Wednesday, November 7, 2012

Enabling Elastic Optical Networking for SDN Architectures

Software Defined Networking (SDN) is a term that has quickly risen to the forefront of the networking industry, with the objective of solving many of the challenges facing network providers today. While there are many varying opinions of exactly what SDN means, there is one common trait amongst them - “programmability”. 

SDN is a means to open up the network and support programmability of the network, often comprised of multiple vendors, multiple domains, and multiple networking layers. For some providers’ networks, programmability and SDN’s functions are viewed as a means to enabling automated, on-demand networking with optimal resource utilization. 

Initial SDN efforts are largely focused on decoupling the control plane from the data plane and enabling a higher level of programmability into packet forwarding tables of switches. But what does this mean for the emerging converged optical transport layer with integrated switching, which is now playing an increasingly important role in optimizing networks and underlies most of the world’s Internet backbone? What does the optical layer need to adequately and economically support a programmable network with on-demand capabilities?

The Evolution of Optical Transport: Opportunities and Challenges

The architecture of the optical network is undergoing a significant transformation – and with this transformation lays some new challenges around automation, elasticity, and capital/operational efficiency.

The Network Efficiency Challenge

Over the past many years, network providers were deploying 10Gbps wavelengths on a large scale, and the predominant service that was transported over the fiber backbone was 10Gb. Initially, it was SONET/SDH OC192/STM64 service, running at 10Gb rate, and more recently, 10Gb Ethernet (10GbE) services have rapidly risen in popularity, driven by Ethernet convergence. In this environment, the transport service speed matches the wavelength bitrate, and the term “wavelength” was used synonymously to mean the optical, analog transmission wavelength as well as the transparent wavelength-like digital service.

Today, however, there is a growing divergence between the wavelength bitrate and the transport services the network needs to support. Layer 0 transmission is rapidly evolving towards 100Gb optical wavelengths equipped with coherent detection, as carriers and network providers strive to increase fiber capacity to multiple Terabits. But the supported transport services are still largely 10Gb, sometimes less. Moreover, the services mix will continue to include a variety of service rates, as dictated by the economics of these services.

While the quest for achieving optimal cost/bit transmission economics is driving the need for 100Gb wavelength technology, the business of transport services and market demand for a broad set of service rates necessitates a different approach than in the 10Gb wavelength era. With the current economics of 10GbE vs. 100GbE services, it is generally expected that 10GbE services will continue to dominate in volume for some time while networks are upgraded with 100Gb optical technology. Further, this divergence of service from optical wavelength speeds will likely continue, as optical technology takes its next step forward to super-channels – wavelengths with bitrates beyond 100Gb. State of the art technology today offers 500Gb super-channels, with 1Tb super-channels soon to follow, as the drive to increase fiber capacity continues.

The Bandwidth Elasticity Challenge
A second challenge facing providers today is the need for on-demand “elastic” bandwidth to efficiently and cost-effectively deliver bits whenever and wherever needed. Evolving traffic patterns driven by cloud network and datacenter communications are driving providers to relook at their network architecture and the relationship between IP and optical transport layers. The conventional practice of over-provisioning the IP layer and running links at low utilization rates, while constraining the optical layer to provide static, “always-on” 100Gb point-to-point capacity, is being scrutinized, as new optical transport solutions with integrated digital switching emerge that can readily flex and adapt to varying and unpredicted bandwidth needs.

While this level of flexibility and adaptability begets greater elasticity, it highlights the more general challenge of multi-layer resource optimization. With resources that can be allocated and repurposed at multiple network layers, network providers require ways to optimally allocate resources to provide the appropriate bandwidth connectivity services that meet the service requirements of applications.

The Network Automation Challenge

In order for the network to provide on-demand bandwidth at Internet speeds, operational processes need to devoid themselves of human intervention. This encompasses not just automation of processes across multiple network layers, from transmission and transport up through IP/MPLS, but also the orchestration of resources between separate domains and amongst multiple vendors. In the optical transport layer, this means enabling rapid delivery of transport bandwidth in a manner that is cost and resource efficient, without burdensome wavelength engineering processes.

All-Optical Networking Dilemma

Conventional all-optical networks based on ROADMs deliver wavelengths on an end-to-end (A-to-Z) path, and constrain the delivery of transport services statically between those two sites. Operating on the principle of photonic switching, ROADMs can only route entire wavelengths and cannot access transport services carried inside the wavelength. Capacity that is not utilized within the wavelength cannot be leveraged by other traffic demands that do not originate at the same locations but which might share the same physical sub-path. 
As networks evolve to 100Gb wavelengths and beyond, this not only presents a resource utilization challenge, but also a bandwidth elasticity challenge. 

