Samsung turns out to be a particularly important supplier. It provides some of the phone's most important components: the flash memory that holds the phone's apps, music and operating software; the working memory, or DRAM; and the applications processor that makes the whole thing work. Together these account for 26% of the component cost of an iPhone.
This puts Samsung in the somewhat unusual position of supplying a significant proportion of one of its main rival's products, since Samsung also makes smartphones and tablet computers of its own. Apple is one of Samsung's largest customers, and Samsung is one of Apple's biggest suppliers. This is actually part of Samsung's business model: acting as a supplier of components for others gives it the scale to produce its own products more cheaply.
"Samsung's business model: acting as a supplier of components for others gives it the scale to produce its own products more cheaply". Thats Commensalism to an extent and time till Samsung becomes self-sufficient in terms of production, popularity, wide spread acceptance and marketing of its products. We will see this relationship turning to parasitic one at that time. Apple understands this and thus all the patent suits we see against Samsung.