuPong.Lau@unisoftnet.com</Email>

</PhoneNumbers>

<Street>12 KenswoodCourt</Street>

<City>HongKong</City>

</Address>

Find out how our expert essay writers can help you with your work...

</Staff>

This document include a reference to DTD, a validating parser should allow process it. But 2 elements are missing which are "Title" and "Cell", so this XML document is well formed but invalid.

<?xml version='1.0' encoding='UTF-8' standalone='no'?>

<!DOCTYPE Staff SYSTEM "staff.dtd" >

<Staff>

<Name>

</Name>

<Title>System Engineer</Title>

<Project>JumboProject</Project>

<Project>TinyProject</Project>

<Project>others</Project>

</Projects>

<Email>YuPong.Lau@unisoftnet.com</Email>

</PhoneNumbers>

You can get expert help with your essays right now. Find out more...

<Street>12 KenswoodCourt</Street>

<City>HongKong</City>

</Address>

</Staff>

This document include a reference to DTD and also syntax correct. So this XML document is well formed and valid.

Section 3 DNS

3 a Define the terms network ID and subnet mask

Ou (2006) defines subnet mask is an important role when defining the size of a subnet. Which the subnet mask could allow you to pinpoint where the end point of the subnet is when you are provide any IP address within that subnet too. The reason why it is calling subnet mask is because it precisely masks out the host bits and the subnet mask leaves only the network ID that begins of the subnet. By the way, the subnet mask consists of 32 bits. In the decimal form, the subnet mask appears just like an IP address. And in the binary form, each of the 32 bits has a value of Zero or One.

Subnets should have a beginning and should have an ending too. The beginning number of the subnet is always a even number and the subnet's ending number is always a odd number. The beginning number is what we called the network ID. Which the network ID is officially design for a particular subnet. Anytime when you would like to refer to a subnet, you should point to its network ID and also point to its subnet mask. Then which defines the size of the subnet mask.

References

P2P World 2006: What is Peer-to-Peer (P2P) Networking?

http://www.solyrich.com/how-p2p-works.asp, [accessed on 21/07/08]

P2P World 2006: Advantages of peer-to-peer networks

http://www.solyrich.com/how-p2p-works.asp, [accessed on 21/07/08]

hassen1 (2007) Types of p2p networks

http://forum.talktopics.com/6298/types-p2p-networks/, [accessed on 22/07/08]

Dubin, J. (2005) P2P availability, confidentiality and authentication vulnerabilities http://searchsecurity.techtarget.com/expert/KnowledgebaseAnswer/0,289625,sid14_gci1140512,00.html, [accessed on 23/07/08]

Berket, K., Essiari, A. & Thompson, M. R. (2005) Securing Resources in Collaborative Environments:

A Peer-to-peer Approach

http://www.osti.gov/bridge/servlets/purl/885232-2TSQUL/885232.PDF, [accessed on 23/07/08]

Wikipedia 2008: Server-side scripting

http://en.wikipedia.org/wiki/Server-side_scripting, [accessed on 27/07/08]

Chatarji, J. (2004) Introduction to Service Oriented Architecture (SOA)

http://www.devshed.com/c/a/Web-Services/Introduction-to-Service-Oriented-Architecture-SOA/4/, [accessed on 27/07/08]

W3Schools 2008: Introduction to XML

http://www.w3schools.com/xml/xml_whatis.asp, [accessed on 28/07/08]

Wikipedia 2008: XML

http://en.wikipedia.org/wiki/XML#Well-formed_and_valid_XML_documents, [accessed on 28/07/08]

Ou, G. (2006) IP subnetting made easy

http://articles.techrepublic.com.com/5100-10878_11-6089187.html?tag=fdpop, [accessed on 28/07/08]

All of the essays in the free essays section were written by students and then submitted to us to display and help others. Thanks to all the students who have submitted their essays to us. You should not hand in our essays as your own. We do not condone plagiarism! If you need custom essay help, then have a look at our essay writing services.