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View Full Version : Length Field of the 802.2 Header


JS08K
November 27th, 2009, 11:08 AM
Explanation of what is happening:
I am designing a micro-controller program that takes in ethernet and converts it to other communication styles. I am not concerned about an IP protocol since I am not going to be dealing with computers per-say. I have designed my micro-controller to first read the target MAC address, then it will read the source MAC address. After it reads these two it will read the length field and make a decision wether or not to read the rest of the packet. If this length field is 01F4h then it will read the packet.
The problem:
The problem that is occurring I am placing 000Ah for the length field, followed with some made up 10 bytes of data. I allow padding to fill up the rest of the packet. When sending the packet, only a few of the sent packets make it through. I have had the length field printed on the receiving side and It does not have any specific value. It should always be received as 000Ah but this is not the case. Could it be that the software has a bug and is not sending out the packet with the Length/Type field directly following the source MAC address?

Colasoft Support
November 30th, 2009, 03:07 AM
Sorry, but I do not understand you well.
Do you mean that you use Colasoft Packet Player to send the packets, and then use your micro-controller program receive it? And you doubt Colasoft Packet Player has a bug, so that it is not sending out packets with Length/Type fiels directly following the source MAC address?