darrell@midgard.ucsc.edu (Darrell Long) (11/19/89)
We're working on getting SLIP up and running between my colleague's 3/50 (he wants to keep it at home) and his Celerity box. So far, we've had success connecting it directly and running it at various speeds. We have two problems: 1. We can't get it to recognize any other machine than the one it is directly connected to. By fooling with routes we can go from nothing to "network unreachable." 2. When using the Telebit 19.2k modems, we get multi-second ping times. This makes no sense, because if we hardwire them even at a low rate like 1200 baud, we get much better performance. There doesn't seem to be high packet lossage, so I am at a loss to explain this. I know several people on this group/mailing list use SLIP, so we'll appreciate the benfit of your experience. Please post, and also e-mail any replies (we often have flakey news) to: darrell@cis.ucsc.edu and arul@sdsu.edu Thanks, DL
weiser.pa@xerox.com (12/03/89)
My experience with telebits and other "smart" modems that try to packetize internally and do compression is that they do not do well at all with SLIP. I suspect the reason is that TCP is also packetizing and estimating round-trip-times (RTT's), and the modems generally are tuned for terminal interactive mode, and so TCP gets very confused. I have heard of a Telebit SLIP mode, but have no definite informatin. Also, older TCP/IP implementations (prior to 4.0.1 for suns) did not have Jacobson's and Karel's TCP RTT estimation improvements, which make a huge difference on any but the most trivial uses of slip. (E.g. they make a huge difference when rcping two files at once, or typing during an rcp). -mark