At #OFC23, member of the Open ROADM Multi-Source Agreement (MSA) and demonstrating interoperability of optical network equipment elements at data rates up to 400G. Participants include AT&T, Ciena, Cisco-Acacia, Fujitsu, Infinera, Juniper, Lumentum, NEC, Nokia, NTT, Orange, and Ribbon in collaboration with the researchers at the OpNeAR laboratory of the University of Texas at Dallas and Politecnico di Milano.
The Open ROADM MSA defines interoperability specifications for disaggregated optical transport networks. These specifications, which also include YANG data models, address Reconfigurable Optical Add/Drop Multiplexers (ROADM), transponders, and pluggable optics. Multi-vendor Open ROADM compliant equipment can be integrated into the same network solution and controlled by the open source Transport PCE (TPCE) controller.
The optical network testbed makes use of interconnected Open ROADM compliant equipment including ROADM nodes, 100G flexponders, Optical Transport Network (OTN) switches, 100G transponders, 400G transponders, 200G/300G/400G muxponders, a 400G single-node 3R regenerator, and CFP2-DCO and QSFP-DD 400G pluggable devices.
Demonstrated functionalities will include interoperability of CFP2-DCO 400G devices from three Original Equipment Manufacturers (OEMs), an Open ROADM compliant 400G single-node 3R regenerator, an automated path restoration mechanism at the physical layer implemented in the open source TPCE controller, interoperability between CFP2-DCO and QSFP-DD 400G pluggable devices, an IPoverWDM architecture with routers hosting QSFP-DD 400G coherent pluggables supporting oFEC, and various multi-layer network monitoring techniques for both optical and data packet transport layers. These demonstrations will be carried out over a single testbed composed of multiple network elements provided by the participating OEMs.
The demonstration also marks the first showing of Open ROADM-compliant 400Gb/s transmission achieved via router-optimized QSFP-DD pluggables, which incorporate embedded amplification and tunable optical filtering to enable simple deployment over any type of ROADM line system. Optical signal Interoperability between CFP2-DCO 400G and QSFP-DD 400G will be showcased. With the ability to support all metro ROADM client performance requisites in the small QSFP-DD form factor, these technologies expand the range of Open ROADM applications to include converged IPoverWDM architectures, which Release 11.0 covers through an extension of both the device and service models to handle such use cases.
Two recently added functions to improve signal reliability in Open ROADM transport networks will also be demonstrated in the OFC’23 testbed. First, an Open ROADM-compliant 3R regenerator with a bidirectional single-node (all optical) design will be applied to a 400G signal routed through four ROADM sites in the testbed. In this single-node design, only network interfaces must be specified (e.g., OTSI, OTSI-group, OTUC4, and ODUC4 for 400G) to achieve reliable high-data rate connections over multi-hop and/or long-distance physical routes.
Second, the automated path restoration mechanism newly implemented in the open source Transport PCE (TPCE) controller will be applied to overcome unexpected quality degradations of a 400G service in the Open ROADM testbed. For any created wave service that is labeled as “restorable,” the open source TPCE controller triggers a restoration mechanism at the physical layer as soon as its signal is subjected to a severe power degradation (e.g., a fiber cut). Upon receiving a change notification of the ROADM degree optical transmission section (OTS) interface operational state, TPCE computes a new candidate path to circumvent the problematic degree and reroutes the wave service over that path.
“AT&T is actively deploying Open ROADM MSA compliant optical network equipment and plans to have more than 10 metro markets supporting 100G and 400G traffic by year end,” says John Gibbons, AVP, Packet Core and Optical Transport, AT&T. “For operators, the interoperability enabled by Open ROADM can encourage lower costs, accelerate technology introduction, help reduce life-cycle costs, and allow networks to remain viable longer. The Open ROADM MSA continues to lead the industry in introducing new interoperable capabilities, as demonstrated by the Open ROADM demo at OFC 2023.”
