Re: [Pandora] Component::notify()

[uaca]

On Thu, Dec 05, 2002 at 11:05:20PM +0100, Simon Patarin wrote:
> 
> 
> > > You feel a little bit lonely, don't you? I have warned you! :)
> > 
> > I didn't understand the joke :-(
> 
> This was just to say that there were not too many people on this list!
> 
> > first I want to measure the RTT using the 3WHS
> 
> I suppose that you know this paper:
> http://www.ieee-infocom.org/2002/papers/678.pdf

I didn't, if I have time I'll take a look at it

[...]
> > in the other hand in ::add() it calls reschedule(2) 
> > 
> > that means it will not accept new packets within 2 seconds?
> 
> no, just that if no other packets (after the reset) are received within 2
> seconds, then the component is cleaned up, which is better than having to
> wait 30 seconds or have 3 components created for nothing.

ok

[...]
> > I think that
> > 
> > + the accept method is more generic, and promises the heaven
> > 
> > + the key based is simpler and efective for the examples here we presented
> 
> Actually, I do not think that I'll have the time to code myself 

I was implicitly proposing myself to do what you think it's better to do, after
all you know the tool

[...]

> However, do you need the other (non SYN) packets elsewhere in the
> stack? 

Well, maybe the FIN handshake can also be used sometimes to estimate RTT.
[more on this later]

> If this is not the case, my own way of doing it would be to put a
> "tcpsynfilter" component that discards any non SYN packets just _before_
> the demux so your stack would look like this:
> 
> @pcap @tcpscan [$reject = false] @tcpsynfilter @demux [$algo = "tcpcnx"] <
>       @mycomponent > @whatever

I think this will not work, because you need SYN, SYN+ACK and the final ACK,
you need to stablish an state for the connection, so IMHO it must to be put
after the demux.

please note that I'm interested in making possible putting the monitor in 
the middle of the network, not "just" in the edge

Also, I'm not just interested in the 3WHS, but also in a few more packets
that lets to calculate other RTT measurement.

my reference is:


> I can let you make the tcpsynfilter component if you feel like it, but it
> would take me less time than writing this mail if you want me to do it!

maybe I should go to bed right now, but I think tcpsynfilter must mantain
some state in a per connection basis, so it's not that easy becuase of putting
the monitor in the middle....

Thanks

        Ulisses
                Debian GNU/Linux: a dream come true
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