Written in 2000 ... I think
At present, I am planning a large project to cut twenty or so OpenVMS machines over from a dual redundant FDDI setup to a switched gigabit ethernet network. There are a few gotchas in this move.
Firstly, the current setup is dual redundant except at the host bus adapter. The HBA is a dual attached station that connects to two independent FDDI rings via Digital Gigaswitches. The plan is to implement full redundancy using two gigabit ethernet HBAs.
Dual attached FDDI is easy to implement at the operating system level because OpenVMS sees the DAS HBA as one device. This means you only need to supply one IP address. However, swapping to a fully redundant setup with two gigabit HBAs requires that there be two IP addresses. Actually, three...
The setup that is being converted uses the MultiNet IP stack from Process Software, making it a relatively easy configuration. Process Software introduced the concept of pseudo-devices in version 4.3 of MultiNet. This enables the systems manager to configure each HBA as an interface with it's own IP address, and then create a pseudo-device with a separate IP address, and "hide" the two physical adapters behind it.
Other than the advantage of providing redundancy, this configuration will also distribute the network load over both adapters. And as each adapter is seriously faster than a DAS FDDI adapter, we expect nice throughput gains on some large file transfers that are done at this site.
The downside to gigabit ethernet for this site is a bit of a joke. Older FDDI cards are generally supplied with MIC type connectors, and the GigaSwitch at the other end of the run is all MIC type connectors. Gigabit adapters are ST type connectors. So, unless you are skilled at fibre termination, you are looking at replacing your fibre runs. For the small number of hosts I am looking at, it is easier to replace (particularly as the network engineers driving this project are supplying the fibre). But it's a bit of a pain. The connector conspiracy in action.