Network locality at the scale of processes

Packets on a LAN can be viewed as a series of references to and from the objects they address. The amount of locality in this reference stream may be critical to the efficiency of network implementations, if the locality can be exploited through caching or scheduling mechanisms. Most previous studies have treated network locality with an addressing granularity of networks or individual hosts. This paper describes some experiments tracing locality at a finer grain, looking at references to individual processes, and with fine-grained time resolution. Observations of typical LANs show high per-process locality; that is, packets to a host usually arrive for the process that most recently sent a packet, and often with little intervening delay.