The samples were taken using the TTCP program. We transferred either 1Mb, or let the transfer continue for 30 seconds, whichever came first. Format: Src Dst Ron Time Bytes Duration Dur_32 Dur_64 Dur_128 Src = Source of transfer Dst = Sink of transfer Ron = 0 was sent directly over the Internet, 1 sent via a throughput optimized RON path bytes = Number of bytes actually sent during the transfer (may be less than 1Mb for transfers that aborted early) Duration = seconds to transfer 1Mb, or seconds at which the transfer was aborted (~30s) Dur_32, 64, 128 = the amount of time it took to send 32, 64, or 128Kbytes of data. Note that these numbers are understatements, because some data went into the socket buffer and was not actually sent across the network. All transfers were made on FreeBSD machines with untuned TCP stacks. Transfers on the Internet2 are likely to vastly underestimate the available bandwidth because of socket buffer limitations. 13,162 bandwidth samples