Hi there. I have built an application that can set up mac frames and then it
can send them through the network using winpcap.
In mac frames when the length of teh data to transmit is less than a
specific value you have to add a pad. I didn't know then which value you
have to put in the length field of the mac frame. I have seen in ethereal
that when i receive MAC frames that transport a bunch of data which has a
length less than 46 octets (theminimum) the value of the length field is set
to the real length of the data being sent, not to the value of that length
plus the pad you have to add (which will sum actually 46).
The problem is that when i construct a frame which has to wear a pad field
and when i put the length field a value of 24,for example, when it arrives
to tha remote system this value has been changed to the value of 46 (the
length of the data plus the pad, which is actually the data im sending).
This is causing me trouble and i don't know who is modifying the value of
this field. So i have thought that this could be happening because the value
of the length field has to be put to the value of all the data being sent
(data+pad). But in that case , how it is possible that i had received mac
frames with pas with the length field set to teh value of teh data being
sent and not the value of 46(data+pad)?
I'm in a mess. Can somebody help me?
can send them through the network using winpcap.
In mac frames when the length of teh data to transmit is less than a
specific value you have to add a pad. I didn't know then which value you
have to put in the length field of the mac frame. I have seen in ethereal
that when i receive MAC frames that transport a bunch of data which has a
length less than 46 octets (theminimum) the value of the length field is set
to the real length of the data being sent, not to the value of that length
plus the pad you have to add (which will sum actually 46).
The problem is that when i construct a frame which has to wear a pad field
and when i put the length field a value of 24,for example, when it arrives
to tha remote system this value has been changed to the value of 46 (the
length of the data plus the pad, which is actually the data im sending).
This is causing me trouble and i don't know who is modifying the value of
this field. So i have thought that this could be happening because the value
of the length field has to be put to the value of all the data being sent
(data+pad). But in that case , how it is possible that i had received mac
frames with pas with the length field set to teh value of teh data being
sent and not the value of 46(data+pad)?
I'm in a mess. Can somebody help me?