SG220 Oversize Packets errors on Trunk ports (802.1q)

[Timo Kokkonen]

SG220-26 (on latest 1.0.0.19 firmware) is logging "Oversize Packets" errors at alarming rate from any trunked ports.

These show up in RMON and EtherLike statistics.

It seems as if switch is (incorrectly) logging 802.1q tagged frames "oversize" when they are over 1518 octets (?)

Is this known problem? 

I'm seeing this on all trunk ports on the switch, other switches are SG200 & SG300 series switches and some HP Procurve switches, so issue seems to be clearly on the SG220 side....

Jumbo Frames are not being used on this network and enabling Jumbo Frames on SG220-26 didn't stop the errors....

[Timo Kokkonen]

After doing some testing, its pretty clear that RMON (and EtherLike) statistics are broken in this firmware version. Switch doesn't take into account the 4 byte tag added to 802.1q Ethernet frames.

So any (valid) 802.1q frames larger than 1518 bytes (payload between 1497-1500 bytes) get logged as "Oversize Packets", and are not counted in "Packets Received" for the interface (very likely "Bytes Received" is off also, but didn't have to time to verify this).

If anyone is doing any accounting and relying statistics pulled from the switch those statistics likely will be way off on any ports configured as trunk ports (receiving lot of 802.1q tagged frames)....

It would be nice if someone would confirm if this issue affects other than SG220-26 switch?

[jonrodr2]

Hello Timo, 

i hope you are doing well, i apologize for any inconvenience with the unit. I recommend that you give us a call as this may be related to a bug. regarding the second question, at this time we don't have any known issues for the same problem on other units. In the meantime please let me know.

-Have you tried to use a different firmware version? if you  did, is it still giving you the same issues?

-Have you tried a factory reset on the unit? 

-Are you experiencing any other issues on the switch, because of this packet errors?

you can contact us at 866-606-866. thanks