What is peer-to-peer networking and what has caused it to come of age? This article discusses the differences between peer-to-peer networks and client/server networks. It describes the new types of peer-to-peer networks that are now possible with the increased use of mobile devices, and it details some of the new products that have been developed for the mobile arena on the principals of peer-to-peer networking. Additionally, it takes a look at security as a concern that peer-to-peer applications should address and touches on the challenges faced by corporations as they struggle to maintain intellectual property.
Peer-to-peer networking has often been considered as the “new-comer” of the computer communication family while the client/server file-share scheme has been the “incumbent.” In fact, many modern, savvy, and otherwise knowledgeable people may not even know what peer-to-peer networking is. It’s not considered mainstream but rather is thought of as a hip and cool underground process for collecting media files (to coin phrases from the 60’s). Discussed in this article are the how and whys of peer-to-peer (P2P) networking, what new benefits are either here already or coming soon in the mobile environment, and finally the main issues that revolve around P2P security, both in the personal and business worlds. Driven by the explosion of mobile devices, peer-to-peer networking is finally growing up and standing on its own two feet.
Arguably, the most widely understood version of networking is the client/server method where many computers are connected to a set of central computers (referred to as servers). These servers handle communication and data transfer between all the other devices (that is, the clients). With peer-to-peer networking the primary concept is that each computer in the network functions as both a server and a client. Communication can occur directly between every connected computer. Bandwidth and resources for each task are allocated by each computer independently. A chat session between Alice’s computer and Bob’s computer will not hinder Charlie’s computer, which is transferring a file from David’s computer.
However, David’s computer might not have all the info that Charlie’s computer needs. Therefore, Charlie would have to initiate a search to locate another computer in the network containing that information. Depending on the search algorithm, the amount of bandwidth used to process that search across a small network probably wouldn’t be significant. Charlie’s computer would have to contact each computer on the network individually and search its list of shared files for the desired data. However, what if the network is thousands or millions of attached devices? Multiply the time and bandwidth spent searching one computer’s files by hundreds, thousands, even millions, and the time and bandwidth expenditure increases dramatically. For this reason, most newer peer-to-peer applications are a mixed breed: a server is used which contains search tools and file location information while file transfers are accomplished directly from computer to computer.
File sharing and downloading of music, video, and games has long been a use defined for peer-to-peer networks. BitTorrent is one of the more popular ones in existence today, and it is free to users. BitTorrent DNA, a new service being offered at the site, focuses on business use, promising faster and more reliable downloads of your content for use in a privately secure peer network.
One of the more widely used peer-to-peer programs is Skype, an internet telephony device that allows users to call other Skype users over the internet for free, or to call any landline or cell phone for a cost. A version of Skype, called Skypein, allows the user to obtain a phone number in their own or another country. Friends in that country would call the local number and the user through their computer would receive the call. This particular service is not available in all areas, and is restricted by each participating country’s regulations.
Phones have generated the creation of several additional forms of peer-to-peer networks. One type, Symella, is specific to a particular kind of phone and has the ability to download files, but not upload. The same company is now offering SymTorrent, which is a client for BitTorrent and offers both uploading and downloading. A Swedish company, TerraNet, is testing a new technology, which will allow a mobile phone to call another mobile phone without the need for connection through a cell tower. Then there are other mobile services such as Fon, a peer-to-peer service where you buy a special Fon access point router (or download software to modify your compatible router) which separates part of your bandwidth for personal use, but the other part is freely accessible to other Fon members. The benefit of this is that you can connect to the internet anywhere in the world where another Fon access point can be found.
Almost everybody uses some form of instant messaging these days. The roots of most instant messaging applications can be found in peer-to-peer networking. There are some companies now that extend those applications to the business world, such as Jabber, Inc., which develops and offers presence and instant messaging products for the commercial world. Presence means users can tell when a friend or co-worker is online and accepting messages. Presence is not isolated to peer-to-peer systems but rather is a part of context awareness. Other context aware elements include temperature, location and sound.
With the advent of wireless adapters, a new breed of peer-to-peer has risen. Ad hoc networks are user created without a connection to a LAN. One device creates the network. Then, other devices with the appropriate adapter and within range can join that network. The Intel Laptop Gaming TDK 2.0 contains a set of APIs to implement gaming over an ad hoc network. In order to talk and communicate with other devices on the network, however, all devices have to have the same or a compatible software application. One further drawback to this type of peer-to-peer network is that you cannot use one adapter to connect to more than one network. That means that a user cannot be connected to both a LAN and the ad hoc network unless that user has two adapters.
