Breaking up gigabit ethernet's VoIP bottlenecks

Gigabit Ethernet is a popular broadband technology for good reason. It not only can transfer large amounts of data through a large network at high speeds, but it also is a mature technology with an appealing performance to cost-of-ownership ratio. Unfortunately, though, gigabit Ethernet suffers a performance drop when it is handling traffic with small packets: it tends to lose them. This is a serious problem because small packets have become important in many real-time applications - in voice over Internet protocol (VoIP), for example, which carries voice conversations over the Internet. We have studied high-rate, small-packet traffic in an Ethernet controller, as implemented in an Intel e1000 network interface card (NIC) Linux driver, which is widely used in high-end systems and servers. We have also evaluated the performance boost provided by the receive descriptor recycling (RDR) technique.