Path: utzoo!mnetor!uunet!husc6!think!ames!lll-lcc!pyramid!cbmvax!grr From: grr@cbmvax.UUCP (George Robbins) Newsgroups: comp.dcom.modems Subject: Trailblazer Speed Stats Message-ID: <3570@cbmvax.UUCP> Date: 4 Apr 88 07:35:09 GMT Reply-To: grr@cbmvax.UUCP (George Robbins) Organization: Commodore Technology, West Chester, PA Lines: 118 Well, the one question that comes to mind when people talk about the Telebit Trailblazer modems is how fast they really are when running the normal uucp protocols in day to day use. I've been collecting some statistics here that shed some light on the subject: Answer: > 10 times as fast as 1200 baud modems > 5 times as fast as 2400 baud modems That's what you really wanted to know, right? 8-) Here are the statistics those numbers were based on. Note that a considerable amounts of "unqualified" data was thrown away because of the caveats below or because I talk to a system at both 1200 or 2400 baud. Unfortunatly, I don't have any Courier HST, Hayes or direct connect lines to compare these numbers with. It would be interesting to some sythetic (i.e. transfer 1 Mbyte) tests with different modems/direct connect lines for contrast. Caveats: 1) The times are based on "receive" transfers only. The "transmit" times uucp gives for trailblazers are highly bogus because uucp thinks the transfer is "done" while the trailblazer still has (allegedly) up to 10K of data buffered internally. This propensity results in considerably inflated speed estimates even on normal size news batches. For the sake of consistancy, all "transmit" times are discarded. 2) "transmit" rates, even on low speed modems, are typically 20-50% faster than "receive" rates. I am not sure where to put the blame for this and the problem with measuring the "transmit" times for the Trailblazers makes it impossible to determine whether this is also the case on higher speed transfers. We'll just have to call lay claim to using "worst case" values... 3) Transfers lasting only a few seconds have been discarded due to the timer granularity in the SYSLOG file. Typically these are "control card" files. The criteria used for the "peak" column are somewhat stricter. 4) cbmvax is a VAX 785 running Ultrix. It is typically fairly lightly loaded except when news batching or unbatching happens to coincide with uucp transfers. There are two Trailblazers used for both incoming and outgoing uucp calls, both in PEP mode and with 1200 and 2400 baud modems. There are also two USR Courier 2400 baud modems available for uucp usage when the Trailblazers are busy, but these haven't seen much usage lately. The innterface rate on the Trailblazers is not "locked". 5) A lot seems to depend on the system the Trailblazer is attached to. I am not sure whether some of the systems I talk to have their interface rates set to 9600 bps instead of 19.2K bps. Doing so tends to limit peak transfer rates to around 7000 bps. Unfortunatly, distance and wimpyness are somewhat correlated in the systems I talk to, so it's hard to draw any supportable conclusions. March 1988: uucp usage report for cbmvax on Sun Apr 3 15:30:36 EDT 1988 1200 baud only ============== system transfer files fail M-bytes hours speed peak ======= ============ ====== ==== ======== ====== ===== ===== allegra slow receive 40 0 0.067 0:15 730 bps 813 bps burdvax slow receive 45 0 0.117 0:24 786 bps 857 bps hutch slow receive 72 0 0.223 0:54 677 bps 785 bps ihnp4 slow receive 106 0 0.439 1:58 619 bps 796 bps liberty slow receive 16 0 0.093 0:20 742 bps 759 bps molly slow receive 21 0 0.099 0:22 733 bps 806 bps snark slow receive 66 0 0.192 0:44 716 bps 792 bps swatsun slow receive 54 0 0.089 0:19 750 bps 818 bps *udel slow receive 31 0 0.061 0:18 554 bps 755 bps ------ ---- -------- ------ ----- 451 0 1.380 5:34 689 bps 2400 baud only ============== system transfer files fail M-bytes hours speed peak ======= ============ ====== ==== ======== ====== ===== ===== amiga slow receive 1058 0 2.997 7:06 1172 bps 1348 bps bpa slow receive 626 0 8.600 16:42 1429 bps 1523 bps *osu-cis slow receive 38 0 3.145 8:15 1058 bps 1151 bps *rutgers slow receive 668 0 20.686 45:45 1255 bps 1594 bps ulowell slow receive 74 0 0.126 0:17 1177 bps 1455 bps uunet slow receive 206 0 0.533 1:20 1098 bps 1322 bps vu-vlsi slow receive 58 0 0.215 0:30 1192 bps 1382 bps ------ ---- -------- ------ ----- 2728 0 36.306 79:55 1260 bps Trailblazer+ uucp ================= system transfer files fail M-bytes hours speed peak ======= ============ ====== ==== ======== ====== ===== ===== amiga fast receive 64 0 1.414 0:52 4513 bps 7016 bps bpa fast receive 4037 0 52.648 17:38 8289 bps 12317 bps pyramid fast receive 15 0 0.059 0:01 6240 bps 7419 bps rutgers fast receive 451 0 13.980 6:53 5636 bps 7246 bps uunet fast receive 247 0 1.167 0:34 5611 bps 10173 bps vu-vlsi fast receive 125 2 0.859 0:20 6876 bps 9117 bps ------ ---- -------- ------ ----- 4939 2 70.127 26:18 7407 bps International X.25 ================== system transfer files fail M-bytes hours speed peak ======= ============ ====== ==== ======== ====== ===== ===== +cbmbsw slow receive 433 0 0.432 8:34 140 bps 169 bps ------ ---- -------- ------ ----- 433 0 0.432 8:34 140 bps * (a terminal server or port switch involved here) + (X.25 via tymenet dialout port at 1200 bps) -- George Robbins - now working for, uucp: {uunet|ihnp4|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@uunet.uu.net Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)