Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!husc6!rutgers!ucla-cs!zen!ucbvax!topaz.rutgers.EDU!hedrick From: hedrick@topaz.rutgers.EDU (Charles Hedrick) Newsgroups: comp.protocols.tcp-ip Subject: Re: Sun routers... Message-ID: <8708270241.AA17670@topaz.rutgers.edu> Date: Wed, 26-Aug-87 22:41:05 EDT Article-I.D.: topaz.8708270241.AA17670 Posted: Wed Aug 26 22:41:05 1987 Date-Received: Sat, 29-Aug-87 06:23:19 EDT References: <18020@amdcad.AMD.COM> Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 47 Sun's Ethernet hardware is quite good. There's no reason in principle why a Sun couldn't be a very good IP gateway. However there are some practical things that make this less than optimal. The versions of SunOS we have seen are based on 4.2. In order to avoid stability problems, gateways have to have much more careful validation of packets than 4.2 does. E.g. they have to recognize every possible broadcast address format, and also refuse to forward packets for invalid addresses (as opposed for example to sending ARP requests for Martian addresses). This is somewhat better in 4.3 than 4.2, but even 4.3 does not recognize all possible old and new style broadcast addresses, nor as far as I can tell does it have a complete Martian filter. We expect our gateways to do proxy ARP (for hosts that can't handle subnets, and a few that can't even deal with routing). This is not present in 4.2, and as far as I know is not in 4.3 either. We expect our gateways to be up all the time. Normal timesharing systems are taken down periodically for PM, software installation, etc. Our gateways (cisco) download software from a server. Going to a new release requires downtime of about 30 seconds. Suns typically require a good deal longer than this to bring up new releases. Some sites also take them down for backups, and now and then they crash (though in honesty I'd have to say that our Suns are very stable). I believe that the operational requirements of a gateway are at least slightly inconsistent with those of a host. If you are building a large or complex network, the vendors whose business is making routers are likely to have better routing technology than routed, to support a wider variety of media, (As an example, we tried to interface our Sun to the Arpanet and found that although 1822 interfaces existed, we couldn't find anyone who knew how to get them.), and to be more aggressive about supporting new network monitoring standards. In the long run, there are going to be performance advantages. At the moment, Suns probably perform at least as well at connecting Ethernets as the typical dedicated routers. We have used Suns as gateways between major Ethernets and restricted Ethernets containing only diskless Suns. They perform very well at this. I'm sure we will continue to use Suns as gateways to one extent or another. However for large networks, those with complex topologies, and those serving machines from many vendors (and with buggy TCP implementations), I would recommend using a gateway from a vendor that specializes in such things.