mah@wu-wien.ac.at (Michael Haberler) (06/12/91)
Archive-name: internet/route/pcroute/1991-05-28 Archive-directory: tacky.cs.olemiss.edu:/pub/pcroute/ [130.74.96.13] Original-posting-by: mah@wu-wien.ac.at (Michael Haberler) Original-subject: Re: PCROUTE? Reposted-by: emv@msen.com (Edward Vielmetti, MSEN) |> ... because we have PCRoute on about |> six trunks at 9600 and 19200. While investigating problems of lost |> routes, it was discovered that PCRoute would go off into the woods |> when two simultaneous transfers were in progress from each end There was a bug in the slip code which caused PCroute to hang under high traffic. It's been a at least a year since this was fixed by the author of the Slip code, David Johnson <dave@tacky.cs.olemiss.edu>. I had a similar problem as you described it, and after applying the fix it went away. No outages in over a year. I include Dave's message; I rather suggest you get a fresh copy of PCroute from tacky.cs.olemiss.edu with ftp. - michael ---------------------------------- Subject: Re: SLIP on pcroute In-Reply-To: Your message of "Sat, 31 Mar 90 19:01:53 EST." <9003311807.AA22631@tacky.cs.olemiss.edu> Date: Sat, 31 Mar 90 17:17:39 -0600 From: David E. Johnson ** Title: Systems Programmer <dave@tacky.cs.olemiss.edu> Michael, For the past several months our router has failed consistently every few days. The symptoms are the same as you reported. The ethernet side still worked but the SLIP side seemed to forget the Xmit interrupts. Since this was our connection to the Internet and also connected a PC (terminal) lab via network to our campus IBM, this problem was significant. After trying every possible solution, we decided to order some 16550's assuming that the 8250 was at fault. However, we have not received these yet. So I decided to have the router report its status via syslog every so often so that maybe we could track the problem down. (A masters student here has not completed the SNMP implementation which would have helped tremendously) While going through the code to place "counters" at strategic locations, I FOUND THE PROBLEM. Not in hardware, but in software. In the routine SLIP_DL_IP_W_ACCESS interrupts are turned off to avoid a possible race condition with the interrupt handler. The problem is that the macro between turning ints off and on has a way to jump out of this pair. When the ethernet side overloads the SLIP side this routine jumps automatically to "no_buffer", thus leaving interrupts OFF. I have removed the cli and sti from this routine and the router has not failed once (about 7 days). If a race condition still exists, it hasn't caused a problem thus far. The cli and sti could be left and a sti placed in the BUFF_CHECK routine just before jumping to "no_buffer", but like I said, we have had no problem thus far. An update will be available soon, but since you have re-assembled anyway, you can just take these out. I would like to know if this solves your problem. I would also like to see any changes you have made or may make for the 16550. Since we have a few coming, we might as well take advantage of them. David E. Johnson ** Title: Systems Programmer Department of Computer Science ** Telephone: (601) 232-7396 The University of Mississippi ** Internet: dave@cs.olemiss.edu 336 Weir Hall ** University, MS 38677 ** -- Michael Haberler mah@wu-wien.ac.at, mah@awiwuw11.bitnet University of Economics and Business Administration A-1090 Vienna, Augasse 2-6 Biz: +43 (1) 31336 x4796 Fax: 347-555 Home: +43 (1) 961-679 (voice & fax) D-Netz: +43 (663) 811-056 -- comp.archives file verification tacky.cs.olemiss.edu total 940 drwxr-xr-x 3 ftp 512 Apr 17 23:35 exp drwxr-xr-x 2 ftp 512 Apr 17 23:35 analyzer -rw-r--r-- 1 ftp 26793 Apr 17 23:35 uncomp.exe -rw-r--r-- 1 ftp 28340 Apr 17 23:35 tar.exe -rw-r--r-- 1 ftp 11321 Apr 17 23:35 readme.pcroute.doc -rw-r--r-- 1 ftp 1284 Apr 17 23:35 readme.1st -rw-r--r-- 1 ftp 6683 Apr 17 23:35 readme.pcbridge.doc -rw-r--r-- 1 ftp 107327 Apr 17 23:35 pcroute2.2.tar.Z -rw-r--r-- 1 ftp 131801 Apr 17 23:35 pcroute2.2.src.tar.Z -rw-r--r-- 1 ftp 30977 Apr 17 23:35 pcbridge1.2.tar.Z -rwxr-xr-x 1 ftp 7553 Apr 17 23:35 analyzer.doc -rw-r--r-- 1 ftp 2054 Apr 17 23:35 copywrit.doc -rw-r--r-- 1 ftp 22310 Apr 17 23:35 pcbridge1.1.tar.Z -rwxr-xr-x 1 ftp 10598 Apr 17 23:35 analyzer.exe -rw-r--r-- 1 ftp 6577 Apr 17 23:35 compress.doc -rw-r--r-- 1 ftp 57197 Apr 17 23:35 pcbridge1.2.src.tar.Z -rw-r--r-- 1 ftp 24692 Apr 17 23:35 pcbridge1.2b.tar.Z -rw-r--r-- 1 ftp 44319 Apr 17 23:35 pcbridge1.2b.src.tar.Z -rw-r--r-- 1 ftp 118607 Apr 17 23:35 pcroute2.2b.src.tar.Z -rw-r--r-- 1 ftp 97213 Apr 17 23:35 pcroute2.1.tar.Z -rw-r--r-- 1 ftp 160611 Apr 17 23:35 pcroute2.1.src.tar.Z found pcroute ok tacky.cs.olemiss.edu:/pub/pcroute/