How Much to Increase MTU for 802.1q VLAN Tag Configuration

B.

When configuring the 802.1q VLAN tag, the MTU (Maximum Transmission Unit) must be increased to accommodate the additional overhead added by the tag. The 802.1q VLAN tag adds a 4-byte header to each Ethernet frame, which includes a 2-byte tag and a 2-byte control information field.

Therefore, the correct answer is B) 4 bytes.

For example, if the original MTU was set to 1500 bytes, it should be increased to 1504 bytes to account for the additional overhead of the VLAN tag.

Failing to adjust the MTU size could result in fragmentation and decreased network performance as larger frames will be split into smaller frames to accommodate the smaller MTU size, and then reassembled on the receiving end, which takes additional time and resources.

In summary, when configuring the 802.1q VLAN tag, the MTU size must be increased by 4 bytes to accommodate the additional overhead added by the tag.