P2P Systems Techniques and Challenges

Peer-to-peer (P2P) applications have recently attracted a large number of Internet users. Traditional P2P systems however, suffer from inefficiency due to lack of information from the underlay, i.e. the physical network.

Despite all the efforts been put in, a gap has been witnessed between the simulation figured and results and actual real world scenarios. Some researchers have admitted that these simulation results can no way be compared to what they might face in real world networking environment, other than a few researches.

Notable effort and resources are yet to be put into most of these researches in order to make them viable for a real world practical application. One such example is the peer to peer communication optimization which can be very useful for multiplayer gaming and overall file sharing and communication on the Internet.

Other such experiments in the labs have shown extremely positive results which can change the dynamics of underlying networks

New P2P Systems:

• File sharing was first P2P application

• Other applications are coming to light

• BitTorrent: focus more on content distribution than file sharing

– Makes use of common research result (DHT) since 2005

• P2P extending beyond file sharing: Skype

– Skype is a P2P telephone “system”

– Can call other computers, or normal phones

– Based on the KaZaA network

• P2P streaming systems

– PPLive, PPStream

P2P	Client-Server
No central server	Central Server
Suitable for small business org.	Scalable
Inexpensive	Expensive
Not secure	Secure

Conclusion:

Both the peer to peer and client server architectures have their own pros and cons. It depends on the organizational architecture that what suits the best in a particular scenario.

Client Server architectures are expensive and can accommodate large number of users. They are scalable.

For an organization with 30 nodes and data security not an issue, peer to peer is the recommended network architecture. It is cost effective as well as suitable for small organizations.

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P2P Overlay Architecture

P2P overlay network has a wide spectrum of communication frameworks in which peers build a self-organized system that is fully distributed and cooperative. Figure 1 depicts the abstract P2P overlay architecture showing different components of the overlay.

The Network Communication layer describes the network characteristics of an end system/node connected via internet, small wireless or sensor-based devices.

The Overlay Nodes Management layer plays its part as management of peers which includes discovery of peers and optimized routing algorithm.

The Features Management layer deals with security, reliability, fault tolerance, and robustness of P2P system.

The Service Specific layer is to provide support to Application layer to utilize the underlying resources in an efficient manner. It schedules the parallel and computation-intensive tasks, and performs task like file management and provides content. Here meta-data describes the information about content stored across the peers and their location information.

The Application level layer describes the actual functionality implemented over the underlying P2P overlay networks.

Structured P2P:

In structured overlay network the network assigns keys to data items and organizes its peers into a graph that maps each data key to a peer. Such structured P2P systems use the Distributed Hash Tables as a substructure where data objects either values or location information is placed.

Unstructured P2P:

In unstructured overlay networks the overlay network organize peers in a random graph in flat or hierarchical manner and uses flooding or random traversing or expanding Time-To-Live search on the graph to query content stored on overlay networks.

Distributed Hash Tables:

­­­­ Current widely-used P2P networks rely on central directory servers or massive message flooding, clearly not scalable solutions. Distributed Hash Tables (DHT) are expected to eliminate flooding and central servers, but can require many long-haul message deliveries.

Although many theoretical schemes for minimizing routing information have been proposed and many designs for DHTs have recently become prominent discussion topics, we are unaware of any practical and efficient system combining both.

Latest Research in P2P:

In order to get the latest that is happening in this area I decided to get some latest research papers online and went through them. According to my limited research that I did on this topic I found out that the over lay under lay mapping is very important in this domain of network models. The nodes that are that are connected logically should be close to each other physically as well in order to avoid network congestions and other delays.

Following is a brief summary of the latest research being carried out.

