Hello,
I believe I have a networking issue that is manifesting itself through software issues; please let me know if I should repost this in the Software forum.

Setup:
Server and clients running fc7 and CUPS 1.3.7
We just upgraded from 10/100 unmanaged switches to GigE POE managed switches. Everything was working great prior to upgrading the switches.

Issue:
Networked printers disappear and reappear on client machines. The printers are still pingable and viewable in the CUPS interface. If I print a test page through the CUPS interface, the printer reappears temporarily. Restarting CUPS on clients or servers does not make missing printers reappear on the client.
Additionally, though perhaps not pertinent, pinging anywhere on the network has some quirks. About 1 in 20 pings will take an inordinate amount of time; what normally takes 3ms spikes to 40ms(+/-20ms) for one ping, then back to normal. I did not notice this prior to upgrading the switches, though I wasn't looking for it then...
We haven't noticed any other issues, though who knows...

If you have any ideas how I could debug this, I'm all ears.

Thanks!

Is there multi-path between client, server or printer? What can the new switch be managed?

Good though, but we're pretty sure there's no loop. The problem persists even after we cut out part of the network.

We have a basic star network setup;
.......-> switch -> switch -> Printers
Server -> switch -> switch -> Clients
.......-> switch -> switch -> Clients


By "managed" switches, I mean there's a user interface where we can turn ports on, off, and mess with all the settings one could ever want to. Not that I know what most of them do...

Thanks for the help! Any more ideas are welcome!

If you are pretty sure no loop, what's your network size? Maybe you should check your MAC table size in new switch. Maybe MAC table overflowed in your new switch.