Bottom-layer optical SDN controllers supply upper management systems with information about optical paths and topology as well as automate wavelength and ODU provisioning. They might function like IP/MPLS controllers as use the same or similar management models: NETCONF/RESTCONF/YANG on northbound interfaces, MPLS-TE, PCE and GMPLS control plane (ASON/WSON) for device management.
Although the technologies are available, the adoption of the programmable way in traditional vendors’ optical solutions is less than in IP/MPLS SDN[1]. Multi-vendor optical controller is also a challenge – separate SDN controllers might be used for different optical vendors’ solutions in short term.
RESTCONF/NETCONF/YANG (API/CLI/text-based) way might be a cultural challenge as GUI-based management is more convenient for optical systems. Thus, familiar SNMP, TL1 and CORBA expected to live in mainstream solutions on southbound interfaces for some time. It is recommended to consider innovative vendors’ solutions to challenge the leaders and push the adoption faster.
OSPF or IS-IS with optical and traffic engineering extensions are usually used to import topology information from optical devices to optical SDN controllers. This functionality should be supported.
[1] which, in its turn, less deep than in datacenter SDN