Use test TCP (TTCP) to test throughput (1)

Preface

You can use the test TCP Program (TTCP) to measure the TCP throughput through the IP path. Use it to start the receiver at one end of the path, and then start the transmitter on the other side. The transmitting end sends the specified number of the TCP information package to the receiving end. At the end of the test, both parties display the number of transmitted bytes and the time passes so that the information package can consume data from one end to the other. You can then use these graphs on the link to calculate the actual throughput. For more information about TTCP, see test and TTCP network performance. The TTCP program can be effective in determining the actual bit rate of a specific Wan or modem connection. However, you can also use this function to test the connectivity between two devices with their IP addresses. For more information about document conventions, see Cisco technical tip conventions.
PrerequisitesReaders of this article should be familiar with the following TTCP requirements & reg; Cisco IOS software version 11.2 and later and feature set IP Plus (image) or service provider (p-image ).
Note:The ttcp command is a hidden, unsupported, and privileged command. Similarly, the availability may change from one Cisco IOS software version to another, so that some versions may not exist. The client's TTCP software is accessible from the http://renoir.csc.ncsu.edu/ttcp/; download ttcp1_zip for Windows client.
Components usedThis document is not limited to specific software and hardware versions.
Prepare a TTCP MEETINGEnsure IP connectivity between the two devices involved in the test. Download and install non-IOS client TTCP software if necessary.

In the following example, we try to determine the connection rate of a modem connection between the Microsoft Windows PC and the AS5300 access server. Even though many of the questions and explanations here are specific to modem connections, the TTCP program can be used between any two devices.
UseThe show modem operational-status Command (modem link) checks the connection parameters. This step is not necessary for other LAN or WAN solutions.
Customer-dialin-sj>
Show modem operational-status 1/51 Parameter
#1 Connect Protocol: LAP-M Parameter #2 Compression:
None...
! --- Output omitted

... Parameter #8 Connected Standard:
V.90 Parameter #9 TX, RX Bit Rate:
45333,24000
The output of this edit indicates that the client contacts at V.90 at a rate of 45333 bps downlink and 24000 BPS uplink. Data Compression is disabled on the client modem. Because the TTCP test mode is highly compreable, all data compression will offset the actual modem link throughput our measurement.
Perform a downlink test (from vro to Windows PC)

Start the PC ttcpw Program (in the DOS window) and run it as the receiver. See the README file with window TTCP software as the appropriate syntax.
C: \ PROGRA ~ 1 \ TTCPW>
Ttcpw-r-s ttcp-r: buflen = 8192, nbuf = 2048,
Align = 16384/0, port = 5001 tcp ttcp-r: socket

Start the TTCP sender (TRANSMITTER) at AS5300. Most settings are left in the default value, except the number of buffers for transmission. The default number of buffers is 2048. TTCP testing takes a long time to complete. By reducing the number of buffers, we can complete the test within a reasonable period of time.
In the following example, we try to determine the connection rate of a modem connection between the Microsoft Windows PC and the AS5300 access server. Even though many of the questions and explanations here are specific to modem connections, the TTCP program can be used between any two devices.
Note:Try to get a snapshot of the modem (port) operation status, as described above, before you start the TTCP test.
Customer-dialin-sj> ttcp
Transmit or receive [receive]:
Transmit
! --- The AS5300 is the ttcp transmitter
Target IP address: 10.1.1.52
! -- Remote device (the Windows PC) IP address
Perform tcp half close [n]: use tcp driver [n]: send buflen [8192]: send nbuf
[1, 2048]: 50
! --- Number of buffers to transmit is now set to 50
(Default is 2048 buffers)

Bufalign [16384]: bufoffset [0]: port
[2, 5001]: sinkmode [y]: buffering on writes [y]: show tcp information at end [n]:
Ttcp-t: buflen = 8192, nbuf = 50, align = 16384/0, port = 5001 tcp-> 10.1.1.52
Ttcp-t: connect (mss 1460, sndwnd 4096, rcvwnd 4128)
This causes Cisco ios ttcp to establish a TCP connection with TTCPW (on a Windows machine ).