124531230 Ciena NextGenOptical Insights PDF

September 2012

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OTN switching gets virtualized

http://www.ciena.com/

Contents

Editor’s letter 3

Main story: OTN switching gets virtualized 4

Q&A: One plane to rule them all 6

White paper: Intelligent optical control 8 plane architecture

White paper: Addressing network uncertainty with 14 an intelligent infrastructure

2 l Next-Gen Optical Insights l www.telecomasia.net

Taking optical to the next level

Anyone who thinks the optical transport equipment market is stoic and boring either cares nothing about technological innovation or isn’t paying attention. Optical networking is evolving well beyond the legacy of Sonet/SDH, and not just in terms of line interfaces reaching 100G throughput speeds and beyond – optical transport is currently in a heavy and eye-catching

transformation phase as carriers become increasingly interested in OTN switching. Indeed, as Andrew Schmitt of Infonetics puts it, legacy optical systems are being made obsolete by 100G

transport, which requires carriers to implement an “optical reboot” to realize the impressive performance gains and lower cost per bit with existing fiber capacity, and that’s creating an opportunity to rethink their optical architectures for switching and managing these 100G-powered networks in a way that improves their TCO.

And OTN switching is just the start. The next step on the horizon is virtualization, in which the control plane is decoupled from the data transport plane, enabling centralized management of hardware resources and services and the associated savings in capex/opex. That concept is already playing out in data centers via development of software defined networking (SDN), and as you’ll see in these pages, it’s set to happen in the optical transport network as well.

As such, the lead story of this Next-Gen Optical e-guide is very much preoccupied with the immediate future of optical transport as OTN switching proliferates and the technology to enable that virtualization lurks just around the corner. Subsequent stories will drill down in detail on the drivers and benefits of intelligent control-plane technology, and how combining OTN, DWDM and ASON can create an “intelligent switched OTN” that could take optical transport to the next level with unprecedented network automation, resilience, and service flexibility across the entire network.

Sincerely,

John C. TannerGlobal Technology Editor

Editor’s Letter


The evolution of the optical transport market tends to push ahead on two different fronts: faster interfaces and improved packet transport. And on both

fronts, the market is currently in its next phase of transformation.

In terms of higher speed interfaces, for example, the market is moving rapidly to 100 gigabit DWDM, says Jimmy Yu, VP of optical transport market research at Dell’Oro Group. “We forecast wavelength shipments to grow at greater than 120% each year for the next five years.”

As for packet transport, he adds, “the market is moving to OTN and MPLS/MPLS-TP as it leaves Sonet /SDH as a legacy network element.”

Of those two transport paths, OTN (optical transport network) is dominating the next-gen optical discussion at the moment – so much so that it’s poised to outpace the overall optical market within the next five years. According to Infonetics Research, the OTN transport and switching market is forecast to grow at a 17% CAGR from 2011 to 2016, compared to just 5.5% CAGR of the overall optical equipment market (which includes WDM and Sonet /SDH).

“Nearly half of all 2011 optical equipment spending worldwide was on OTN transport and switching hardware, and by 2016 we expect this to rise to almost 80%, with the burgeoning OTN switching segment growing the fastest,” says Andrew Schmitt, principal analyst for optical at Infonetics.

Schmitt adds that demand for OTN switching

OTN switching is the dominant trend in the optical transport space as 100G goes mainstream. The next step: a decoupled intelligent optical

control plane for optimum capacity utilization and

capex/opex savings

John C. Tanner

is coming from carriers of all sizes looking to build efficient transport networks, but China is at the vanguard. “China’s telecom carriers are leading the way and are issuing substantial RFPs for OTN switching in the core this year.”

More to the point, however, carriers are fast reaching the point where legacy optical systems are being made obsolete by 100G transport, which offers impressive performance gains and lower cost per bit with existing fiber capacity, but may require greenfield transport terminals to achieve maximum return, Schmitt observed in a research report. As such, carriers will effectively be implementing an “optical reboot” of their systems.

