Self provisioning for multi degree ROADMs
Colorless, directionless and contentionless multi-degree ROADM has brought a precious switching capability to the lower layer of the optical transport. This switching capability brings now flexibility in the part of network that was previously static and yearly configured on the field. This flexibility is all the more interesting if it can be controlled through dedicated distributed logical functions, called control plane that transforms such optical networks into true service driven-networks.
Such control plane i.e Automatic switch Transport networks (ASTN) or Generalized Multi-Protocol Label Switching (GMPLS) gave a service architecture and components for optical cross-connect equipment vendors to build advanced services in a framework that minimized development efforts.
The IETF Wavelength Switching Optical Network (WSON) working group jointly with ITU-T and the OIF, has defined the essential building blocks to build more advanced features as true differentiators for equipment vendors.
Thanks to the Optical Supervisory Channel (OSC) that inter-connects all the optical devices through the light path as an IP dedicated out of band network, the GMPLS control plane is a turnkey solution for such advanced key services:
- Discovery of physical resources through extension of Link Layer Discovery Protocol (LLDP) that would run on the OSC that inter connects all the devices that are composing the light path.
- Link property correlation procedures to avoid misconfiguration between Add Drop Multiplexers (ADM) and Raman or Erbium Fiber doped amplifiers and 3R regenerators.
- End to End channel setup or tear-down through multiple ROADM within interconnected rings or even mesh networks.
- Automated restoration procedures in case of failure via pre-signaled nodes and shared risk link group disjoint protecting paths. This protecting channel path can be dedicated and already optically cross-connected. This Optical channel path (Och) can be restored in a reduced mean time of recovery i.e. few minutes instead of days. Resource optimization could be made through the use of segment protection or shared protection (1:N or shared mesh restoration)
- An Optical User to Network Interface (O-UNI) to build the transport network as a service layer for the packet routers. Actually, UNI has been defined in the ASON architecture as a dedicated user interface to the overlay architecture.
MARBEN GMPLS for ROADM
Marben has designed and implemented an off-the-shelf GMPLS solution for colorless and directionless multi degree ROADM.
- Discovery and link property correlation
- MARBEN LLDP gives a great bootstrap for a discovery protocol adapted to GMPLS and the optical constraints of the lambda switching.
MARBEN LMP is an off-the-shelf implementation that completes this discovery with a link property correlation and link verification procedures. Using such component reduces risk for the management of identifiers of resources, and error prone configurations.
- End-to-End light path connection
- This service is built through the combination of MARBEN RSVP-TE, MARBEN OSPF-TE/ISIS-TE, MARBEN PCE and above all MARBEN Controllers. Combined Resource Wavelength Assignment (R&WA) and Routing and Distributed WA (R+DWA) per RFC 6163 are supported. Optical impairments issued can even be covered by customized objects that Marben let users configured through its standard API.
- Recovery procedures
- 1+1 protection and rerouting, shared mesh and 1:N restoration are fully implemented within MARBEN Controllers. Those features are off-the-shelf while it operates interactions between RSVP-TE, OSPF-TE/ISIS-TE and PCE as defined in RFC 3473 and RFC 3630.
- MARBEN GMPLS supports a dedicated GMPLS UNI role for ROADM in its MARBEN Controllers. The GMPLS UNI as per RFC 4208 requires MARBEN RSVP-TE and MARBEN Devkits with the GMPLS UNI profile.
Benefits from Marben
Marben has references among all size of optical cross connects organizations from large ones to smaller ones, on this specific technology. Such large spectrum of customers gives the credit to Marben as being able to work with the whole diversity of actors in such fields.
Marben has first released GMPLS for ROADM in the scope of the ITEA Tbones project in 2003.