SummaryThe Exinda can support Jumbo Frames with a small change to the default MTU used on the interfaces of the Exinda
Jumbo Frames are a relatively new technology that aim to decrease CPU overhead with packet reassembly. By default, IPv4 packets only send 1500 bytes of payload data per packet, with a header and a trailer that consist of all the other information such as source, destination, flags, etc. When a destination receives these IPv4 packets, the goal is to reassemble the data into the full payload by stripping off the header and trailer, and combining all the datagrams together in order.
However, when a large amount of packets are sent for a large file, the overhead to recombine the packets might be too much for a receiving device. The concept of jumbo frames was to reduce the total number of packets for a transmission, while still having the full amount of data transmitted. The resolution was to make a jumbo frame that has a payload data of a maximum of 9200 bytes with only one header and trailer. That is the equivalent of 6 standard IPv4 packets.
The Exinda, by default, has a Maximum Transmission Unit (MTU) of 1500, as that is the standard for IPv4. This MTU is completely controllable by admins to allow through packets of any desired size. The most common size to change it to, would be to 9200 in order to accommodate jumbo frames. Note, however, that the Exinda will pass traffic with a higher MTU than it is set for without incident. It will however log rx_errors and alert the administrators. This does not mean the traffic is dropping.
To change the MTU size on the Exinda to support Jumbo Frames:
1. Navigate to Configuration > System > Network.
2. On the first tab will be a list of interfaces on the device in a table; one column is called MTU. All of them are set to 1500 by default.
3. Change the MTU to '9200' on the desired interfaces.
4. Click 'Apply Changes' directly underneath the table
5. Save the configuration changes made.
Once this is done, the interface will accept any MTU that is 9200 bytes or less without generating an error.