Allow Oversize Frames / Feature Request

[Phil Lewis]

We use packEth to test our Ethernet switch hardware/software. We are required to support double-tagged frames of at least 1526 octets in length. Can a parameter be added to allow oversize frames. I had previously tweaked 1.2 to allow this, but now I need to do it again for 1.3.

thanks
Phil

[Miha Jemec]

Hi Phil,

regarding packETH, I can remove all the length checking and allow arbitrary packet length. But I don't know what the ethernet card driver will said on that. And since there is different driver for different cards I'm not sure if this will work in general. Anyway, I will do some tests, in the mean time you will have to change the source in 1.3 as you did for 1.2. But the code here didn't change a lot, so you won't have much work.

Regards, Miha

[Phil Lewis]

I would like to modify packETH to allow sending 'jumbo' frames - 1600 bytes.
Can you suggest a good starting point?

thanks
Phil Lewis

[Miha Jemec]

Hi Phil!

One thing is to change packETH to "allow" creation of packets, larger than 1500 bytes (without ethernet header). This is not a problem to change in the code, I think you already did this before.

Another thing is to have driver that allows this and change the settings. I found on the google (good starting point anyway!) this command:

"...
If jumbo frames are supported by the driver:

ifconfig eth0 mtu xxxx, where xxxx up to 9022 (bytes) or sometimes
16110 (bytes)
..."

You can try this, maybe it will work.

Regards, Miha