Is it possible for an ISP to provide a second subnet (different from the one used on the router serial links) and allow it to be used for externally accessible devices? If so how is this accomplished? Can the ISP route the new subnet to the existing one? Currently we have a /28 subnet on our serials, and we are running out of avaialable addresses for externally accessible devices. Can they just add an additional /27 subnet without changing the addressing of the interfaces and already configured devices? Please excuse my ignorance in these matters.