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Posted: April 11, 2012 07:08 pm
Member No.: 35,624
Joined: August 25, 2011
Hello everybody, I'm reading something about the Ethernet protocol that is going to help me for my next project and I'd like to know if what I read is correct.
The ethernet frame structure is composed by:
- Preamble: 7 bytes, all of them assume the value 0xAA (b'10101010')
- SFD (Start Frame Delimiter): 1 byte, 0xAB (b'10101011')
- MAC destination: 6 bytes, physical address of the receving device (* need to know more about this, can I send any number between 0x000000 and 0xFFFFFF?)
- MAC source: 6 bytes, physical address of the sending device (* need to know more about this, can I send any number between 0x000000 and 0xFFFFFF?)
- Length: 2 bytes, specifies the length of the "Data packet" (this number must be between 46 and 1500)
- Data: 46<=bytes<=1500, data I want to send (what if I want to send less then 46 bytes?)
- FCS (Frame Check Sequence): 4bytes, * I have no idea about how it works
- Pause: 12 bytes (I guess they're all 0x00 right?)
Preamble, SFD and Pause bytes are not necessary.
Is it correct? Is there something else I should know (in addition to what I said I don't now)?
Thanks for your help
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