VLANs This and Thats

There are several additional things that we need to know about VLANs. These things will be discussed below:

- On trunking, the port speed and the duplex settings should be the same

- Giants are frames larger than 1518 bytes and can occur because of ISL that has 30 bytes header and trailer to the frame (according to IEEE 802.3ac the max frame length can be extended to 1522 bytes for dot1q additional 4 bytes header). The opposite is called runt that transmits frames less than 64 bytes.

- Both of the switches must be in the same domain when trunking.

- Changing a native VLAN does not dynamically change the native VLAN on the peering switch.

- End to end VLAN design means that the VLAN spans over several switches and physical LANs. In this case 80% of its traffic will stay in the local area while 20% goes across. The opposite happens with local VLANs where only 20% stays in the local network while 80% goes across.