[Click] Blocking queue element?

[Eddie Kohler]

Hmm.  I'm not sure that your ping process would get blocked without Click, would 
it?  I mean Click's queue happens below the IP layer.

However, it is true that Click's "device queue" is not being reflected in its 
"device".  What you want is for Click's FromHost element to mark itself as 
"busy", if the Click Queue is relatively full.

Are you up for some hacking?  You could hack FromHost to mark itself busy when 
the particular downstream Queue is full -- or even just change it to mark itself 
busy randomly, and see whether this blocks the upstream ping process.  If it 
_would_ block that process, then we can work on making FromHost "do the right 
thing".

Eddie


Charles Reis wrote:
> Thanks--
>   It looks like that would work for TCP connections (which adjust when 
> they see dropped packets), but my current experiment involves sending a 
> ping flood.  With either Queue or RED, most of the packets will end up 
> dropped unless the ping process is blocked (as it normally would be 
> without Click).
> 
>   Any other thoughts?  I'll probably try the InfiniteSource element as 
> an alternative to ping, but this issue seems like it could come up in 
> many contexts.
> 
> Thanks,
> Charlie
> 
> 
> Beyers Cronje wrote:
> 
>> Hi,
>>  
>> Have a look at RED  http://www.pdos.lcs.mit.edu/click/doc/RED.n.html 
>> and http://www.pdos.lcs.mit.edu/click/doc/AdaptiveRED.n.html 
>> AdaptiveRED elements.
>> "Random Early Detection (RED) is a congestion avoidance mechanism 
>> designed for packet switched networks that aims to control the average 
>> queue size by indicating to the end hosts when they should temporarily 
>> stop sending packets." http://www.cisco.com/warp/public/732/Tech/red/
>>  
>>
>> ------------------------------------------------------------------------
>> *From:* click-bounces at amsterdam.lcs.mit.edu on behalf of Charles Reis
>> *Sent:* Wed 2004/09/22 09:25 PM
>> *To:* click at amsterdam.lcs.mit.edu
>> *Subject:* [Click] Blocking queue element?
>>
>> Hi--
>>    I'm using Click and the stripped madwifi driver, with a click
>> configuration based on the gen_config_pseudo_ibss.pl script that comes
>> with the driver.
>>
>>    I've noticed that any packets sent out while the Queue element is
>> full are simply dropped.  Are there any elements that cause the sender
>> to block instead if the queue is full?
>>
>> Thanks,
>> Charlie Reis
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