Change MTU for interface and check for too-large packets (Cisco)

From ben.goodacre.name/tech

Check for packets exxeeding MTU

The number of packets exceeding MTU are listed under the giant counter on the interface:

cloud.net#sh int BVI1 | i giant
     Received 0 broadcasts, 0 runts, 85 giants, 0 throttles

Change MTU

en
conf t
int dsl0
mtu <mtu in bytes>
exit
copy running-config startup-config