Sunday, January 30, 2011
Nagpur university syllabus (Revised) MBA 3 rd sem IT
Unit 4 -
Friday, December 10, 2010
Mobility Management
1. Infrastructure management that connects two or more cells or networks.
2. Location management and registration management by handoff when mobile devices move from one cell to another cell.
The technique of mobility management is as shown in following diagram:
Tuesday, November 9, 2010
Grid Computing
Grid computing is simply means that the different things to different users. A grid is a collection of machines called as nodes, resources, or clients. Some resources may be used by all users of the grid, while some of them have certain restrictions. Thus grid computing can be defined as pervasive computing in which individual users gain access to computing resources as per their requirements with no information about the location of these resources and technologies hardware, operating system used. Therefore, grid computing can be defined as path of integrating various technologies as well as solutions. Although various kinds of resources on the grid may be shared and used, they are usually accessed by executing application or job. Jobs are programs that are executed at a specific point on the grid. In some cases these job are not executed in parallel due to some restrictions on them else they are executes in parallel. For example, some time some jobs require the output of another jobs. Initially grid computing is implemented internally for particular company or organization. However, nowadays, cross-organizational grids are also being implemented and are important part of business optimization and computing.
Benefits of grid computing:
There are many aspects to grid computing that are typically controlled by sophisticated software’s. These software ranges in capabilities as well as availability.
Grid computing takes the advantage of various computing resources in such a way which is not previously possible.
They can take advantage of underutilized resources to minimizing additional costs in business or organization.
Grid computing uses parallel processing in order to make many applications economically feasible and help in finishing them as soon as possible.
Grid computing makes more resources available to organizations which enhances resource balancing, reliability, and manageability.
The basic security components such as authentication, authorization, and confidentiality used to make data secured while processing within the grid.
Grid topologies:
There are three types of Grid topologies:Intragrid, extragrid and intergrid which are as shown below:
From fig. it is cleared that intragrid consist of basic set of services within a single organization only, extragrid is a combination of two or more intragrids and intergrids consist of dynamic integration of applications, resources, and services with patterns, customers and organizations.
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This article is the topic of unit " Communication Technologies-II " from RTMNU MBA 3 rd sem IT syllabus notes.Further topics will be covered in upcoming blogs For more notes you can also refer to other links as given below:
- http://www.rtmnunetworkingtechnology.blogspot.com
)
Friday, November 5, 2010
Cluster computing
There is an enormous requirement of processing power in many enterprises in order to manage their desktop applications, databases and knowledge management. The solution for this is nothing but cluster computing. Cluster computing is thus referred as the use of multiple computers, typically PCs or UNIX workstations, multiple storage devices in order to provide a single highly available system. Cluster computing is used in many areas such as in hosting websites, in managing game server and in big and/or complex projects in which large mathematical calculations are to be executed.
Definitions:
• Cluster computing is defined as the technique of linking two or more computers into a network by using the advantages of the parallel processing power of those computers.
• Cluster computing is a form of computing in which a group of computers are connected with each other and acts like a single entity.
Benefits:
Benefits of computer clusters are as follows:
1) Helps in reducing the cost.
2) Parallel processing power of clustering are very effective and faster.
3) Provides improved network technology.
4) Computer clusters can be easily expanded by adding more nodes into a network as per the requirements.
5) If a node fails in network then its operation can be simply transferred to another node within cluster, ensuring that there is no interruption in service.
Types of computer clusters:
There are three types of computer cluster which are as follows:
Load-balancing clusters:
It divides the workload efficiently between the available nodes. Thus by distributing the workload, it ensures the optimization of limited processing power.
High availability clusters:
Whenever the problems arise due to mainframe failure in the organizations then high availability clusters are used. It ensures 24/7 access to computational power. In business where data processing is time sensitive, this feature of high availability clusters becomes important.
High performance clusters:
They are designed to perform functions that requires node to communicate as they perform their tasks. E. g, when calculating results from one node will affect future results from another.
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This article is the topic of unit " Communication Technologies-II " from RTMNU MBA 3 rd sem IT syllabus notes.Further topics will be covered in upcoming blogs For more notes you can also refer to other links as given below:
2.http://rtmnuittrends.blogspot.com
3.http://www.rtmnunetworkingtechnology.blogspot.com
)
Sunday, October 31, 2010
Network security and privacy
Security is needed in order to maintain privacy. Thus network must provide security to the data whenever transmitted from one end point to another end point. The desirable properties of secure communication are confidentiality, authentication, message integrity and non repudiation.
Cryptography
technique is generally used in order to provide security to the data while transmitting over network. Thus cryptography keeps information secure from getting into the unauthorized hands or intruders . Basically, Cryptography is the process in which plain text is first encrypted and then transmitted over the network and is then recovered into plain text at destination by using decryption. Process of Cryptography is as shown in following figure.
Encrypted data is referred as cipher text. Various cryptography algorithms are available and are used for encryption as well as decryption of data transmitted over the communication channel. Algorithm uses one or more keys. there are two types of keys: Public key which is publicly available and private key which is known to belonging person only. Intruders may present in between the communication channel. Encryption or decryption algorithms are classified into two types as symmetric and/or asymmetric algorithms. These algorithms help in achieving confidentially and privacy.
This article is the topic of unit " Communication Technologies-II " from RTMNU MBA 3 rd sem IT syllabus notes.Further topics will be covered in upcoming blogs For more notes you can also refer to other links as given below:
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Sunday, October 24, 2010
CDMA
Concept:
CDMA uses cellular network and is used for long distance communication. The initial evolution of CDMA was as 2.5 G. Nowadays CDMA supports high data rate and is thus considered as 3G. It transmits not only voice but also data and multimedia streams.
The important features of CDMA systems are:
1. It is more robust for multi-path delay.
2. Signals from each mobile station are coded with two or three codes.
3. It gives higher quality voice and data transmission with small bit error rate.
4. It has soft handover.
5. It performs power control by open loop or close loop methods.
An autocorrelation code is a multi-bit code which is used for coding the symbols before transmitting, allows the receiver to correlate and extract the symbols automatically. Barker codes and Pseudo-noise (PN) codes are the examples of autocorrelation codes. Barker code gives strong autocorrelation where as PN code gives strong peak with few, low and non-zero values which may results in interference with the users using same spread. Long M-sequence PN code has strong autocorrelation and is used as scrambling code. A short PN code also has strong autocorrelation. for example, in WCDMA short PN code is used.
2. Orthogonal Codes:
Two codes used for coding are referred as orthogonal when there is no effect of interference between two sets of signals on the received output. Orthogonal code do not show the strong autocorrelation property and thus requires the synchronization between transmitter and receiver. It gives zero cross-correlation. Examples of this code are Best code and Walsh code.
Best codes are optimized codes which allows significant correlation and do not create interference in between different channels. Whereas Walsh code are generated from Hadamard matrix with all pairs of rows are orthogonal. Walsh code is used in IS-95/cdmaOne. This code is used for channelization due to orthogonality property. Following table gives information about the different CDMA standards.
Conclusion:
Here we discussed about concept, features, types of codes used in different CDMA standards and different CDMA standards with their properties and uses also.
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This article is the topic of unit " Communication Technologies-II " from RTMNU MBA 3 rd sem IT syllabus notes.Further topics will be covered in upcoming blogs For more notes you can also refer to other links as given below:
1.
http://rtmnupervasivecomp.blogspot.com/
2.
3.
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