Patricia Gilfeather and Todd Underwood (2001)
Fragmentation and High Performance IP
In: 15th International Parallel and Distributed Processing Symposium (IPDPS'01) Workshops, pp. 30165a, IEEE Press.
Although the networking world is still dominated by IP over Ethernet, these protocol suites were not originally designed to work on modern Gigabit or Gigabyte networks. The major problem facing IP at 1 Gb/s and 10 Gb/s speeds is interrupt processing overhead and the resulting low CPU availability for applications. One solution to this problem is to implement endpoint fragmentation on a Network Interface Card (NIC), where an Ethernet driver sends large packets to the NIC and the NIC fragments the packets into frames. This approach reduces interrupt overhead and CPU utilization on the receiver.
In order to demonstrate the plausibility of this method, we modified the firmware of Alteon Acenic 2 Gigabit Ether-net cards and the standard Linux (2.4 series) driver to allow the driver to use an MTU of up to 64000 bytes without changing the 9K MTU limitation of the MAC layer. Each datagram is fragmented in the firmware on one end and re-assembled in firmware at the other.
Our implementation matched peak bandwidth performance of the standard driver and firmware, while demonstrating a significant reduction in CPU utilization.