All-optical networks empowered with ROADMs are capable of “flexing” to dynamic bandwidth demands with wavelength granularity only. They facilitate turn-up of new end-to-end wavelengths, but the inability for all-optical networks to 1) manipulate the services inside the wavelength or to 2) pool capacity together and dynamically allocate bandwidth leads to static, underutilized wavelengths and excessive deployed capital. As the pressure to increase fiber capacity grows, leading to larger but fewer super-channels, the wavelength fragmentation challenge is exacerbated.

With the evolution of optical wavelengths from 100Gb today towards 1Tb super-channels in the future, the role of ROADMs will inevitably evolve towards steering large chunks of capacity between major hubs, and less for turning up and delivering digital services to end users. Tightly coupling the allocation of dedicated wavelengths between A-to-Z network locations for on-demand delivery of services does not scale.

Nevertheless, programmability of the ROADM, as well as key optical transmission parameters such as modulation scheme for trading off reach versus capacity, are important elements of SDN for the overall optical transport layer.

In order for a network to offer truly elastic bandwidth, and enable transport bandwidth service to be efficiently delivered over any optical wavelength, virtualization of the wavelengths is a necessity. This entails creation of an abstraction layer that represents the creation of a pool of optical resources that can be leveraged for any bandwidth demands.

The Solution: Bandwidth Virtualization

Facilitating SDN’s programmable networking concept in a manner that simultaneously optimizes utilization of optical capacity and enabling real-time delivery of optimally-sized bandwidth requires a means to decouple transport service delivery from the transmission layer. It requires an abstraction layer that virtualizes wavelengths and pools the capacity together on each link, and promotes sharing of that bandwidth for any transport circuit traversing that link. Instead of a dedicated resource between 2 fixed locations, wavelengths can be transformed into a shared resource supporting services between any network locations.

Not surprisingly, this concept is very similar to IT resource virtualization, where the collective power of multiple physical resources are pooled together and shared amongst multiple Virtual Machines (VMs). VMs supporting applications can be dynamically instantiated or decommissioned from this shared pool of resources, maximizing utilization and efficiency. Bandwidth Virtualization achieves a similar objective by forming an abstraction layer representing a bandwidth pool and hiding details of the underlying optical wavelength resources. Any bandwidth service can be flexibly mapped to any physical wavelength resource on each digital network link, whether the wavelength bitrate is 10Gb, 100Gb, or 1Tb.

This is essential as optical transport evolves towards super-channels. Additionally, through finer granularity switching of transport services rather than coarse wavelengths, Bandwidth Virtualization provides the foundation for SDN programmability. With Bandwidth Virtualization, the transport service provisioning process is decoupled from wavelength engineering, leading to significant benefits including:

  • Reduced time to delivery of new bandwidth services to meet unexpected demands
  • Responsiveness and adaptability of the optical transport layer to dynamic needs of the application and IP layers with appropriately sized optical transport capacity
  • Efficient on-demand allocation of bandwidth from available resources to maximize wavelength utilization
The capability of digitally switching individual transport services rather than just optically redirecting coarse wavelengths provides a level of bandwidth service flexibility that is decoupled from the evolution of optical transmission technology.

Enabling Bandwidth Virtualization

The virtualization of the optical wavelengths requires abstraction into a shared pool of digital bits that can then be rapidly allocated to support any transport service. Key enablers of the Bandwidth Virtualization paradigm include (a) cost-effective OEO conversion to gain accessibility to the individual services being transported via optical carriers and (b) integrated digital switching. Conversion of wavelengths into the electrical domain normalizes the traffic into a form where it can be managed, independent of wavelength bitrate and origin, and enables individual bit-based services to be sorted (demultiplexed), switched, and groomed, before being remapped on to an outbound optical carrier. These functions provide important network capabilities including:

  • Redirection of individual transport services for optimal latency routes
  • Optional redirection for protection against network failures
  • Maximum level of wavelength utilization through mixing and matching of any services on to any wavelengths
  • Mitigation of wavelength reach limitations or wavelength blocking situations
  • Decoupling of the service provisioning process from complex analog wavelength engineering and turn-up
Critical design requirements for Bandwidth Virtualization solutions include minimal latency, minimal space/power, and scalability commensurate with the optical domain. Additionally, Bandwidth Virtualization must be economically viable – implementations that necessitate excessive “boxes” linked together with optics may technically deliver the same capability, but are not as economic as converged solutions with internal integrated switching.

