m1rga00@uunet.uu.net (Richard G. Anderson) (04/18/91)
While it pains me to admit it, I have a friend in Cleveland. He used to work in Washington, but preferred nice housing and food for his family over three hours per day commuting... (is that rational?) He has asked that I post this to comp.sys.sun. Replies may be U.S. Mailed to him or sent to me. Cleveland isn't on usenet yet. -- Richard Anderson, Federal Reserve Board Help! I am trying to get a Sparcstation2 to work with PC's on a twisted pair Ethernet. The trouble is that I can send stuff to the Sun very quickly, but sending from the Sun to PC's is extremely slow. Here's the hardware layout: An AUI cable runs from the Sun to a 10-BaseT transceiver made by ExpressNet. The transceiver is connected by an eight wire twisted pair modular cable to twisted pair wiring in the wall, terminating in a wiring closet. There we have a Wang 10-BaseT concentrator. We also have several PC's (in different offices) with 3C503TP boards which also have modular TP cables that run into the wall, to the wiring closet, and into the Wang concentrator. Also connected is a 386 acting as a Banyan Vines server. Not only that, but the knee bone's connected to the ... thigh bone, an' the thigh bone's connected to the ... hip bone, and the hip bo -- Well, you get the idea. On the Sun, I made appropriate entries in the /etc/ethers, /etc/hosts, and /etc/networks files for several PC's. On the PC I have tried FTP software from both Beame and Whiteside, Inc., and from FTP Software, Inc. What happens with both is that I can upload files from the PC to the Sun very quickly, at rates of about 80 - 100 KBytes per second. But sending files from the Sun to the PC is very slow, only about 1200 - 1500 bytes per second. No such delays are evident when I use another PC as an FTP server and transfer files back and forth from it to my PC, so I don't think my PC is the problem. The problem is also noticeable when I use my PC with VT220 emulation software: with no one else using the Sun I still get unpredictable delays of a second or two in screen updates and local echoing of characters I type. Finally, I have also tried Beame and Whiteside's NFS, and again I find that uploading to the Sun is very quick, but downloading is so slow that files much larger than a few Kbytes seem to hang the PC. The Expressnet transceiver (which is hooked to the Sun) has lights on the side to indicate Signal Quality Error, Link Status, Power, Transmit, and Receive. I've noticed that the Collision and Transmit lights often blink on and off together when the Sun is sending something. This happens quite a lot even when I'm the only person on the network. I have tried swapping the AUI cable, the transceiver, and the cable from transceiver to the wall. I've also tried moving the Sun to another room so as to make use of a different pair of wires to the closet. None of this has made any differnce at all. Since the PC's on the network seem to communicate just fine, I'm led to believe that the Sun is the problem. The Sun is still under warranty, so I called the 800 number for help. The rep I talked to is trying to be helpful by sending me a new CPU board and referring me to the software people, but he doubts that it actually is a hardware problem. What he thinks might be happening is this: The Sun sends out a packet and waits a very short time for an acknowlegement. The PC is too slow to respond in such a short time. So the Sun knocks its transmission speed down a step and tries again. The process repeats itself until the Sun finds a speed the PC can handle. The trouble arises because the step down in transmission speed is exponential, which means that things slow down very quickly indeed. I don't whether to believe this story or not. Unless I missed something, it doesn't explain why I see that collision light blinking on so often. It also leads me to wonder why I don't have any trouble sending things between PC's on the network. I would have thought that the Ethernet and 10-BaseT specifications define procedures for negotiating transmission speeds between devices. If these procedures work the same way on the PC's as they do on the Sun, I should be having the same troubles everywhere. So I'm asking the net for help. Has anyone out there tried to put the SS2 on a twisted pair ehternet with PC's? Did it work for you? How did you do it? Would a faster NIC in my PC solve my problem? Has anyone out there had a similar problem? Is is fixable? If I really have a software problem, is there a patch? Please reply by email to the poster. He will forward it to me by snail mail, since I'm not back on USENET yet. Thanks. Jeff Hallman Research Department Federal Reserve Bank of Cleveland P.O. Box 6387 Cleveland, OH 44101 (216) 579 - 3001 Fax (216) 579 - 3050