A prime number based pointer allocation technique. A packet-forwarding system incorporating the technique stores cells of a packet in packet memory, according to allocated pointers that have a fixed correspondence to locations in the packet memory. Each packet input interface of an ingress module has a memory parameter counter that is incremented by a different prime number each time a memory pointer is allocated to that input interface. The memory parameter counter includes a memory interface portion and a memory bank portion that correspond to the memory interfaces and memory banks of a packet memory with which the memory pointers are associated.