What are potter five forces?

Michael Potter's five forces framework can be used to determine whether the industry is attractive enough to sustain a small or medium size enterprise. The five forces of Entry, Rivalry, Substitutes, Buyers and Suppliers jointly determine the intensity of competition and profit potential for a small and medium size firm in a given industry or market sector. In analysing each market force, the question is whether it is sufficiently strong to reduce or eliminate industry profits. The focus at this stage is at the industry level because industry dynamics and profits of necessity dictate profits of other firms that enter the industry. Also, in carrying out a five forces analysis we want to be able to answer this question: If the competitive forces in the industry are strong, is there some strategy that firms might employ to defend it, or influence the forces in their own favour?