All things related to multicast

[Jon Dugan <>]

On Thu, Jan 18, 2001 at 02:47:39PM +1100, Markus Buchhorn wrote:
> At 21:25 17/01/01 -0600, Tony Rimovsky wrote:
> >Does anyone have advice on a good rate limit value?  Some earlier mail 
> >from 
> >Matt indicated that 50k SA's in 5 minutes had caused a problem.
> [...]
> >two sources, I generated 510 SA's in about 3 seconds (sending from NCSA 
> >(AS1224) and visible at ACCESS-DC (AS 5640).  All the SA's made it to 
> >ACCESS-DC and as far as I can tell, that rate generated no problem for 
> >abilene.  I am obviously leery of pushing this experiment too far.
> 
> Is it really the *rate* of SA's that is a problem? Or the total number of
> SA's? The issue seemed to be cpuhogging when the routers had 50k SA state
> to deal with under the pressure of a normal background multicast flow.
> Would it perhaps be better to limit the size of the total SA state? I
> wonder what would happen if the 50k SA state has been slowly built up (over
> days, rather than minutes).

  Unfortunately we have to work with what we're given.  JUNOS (and IOS AFAIK)
  doesn't support limiting the number of SAs (or other MSDP state) at the
  present time.  However, we can rate limit packets with that source or
  destinate port.  

  I think this is good enough for now, because the SAs are triggered by
  traffic that looks like a new multicast source but doesn't stay around very
  long (one packet I think... I suppose I should go read the source...).  

Jon
-- 
Jon Dugan             |  Senior Network Engineer, NCSA Network Development

  |  57C CAB, 605 E Springfield, Champaign, IL 61820
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