Using Test TCP
(TTCP) to Test Throughput
You can use the Test
TCP utility (TTCP) to measure TCP throughput through an IP path. In order to
use it, start the receiver on one side of the path, then start the transmitter
on the other side. The transmitting side sends a specified number of TCP
packets to the receiving side. At the end of the test, the two sides display
the number of bytes transmitted and the time elapsed for the packets to pass
from one end to the other. You can then use these figures to calculate the
actual throughput on the link.
The TTCP utility can
be effective in determining the actual bit rate of a particular WAN or modem
connection. However, you can also use this feature to test the connection speed
between any two devices with IP connectivity between them.
Since it is most
common to evaluate connect speeds in kbps (kilobits per second, or 1000 bits
per second) rather that kbps (kilobytes per second, or 1024 bytes per second),
we must use the information from TTCP to calculate the bit rate (in kbps). Use
the number of bytes received and the transfer time to calculate the actual bit
rate for the connection. Calculate the bit rate by converting the number of
bytes into bits and then divide this by the time for the transfer. For example,
if the host received 409600 bytes in 84.94 seconds, you can calculate the bit
rate to be (409600 bytes * 8 bits per byte) divided by 84.94 seconds=38577 bps
or 38.577 kbps.
For more information
on the commands for configuring TTCP, see the
module in the
Cisco ASR 9000
Series Aggregation Services Router System Monitoring Command Reference
for Implementing TTCP Utility
This feature was introduced.