Maintaining statistics counters in router line cards

Abstract

A network device stores and updates statistics counters. Using an optimal counter management algorithm minimizes required SRAM size and ensures correct line-rate operation for many counters. We use a well known architecture for storing and updating statistics counters. This approach maintains smaller-size counters in fast (potentially on-chip) SRAM, while maintaining full-size counters in a large, slower DRAM. Our goal is to ensure that the system always correctly maintains counter values at line rate. An optimal counter management algorithm (CMA) minimizes the required SRAM size while ensuring correct line-rate operation for a large number of counters.