Subject: [Sipping] [Fwd: comment related to draft-hilt-sipping-overload-00.txt]

From: Stefaan Willaert <[email-masked]>
Date: Fri, 15 Dec 2006 10:19:25 +0100

Subject: comment related to draft-hilt-sipping-overload-00.txt
From: Stefaan Willaert <[email-masked]>
To: [email-masked]
Date: Fri, 15 Dec 2006 10:13:32 +0100

Hello,

  In the draft a feedback control loop is presented, by which an 
overloaded server provides
  a load feedback to a upstream server. The load feedback contains a 
throttle x% which instructs
  the upstream server to reduce the load it would normally forward to 
the receiving server by x%..
 
  Should the forwarding server also not take into account the change in 
the received traffic intended
  for the overloaded server.
  If a time t0 : downstream server is overloaded it sends back throttle 
a% > 0. This throttle is applied by the
  upstream server. Later at time t1: the downstream server is out of 
overload, so a  throttle  0% is  send back.
  If the received  traffic intended for this server did not change, and 
the upstream server applies the throttle
  as received, this might lead to traffic oscillation.
 
Cheers,
Stefaan

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---

From: Volker Hilt <[email-masked]>
Date: Fri, 15 Dec 2006 18:10:49 -0500

Stefaan,

if the forwarding server would take changes in the current traffic rate 
into account, the percentage value would almost be like using a fixed 
call rate. Essentially, this would be as if the upstream server would 
take the percentage value and calculate a fixed call rate based on 
current traffic and then use the fixed rate.

Both, a fixed call rate and a percentage value, seem to be valid types 
of load feedback each with their own pros and cons. A better discussion 
of the different feedback types needs to go into the next rev of the 
draft.

Volker

Stefaan Willaert wrote:
>  the upstream server to reduce the load it would normally forward to the 
> receiving server by x%..
> 
> ------------------------------------------------------------------------
>