Why is measuring streams hard? Cheap memories (dram)are too slow to count all packets Fast memories(SRAM)are too small to keep counters for all streams Opportunity: elephants matter, mice dont Problem: usually we dont know in advance which streams are large SIGCOMM 2002SIGCOMM 2002 Why is measuring streams hard? • Cheap memories (DRAM) are too slow to count all packets • Fast memories (SRAM) are too small to keep counters for all streams • Opportunity: elephants matter, mice don’t • Problem: usually we don’t know in advance which streams are large