[HECnet] What use are *you* making of HECnet?

"Jason" == Jason Stevens <neozeed at gmail.com> writes: Jason> Ah I had thought fragmentation was a 'feature' of TCP not Jason> UDP.. well then that would take care of it then. There are two things that serve similar purposes and have confusingly similar names. "Segmentation" is what TCP does to break user data into convenient size chunks. That chunk size is MSS (Max Segment Size), it's negotiated at TCP connection setup. "Fragmentation" is what IPv4 does to break datagrams into chunks that fit on the wire (that size is MTU, Max Transmission Unit). Segmentation is more efficient than fragmentation, so with TCP the normal approach is to pick MSS such that the resulting packets end up no larger than MTU. In the case of UDP, the packet size is set by the application (because each application send results in exactly one UDP packet), so fragmentation will occur if the application sends stuff bigger than MTU - header size. paul