[Beowulf] odd vlan issue

Michael Di Domenico mdidomenico4 at gmail.com
Wed Jun 16 13:41:24 UTC 2021

On Wed, Jun 16, 2021 at 9:25 AM Robert Taylor <rgt at wi.mit.edu> wrote:
>  I’ve seen it happen with udp, in my case it was a syslog server, that hardly ever “spoke” so eventually it’s MAC address disappears from the Cam table long before it leaves the arp table and the UDP packets get flooded hoping to find the server.
> I’ve also seen this happen in an HA environment, Where it’s possible that traffic can take an asymmetric path. It happens enough that Cisco wrote an article about it years ago.
> https://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/23563-143.html

the udp scenario is definitely not what's happening.  but the unicast
flooding appears to be.  the article linked is what lead me to find
the initial problem and prove the theory yesterday.  the messed up
asymmetric nature of our network is where the problem lies.  <rant>but
that's what happens when you give network guys an unlimited budget and
they buy more/larger network gear then they can handle.</rant>

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