Recently snooping around an existing installation, I noticed something peculiar with regards to XDAB. This system has two separate equipment room locations, each with a cluster of Nions. Each cluster is locally connected via XDAB and both clusters are connected to the same global CobraNet network, resulting in two XDAB networks and one CobraNet conductor. What struck me was both clusters appeared to be running the same project. As the processing requirements of each cluster are quite dissimilar, there was no way a single project deployed separately in each location would work, leaving the possibility that they all must be part of the same project. Firing up NWare and going online confirmed this; it was a single project containing both clusters' roles with *two* XDAB device instances. I double checked the KB article on XDABs and VLANs, even though the VLAN application didn't apply. The article depicts obvious network segregation, but I am assuming the article assumes (a squared assumption is probably never good) that XDAB instances are discrete projects. Although the current clock arrangement didn't seem to break any of those rules, I was understanding that a project may only contain a single XDAB instance.

I had thought that too; but I think the rule is that each NioNode can only connect to one XDAB device, so multiple XDAB clusters can exist in one project. Not sure I'd do it that way, though.
There's a new entry in the KC (1.6.0):
NWare User Guide » Adding more advanced features to your design  » Using XDAB to share DSP resources  » XDAB wiring rules