Chris Wedgwood <cw(a)f00f.org> wrote:
On Thu, Jun 07, 2001 at 04:13:12PM +1200, Don Stokes wrote: You can of course run uucp over TCP, but that means running an error correcting protocol over an already reliable protocol. In a word, yuck.
Its hardly a crime, IP has checksums as do ethernet frames, as so other encpsulation technologies...
Well, no, but then ethernet (in common with every other sensible link level protocol) doesn't send acknowledgments. TCP does and uucp (g protocol at least) does, so you have a bunch of TCP packets flying back to the other end carrying uucp acknowledgments. You're also carrying more data, as you send the uucp protocol overhead on top of the TCP, IP and link level stuff. And you get uucp's windowing rules kicking in before TCP's do (once the transfer is underway), even if you adjust your uucp parameters to maximum window and packet sizes -- the defaults are small enough that any amount of latency slows things down quite badly and even the maximums are often not enough with V.42bis and friends plus latencies from TCP packetising and network delays in the way. uucp is a batch serial line file transfer protocol. It happens to have mail and news transfers layered on top of it, but it's still a serial line protocol. You wouldn't transfer mail with Kermit, would you? (Actually, I've heard of that being done too...) Pete <speed(a)advcomm.co.nz> wrote:
But of course you also gain the benifit of using a protocol that can incorporate compression, which can be a saviour on low-speed links, like rural dialup customers. In a word, nice.
You wish. Compression was a feature of uucp news transfer, but not mail transfer, i.e. news batches would be compressed, then put in the queue to send, while mail just got a From_ line prepended and an rmail command for the message submitted. Anyway, text compresses nicely with modern modems. Oh, IME, most PC uucp packages are garbage anyway. Yuck. -- don --------- To unsubscribe from nznog, send email to majordomo(a)list.waikato.ac.nz where the body of your message reads: unsubscribe nznog