Routing Protocol Definition. A routing protocol is a set of rules used by routers to determine the most appropriate paths into which they should forward packets towards their intended destinations.
Spindle fibers are protein structures that form early in mitosis, or cell division. They consist of microtubules that originate from the centrioles, two wheel-shaped bodies located in the centromere area of the cell. The centromere is also known as the microtubule organizing center.
Nucleus and nucleolus disappear during pro-phase stage of  mitosis,to be specific it disappears in late pro-phase stage and  reappers during telophase stage of mitosis.