EGOIST Overlay Routing using Selfish Neighbor Selection

This paper discusses the issue of connectivity management, folding new arrivals into an existing overlay. Work has been done on this matter before dealing with devising practical heuristics for specific applications designed to work well in real deployments, and providing abstractions for the underlying problem that are analytically tractable, especially via game-theoretic analysis. The authors of this paper have combined these two approaches and came up with a distributed overlay routing system called “Egoist”. Connectivity management is called upon when having to wire a newcomer into the existing mesh of nodes (bootstrapping), or when having to rewire the links be- tween overlay nodes to deal with churn and changing network conditions. Connectivity management is particularly challenging for overlay networks because over- lays often consist of nodes that are distributed across multiple administrative domains, in which auditing or enforcing global behavior can be difficult or impossible.

In a typical overlay network, a node must select a fixed number (k) of immediate overlay neighbors for routing traffic or queries for files. To solve this, the authors tried and tested the selfish neighbor selection technique which was different from traditional techniques. DHTs are able to provide the best possible indexing of objects in a network. On the other hand, routing of traffic on DHTs has been shown to be sub-optimal due to local forwarding [17, 24]. Egoist can be integrated as a different layer in DHTs; when an object is mapped onto a node, Egoist is responsible to optimally route the content. In Egoist, a newcomer overlay node vi connects to the system by querying a bootstrap node, from which it receives a list of potential overlay neighbors. The new- comer connects to at least one of these nodes, enabling it to participate in the link-state routing protocol running at the overlay layer. As a result, after some time, vi obtains the full residual graph G−i of the overlay. By running all-pairs shortest path algorithm on G−i, using Dijkstra’s algorithm, the newcomer is able to obtain the pair-wise distance (delay) function dG−i . In addition to this information, the newcomer estimates dij , the weight of a potential direct overlay link from it- self to node vj , for all vj ∈ V−i. Using the values of dij and dG−i , the newcomer connects to G−i using one of a number of wiring policies. Each node listens to all the control messages of the link state protocol and propagates them only to its immediate neighbors. In order to reduce system’s control traffic, each node propagates only unique messages by dropping messages that have been received more than once or have been superseded. In Egoist, a node selects its neighbor based on best response strategy. They also employed fast approximation versions based on local search instead of long arithmetic computation which will not only reduce computational cost but also enhance scalability. Egoist’s BR neighbor

selection strategy assumes that existing nodes never leave the overlay. Therefore, even in an extreme case in which some nodes are reachable through only a unique path, a node can count on this path always being in place. This can be a one set back of this technique. Egoist also deals with the cheating nodes (using the system to route one’s own traffic but denying routing to any incoming traffic from other nodes) very efficiently in which the nodes periodically select a random subset of remote nodes and “audit them” by querying the coordinate system for the delays of the outgoing links of the audited nodes and comparing them to the actual values that the audited nodes declare on the link-state routing protocol.

Delays are natural cost metrics for many applications, especially those involving interactive communication. To obtain the delay cost metric, a node needs to obtain estimates for its own delay to potential neighbors, and for the delay between pairs of overlay nodes already in the network. Using ping, one-way delay is estimated to be one half of the measured ping round-trip-times (RTT) averaged over enough samples. The performance of the system was measured on the basis of different cost metrics such as link and path delays, node load and available bandwidth. Results of the experiments are represented graphically which showed a positive outcome and the system out performed similar previous work done relating to this. They’ve also made it available for use for any third party application through their API. This way, both the application and its Egoist node run at the same node.

This was a very comprehensive paper about the work that authors of this paper carried out. All the basic working, idea behind it and the results were shown in detail explaining every aspect if the new system that they’ve designed. This work definitely have a lot of real world application as the one they’ve explained (Multiplayer P2P gaming) which makes it an extremely appealing and the best strong point of this paper.

Other Hot Areas:

·        

    Improving Unstructured Peer-to-Peer Systems by Adaptive Connection Establishment

    ·           Improving the Interaction between Overlay Routing and Traffic Engineering

    ·         ISP-Friendly Live P2P Streaming

    ·         Scalable Resilient Overlay Networks Using Destination-Guided Detouring

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Peer to peer

Peer to peer is a network model in which all the nodes (peers) interact with each other directly. There is no central server involved to handle the requests.

