tim@cmu-cs-k.ARPA (Tim Maroney) (03/12/85)
If throughput is really vital, your best bet may be to forget the Internet protocols entirely. The overhead is fairly high. It is easy to modify the 4.2bsd Ethernet drivers to allow your own packet types. The data from the packets can be directed to raw or customized socket drivers. By tailoring the protocol to the application, I expect you could get significantly better performance, albeit with some loss of portability. Incidentally, I have actually done something like this, a raw socket interface directly to the Ethernet, but the sources belong to IBM or C-MU or someone else who is not me. It was easy. Any experienced 4.2bsd kernel hacker should have little difficulty and finish in under two weeks (depending on what fraction of his time is devoted to it, of course). The only hassle with raw sockets is that their performance tends to be inversely proportional to the number of them in use. -=- Tim Maroney, Carnegie-Mellon University, Networking ARPA: Tim.Maroney@CMU-CS-K uucp: seismo!cmu-cs-k!tim CompuServe: 74176,1360 audio: shout "Hey, Tim!"
jbn@wdl1.UUCP (03/14/85)
If throughput is really vital, check out the Communications Machinery Corporation card. They claim 1Mb end to end FTP on an Ethernet, using a UNIX system V with their driver, using IP/TCP. Their Ethernet card has a 12Mhz M68000 to do the protocols and a LANCE chip for the Ethernet, along with 128KB of onboard RAM. We have one, but haven't fired it up yet. John Nagle