luasocket, udp, send/receive different max datagram size?

[Valerio Schiavoni <valerio.schiavoni@...>]

Hello,

I just noticed the following about LuaSocket's UDP support for send and receive.

In receive (http://w3.impa.br/~diego/software/luasocket/udp.html#receive) :

If size is omitted, the maximum datagram size is used (which is currently limited by the implementation to 8192 bytes).

In send (http://w3.impa.br/~diego/software/luasocket/udp.html#send) :

 "The maximum datagram size for UDP is 64K minus IP layer overhead."

What is the technical reason for  not being of the same size ? 

thanks,

Valerio