Simulate network/transmission latency

Sep 08, 2005 6 Replies

I ahve several router in a test bed, however I need to simulate



80-100ms latency between the links, either serial or ethernet. Are there any tools to do this?

Tx



Lowering the speed of the serial lines can significantly increase the delay.

DT

There are a bunch of software tools you can run of a PC etc to sinthesize a delay, but you then would need serial interfaces card or to use ethernet

you can find these by searching google.

i prefer dedicated hardware to do this since that way it doesnt vanish from the lab when i dont use it for a while :)

i have used a hardware box designed to simulate anything up to satellite delays (much cheaper than a satellite link!) - 1st came across this when we were debugging a satellite link.

i like this one as you can just alter the delay and error rate on the front panel

formatting link

a few 1000 UK pounds - YMMV - i havent spent money on them for a while.

E1 (G.703) interfaces cost extra.

I just installed NISTNet on a PC with 2 nics and Fedora 4 and it works pretty well. I had to simulate a 140ms delay for a connection from Wisconsin to Czech Republic for app testing. Here is what I did:

TestPC-2611Router-DTE/DCESerialCable-2621Router-NISTNet-CoreNetwork

The serial connection allows me to adjust clock rate to adjust serialization delay. This is important because here is how my results varied:

Real Circuit:

32 byte ping 140ms 1400 byte ping 156ms

Test w/384000 clock rate:

32 byte ping 139ms 1400 byte ping 193ms

Test w/1300000 clock rate:

32 byte ping 139ms 1400 byte ping 153ms

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