IP Concatenation: The Method for Enhancement of IPsec Performance

IPsec provides security services at the IP layer. The performance of IPsec is markedly decreased when it handles small packets. In this paper, we propose a method, IP packet concatenation (IPConc), to improve throughput of small packet processing. Our proposal reduces the number of packets and overall load for packet processing and IPsec processing. We implemented IPConc with Linux 2.4.17 and FreeS/WAN 1.95. The system which is enhanced by our proposal performed significantly better than original version. The throughput with 64 byte packets was increased as much as 250%.