AT&T clearly is redefining itself -- and the industry -- from within, relying on software, optical and open source to transform both the company and telecommunications. Part of this makeover relies on AT&T's application of software control and open hardware to ROADM network switches.
Reconfigurable Optical Add/Drop Multiplexers are hardware devices that manage and route data traffic entering a network over high-capacity fiber optic lines. While most ROADMs use so-called lanes dedicated to each wavelength of laser light that enters the switch, software-controlled ROADMs automatically detect and adjust bandwidth and move traffic to less congested lanes if needed, according to AT&T Inc. (NYSE: T) (See: AT&T Targets Virtualized ROADMs).
AT&T recently launched Open ROADM, a group designed to build and publish open standards for ROADMs to replace the small group of specialized hardware vendors that currently design and build proprietary ROADMs. Today's approach stifles innovation, curtails interoperability and damages customer experience, says by Andre Fuetsch, senior vice president of Architecture and Design at AT&T in a blog post.
Interested in learning more, The New IP editor Alison Diana checked in with Fuetsch for a deeper dive into AT&T's ROADM plan, the future of optical fiber and open standards.
Taking a ROADM Trip
Alison Diana: Please could you set the stage a little for why telecom service providers, developers and customers need open standards for ROADMs?
Andre Fuetsch: Today in a metro area we use ROADMs from a single vendor, which do not interoperate with others. We also buy the transponders from that same vendor, as well as the software (EMS and planning tool). We can use another vendor in a different metro, but not in the same metro area. The ROADMs are fixed, and require truck rolls to set up wavelengths between locations. Having an open and flexible ROADM connected to our Global SDN Controller and ECOMP allows us to use the best technology for us regardless of the supplier, avoiding the lock-in we see today. And because the ROADMs are now software controlled and flexible, we can provision wavelengths without the need for manual intervention. These are the drivers for us for Open ROADM, multi-vendor using open interfaces and SDN control through flexibility.
AD: How does AT&T's role in Open ROADM fit with the company's overall approach to setting, abiding by or adopting standards across the New IP network?
AF: We believe that this is consistent with our approach to setting standards for openness. With the Open ROADM Multi Source Agreement (MSA) we encourage others to join us to evolve our interface definitions, both for the physical layer (Wavelength and Multi-Wavelength meets) and for the APIs. Together with the 3 other MSA founders, we have published our specifications, and we look for others to join in and add and improve them so that we can all take advantage of the benefits. If others are interested, they can go to Openroadm.org to have a look at the specs or to join.
AD: What will encourage leading proprietary vendors to participate in these open standards?
AF: I think that the world is changing, and vendors will no longer be able to live in a world where they do not open up their systems and interfaces. You saw that at OFC, there is a strong trend toward openness across both the datacenter and telecom worlds. Suppliers need to adapt, and leverage their software and system advantages to compete in an open environment. As more service providers and Web 2.0 companies drive away from proprietary and closed systems, they will adapt.
AD: Could you please describe who is developing the open standards and the way you're accomplishing this task?
AF: We worked with 3 equipment suppliers -- Ciena, Fujitsu and Nokia -- on the initial MSA specifications. They were able to bring to the table a view of the tradeoffs between specifications and cost and complexity and help us drive to the best solution. We would like others to join the MSA and help us continue to improve both the hardware specs as well as the Yang models for the device, network and systems that can cross the hardware implementations of multiple vendors.
AD: What are some of the other benefits customers realize from adoption of Open ROADM?
AF: Some of the benefits to customers include lower latency, less network congestion and the ability to deploy new technologies faster, since interoperability won't be a problem. Multi-vendor flexible ROADMs allow optimization, moving wavelengths to better paths -- shorter, lower latency, better costs -- when they are available and allow defragging of the network to avoid overbuilds. It also enables multi-layer interworking, using optical layer rearrangements to avoid congestion or automate maintenance events. Openness also allows the best technology solutions to get to the field quicker, without the need for lengthy test cycles or custom IT development. Innovation can happen much quicker when legacy proprietary solutions don't create barriers. Customers benefit because they get a smoother experience and we can deploy new services and capabilities much more quickly.
AD: How would you describe the next generation of optical fiber?
AF: AT&T is fortunate to have a large base of high-quality optical fiber, unlike many of our competitors. This allows us to avoid costly regeneration to overcome fiber impairments on a regular basis. We continue to look at new fiber technology advancements and will take advantage of some of the improvements, but we for now we do not need a massive overhaul on our fiber plant.
AD: Other than standards -- which you're addressing with partners – what other challenges might there be for more widespread adoption of optical fiber?
AF: In the metro and Core, fiber is ubiquitous and fully adopted. What is changing is that we are driving fiber and optical technologies closer and closer to the customer. But for optics to make sense for lower volumes of traffic, the costs need to continue to come down and the technology needs to be plug and play, so that it is as easy to use optics as it is electronics in those spaces.
AD: How critical is optical fiber to 5G? Why?
AF: 5G will involve SDN/NFV capabilities at the cell site, thus requiring high performing and resilient optical capabilities, as well.
AD: You say AT&T has built a nationwide software-controlled optical network. Are software-controlled networks proprietary and standalone, in that they don't need to integrate with other companies' networks? Does this national optical network support all AT&T customers or will you need to expand it as your customer base continues to grow?
AF: Right now there is no real need to integrate our networks with Verizon or others at the ROADM level, but interconnection via packet switches or even in the future an optical switch will allow us to extend SDN out to the edges and serve customers better with automated meets. We are always expanding our ROADM networks by adding new nodes and more direct paths as customer demands grow or topologies change. That is why the flexibility we get is important, as we grow the network out with new more direct paths we can now move service to the optimum route over time.
AD: Is AT&T duplicating this success -- the implementation of software-controlled optical networks -- around the world?
AF: Overseas optically we use a mix of our own optical systems and those of partners. Both of them are moving to SDN control, allowing us to turn up wavelengths on demand through software. So we expect to see the same advantages of multi-layer and software control in the global network as we see here domestically.