We currently have a private class C network attached to our class B site LAN via a low end cisco router. The private subnet, currently used by around 20 devices, is 192.168.10.x, for political reasons we need to change this to 193.168.10.x. The migration of the 20 devices will need to be gradual over several weeks due to other constraints, so we need to maintain both subnets in the interim on the same physical private LAN. (the migrated devices need not communicate with the non-migrated devices during the interim period, mostly data servers to site LAN)
What are my options?
1. Can the router be configured to route both subnets for the interim period.
2. Or would I need an additional router for the interim to route the new subnet.
3. Is it wise to allow two subnets to share the same physical LAN?