Date: Fri, 26 May 89 20:59:53 EST From: Dwight D. McKay (The Moderator) Reply-To: Suns-at-Home@orchestra.ecn.purdue.edu Subject: Suns-at-Home Digest V2 #13 To: Suns-at-Home-List Suns-at-Home Digest Fri, 26 May 89 Volume 2 : Issue 13 Today's Topics: Best modems for SLIP: summary of responses +--------------------------------------------------------------------+ | Submissions: suns-at-home \ @orchestra.ecn.purdue.edu | | Requests: suns-at-home-request > -- or -- | | Archives: suns-at-home-archives / ...rutgers!pur-ee!... | +--------------------------------------------------------------------+ ---------------------------------------------------------------------- Date: Mon, 22 May 89 18:05:21 EDT From: "Doug Arnold" Subject: Best modems for SLIP: summary of responses To: Suns-at-Home@orchestra.ecn.purdue.edu On May 9 I posted the following query to the comp.dcom.modems newsgroup and the suns-at-home mailing list: I'm about to obtain two Sun SPARCstations, which I intend to connect via SLIP over a dialup line across a distance of five or ten miles. I'd like to hear opinions of the best modems for this purpose. I'm interested in peoples' experiences concerning speed, reliability, price, availability, etc. I've heard that PEP modems don't do so well because of the line turnaround time and I've heard that MNP compression has trouble with SLIP packets. Can anyone verify (or contradict)? The longest response was from Greg Earle (earle@mahendo.Jpl.Nasa.Gov), and appeared in Suns-at-Home Digest V2 #12. The other responses which I received follow (slightly edited). --------------- From: watmath!cs.AthabascaU.CA!lyndon@uunet.UU.NET (Lyndon Nerenberg) Your best bet is a *fully* compliant V.32 (ie 9600 FULL DUPLEX BOTH DIRECTIONS AT THE SAME TIME) modem. I know the Hayes doesn't cut it. I haven't tried the Telebit T2500 yet. The T1000/2000 will work although the bac channel delays are noticeable. The version 6 PROMs for the TB's will have onboard SLIP support which will cure that problem. --------------- From: JQ Johnson One point of importance is that telnet traffic is very different from NFS traffic. Telnet is typically 1 or 2 small packets in one direction, then echo and ack. NFS is often a stream of very large packets followed by a response. So a priori the turnaround cost for NFS traffic will be much less than that for telnet and friends. I've been using some Fujitsu 19.2Kb trellis leased line modems, and find that the encoding adds about 60ms latency to the start of each packet. They are full duplex, but the latency translates into longer RTT. --------------- From: weiser.pa@Xerox.COM (Mark Weiser) I use a pair of V.32 9600 baud modems from Codex. They work fine. Avoid modem with compression (MNP), these do not work well with SLIP. --------------- From: Vaughan Pratt I use slip extensively over trailblazers running at close to 18K (line is clean and short). The echo performance is *miserable* compared to a direct line at 9.6K. If you type a burst of characters, the first character is echoed a second later, then the remaining characters are echoed another second later. It is distractingly painful to use slip for interactive work. Some of my delay I think can be attributed to going through a line concentrator at the other end. Timing the round trip delay of echoing single characters without slip, comparing a trailblazer to a Supra 2400 baud modem, it appears that when the trailblazer is used the delay roughly doubles. --------------- From: Sergei A. Gourevitch I can vouch for the fact that Trailblazer plus modems don't do SLIP well. I don't have any reports on which modems do well. --------------- Thanks to everyone who replied. I would welcome further comments from anyone else with experience with SLIP over modems. -- Doug Arnold dna@emmy.umd.edu ------------------------------ End of Suns-at-Home Digest ******************************