Denis.Russell@newcastle.ac.uk (10/19/90)
On 4th Oct I sent out a query about routing extensive IP over an X.25 network. This is a brief summary of the responses, and other information gathered at the same time. Many thanks to all those who responded. I got several messages in reply. It seems that the main commercial routers have the right characteristics for the task. They can support high speed, have settable inactivity timers, multiple X.25 calls, use X.25 calls for two-way traffic. All the things we'd hoped for, even expected, but weren't actually certain about. It was confirmed that the Sun software established permanent X.25 calls and never cleared them down, but several people referred us to the Nottingham software that did not suffer from these problems. Several people warned us that large packet and window sizes were an absolute must for throughput. Sadly, and despite a couple of specific queries, there were no responses directly from people relating experience of setting up an extensive IP network on top of an X.25 network rather than just operating a few links. However, the second-hand wisdom (which I do not doubt) was that it was not an ideal way to run an IP network, but that, subject to tuning, etc, it would work OK. Denis.