P2P is in contrast to Client-server in which there are clearly defined roles for client and server.

An example of p2p organization of nodes

Nodes can be organized in any topology but the real essence od peer to peer systems is that there is no central service provider involved but peers interact with each other on equality basis. It has its pros and cons.

Introduction:

Peer to peer systems are those systems which take advantage of storage, cycles, human presence or content available at the end systems of the internet while overlay networks are termed as those networks that are constructed on top of other networks e.g. IP. So peer-to-peer overlay network is a network which is created by the internet peers in the application layer on top of the IP network. In these types of systems the end nodes/systems share their resources such as processing power, network bandwidth and memory storage among themselves to accomplish a set of common tasks in a distributive manner without need of any central coordination system. These systems are self-organized. All peers organize themselves into an application layer on top of IP layer. These are highly scalable and have the capability to grow accordingly with utilization. End systems empowers each other as the consumers are also provider of their resources at the same time. P2P overlay networks are highly reliable too as there is no single point of failure and redundant overlay links ensures availability if a single link got damage or disconnected. These systems are easy to deploy because they are self-organized and there is no need to deploy any server. Now a days peer to peer networks are being used in many ways. Some of them are P2P file sharing applications like Napster, Gnutella, Kaza, Emule, Edonkey, Bittorent etc., media streaming, Grid computing, community networks, instant messaging systems, online chat networks and a very interesting use is Bitcoin a peer-to-peer based digital currency. In peer-to-peer overlay systems there is symmetry in roles where every nodes is client and a server at the same time.

P2P Basic Principle:

The main concept of the p2p and its characteristics are;

– Self-organizing, no central management

– Resource sharing, e.g., files

– Based on voluntary collaboration

– Peers in P2P are all equal (more or less)

– Large number of peers in the network

Definition of P2P:

A P2P system exhibits the following characteristics:

1. High degree of autonomy from central servers

2. Exploits resources at the edge of the network

3. Individual nodes have intermittent connectivity

• No strict requirements, instead typical characteristics

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Virtualization

Virtualization:

It refers to the concept of creating something that does not exist in real. In virtualization an imaginary version of something is created rather than creating that in real.

The concept of virtualization is not limited to software only. Hardware resources are also associated with this concept now.

Definition:

          “It is a technique for hiding the physical characteristics of computing resources from the way in which other systems, applications, or end users interact with those resources”

History:

It was started in the 60’s by IBM M44/44X

It was abandoned in the 80’s and 90’s because the cheaper  x86 machines were more famous.

But VMware started virtualization in 99.

CPU Virtualization Architecture:

Full Virtualization:

Virtualization layer uses binary translation to replace with privileged instruction with instructions that have the same affect on the Virtual Machine.

Para Virtualization:

Guest operating systems is modified to call functions instead of issuing privileged instructions.

Hardware assist:

CPU support of virtualization is present that eliminates the needs for binary translation.

 Memory Virtualization Architecture:

Hardware supports virtual to physical translation of messages. Another layer from guest physical to host physical is needed for virtualization. This is done with shadow page tables that hold guest virtual to host virtual translation that are loaded to the hardware for direct translation.

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Client Server Architecture

The client server is one of the most common and widely used models in the world right now. In this model there is a dedicated machine called server that has all the resources (software and in some cases hardware too) and other terminal make use of those resources by sending request to that central server.

It is a distributed application structure in which the server serves the clients as per their requests. There are many models developed and design for the handling of these requests from the client. Mostly FIFO is implemented in which the clients coming first are served first.

Servers are powerful machines normally that are dedicated to manage the resources like disk drives, printers etc.

The main advantage of client server architecture is the security that it provides. The content is placed on one central server so you just have to secure that machine. The point that comes against this argument is the single point of failure aspect of client server model that has been continuously under debate for a very long time now.

