Bill Melohn (melohn@Sun.COM)
Thu, 27 Aug 87 15:07:12 PDT
>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
We have gradually introduced many 4.3 networking features into various
release of SunOS, beginning with SunOS 3.3. We plan to have all of
4.3 features in the next major release of SunOS.
>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.
Proxy ARP exists for Sun machines. If it is generally felt that
this is a hinderance to using Suns as internet gateways, we will look
into making it a supported part of the product.
>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.
This is historically a reasonable arguement, especially when dealing
with large host systems that support timesharing or other loads.
Within our own internal network we have many dedicated gateway
machines with no local file system to backup whose uptime is regularly
measured in weeks. Our network is built mostly out of file server
machines with two ethernet interfaces; these are maintained by a
central support staff, and support both diskless clients and
internetworking connectivity. Having several gateways between each
network distributes the load and increases the redundancy if any
particular node fails. A diskless Sun running as a dedicated network
server offers much the same network-loadable gateway capability as a
cisco box at approximetly the same cost, albeit both the client and
its server must be reliable.
>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
Here, I take strong exception to your statements! Pardon the
commercial, but I don't know of any gateway box vendor who supports
the range of media AND protocols that Sun currently supports. We run
IP over Ethernet, Token bus, and load-shared sync connections; we
offer gateways to DECnet, OSI, SNA, etc. We have had an DDN gateway
product for almost a year, supporting both 1822 and X.25. We are
actively involved in both Internet and OSI protocol committees, and as
standards emerge that replace routed, EGP, and friends, we will have
products that implement those 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.
Sun continues to be very agressive in delivering multiple MIPS at the
lowest cost per MIP in the business. The technology that brings forth
low cost high powered workstations can also be used just as
effectively for high speed internet gateways.
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