This is a cosmetic issue and does not affect performance.
CSCec14238 - 3750 connected using dot1q cause Runts increase on interface.
Symptom:
When using dot1q on trunk interface on the Cat3750, runts may be seen on show interface output because valid dot1q encapsulated packets which are 61-64 bytes including the q-tag are counted by the Cat3750 as undersized frames, even though these packets are forwarded correctly. In addition, these packets are not reported in the appropriate category (unicast,
multicast, broadcast) in receive statistics.
Workaround:
This is a h/w limitation of the Cat3750 platform. There is no workaround.
