Ok, installed brand new 3650 L3 switches last week, replacing some older Cisco 3750s. Been adding and removing VLANs and large quantity of IPv4 addresses without issues. Observium shows less than 20% CPU/RAM usage, everything is fine there. For some oddball reason tonight, I was trying to add a /29 subnet to one of the VLANS already there, as secondary subnet. The very second I do this, my entire network crawls to a halt and stays that way even for over 15 minutes, literally everything public but my access in the switch remains normal (?). The very second I remove that secondary subnet that was added, network immediately returns to normal. NOT NORMAL!
I replicated this with different VLANS and also entirely different C class subnets. Same issue, very strange and never seen this ever happen even on the old 3750s. Why is this happening suddenly on the new, far more powerful 3650's especially after a week with no problems at all, I'm baffled and need to know.
Any help would greatly be appreciated.
Info:
- replicated 2 different VLANS, 2 different C classes entirely
- CPU 20%
- 2 x 3650 switches stacked
- not network backbone issue at all, total throughout is between 80-150MBPs. My burstable is 300Mbps.
- been using these switches since Saturday without issues
- Model: WS-C3650-24TS (both switches)
