Xref: utzoo comp.protocols.tcp-ip:6655 comp.dcom.lans:2626 Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!accuvax.nwu.edu!morrison From: morrison@accuvax.nwu.edu (Vance Morrison ) Newsgroups: comp.protocols.tcp-ip,comp.dcom.lans Subject: Super Cheap IP router (< $1000) Message-ID: <583@accuvax.nwu.edu.NWU.EDU> Date: 3 Apr 89 16:51:06 GMT Sender: news@accuvax.nwu.edu.NWU.EDU Reply-To: morrison@accuvax.nwu.edu (Vance Morrison ) Organization: Northwestern Univ. Evanston, Il. Lines: 192 Hello All, I have developed software for Turning a klunky old IBM XT into a IP router. Below is a description of the software I wrote. The software is available via anonymous FTP from accuvax.nwu.edu (129.105.49.1) in the directory pub/pcroute. We here at Northwestern have found this program to be very useful Already we have replaced a major Hub in our network with a PCrouter and others additions/substitutions are planned. If you find this program useful, let me know, it helps my ego (:-). Vance -------------------------------------------------------------------------- PCROUTE - and IP routing program from the IBM PC Vance Morrison morrison@accuvax.nwu.edu Traditionally IP routers have been fairly high performance, expensive machines. Typically they run about $5000-$10,000 a unit. Until now a IP router for under $5000 was just about impossible to get. Recent developments in PC hardware, however, has made it possible to convert a PC to an IP router for a TOTAL of $800-$1000 a unit. This price is less that the cost of many ethernet boards and thus it now makes sense to always use dedicated router to perform IP gatewaying functions. --------------------------------------------------------------------- What is PCroute? PCroute is software written for an PC/XT (or AT) that will allow it to act as a IP router that will gateway between the following kinds of Physical media. Ethernet - Ethernet Ethernet - Starlan Starlan - Starlan In addition to the XT, the only other hardware needed are the networking cards, which at present run about $200-$250 a piece. Since you can buy an XT (without an monitor) for $400, the total cost for the hardware is $800-$900. --------------------------------------------------------------------- What do I need to install PCroute? 1) An XT computer (does not need monitor) 2) 2 Western Digital WD8003 network cards WD8003E Ethercard Plus WD8003S Starcard Plus WD8003SH Starlink Plus --------------------------------------------------------------------- How Fast is PC route? Some may argue that a PC simply is not fast enough to be a good IP router. This would true if the PC had to do all the work, but in fact, the ethernet cards do most of the work. All the PC needs to do is determine the route, and copy the packet from one interface to the other. By programming in assembler and optimizing for peak efficiency, the PC is up to the task. Actual tests indicate that that following formula is a worst case estimate of throughput of PCroute on a 4.77Mhz XT packet_delay = .473 + .00393 * len msec Where 'len' is the length of the packet in bytes. Thus PCroute has a fix per packet overhead of .473msec and takes 3.93usec/byte to transfer the packet from one network to the other. Thus for the largest packet size (1514) we get throughput of packet_delay = .473 + .00393 * 1514 = 6.4 ms throughput = len*8/packet_delay = 1.9 Mbit/sec For the smallest packet size (64) we get a throughput of packet_delay = .473 + .00393 * 64 = .724 ms throughput = len*8/packet_delay = .7 Mbit/sec If you were to buy a XT clone, (even the $400 variety) it would undoubtedly be a 8Mhz or 10Mhz machine, so you should expect to do 1.6 and 2.0 times better respectively with these machines. I most strongly suggest that you get the 10Mhz variety since they are usually only $30 more and will give you a 12% performance boost In addition the Ethernet boards have an on-board 6.5K packet buffer. Thus packets that come at the PCrouter too fast for it to process will be queued. The router will start dropping packets after this 6.5K buffer is exhausted. Note that since SUN NFS likes to send 8K blocks in fast spurts this will sometimes cause the router to drop packets. I suggest that you set this block size down to 4K if you expect a lot of NFS traffic through the router (look for 'wsize' in man fstab). --------------------------------------------------------------------- What PC route supports? PCroute was designed to be as simple as possible yet perform well as a IP router. In particular it supports 1) IP routing with Subsets (however the subnet mask must begin with 255.255) 2) Static routing with up to 250 routes. 3) responds to ICMP echo (ping) 3) Directed broadcasts The PCrouter also has support for more than two network interfaces, but this requires recompilation of the code, so for now you will have to contact me. --------------------------------------------------------------------- What PC route DOESN'T support? 1) Dynamic routing (yet) 2) Booting off the network (BOOTP) (yet) 3) Any IP services besides routing and ICMP echo. 4) Any other Ethernet/starlan card besides Western Digital WD8003 --------------------------------------------------------------------- Coming Soon. 1) RIP Support 2) Appletalk - Ethernet Support (like a KIP box but you can tunnel IP packets through the Appletalk network) Here at NU we use this so that we can get cheap, reasonably fast network access between buildings. 3) Network Booting a la BOOTP 4) The other ICMP functions so that router conforms to RFC1009 --------------------------------------------------------------------- Hints 1) We found that the 10Mhz XT clones that Jamco and others sell work very well. One nice feature about these units is their BIOS. By setting the dip switches in the PC, you can tell it that there is no Monitor. This also tells the BIOS not to check for a keyboard either. Thus you don't need to buy either the keyboard or the monitor. Other XT BIOS ALWAYS check for the keyboard, and thus you have to plug it in even though you never use it. --------------------------------------------------------------------- Reliability The reliability of PCroute has been EXCELLENT. We have been using these routers for months now in three places with absolutely no failures. If you wish to PING one for yourself here are some PC routers on our campus 129.105.49.13 129.105.1.1 129.105.7.1 --------------------------------------------------------------------- Comments and Bug reports I am interested in finding out what you think of PCroute and how well it performs for you. I am also interested in hearing about any problems you have or bugs in the documentation. You should send your comments to Vance Morrison Note that since I am not paid to support this software, I can not guarantee that I can respond to your problem, but I will try. Vance Morrison Northwestern University