[Click] control packetflow

[Michael Neufeld]

If you aren't already using the "Paint" annotation for something, I'd be 
tempted to use that. So instead of Element A controlling Element B 
directly, it'd paint packets depending on its current state. Downstream, 
Element B would examine the Paint annotation and do the approprate 
splitting/duplication.

More concretely, say that Element A paints packets 0 if they're going 
out to just 0, 1 if they're going out to 1, and 2 if to both.
Element B could then be a compound element something like this:

PaintSwitch() :: sortpackets;
input[0] -> sortpackets;
sortpackets[0] -> [0]output;
sortpackets[1] -> [1]output;
sortpackets[2] -> duplicator :: Tee(2);
duplicator[0] -> [0]output;
duplicator[1] -> [1]output;

Not *technically* a single off-the-shelf element, but it only uses stock 
Click elements. It's also just a little different than explicitly 
controlling the downstream element directly, but unless I'm missing 
something it ought to behave pretty similarly.

-Mike

Peter De Cleyn wrote:
> Hi all,
> 
> I would like to control the flow of packets at runtime using some state in
> the system  and I was wondering if such an flowcontrolelement already
> exist.
> 
> Let me explain more carefully with an example. Based on commands from
> Element A, Element B should pass the packets arriving at its input to
> either
> 
>    port 0 and port 1
>    or only port 0
>    or only port 1
> 
> 
>     |
>     |
>   -------------
>   | Element B |
>   -------------
>    |   |
>   | |  |
>   | |  |
>   | |  |
>   ---
>    |   |
>    |  /
>    \ /
>     |
>   -------------
>   | Element A |
>   -------------
>      |
>      |
> 
> Could you tell me if this is already possible before I start writing
> something like it? I do not seem to find it in the elementlist online.
> 
> Thanks!
> 
> Peter
> 
>  ______________
> /Peter De Cleyn\
> -------------------------------------
> University of Antwerp
> Dep. Math. and Computer Science
> PATS research group
> -------------------------------------
> Middelheimlaan 1
> Building G
> B-2020 Antwerp
> -------------------------------------
> http://www.ua.ac.be
> http://win-www.ruca.ua.ac.be
> peter.decleyn at ua.ac.be
> +32 3 265 33 64
> 
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