[c-nsp] OSPF fast hellos

[Rodney Dunn]

On Thu, Oct 30, 2008 at 08:06:36AM +1030, Ben Steele wrote:
> Because I couldn't see bfd support for 3750's, best it can do is UDLD,
> otherwise that would be my preferred method.
> 
> Are you advising against fast hello's?

No totally.

 Have you seen many issues with people
> using them?

Yes. They have to be scheduled on the CPU as a process and that is more
variable because IOS is run to completion, except for psuedo preemption
added for BFD.

Even that isn't 100% bullet proof but it's better than OSPF fast hellos
from that perspective.



> 
> -----Original Message-----
> From: Rodney Dunn [mailto:rodunn at cisco.com] 
> Sent: Wednesday, 29 October 2008 11:41 PM
> To: Ben Steele
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] OSPF fast hellos
> 
> Why don't you use BFD instead. It's designed with something called
> pseudo preemption from an OS scheduler perspective that helps
> reduce false positives and the fact that BFD frames are handled
> under interrupt and not process scheduled for rx/tx.
> 
> Rodney
> 
> On Wed, Oct 29, 2008 at 04:09:45PM +1030, Ben Steele wrote:
> > Anyone currently using this in a fairly demanding environment? Ie 5-10Gbs+
> > Campus/DC model.
> > 
> >  
> > 
> > Curious as to whether you've had any/many false dead peers with such a
> short
> > interval, subsecond dead peer detection does sound very temping though.
> > 
> >  
> > 
> > Cheers
> > 
> >  
> > 
> > Ben
> > 
> >  
> > 
> >  
> > 
> > _______________________________________________
> > cisco-nsp mailing list  cisco-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-nsp
> > archive at http://puck.nether.net/pipermail/cisco-nsp/
> 
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com 
> Version: 8.0.175 / Virus Database: 270.8.4/1752 - Release Date: 28/10/2008
> 10:04 AM