I see many articles on line stating that the overhead of Ethernet is 18 bytes (example: http://www.learnios.com/viewtopic.php?f=8&t=18887)
Looking at this wiki article (http://en.wikipedia.org/wiki/Ethernet_frame#Structure) 18 bytes is the following fields;
- Destination MAC
- Source MAC
Why do the preamble, start of frame delimiter and inter-frame gap not count towards this, are they not included in every frame? This would take the Ethernet overhead up to 26 bytes.
The original article I linked was with regards to calculating the required MTU for MPLS networks (encapsulating layer 2 traffic into MPLS frames). I want to understand why 18 bytes is being added on to the standard 1500 bytes and not 26 bytes (plus the MPLS label stacks and any do1q tags).