A TCP Tuning Daemon

Abstract

Many high performance distributed applications require high network throughput but are able to achieve only a small fraction of the available bandwidth. A common cause of this problem is improperly tuned network settings. Tuning techniques, such as setting the correct TCP buffers and using parallel streams, are well known in the networking community, but outside the networking community they are infrequently applied. In this paper, we describe a tuning daemon that uses TCP instrumentation data from the Unix kernel to transparently tune TCP parameters for specified individual flows over designated paths. No modifications are required to the application, and the user does not need to understand network or TCP characteristics.

Dynamic Adaptation of Parallelism Level in Data Transfer Scheduling

“…The optimal buffer size is related to bandwidth-delay product which is the product of the data link capacity (bandwidth of the bottleneck link) with end-to-end delay (the round trip time of the connection) [5,6,7]. There have been many studies that investigate diagnosis techniques to measure bandwidth and round-trip time of a given connection [4]. The bandwidth-delay product can vary in a shared wide-area network environment.…”

A simulation-based study of HighSpeed TCP and its deployment

“…Other media support a larger MTU: FDDI has a 4392-byte MTU, GigE jumbo-frames have a 9000-byte MTU, IP-over-ATM uses a 9180-byte MTU, and HiPPI uses a 65535-byte MTU. However, these are being phased out in favor of higher speed Ethernet [7,11].…”

“…As network throughput capacity has increased in recent years, operating systems have gradually changed the default buffer size from common values of 8 kilobytes to as much as 64 KBytes. However, this is still far too small for today's high speed networks [11], and prevents TCP from using all the bandwidth available.…”

A New Model for Cluster Communications Optimization

“…The projects developed so far, like WAD (Work Around Daemon) [1] or ENABLE [2] don't meet the imposed requirements, as for WAD a modified kernel must be used, and for ENABLE the applications must be rewritten.…”