No, I figured he was having me on... Kurt
On Fri, Sep 20, 2013 at 11:07 AM, Jonathan Link <jonathan.l...@gmail.com> wrote: > Is this the equivalent of Vader saying "Your powers are weak, old man" to > Obi Wan? > > > On Fri, Sep 20, 2013 at 1:55 PM, Kurt Buff <kurt.b...@gmail.com> wrote: >> >> Sigh. Yes, but... >> >> "The 5-4-3 rule was created when 10BASE5 and 10BASE2 were the only >> types of Ethernet network available. The rule only applies to >> shared-access 10 Mbit/s Ethernet backbones. The rule does not apply to >> switched Ethernet because each port on a switch constitutes a separate >> collision domain." >> >> :) >> >> Kurt >> >> On Fri, Sep 20, 2013 at 10:37 AM, Michael B. Smith >> <mich...@smithcons.com> wrote: >> > http://en.wikipedia.org/wiki/5-4-3_rule >> > >> > >> > -----Original Message----- >> > From: listsad...@lists.myitforum.com >> > [mailto:listsad...@lists.myitforum.com] On Behalf Of Kurt Buff >> > Sent: Friday, September 20, 2013 12:59 PM >> > To: NTSysADM@lists.myitforum.com >> > Subject: [NTSysADM] Semi-OT: Network problem >> > >> > All, >> > >> > In the past couple of weeks, $work has had a problem with network >> > interruptions - frequent gaps in network connectivity were all contact is >> > lost with servers for brief periods of time (1-2 minutes, usually). >> > >> > I could see the gaps in the graphs on my (very new and incomplete - long >> > story, don't ask) cacti installation. Unfortunately, I've been unable to >> > get >> > cacti to graph CPU utilization for the switches, because they're Procurves, >> > and I couldn't find a working XML file or configuration for that. >> > >> > It's always happened while I've been unavailable, until today. >> > >> > Just now, I was able to show conclusively that our core layer3 switch >> > (Procurve 3400cl-48G), which was hit hardest, spikes its CPU to 99% during >> > these episodes. Volume of traffic is normal - ho huge spikes in that, just >> > normal variation, AFAICT, from the cacti graphs. I haven't had time to see >> > if other switches also spike their CPU, but given the gaps in the graphs, I >> > suspect that's the case. >> > >> > I suspect someone is doing something stupid to create layer2 loop, as we >> > have lots of little 5 and 8 port switches on desktops and in our >> > engineering >> > lab - and in spite of the fact that I've set our core switch as the root of >> > the spanning tree. >> > >> > I'm setting up a box to do a tcpdump in a ring buffer with smallish >> > files so that I can do analysis on them more easily. >> > >> > I'm not a packet analysis guy, though I've done some looking on >> > occasion. >> > >> > Anyone have thoughts on what to look for when I start my analysis? >> > >> > Kurt >> > >> > >> >> >