Along with integrated switching, considerations for supporting the broad set of transport services must be made. Generalized optical transport infrastructures typically need to support multiple rates and protocols, and full transparency of the service with stringent performance requirements is mandatory. Additionally, dynamic scaling of the transport service upwards and downwards is also important for optimizing consumption of optical capacity. With this set of capabilities, networks can capitalize on a new level of transport elasticity that provides appropriately sized bandwidth services whenever and wherever needed in the network.

A New Approach: Elastic Optical Transport

The emergence of optical transport with integrated switching is changing the way architects design cloud networks. Instead of the traditional model of “dumb pipes” interconnecting large routers and relegating all bandwidth management functions within routers, network providers now have the option of deploying cost-efficient, flexible optical transport networks with integrated switching and offloading transport bandwidth from routers.

Evolving traffic patterns in clouds coupled with large amounts of data traffic between data centers warrants traffic more optimally being transported and switched within the optical layer, not solely at the more expensive router layer. This evolution towards a more flexible architecture with multiple dynamic switching layers calls for more intelligence in managing not just multi-layer networks, but also networks involving multiple network domains and multiple vendors. The convergence of WDM, OTN and packet bandwidth management functions into the next generation optical transport layer is creating new opportunities for network providers to further reduce the total cost of ownership of their network infrastructure, inclusive of the IP/MPLS layer, while also providing a more scalable, adaptable, and cost-efficient solution that meets the dynamic demands of emerging cloud architectures.

SDN: Ready for Elastic Optical Transport?

The SDN philosophy of decoupling the control plane from the data plane is an important paradigm many in the industry are investigating as a means for automating processes across a multi-layer, multi-vendor, multi-domain network, and orchestrating the many moving parts through network Application Programming Interfaces (APIs) to provide an optimal bandwidth solution for applications that takes maximum advantage of what each network layer has to offer. Centralization of information creates the opportunity to make better over-arching decisions, as it provides globalized visibility across layers, domains, and vendors that is necessary to understand and make appropriate tradeoffs between cost, performance, survivability, and other key SLA metrics.

In order for SDN to be truly useful in multi-domain & multi-layer networks, SDN needs to incorporate not just broader network management functionality, such as network discovery and monitoring and correlation, but also deepen its control to include the emerging next-generation optical transport layer, where integrated switching adds substantial network value and has significant impact on overall network architecture, including what happens at higher layers. This broader vision ensures the entire network stack becomes open and programmable. With expansion of SDN to include elastic optical transport and abstractions like Bandwidth Virtualization, network providers will be able to unlock the real potential of the multi-layer network and fully leverage the resources available at all layers.

América Móvil Launches LTE in Mexico with Ericsson

América Móvil's Telcel brand officially launched its LTE service in Mexico.

The service delivers downstream rates of up to 20 Mbps.  Telcel said its initial rollout covers 30 zones in nine of the country's largest cities: Mexico DF, Guadalajara, Monterrey, Querétaro, Puebla, Ciudad Juárez, Tijuana, Hermosillo and Mérida.

Telcel has about 69 million subscribers it has an estimated market share of about 77% in wireless services in Mexico.

Ericsson is the key LTE supplier for the Telcel network in Mexico.  Ericsson's contract covers deployment of RBS6000 base stations for LTE in multiple bands.  The deal also includes the Evolved Packet Core with Home Subscriber Server (HSS) for user data management and SGSN-MME as the mobility management entity that handles control signaling and traffic and can be used for all three generations of mobile data services. Ericsson will also deliver Operating Support Systems (OSS). Financial terms were not disclosed.

Ericsson Hits 223 Mbps with TDD LTE Advanced

Ericsson announced a demonstration of LTE TDD (TD-LTE) carrier aggregation for China Mobile.  The test achieved a peak download speed of 223 Mbps using two carriers of 20MHz each over a standard radio unit.

The demonstration was performed in Beijing on standard Ericsson Evolved Packet Core (EPC) and Ericsson RBS 6000 radio hardware already running in China Mobile’s network, along with standard radio units and data link boards supporting carrier aggregation. Aeroflex provided the TM500 test user equipment.

"This demonstrates what is technically possible today, showing how operators with LTE TDD networks can benefit from their frequency holdings with Ericsson’s help. It proves that TDD operators can provide competitive peak-rate performance for their users," stated Per Narvinger, Head of Product Line LTE, Business Unit Networks at Ericsson.

