On Oct 10, 2013, at 4:19 AM, Mark Wickens <mark at wickensonline.co.uk> wrote: Even though I think I know the answer to this question, I'll ask it any way... Is it OK to run machines that are in the same area on different subnets? For example, passing traffic between SLAVE:: and RIPLEY:: both on DECnet area 4 but on different subnets connected via a bridge? I think it is and that the bridge is transparent, but for some reason in the back of my mind I have the concept of 'area router' and that doesn't fit with this model. "Subnet" is an IP term, it has no relevance to DECnet nor to Ethernet. Since you mentioned bridges, the term to use is "LAN". (A bridge connects LANs into an Extended LAN). And yes, as others have answered, bridges are transparent to routers. The area router rule is that area routers have to be directly connected. "Directly" means a datalink layer path between L2 routers, either a point to point link (DDCMP for example) or a LAN link. More precisely, for the latter case that is "Extended LAN link". paul