ZTE announced that the ‘MPLS-TP OpenFlow Protocol Extensions for SPTN’ (ONF TS-029) technical document proposed by China Mobile has become a formal standard of the ONF (Open Networking Foundation) after receiving unanimous approval from the forum’s board of directors.
The release of MPLS-TP OpenFlow Protocol Extensions for SPTN is intended to provide a foundation for interworking between devices from heterogeneous vendors, and between devices and controllers. ZTE noted that China Mobile’s large-scale deployment of software-defined packet transport network (SPTN) devices provides an example for other operators, while five operators are believed to be planning to implement the standard in the near future.
ZTE stated that packet transport network (PTN) technology features separate forwarding/control and a centralised management architecture, while OpenFlow offers an open protocol that performs programmable control for flow tables on the forwarding plane. In addition, an abstract adaptation layer supporting OpenFlow to encapsulate the existing forwarding functions of PTN is intended to provide an efficient means of enabling PTN devices with open and software-defined features.
Additionally, this design is expected to facilitate the commercialisation of PTN devices supporting SDN and thereby accelerate the development of the SPTN supply chain.
It was noted that China Mobile has a longstanding commitment to SPTN technology, in mid-2015, working with ZTE, Broadcom and Microsemi, establishing a discussion group within the ONF to research device specifications for SPTN based on OpenFlow and table type pattern (TTP).
In November 2015, a first ONF draft was proposed based on SPTN TTP that extended flow tables, group tables and related fields supporting MPLS-TP, expanded the OF-Config protocol to support QOS, OAM, protection and alarm performance configuration, and leveraged local OAM processing units to ensure a 50 ms protection switching time.
In tandem with the draft specification, China Mobile also organised lab tests for SPTN devices complying with the specifications and amended the document in accordance with the test results. The draft document was subsequently passed for review by experts from a number of ONF technical groups and adopted as a formal standard.
ZTE stated that MPLS-TP OpenFlow Protocol Extensions for SPTN standard is supported by the SPTN industrial supply chain, including chip manufacturers Broadcom, Microsemi, Centec and Marvell, equipment providers ZTE, Ericsson, Fiberhome, Raisecom, Greenwell, Chuling and Huahuan, instrument manufacturer Spirent and open source software Open Daylight and ONOS.
To date it is estimated that more than 50 operators have deployed MPLS-TP-based PTN devices at scale, including China Mobile, which purchased around 590,000 group customer devices compliant with the SPTN TTP standard in 2016. In addition, six equipment vendors have worked with China Mobile to deploy the networks.
