I have MV64360 Marvell board and I try to send Jumbo frames. I configured the Port Serial Control Register to support Jumbo frames. When I send block in length up to 1500 bytes it works, more then 1500 it does not work and I don't receive any error from the SW. Why?
The rest of your networking gear must also support and be configured for jumbo frames. If not they simply throw your frames away as "errors"
It is at least known that most network equipment will support slightly over 1500, as it is needed to support vlan tagged frames.
If things really stop exactly at 1500, it is not likely in layer 2 equipment.
Try a cable directly between two such devices configured for jumbo frames and see if it works that way.
-- glen
According to what I've read in O'Reilly's Ethernet book, the maximum value is 1535 bytes, so any equipment complying with the 802.3 spec, should be able to handle that.
:> It is at least known that most network equipment will support :> slightly over 1500, as it is needed to support vlan tagged frames.
:> If things really stop exactly at 1500, it is not likely in layer 2 :> equipment.
:According to what I've read in O'Reilly's Ethernet book, the maximum value :is 1535 bytes, so any equipment complying with the 802.3 spec, should be :able to handle that.
When '1500' is being used, the figure does not usually include the preamble or CRC, and certainly not the intra-frame gap (IFG). '1500' also may not include the source and destination MAC addresses.
'1535', though, includes everything except perhaps the IFG, and might include VLAN tags: without the tags, the total length including preamble, CRC, and IFG is 1540 octet-times if I recall properly.
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