Definition of Client-Server Network model:

      

  “An architecture in which the user's PC (the client) is the requesting machine and the server is the supplying machine, both of which are connected via a local area network (LAN) or a wide area network (WAN) such as the Internet”

Advantages of Client-Server Network model:

Centralization:

The main advantage of the Client Server architecture is the centralization of resources. There is just one place that needs that needs ot be managed in terms if data security and access rights.

Scalability:

These systems are scalable and any number of clients can be handled if the server capacity is increased. The main reason behind that is that any element can be upgraded as and when wanted so it increases the computing power of the server.

Flexibility:

­The modularity in the system architecture provides the benefit of flexibility. Any change can be reversed or deployed as per requirements. The system is adaptable to these changes as it has been designed that way.

Interoperability:

All the components involved in this architecture work together. These components include client, server and other network components.

Security:

It is easy to maintain a single node’s security then to manage a distributed system in which nodes come and leave any time.

Disadvantages of Client-Server Network model:

Overloaded Servers:

Traffic congestion is caused when the servers are busy for longer periods of time. The client requests start queuing up which can cause the network to slow down.

Single point of Attack:

Due to the centralized server, the network can be attacked by exploiting a single machine only. The security of the server become ultra important when there is just one point of attack.

Single point of failure:

Whole of the network can go down if there is just one point that is serving the nodes. The super node (server) has all the information related to the network .If that node is compromised then it will be impossible to communicate through that network as nodes don’t have information of the network independently. 

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What is big data?

  Ans:

The data lying in the servers of your company was just data until yesterday – sorted and filed. Suddenly, the slang Big Data got popular and now the data in your company is Big Data. The term covers each and every piece of data your organization has stored till now. It includes data stored in clouds and even the URLs that you bookmarked. Your company might not have digitized all the data. You may not have structured all the data already. But then, all the digital, papers, structured and non-structured data with your company is now Big Data.

Big Data is essentially the data that you analyze for results that you can use for predictions and for other uses. When using the term Big Data, suddenly your company or organization is working with top level Information technology to deduce different types of results using the same data that you stored intentionally or unintentionally over years.

Big Data Concepts:

This is another point where most people don’t agree. Some experts say that the Big Data Concepts are three Vs:

1.      Volume

2.      Velocity

3.      Variety

Some others add few more Vs to the concept:

4.      Visualization

5.      Veracity (Reliability)

6.      Variability and

7.      Value

ü  "Big Data Are high-volume, high-velocity and/or high-variety information assets that require new forms of processing to enable enhanced decision making, insight discovery and process optimization”.

ü  Complicated (intelligent) analysis of data may make a small data “appear” to be “big”

ü  Bottom line: Any Data that exceeds our current capability of processing can be regarded as “big”

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What is Cloud Computing?

  Ans:

"Cloud computing is a new approach that reduces IT complexity by leveraging the efficient pooling of on-demand, self-managed virtual infrastructure, consumed as a service"

A film spotlighting the aspects of using cloud storage that should be addressed by users for data and personal security. Cloud Computing is the internet-based storage for files, applications, and infrastructure. One could say cloud computing has been around for many years, but now a company may buy or rent space for their daily operations. The cost savings in implementing a cloud system is substantial, and the pricing for use of cloud computing can easily be scaled up or down as determined by necessity.

According to Wikipedia:

“Cloud computing is Internet-based computing, whereby shared resource, software, and information are provided to computers and other devices on demand, like the electricity grid.”

Generally speaking, cloud computing can be thought of as anything that involves delivering hosted services over the Internet. According to NIST Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

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What is 5G? What are the Security Concerns?

Ans:   

5G is going to become necessity for the future of the world due to the increasing traffic rate of the data, voice or video streaming in this modern era. The present technologies such as 3G and 4G cannot fulfill the future requirements of the increasing capacity of the traffic of internet data. There is no unique definition for 5G. It is basic step to know that “What is 5G?” in real sense. First of all, we have to take step to clarify the real means of 5G in technological sense.

