SLAC ESD Software Engineering Group
Stanford Linear Accelerator Center

Network Speed Test

SLAC Computing
Software Engineering






Created: Ken Brobeck    May 4, 2017

Modified: May 4, 2017

Use ttcp to test network speed (01/24/14)


ttcp is installed in /home/jingchen/bin/ttcp


- Test network speed between lcls-opi09 and lcls-opi10 (on a 100Mbps link)


on lcls-opi10 (receive side)

ttcp -f M -r -s -n 204800  

on lcls-opi09 (send side)  

ttcp -f M -t -s  -n 204800


204800 is number of buffers sent; buffer length is 8192 Bytes: i.e., total of 1677721600 bytes (1677MB) sent to (lcls-opi10)



ttcp-t: 1677721600 bytes in 142.34 real seconds = 11.24 MB/sec +++ The speed of the nework between lcls-opi09 and lcls-opi10 is  11.24 MB/sec

(or 11.24 x 8 = 89 Mbps)                                                 


- Test network speed  between lcls-builder and lcls-srv05 (on a 1Gbps link)

[jingchen@lcls-srv05 ~]$ ttcp -f M -r -s -n 204800                         

[jingchen@lcls-builder ~]$ ttcp -f M -t -s  -n 204800          



ttcp-t: 1677721600 bytes in 14.38 real seconds = 111.25 MB/sec +++

(or 111.25 x 8 = 890 Mbps)                                       


The results make sense, as lower than the link speed.



[SLAC ESD Software Engineering Group][ SLAC Home Page]

Author:K. Brobeck

Modified: 04-May-2017