[CentOS] Jumbo frames problem with Realtek NICs?

Fri Jun 24 08:02:01 UTC 2011
Christopher Chan <christopher.chan at bradbury.edu.hk>

On Friday, June 24, 2011 02:33 PM, Emmanuel Noobadmin wrote:
> On 6/24/11, Christopher Chan<christopher.chan at bradbury.edu.hk>  wrote:
>> On Friday, June 24, 2011 01:20 AM, Emmanuel Noobadmin wrote:
>>> First bottleneck was discovering the max MTU allowed on these is 7K
>>> instead of 9K but googling seems to indicate that the RTL8168B is only
>>> capable of 4K frames.
>>
>> Yeah, the 8168C goes up to 7k. Some 8168B go up to 6k.
>
> In cases like this where there are conflicting sources of information
> regarding the max MTU of a NIC, what would be the correct way to
> determine the actual max MTU? I figured the 7K limit basically by
> doing a binary search with the ifconfig mtu commands. But is the this
> figure simply what the driver will accept for the controller it
> identified or is that the actual hardware limit?

Given that these are the limits from Realtek's own Windows drivers, I'd 
say they are hardware limits and different from chipset/rev.