What does an ethernet header look like?
11,326
Neither of them. Following the specs the frame looks like:
- Preamble: 8 bytes
- Destination mac: 6 bytes
- Source mac: 6 bytes
- Type/length: 2 bytes
- Data: 46-1500 bytes
- Frame check: 4 bytes
The specs are here: http://standards.ieee.org/about/get/802/802.3.html
A more useful and easily accessible explanation is here: http://wiki.wireshark.org/Ethernet
The header is the frame before the data. The MAC header is point 2-4 (14 bytes). The MAC trailer is 4 bytes (last point). The ethernet frame thus consists of the preamble (8 bytes), the MAC header (14 bytes), data and the trailer (4 bytes).
Author by
user2025406
Updated on June 04, 2022Comments
-
user2025406 almost 2 years
What does the ethernet header look like?
Is it:
1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31| ..................................destination mac.................................. ...................................|...................source mac.................. ...................................................................................| ...............type................|
Or:
1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31| ..................................destination mac.................................. ...................................|...................source mac.................. ...................................................................................| ...............type................|.......................data.................... ......................................up to 1500...................................| crc/fcs|
Or is it:
1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31| ...Preamble..|................................destination mac...................... ...........................................................|source mac............. ................................................................................... .............|.type........................................|data.................... ......................................up to 1500...................................| crc/fcs|
I found many different opinions on this in the web.