[Spread-users] Spread daemon -8 and -11 errors

Chetan Gadgil cgadgil_list at cxoindia.dnsalias.com
Wed Dec 24 05:20:38 EST 2003


I guess it's a matter of perspective. In a typical DoS attack, I see the
sender as the culprit.

In practical terms, a sender can always re-send a message if sending
fails in the first place. However, a receiver will not know how many
messages it has missed if it were forced to disconnect. This would be a
redefinition of "reliable" delivery.

The send can be made more expensive. E.g some function of the number of
messages buffered for a given group.

  An account mostly false, of events mostly unimportant, which are
brought about by rulers mostly knaves, and soldiers mostly fools. 
    - Ambrose Bierce, The Devil's Dictionary

> -----Original Message-----
> From: George Schlossnagle [mailto:george at omniti.com] 
> Sent: Wednesday, December 24, 2003 3:42 PM
> To: cgadgil_list at cxoindia.dnsalias.com
> Cc: jgreen at spreadconcepts.com; spread-users at lists.spread.org
> Subject: Re: [Spread-users] Spread daemon -8 and -11 errors
> On Dec 24, 2003, at 2:43 AM, Chetan Gadgil wrote:
> > Ideally, the flow control should be done by the spread 
> library itself. 
> > If the messages are pushed at a much higher rate than they 
> are pulled, 
> > the "push" operation (SP_multicast) can become 
> progressively more and 
> > more expensive in terms of time. i.e. it will take 
> progressively more 
> > time to return from the call. (This can be made "intelligent" and 
> > configurable - per group, type of message etc.)
> >
> > In any case, killing the receiver seems un-intuitive. If at 
> all, you 
> > should kill the sender.
> But it's the receiver that is being slow.  There are potentially many 
> receivers and many senders - you should kill the culprit.
> George
> // George Schlossnagle
> // Postal Engine -- http://www.postalengine.com/
> // Ecelerity: fastest MTA on earth

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