[CentOS] Jumbo frames problem with Realtek NICs?

Emmanuel Noobadmin centos.admin at gmail.com
Fri Jun 24 06:33:27 UTC 2011


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?



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