- Driving NetroSphere with Network Architecture (MSF) Maximizing General-purpose Equipment -

Nippon Telegraph and Telephone Corporation (NTT hereinafter), headquartered in Tokyo, has attained transport functions for carrier networks using white-box switches (*1), which is general-purpose communications equipment, and demonstrated the possibility of configuring carrier-provided Tbps-level virtual networks using only general-purpose communications equipment.

This has been achieved by software that enables the use of functions (MPLS functions) required for virtual networks, which were prepared as hardware for commercial white-box switches but could not be used. NTT has developed it with a completely open technology so that many equipment vendors and carriers will be able to use this software in the future.

As equipment vendors use this software, the white-box switch market that was limited to the small-scale networks used in data centers and so forth holds the promise of expanding into the carrier network field.

As well as having a much greater range of choices of network equipment, carriers will also have the ability to add functionality with network operating systems (*2) themselves. This will make network configuration more flexible, and make it easier to provide even faster communication speeds and more customer-oriented services.

These achievements are a big step towards the realization of the general-purpose, modularized networks aimed for by the Multi-Service Fabric (MSF), which is an elemental technology of NTT's NetroSphere concept established in 2015.

With ongoing studies, NTT will engage in the experimental "NetroSpherePIT" operation and wide-ranging partnering as initiatives for never-before-seen openness while establishing this technology through further expansion of functionality.

(*1) White-box switch: General-purpose communications equipment that runs on equipment vendor hardware, for which software can be freely selected and developed.

(*2) Network Operating System (network OS): Control software that runs internally in network equipment such as routers and switches.

- Backgrounds

With the development of better server performance and software technologies in recent years, increasing amounts of virtual technologies have been adopted to economically achieve higher scalability and reliability, mainly in data centers. Adapting these technologies for carrier networks by virtualizing computer and hardware resources to virtualize networks has been gaining attention.

Based on the NetroSphere concept (*3), NTT aims to provide both virtualization and speedy, highly reliable and even more diverse services to customers and service providers by driving commonization and modularization of network equipment. (Fig.1)

As part of these efforts, NTT is promoting its Multi-Service Fabric (MSF) (*4) initiatives to build networks using general-purpose equipment by using general-purpose products with simple functionality instead of high-functionality specialized equipment. (Fig.2)

Since network functions can be developed independently, MSF provides network architecture in which (1) simplified hardware for transport functions and (2) software for network control can be separated and redefined. This architecture aims for (1) transport functions making maximum use of generic network switches (general-purpose switches (*5)) and (2) flexible software functionality for network control. (Fig.3)

Fig.1: Network virtualization and commonization

http://www.ntt.co.jp/news2016/1609e/160928b_1.html

Fig.2: MSF high-level architecture

http://www.ntt.co.jp/news2016/1609e/160928b_2.html

Fig.3: Overview of MSF (functions separated and redefined)

http://www.ntt.co.jp/news2016/1609e/160928b_3.html

- Software maximizing use of white-box switching

Using generic switches mainly used in data centers, MSF aims for carrier network virtualization (to configure network slices), although this requires transport functions that use MPLS (*6) technologies.

To date, however, MPLS transport functions were only provided with software (network OS) by some router vendors even though hardware was equipped with many general-purpose switches.

Hence, NTT has created a software product that is equivalent to a network OS, which can be mounted on white-box switches to achieve MPLS transport functionality by making full use of hardware performance.

Fig.4: MSF transfer function problems and solutions

http://www.ntt.co.jp/news2016/1609e/160928b_4.html

- Software overview and effects

Using two techniques to achieve MPLS transport, the software generates optimal pathways by exchanging network path data (*7) with other MPLS routers, and writing the generated paths to hardware through an interface that supports MPLS transport. Because software functions are configured using only commercially available open-source technologies such as OSS (*8), white-boxing is possible even in internal software configurations.

At the same time, using architecture that maximizes hardware performance achieves high-capacity, carrier-grade transport with white-box switching (1Tbps/tens of thousands of paths).

With the potential to apply general-purpose switches to carrier networks as a result of these achievements, equipment vendors will be able to pioneer new markets (for general-purpose switches for carrier networks), which should bring down prices for general-purpose switches as well as invigorating additional functionality through competition among vendors. As well as that, carriers will have a greater selection of equipment with which to build networks, and will be able to modify network OS software by themselves.

These developments are driving the NetroSphere concept and MSF objectives of network commonization and modularization, and will make it easier to meet customer requirements with even faster communication speeds.

Fig.5: Technical overview (software for white-box switches)

http://www.ntt.co.jp/news2016/1609e/160928b_5.html

- Future outlook

Beginning with NetroSpherePIT (*9), NTT will engage in studies on experimental operations and further expansion of functionality to establish this technology, and engage in even greater levels of openness by forming wide-ranging partnerships.

Glossary

(*3) NetroSphere Concept

Set down by NTT in February of 2015, a concept for developing technologies for the communications networks of the future. http://www.ntt.co.jp/news2015/1502e/150219a.html

(*4) Multi-Service Fabric (MSF)

Elemental technology in the NetroSphere concept that enables network architecture based on general-purpose products with simple functionality instead of high-functionality specialized equipment such as core and edge routers.

http://www.ntt.co.jp/journal/1608/files/jn20160825.pdf (in Japanese)

(*5) General-purpose switches

Switches on networks consisting of generic equipment. Currently, these are mainly used in data centers. These include switches such as switches provided by equipment vendors that provide hardware and software, and white-box switches for which software can be freely selected or developed to run on hardware provided by the device vendor.

(*6) MPLS (Multi-Protocol Label Switching)

A type of packet transport technology that uses tags called "labels" to provide network virtualization functions.

(*7) Path information

Information used to determine the destination network (port) when network equipment receives communication packages.

(*8) OSS (Open Source Software)

Software with published source code for which modification or redistribution is permitted.

(*9) NetroSpherePIT

A testing environment (test-bed) to enable various testing toward achieving the NetroSphere concept.

About Nippon Telegraph and Telephone Corporation

Headquarters: Chiyoda-ku, Tokyo

President and CEO: Hiroo Unoura