According to researchers, Scientists and Engineers the 5G will facilitate user with 1000 times greater bandwidth as well as 100 times larger data rate to cover the huge applications of future mobile stations. [2] It is also expected that various techniques to fulfill the user requirements which will be used in 5G, one of them will be THz band mobile communication. [3] The 5th wireless mobile internet networks are real wireless world which shall be supported by LAS-CDMA, OFDM, MC-CDMA, UWB, Network-LMDS and IPv6. Both 4G and 5G has basic protocol which is IPv6.

A number of generation changes have been experienced by mobile technologies, which have transformed the cellular background into a global set of interrelated networks. By the 2020, fifth generation will supports the voice, video streaming and very complex range of communication services over more than Nine billion of the subscribers as well as the billions of  devices which will be connected to each other. But what is 5G? 5G provides the new path to think. It includes radical network design for installing machine-type communication (MTC). And 5G networks will be able to provide efficient support applications with widely varying operational parameters, providing greater elasticity to install services. As the previous generations, 5G is combination of progressed network technologies.

 Coming technology (5G) would have the ability to share date everywhere, every time by everyone and everything for the benefit of human, businesses and society as well as the technological environment by using bandwidth of unlimited access for carrying information. The year 2016 is an expected year to take steps for proper and Standard activities are started and leading to commercial availability of the equipment and machinery around 2020. Future technology (5G) is much more than new set of technologies that will require enormous equipment/devices or machinery upgrades as compare to the previous generations. The purpose of this technology is to build on the development that the telecommunication systems have already been reached. The complementary technologies (Combination of core and cloud technologies are called complementary technologies) which evolve many existing radio access will be used to cater more traffic of data, more types of devices under different operating requirements with different cases in 5G.

Nevertheless, a universal agreement is building around the idea that 5G is simply integration of number of techniques, scenarios and use cases rather than the origination of a new single radio access technology. The estimated performance levels that 5G [6] technologies will need to cater for:

§  10 to 100 times higher typical user data rate,

§  10 times longer battery life for low power devices,

§  10 to 100 times higher number of connected devices,

§  5 times reduced end-to-end latency,

§  1000 times higher mobile data volume per area. 

Figure 1 shows estimated performance levels of fifth generation technology need to meet requirements.

Now the problem is that “How will we get there?” Next generation (5G) will mostly allow for connectivity. But this technology is not developed in separation. The developing next generation will play significant role in shaping various factors such as long term sustainability, cost, and security and need to give connectivity to the billions of subscribers. While the comprehensive conditions for 5G have nevertheless to be set, it is clear that flexibility to accommodate for thousands of use cases is the key to 5G and what it will enable. The parameters that 5G technology will be developed upon include:

§  Data integrity,

§  Latency,

§  Smart communication.

§  Traffic capacity,

§  Data throughput,

§  Energy consumption, 

§  Technology convergence.

A cognitive radio is an intelligent radio that can be programmed and configured dynamically. Its transceiver is designed to use the best wireless channels in its vicinity. Such a radio automatically detects available channels in wireless spectrum, then accordingly changes its transmission or reception parameters to allow more concurrent wireless communications in a given spectrum band at one location. This process is a form of dynamic spectrum management.

