Hi all.... question for the experts out there....
I am using netem to simulate alot of network impairments (mostly bw and latency). I"ve written some simple scripts to keep changing the values. With simple ping tool I can see that my latency is tracking, and I use iPerf to track the bw utilization matches.
I have the netem box in between 2 hosts running in bridge mode.
My problem is that at certain points in time, I'd like to completely shut down any traffic. IE: I'm attempting to set the rate to 0bps for very short fractions of time. (50 to 100 ms). I've noticed that the tool wont accept a 0bps value, so I decided well it'll be pretty close if i set it to a very very small trickle, so I set it .1Kbit.
Whats strange is that while this does act to basically stop any data traffic, when I open it back up, I don't see it recover... the Pings still seem to be lost.
I'm thinking this may be related to the buffer backup that occurs and then pings are just timing out - but if i kill the ping and restart, it starts working again just fine right away.
I guess my question, any ideas? Is this possibly an application issue or a netem not recovering issue? Anyone know of a better way to kill traffic throughput dynamically? I'm fine with traffic being dropped (once assigned buffers are full) , like would happen on a real router....
Thanks for any advice or pointers!
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