Hi Michael, thanks for your reply. Deactivating the layer, either manually by unchecking it in the TOC or programmatically, is certainly the way to go once the user realizes that the service is unresponsive. My question is whether we can do something about the behaviour of ArcMap (no reaction, whiteout, ...) when the service starts acting up. Since we observe strong fluctuation of response times (2-3 s optimum, maximum >> 60 s), a timeout would be the ideal solution. Switching the service layer off for longer periods of time is not really an option since the information is needed regularly.
The reasons for the service being slow are fairly clear - at certain times of the day, the load on the infrastructure (network, servers) etc. simply gets to high and response times go down. Technically, it's fairly obvious how to fix this. The problems lie on the administrative and financial side.
I can find out the WMS version if that would help, but since the service itself is out of our control, I haven't checked yet (also, it's not an ArcGIS Server-based service).
Martin
