[vlc-devel] [RFC] stream output MTU

[Marian Ďurkovič]

Hi,

   in the past I've commited a few fixes that account for IP, UDP and RTP
headers - see:

#define MTU_REDUCE 50

Unless those were removed, value of 1500 should be fine, since it gives
1450 after MTU_REDUCE, which is fine for IPv6 as well.

It's well known that ethernet MTU is 1500, having some other value might
create unnecessary confusion.

     With kind regards,

        M.
   


On Fri, 31 Aug 2007 15:00:33 +0300, Rémi Denis-Courmont wrote
> Hello,
> 
> Currently, we have a default "MTU" of 1500 bytes in a few places in 
> the stream output stuff. As far as I understand, that "MTU" represent 
> the UDP payload size, including the potential RTP header, but 
> excluding transport and network header, as is customary for a "MTU".
> 
> Therefore, it would seem that 1500 is not such a wise default value. 
> For a typical fast Ethernet (or Wi-Fi) attachment, the MTU would 
> actually be 1472 resp 1452 for IP version 4 resp 6. For more intricate 
> scenarii, it could be slightly lower (e.g. PPPoE eats an extra 8 bytes).
> 
> Am I being confused? is there any rationale for the current value?
> 
> -- 
> Rémi Denis-Courmont
> http://www.remlab.net/