TDD operators often have access to relatively large swathes of spectrum. The carrier aggregation can efficiently make use of this spectrum by combining two or more carriers into one channel (for example, 20+20MHz), effectively putting them on the same terms as FDD operators that have access to 20MHz for uplink and downlink separately.

Consumer devices that support TD-LTE with carrier aggregation are expected to reach the market in 2014.

Internet2 Deploys Brocade for National-Scale, 100GbE SDN

Internet2 is using Brocade's MLXe Core Routers as an integral component of its 100 Gigabit Ethernet (GbE)  network.

"Networking infrastructure is being transformed by SDN into an open platform for innovation. We are excited that Brocade 100 GbE and true Hybrid-Mode OpenFlow technologies are part of the new Internet2 Network. By working with Internet2 and its members, Brocade will build upon its pioneering work on high-speed software-defined networks," said Ken Cheng, vice president of the Routing, Application Delivery and Software Networking Group at Brocade.

The Brocade MLXe 100 GbE routers enable programmatic control of the network infrastructure to deliver massive scale and intelligent service delivery capabilities.  Notably, Brocade is offering support for OpenFlow in Hybrid Mode, enabling the 10 GbE and 100 GbE Brocade MLXe solutions to integrate SDN with existing IP/MPLS networks. Brocade said this unique capability enables network operators such as Internet2 to integrate OpenFlow into existing networks, giving them the programmatic control offered by SDN for specific flows while the remaining traffic is handled as before.

Ericsson to Cut 1,550 Jobs in Sweden

Ericsson plans to eliminate about 1,550 positions in Sweden, covering all job areas, including sales, general and administration, research and development, supply and service delivery.

The majority of cuts will hit Ericsson's Networks unit, but all parts of the organization in Sweden are to some extent affected, impacting all its Swedish sites except Falun, Hudiksvall, Kalmar and Katrineholm.

"It is naturally a difficult message for our employees in Sweden," says Tomas Qvist, head of Ericsson's Human Resources in Sweden. "We must ensure that we can continue to execute on our strategy to maintain our market leadership, invest in R&D and meet our customers' needs. To secure this we need to focus on reducing cost, driving commercial excellence and operational effectiveness. This will enable us to secure our future competitiveness.

  • In October, the European Investment Bank (EIB) announced a loan of EUR 500 million to Ericsson to support its R&D efforts for the next generation of mobile broadband technology.  The load is designated for research sites in Sweden and Finland.
  • Ericsson's total number of employees at the end of Q3 2012 was 109,214, up from 108,095 in the prior quarter due to the addition of service professionals mainly in India and the acquisition of Technicolor Broadcast Service Division.

FCC Chairman Comments on AT&T Plan

FCC Chairman Julius Genachowski welcomed AT&T investment plan while noting that AT&T also filed a petition concerning rules on the evolving access network.

“AT&T’s announcement of billions of dollars in new investment in wired and wireless broadband networks is proof positive that the climate for investment and innovation in the U.S. communications sector is healthy. Today’s announcement adds to nearly $200 billion of investment in wireless and wireline broadband networks since 2009, and powerful growth in the Internet economy," stated Julius Genachowski.

“AT&T has also filed a petition with the FCC today suggesting issues to consider in our ongoing work to
modernize our rules for the evolving communications market. As we review AT&T's filing, we will
focus on the principles that have guided our actions since I became Chairman: driving the virtuous cycle
of private investment and innovation in the broadband ecosystem, promoting competition, and protecting

AT&T's Project Velocity IP (VIP) Boosts CAPEX by $14 Billion

AT&T unveiled Project Velocity IP (VIP) -- its plan to invest $14 billion over the next three years to significantly expand and enhance its wireless and wireline IP broadband network. The plan adds $8 billion for wireless initiatives and $6 billion for wireline initiatives.  It also makes a distinction between areas where the company believes are better served wirelessly rather the through a traditional copper network or deploying a fiber infrastructure.

Total capital spending is now expected to be approximately $22 billion for each of next three years. The company said a stronger balance sheet has provided it the financial footing to invest. AT&T is also increasing its quarterly dividend 2.3 percent and is predicting EPS will grow by mid-single digits for the next 3 years with opportunity for stronger growth going forward.

“This is a major commitment to invest in 21st Century communications infrastructure for the United States and bring high-speed Internet connectivity — 4G LTE mobile and wireline IP broadband — to millions more Americans,” said Randall Stephenson, AT&T chairman and chief executive officer. “We have the opportunity to improve AT&T's revenue growth and cost structure for years to come, and create substantial value for shareowners.