As with most everything, there are good and bad things about peer-to-peer networks. A positive point for peer-to-peer is that the resources of all devices spread the load and increase the strength of the network. For example, there is the case where the demand for a file on one computer is requested by many people at once. Peer-to-peer networking has adopted a strategy for handling this situation.
Let’s go back to users Alice, Bob, Charlie, and David. They all want a file that can only be found on Zoe’s computer. Zoe’s computer becomes bogged down with all the requests. However, Alice and Charlie got started on the transfer slightly ahead of anyone else. So, rather than David downloading the first chunk of the file from Zoe, David gets the first chunk of the file from Alice, a second chunk from Charlie and so on. Having many users obtain the file in this manner eases the bandwidth demand on Zoe’s computer and can make all of the transfers complete faster. This “piecemeal” downloading is a lot more cost effective than having to add more bandwidth to a server so that a temporary large demand for one file can be satisfied.
Certainly some of the benefits of having a mobile peer-to-peer connection such as Fon would be the ability for internet access all over the world. To a person who travels for a living, this could top the plus side of the ledger. Of course, that depends on the availability of other Fon members in whatever areas you are traveling. Reports are that there are more than 190,000 Fon access spots in the world. Mobile phone peer-to-peer networks are also a great way to find and share music or ringtones.
There is also the bonus of presence instant messaging brings. More and more corporations are finding that having an internal IM application is increasing worker productivity. Business use of these programs is increasing acceptance of peer-to-peer networking within the work environment.
According to Todd Sundsted in his 2002 paper, The practice of peer-to-peer computer: Trust and security in peer-to-peer networks, the third fundamental concern with security would be encryption.
Andy Oram, a peer-to-peer leader for many years, said in 2003, “There are three things that P2P really lacks, namely a consistent addressing scheme, metadata, and a way to ensure the reputation of participants in the network”.
Within financial institutions the US Securities and Exchange Commission requires that instant messages be logged and archived as well as all other types of communications. Most of the IM products readily adopted through the internet are based on peer-to-peer elements and have few or no security methods enabled, and no way to record and log messages. Newer, specialized software has been designed to work inside a corporation’s firewall and allow employees to interact with each other. For example, Jabber, Inc., mentioned earlier, has full security handling authorization, authentication, and encryption.
One of the Skype features is secure communication. Among the security protocols it uses are Advanced Encryption Standard and the RSA public-key algorithm. Skype’s security page gives more information on how authorization, authentication, and encryption are handled while using this program.
The new ad-hoc networks have some security issues even without involving the internet. Once a network is created, it is difficult to refuse access to anyone who is within the 50-meter range and can see the network with their adapter. The good news is that some ad-hoc stacks are equipped so the user can enter the MAC addresses of the devices that are allowed to join. The software used to communicate within the network may have security in place, but how much or what type would be defined on a product-by-product basis.
As a final word on enjoying the benefits of peer-to-peer networking in any or all of its forms, security is ultimately up to the user. When setting up any type of file-sharing application network security should be studied and careful thought made as to the areas and files left open for sharing. There are many peer-to-peer network applications, which have active and strong security measures in place.
Peer-to-peer networks are truly connections, which are greater than the sum of their parts, at least in the areas of file sharing and download speed. As mobile devices and strategies expand, so do the number and variety of ways to utilize peer-to-peer in a mobile society. Far from being just a method for obtaining media files, peer-to-peer networking has branched out to provide worldwide internet access, increased presence, and collaboration in the business environment. There are some security conc erns to be dealt with in both the business and consumer areas, and each user needs to proceed with caution when allowing access to personal devices. Despite that, with the growth and expansion of the mobile society, peer-to-peer has passed through childhood and is finally enjoying a mobile coming of age.
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 Bangeman, Eric, P2P comes to mobile phones, promises free calls, 9/11/2007, http://arstechnica.com/news.ars/post/20070911-p2p-comes-to-mobile-phones-promises-free-calls.html.
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 Subramanian, Satheesh and Nguyen, Loc, Conversation on 10/17/2007 of the Client Scale Enabling team of Intel’s Software and Solutions Group on Ad Hoc Networking. /en-us/articles/gaming-over-ad-hoc-peer-to-peer-networks
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Judy Hartley is a Software Applications Engineer working for Intel Corporation’s Software and Solutions Group in Hillsboro, OR. She worked for 5 years in Chandler, Arizona as a Product Development Engineer before transitioning to SSG in November of 2005.
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