Motivation to Adopt P2P

Three primary business and technology issues are driving the adoption of P2P:

• Decentralization Businesses realize greater efficiency and profits by attaining a flexible state. Consequently, business leaders have been decentralizing for decades. We have gone from mainframes, to a client/server model, to Internet computing, and now to P2P. The trend is undeniably decentralized and distributed.

• Cost and efficiency Hardware and software will continue to be inexpensive and powerful. New systems that increase the efficiency or utilization of hardware or software present a compelling case for making the investment. P2P additionally has the capability to exploit resources that in the past went unrecognized.

• Pervasive computing Imagine information systems everywhere: computer chips in clothing, appliances, automobiles, devices, anything you can think of. Not only are they everywhere, but they are connected. The market for network-connected devices continues to grow, and P2P systems are being designed to support the device market.

As enterprises advance their e-commerce efforts, they are increasingly recognizing the need to couple transaction flows and communication flows. Similarly, they are also recognizing the natural tendency for co-workers and their external counterparts to establish "communities" in order to perform both routine and special-purpose tasks. Growth in e-commerce should fuel more demand for collaborative commerce. P2P technology is a natural fit for this growing trend to establish distributed special-purpose communities.

Decentralization

Centralized systems have many advantages and are not disappearing. However, there are problems with centralized systems, as the next sections will show.

Eliminating Single Points of Failure

Centralized systems often suffer from single points of failure. These can occur as a result of a network problem, a hardware problem, or a malfunctioning application. It is expensive and sometimes impractical to build redundancy into every component of your system. When a centralized system fails, it brings business operations to a halt, resulting in costly downtime. P2P systems are proving to be resilient even in unstable environments.

Improving Scalability and Reducing Bottlenecks

Although centralized servers can process requests in parallel, every server has a characteristic threshold after which it slows to a crawl or crashes. Bottlenecks in centralized systems have often been addressed by the philosophy "buy bigger hardware." However, this is more of a stopgap measure than a long-term solution. Distribution of load across multiple machines (load balancing) is a popular solution to alleviate bottlenecks and scale systems. P2P systems are proving to be scalable.

Central Administration

Central administration can suffer from the lack of timely response to user requests. Users tend to be treated generically. The administrator must meet the needs of all users on the network, and therefore usually establishes broad settings like maximum storage limits and file access rights. Because it would require constant maintenance, granular attention is generally unavailable.

Location of Information

Decentralization can move resources closer to where they are accessed. This results in a number of benefits: Response time can be decreased, because network latency can be reduced or eliminated. Storage requirements can be partitioned and allocated to more closely resemble organizational use. Decentralization actually reflects the organizational reality that exists in corporations today.

Symmetric Versus Asymmetric Participation

Centralized systems suffer from one-way, or unidirectional communication. Most users connect to a central server, and push and pull data from that central server. The value of the network is decreased because of this unidirectional communication channel. Central servers often add no value to the communication. A more symmetric flow of information is established in P2P systems. This allows communication to flow from device to device, thus increasing the value of the network.

Removing Islands of Computation

Centralized systems tend to create information silos. These islands of computation are isolated and cut off from other systems and networks. Often, redundant information is housed in these silos that is neither current or correct.

Cost and Effective Resource Allocation

A client/server system is expensive. It requires client hardware and software, server hardware and software, a plethora of storage devices and software, and maintenance. P2P greatly increases the utilization of three valuable technology assets:

• Storage

• Bandwidth

• Computing resources

All of these are underutilized at this time, partly because of the traditional client/server computing model. Despite a decentralized Internet, the client/server model still dominates. Decentralized and mesh network topologies such as the SETI project will more effectively use resources that already exist.

Pervasive Computing and Edge Services

Non-PC devices such as PDAs, cell phones, life-enhancing appliances, and so on continue to proliferate. Interconnected devices are enabling a new generation of communication, information exchange, and pervasive computing.

Increased Connections

The number of connections is surging the result of devices communicating directly with other devices, not through servers acting as intermediaries for devices. This increased connectivity will be supported by P2P-style architectures.

Enhanced connectivity provides the catalyst to promote edge services. Edge services reside on devices and common PCs across the Internet. Peer-to-peer networks make use of these resources. Edge services move data closer to the point at which it is actually consumed, acting as a network caching mechanism. This speeds up data access and better utilizes existing storage space, thereby saving money by eliminating the need for storage on servers.

With the right system design and architectural choices, these P2P applications have the ability to spread across the entire Internet and provide people with greater productivity and knowledge than ever before. Unfortunately, with the wrong architecture and design, the same P2P applications can fall apart at the seams.