Maximum Transmission Unit (MTU) the size (in bytes) of the largest packet or frame that a given layer of a communications protocol can pass onwards. The MTU may be fixed by standards (as is the case with Ethernet) or decided at connect time. A higher MTU brings higher bandwidth efficiency. However, large packets can block up a slow interface for some time, increasing the lag for further packets.
The MTU for ethernet is 1500 bytes, 1492 for PPPoE and 576 for Dialup. In very rare occasions, you may need to change the MTU size due to connectivity issues with your ISPs or in a VPN environment on your openSUSE.
The following procedure should help to change the Maximum Transmission Unit (MTU) in openSUSE.