AT&T highlights the following aspects of Project VIP:

4G LTE Expansion. AT&T plans to expand its 4G LTE network to cover 300 million people in the United States by year-end 2014, up from its current plans to deploy 4G LTE to about 250 million people by year-end 2013. In AT&T's 22-state wireline service area, the company expects its 4G LTE network will cover 99 percent of all customer locations. Spectrum. AT&T has acquired spectrum through more than 40 spectrum deals this year (some pending regulatory review) and has plans to buy additional wireless spectrum to support its 4G LTE network. Much of the additional spectrum came from an innovative solution in which AT&T gained FCC approval to use WCS spectrum for mobile broadband. Between what the company already owns and transactions pending regulatory approval, AT&T expects to have about 118Mhz of spectrum nationwide. The company will continue to advocate with the FCC for release of additional spectrum for the industry's long-term needs.

Densification & Small Cell Technology. As part of Project VIP, AT&T expects to deploy small cell technology, macro cells and additional distributed antenna systems to increase the density of its wireless network, which is expected to further improve network quality and increase spectrum efficiency.

Investing in Wireline IP Network Growth. AT&T plans to expand and enhance its wireline IP network to 57 million customer locations (consumer and small business) or 75 percent of all customer locations in its wireline service area by year-end 2015. This network expansion will consist of:
  • U-verse. AT&T plans to expand U-verse (TV, Internet, Voice over IP) by more than one-third or about 8.5 million additional customer locations, for a total potential U-verse market of 33 million customer locations¹. The expansion is expected to be essentially complete by year-end 2015.
  • U-verse IPDSLAM. The company plans to offer U-verse IPDSLAM service (high-speed IP Internet access and VoIP) to 24 million customer locations in its wireline service area by year-end 2013.
  • Speed Upgrades. The Project VIP plan includes an upgrade for U-verse to speeds of up to 75Mbps and for U-verse IPDSLAM to speeds of up to 45Mbps, with a path to deliver even higher speeds in the future.
  • In the 25 percent of AT&T's wireline customer locations where it's currently not economically feasible to build a competitive IP wireline network, the company said it will utilize its expanding 4G LTE wireless network -- as it becomes available -- to offer voice and high-speed IP Internet services. The company's 4G LTE network will cover 99 percent of all in-region customer locations. AT&T's 4G LTE network offers speeds competitive with, if not higher than, what is available on wired broadband networks today. And in many places, AT&T's 4G LTE service will be the first high speed IP broadband service available to many customers.
  • Fiber to Multi-Tenant Business Buildings. AT&T plans to proactively expand its fiber network to reach an additional one million business customer locations – 50 percent of the multi-tenant business buildings² in its wireline service area. AT&T expects the proactive fiber deployment to increase business revenue growth, accelerate provisioning and facilitate the installation of distributed antennas systems and small cell technology to help offload wireless network traffic.

Sprint to Acquire 20 MHz of Mid-West PCS Spectrum from U.S. Cellular

Sprint will acquire 20 MHz of PCS spectrum in the 1900 MHz band in various Midwest markets from  U.S. Cellular for $480 million in cash and certain liabilities.  The deal includes 20 MHz of PCS spectrum in Chicago, South Bend, Ind. and Champaign, Ill. and 10 MHz of PCS spectrum in the St. Louis market. In addition, the transaction involves approximately 585,000 U.S. Cellular customers. U.S Cellular will continue its business operations outside of these markets following the closing.

Sprint said the additional spectrum will be used to supplement coverage in these areas as it continues to deploy its Network Vision upgrade and roll out 4G LTE nationally.

For U.S. Cellular, the transfer of 585,000 customers represents about 10% of its subscriber base. U.S. Cellular also announced that it will transition its Bolingbrook Customer Care Center operations to an existing vendor partner, effective Jan. 1, 2013.  The company said these moves lets it play to its strengths in markets where it has greater penetration.

“This transaction will enable us to strengthen our business and become a more robust competitor,” said Dan Hesse, Sprint’s CEO. “Acquiring this spectrum will significantly increase Sprint’s network capacity and improve the customer experience in several important Midwest markets including Chicago and St. Louis. We welcome the new customers in these markets and look forward to providing them with Sprint’s unique combination of unlimited plans, an iconic device portfolio and unmatched customer service.”

The companies expect to gain approvals from the Department of Justice and the FCC by mid-2013.

See also