A we all know, one of the fundamental issue is the increasing challenge of acquiring adequate spectral resources in radio frequency bands to operate 5G cellular systems. All over the world, a large amount of spectral resources are still utilized in a static and therefore, inefficient manner. Hence, Cognitive Radio (CR), with the capability to be aware of radio environments and flexibility adjust its transceiver parameters, has drawn much attention in academia and recently also in industry and has been proposed as an enabling technique to dynamically access the underutilized spectral resources. The previous research on CR was focusing on improving the utilization of radio spectrum resources mainly within the primary-secondary user models in the UHF TV band. In 5G wireless communications, to meet the challenging requirements of huge capacity, massive connectivity, high reliability and low latency, CR is expected to play an important role in two aspects. First, since the spectrum band for 5G will be extended to even mm Wave range, CR can still be used to improve the spectrum utilization while protecting much larger range of coexisting users and within broader types of spectrum sharing models, such as licensed spectrum sharing (LSA) and dynamic spectrum leasing etc. Second, 5G will take aggressive spatial reuse of spectrum as one of the key enablers with new techniques such as massive MIMO and Ultra-dense Deployment. In this context, CR can be used to mitigate the interference issues from space, frequency and time domains with a very dynamic manner. We define an attack on cognitive networks as any activity that results in

1.      Unacceptable interference to the licensed primary users or

2.      Missed opportunities for secondary users

Attacks against CRs and CRNs are:

1.      Incumbent Emulation attacks

2.      Spectrum Sensing Data Falsification attacks

3.      Cross layer attacks

Security Concerns in 5G:

Where there is information, there is a critical need for security. Security is one of the important issues for the proposed adaptive and reconfigurable wireless network testbed. The meaning of security is twofold. First, the data sent out by the nodes should be encrypted, to prevent unauthorized users from intercepting the data over the air. However, cryptographic algorithms impose tremendous processing power demands that can be a bottleneck in high-speed networks. The use of FPGAs for cryptographic applications has become highly attractive.

Cryptographic algorithms will be implemented on the two FPGAs on the proposed motherboard for the nodes of the network testbed. However, for the network testbed for smart grid, the optimal choice for the cryptographic scheme is the topic of ongoing research. Second, the reconfigurable FPGAs in the network testbed should have the capability of protecting themselves from being invaded or tampered.

Security is more important than any other performance of interest for the micro grid. To realize a secure system, security should pervade every aspect of the system design, and be integrated into every system component. For information flow, information security for the micro grid should include data confidentiality, data authenticity, data integrity, data freshness, data privacy, public key infrastructure, trusted computing, attack detection, attack survivability, intelligent monitoring, cybersecurity, and so on. For power flow, autonomous recovery is the main security consideration. The micro grid should have the capability of performing real-time monitoring and quick response.

ü  Heterogeneity of wireless networks complicate the security issues. Dynamic reconfigurable, adaptive and lightweight security mechanism should be developed.

ü  Authentication of user is a big problem in heterogeneous wireless networks.

ü  Security in smart grids may be generalized into two main areas:

·         Physical layer

·         Cybersecurity

ü  Interoperability of Security enabled IoT.

ü  Security for M2M Communication.

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What is Website designing?

                            Website designing is very large platform in this world. Every person want to start

own business at home. But this is true it is not easy job. Every person wants to earn money from internet through the website. Website is main source to earn money from internet. Google adsence is a big way to earn money from internet. When we design and develop a complete site then we customize in google through google webmaster tool. We add the web pages in Google Master tool then Google index the our all web pages.

Website Designing:

                            When we start a build the website then we must think about in this thing which data we provide to common user. These are languages must use in website designing.

1.       HTML

2.       CSS

3.       CSS3

4.       HTML5

HTML:

HTML stands for Hyper Text Markup Language. HTML is basic language of Website designing. We cannot develop and design the website without HTML. HTML provides us basic tags and elements for build the website.

CSS:

CSS stands for Cascading Style Sheets. We can use the colors, width, height, padding, margin, borders, color adjustment, hover, text-style, and more properties for designing the website.

 

CSS3:

 

CSS3 is most advance language. We can design stylish text box, stylish popup menus, text shadow, text rotate, and more advance properties in website.

 

HTML5

 

HTML5 is most advance Language. We can add the movies, audio files, video files and other files with the help of HTML5. We can also make mobile application, web games, web base application in HTML5. 

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