Cisco IOS IP SLA Traffic Generator

Also I could not find lesson on TTCP or am I missing somewhere? That would not be bad either, whatever lower traffic it can generate.

IP SLA is great to generate some traffic so that you can test QoS with different traffic types and DSCP values but it really isn’t suitable for high bandwidth since it uses the CPU to generate traffic. For some more information, take a look at this article:

UDP-Jitter Probe for VoIP (G.729a) Running Eng 3-Cisco IOS Release 15.1(4)M Default Parameters: Frequency 60secs), Codec Packet Size (32bytes), Codec Interval (20ms), Codec Number of Packets (1000)

1921 2921 3925 3945 3945E
Operations (Total) 150 225 275 400 900
Operations/Second 2.5 3.75 4.58 6.7 15.0
Packets per Second 2500 3750 4583 6733 15000
Operations/Min 150 225 275 400 900
CPU Usage ~59% ~61% ~43% ~54% ~43%

You might get some different results with larger packets but there is quite a hit on the CPU.

TTCP is a simple tool you can use to generate some traffic:

R1#ttcp receive

ttcp-r: buflen=8192, align=16384/0, port=5001
rcvwndsize=0, delayedack=yes  tcp
ttcp-r: accept from


R2#ttcp transmit

ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5001  tcp  ->
ttcp-t: connect

If you don’t specify a parameter, you can do some things like setting a different TCP port number or window size. I think it’s a bit of a hassle so I never use it :smiley:

Rene, the image file named as “ethernet-ip-udp-payload-sizes.png” in this post is broken!

Hi Marcus,

Thanks for letting us know. I just fixed it.