Hi
I just got this CBS220-24T-4G V02 a hand full of weeks ago and I'm struggling a bit with this device. My today's topic is the Oversized Packets reported under "Status and Statistics/Etherlike".
I got a couple of interfaces configured in VLAN trunk mode. These are individuals/physicals as well as one link aggregation of two physical ports. All these ports, the ones having the vlan trunk configured directly on them, the link aggregation being configured in VLAN trunk mode, even the "raw" physical ports being part of the link aggregation reporting Oversized Packets.
This happens if a package is being forwarded which has a length of 1514 byte, e.g. by sending pings filling the whole MTU of 1500.
These packages are not getting dropped and it looks like everything is working fine beside the fact of seeing them being reported as oversized.
On the other hand, running the same tests with e.g. ping on ports in VLAN access mode, not a single Oversize Packets entry gets reported there.
It very well might be that I just do not understand the whole thing but this looks very strange to me. I investigated deeply, even tracing the network traffic with WireShark, comparing the tests agains trunk and access mode ports. I did not find any differences in those test because, of course, there aren't any. I somehow have the feeling that there is a bug in the firmware. BTW: Im running the latest one on this switch which is 2.0.1.9.
So, anybody out there being able to tell me about the missing link or maybe from Cisco if this acctually might be a bug?
Best,
dialsc
