================ All PCI/PCIe 8169/8168 10/100/1000 NETWORK ADAPTER =============

Q. What is 'Jumbo Frame' ? What is the purpose of this feature ? 

A. This feature is for performance. It increases the maximum length of one packet.

   This feature is out of ethernet specific and has ethernet switch/hub compatibility.
   If the ethernet switch could not support the jumbo frame, the packet will be discarded.
   Users may directly link the 2 machines to avoid the maximum length limitation but this also limit the connectivity.

   Driver will disable 'Large Send Offload (IPv4)' after user enables this feautre, 
   TCP/IP could has better performance if it use jumbo frame without large send.
   If users enable both of them, the driver automatically chooses 'Jumbo Packet'.

   For switch compatibility and TCP/IP performance ,  it is better to use 'Large Send Offload (IPv4)'  instead of 'Jumbo frame'

 PS:

 Althrough, the 'Advanced' page has 'Disable, 2KB MTU, 3KB MTU, ... 7KB MTU'. 
 Driver will not enable the option which exceeds the NIC hardware limitation.
 If exceeds, driver automatically decreases the length to a proper value.

 PCI 8169 (8169S/8169SB/8169SC) : 7KB
 Cardbus (8169SB) : 3KB
 PCIe 8168B rev B: 4KB
 PCIe 8168B rev C: 6KB

 How to verify jumboframe works :

 1. Both sides enable the jumboframe to a identical value.  
    If two sides has different jumboframe length limitation, use smaller value.
    For example, cardbus 8169 and PCI 8169 should use 3KB.

 2. Both side must disable firewall.

 3. To avoid switch/hub compatiblity issue , please connect the two NICs directly.

 4. Ping a large packet to the other machine.  Ping xxx.xxx.xxx.xxx -l 65000

 5. If responses successfully, the jumboframe works.
