On 2009-01-13, Steve Holden <st...@holdenweb.com> wrote: > K-man wrote: >> >> I am sending data using the socket interface in python, but I >> want to know how big the ethernet packet size is (in bytes). >> I didn't really see a way using the socket library of how to >> do this. Any suggestions? > > There is no way to know what size Ethernet packets will result > from specific traffic.
Unless he's using a low level API such as AF_PACKET/SOCK_RAW. If that's the case then the packets will be exactly as big as he makes them. And he wouldn't be asking this question. :) > Or do you want to know the MTU size (largest possible Ethernet > packet size)? This shouldn't really matter, since large TCP > messages will be split into a sequence of IP datagrams, and > large IP datagrams will be automatically fragmented and then > reassembled at the other end. > > Is there a specific reason this is important to you? If it's just idle curiosity, then wireshark or tcpdump can show one exactly what's going on on the wire. A reading of http://en.wikipedia.org/wiki/Transmission_Control_Protocol should also allow one to predict pretty accurately what's going to happen when you call send(). -- Grant Edwards grante Yow! I want EARS! I want at two ROUND BLACK EARS visi.com to make me feel warm 'n secure!! -- http://mail.python.org/mailman/listinfo/python-list
