[Testbed-admins] RV: Event system questions

["Manuel Requena" <mrequena@cttc.es>]

Sorry, I forgot the list...

> 
> Thus spake Manuel Requena on Thu, Oct 01, 2009 at 01:40:05PM +0200:
> > When I swap in or modify an experiment, the events are not scheduled. I
> know
> > it because I launch some "tcpdump" in the nodes. Are there some log
> files to
> > see when the events are scheduled? I don't see my UDP packets (every 5ms
> > during 20 secs with a length of 500 bytes). But in the first 2 secs and
> > every 10ms, I see some UDP packets (not mine ones) of 62 bytes (ethernet
> > length) between the 2 nodes. What are these packets?
> 
> Hard to say - many switches send synchronization packets (for spanning
> tree, etc.), and this might be what they are - are the source MAC
> adresses ones the belong to the nodes themselves?
> 
> None of the Emulab software should be automatically sending packets on
> the experimental net (except for the traffic generators, if you have
> them set up...)
> 

The packets belong to the nodes. I create some UDP and TCP flows with TCL
commands but I don't schedule them with "at". For example, I create a TCP
flow, I don't schedule it ($ns at X "$tcp1 start/stop"). But even in this
case, I can see the 3-way handshake packets when the experiment starts (time
= 0.0 seconds).

It seems that the other packets also belong to these non-scheduled flows.

How and where the flows are scheduled?