On 4/24/09, Ramcharan, Vijay A <[email protected]> wrote: > Last I checked "no ip unreachables" breaks PMTUD which can be fine in your > environment or cause other serious problems.
Earlier Q&A in the thread: > how many routed interfaces do you have ( sh ip int brief with ip addresses ) ? > > 1 routed interface. Is "no ip unreachables" going to break PMTUD on that box? Lee > > Vijay Ramcharan > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Lee > Sent: April 24, 2009 11:10 > To: Marian Ďurkovič > Cc: Chris Lane; Richard Gallagher; cisco-nsp > Subject: Re: [c-nsp] 3750 High Cpu IP Input > > On 4/24/09, Marian Ďurkovič <[email protected]> wrote: >> On Fri, Apr 24, 2009 at 10:01:08AM -0400, Lee wrote: >>> > These TTL=1 are causing the high CPU. >> >> Yes, those are not HW switched but punted to CPU in order to generate >> TTL_Exceeded ICMP message. Not sure if there's any knob to discard >> them silently. > > I thought that's what "no ip unreachable" was for.. > > >>> Just out of curiousity, would adding "ip multicast ttl-threshold 3" >> >> Beware, this is real evil. On most switch platforms this will completely >> disable HW forwarding of multicast packets and punt them *all* to CPU. > > oops... shows how much I know <grin> > > Thanks, > Lee > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > > ______________________________________________________________________ > This e-mail has been scanned by Verizon Managed Email Content Service, using > Skeptic technology powered by MessageLabs. For more information on Verizon > Managed Email Content Service, visit http://www.verizonbusiness.com. > ______________________________________________________________________ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
