What are the “Peer” and “Overlay” models?
GMPLS supports two methods of operation, peer and overlay. In the peer model, all devices in a given domain share the same control plane. This provides true integration between optical switches and routers. Routers have visibility into the optical topology and routers peer with optical switches. In the overlay model, the optical and routed (IP) layers are separated, with minimal interaction. Think of the overlay model as the equivalent of today’s ATM and IP networks, where there is no direct connection between the ATM layer and the IP routing layer.