Porter's five force strategy is a framework for making a qualitative evaluation of a firm'sstrategic position which according to Porter should be used at the industry level, a marketplace inwhich closely related substitutable products or services are sold. Porter's analytical framework consists of those forces that affect a producer's ability to serve its customers and its profitability.A change in any of these five forces requires a re$-$assessment of the marketplace.According to this model, success in a business is primary based on managers knowledge of competition in the industry, customers, suppliers, potential entrants, and substitute products. The extended rivalry that results from all five forces defines an industry's structure and shapes the nature of competitive interaction within an industry