“Beyond achieving cost per bit gains with 100 Gbps, carriers are seizing this opportunity to roll out new architectures that will further improve the total cost of ownership of their networks,” Schmitt said. “The most important of these is a more sophisticated and efficient architecture for switching and managing these optical networks, which will use 100-Gbps wavelengths efficiently and allow carriers to meet future operational cost targets.”

OTN switching fits the bill perfectly to enable that architecture. But that’s not the end of the story. The next step will be to bring virtualization into the picture, in which the control plane is decoupled from the data transport plane, which enables centralized management of hardware resources and services, which in turn improves efficiencies that translate into both capex and opex savings. This is already happening in data centers via industry forums like the Open Networking Foundation to develop


Main Story



protocols for software defined networking (SDN) such as OpenFlow.

The same principle can also be applied to the optical transport space, says Schmitt. “We need a transport protocol that is service-independent to realize this vision of a virtualized optical network – something able to carry everything from legacy SONET/SDH to Ethernet, MPLS, IP and other protocols such as Fibre Channel.”

Proponents say that adding an intelligent optical control plane to OTN gives operators network-wide service visibility to make optimum use of capacity, and enables network automation for network provisioning and network survival in the event of failures via automated restoration. It also gives service providers the flexibility to tailor individual networks with new and differentiated service capabilities and classes.

The catch: the decoupled optical control plane and the network elements connected to it have to be intelligent enough to facilitate policy-based programming control and automate certain functionality across an entire optical network.

More than SDNAutomated control plane-based optical

networks have been operating for years in core networks with great success, notes Ron Kline, principal analyst at Ovum. But, he adds, “Extending control plane functionality to the network edge and adding policy-based programming control substantially increases an operator’s ability to differentiate and create new services to monetize network assets. Therefore, we anticipate growing interest in such features.”

While the concept of an intelligent optical control plane sounds similar in principle to efforts to develop SDN technology within data centers, Anup Changaroth, director of portfolio marketing for Ciena Asia Pacific, says they’re not exactly the same thing.

“One of the primary goals of software-defined networking is the literal separation of the control-plane function from the data-plane function into physically separate platforms,” he explains. “A claimed benefit of this approach is of course the ability to then push for commoditization of the data-plane hardware. Combined with a centralized control-plane platform, this forms the basis for significantly improving the overall capex/opex model of a network.”

However, he adds, “This ignores the fact that true network service differentiation and flexibility requires some form of on-board intelligence to manage it, and the model of SDN alone is inadequate to address this need. What you really need is distributed intelligence embedded within individual network elements that works in concert

network-wide to offer customers true service differentiation.”

Ciena recently launched an intelligent optical control plane solution called OneConnect that it says does just that.

However, Changaroth notes that Ciena is not competing with SDN, and that its solution isn’t mutually exclusive with an SDN model. “In fact, it’s complimentary in that it provides a level of hardware abstraction for Ciena network elements that then enables a much simpler implementation of off-board SDN ‘control-function’ similar to Ciena’s V-WAN Hypervisor platform.”

And that doesn’t mean carriers run the risk of a vendor lock-in with Ciena-only gear, he adds. “Non-Ciena network elements can in the future easily be directed through OpenFlow implementation off this centralized controller.”

Plan carefullyWhat are the challenges they face in

implementing it? While Infonetics’ Schmitt talks of an optical

“reboot” required to take full advantage of next-gen optical technologies like 100G, OTN switching and virtualization, Changaroth says that adding an intelligent control-plane enabled switching layer is a “relatively simple process” – provided the carrier has an existing legacy Sonet/SDH cross-connect switching layer within its network.

“For operators that don’t already have a Sonet/SDH switching layer, the addition of an intelligent switching layer can be a more complicated scenario, though many customers have gone through this process in the past,” he says.

Meanwhile, he adds, operators adding an intelligent optical control plane also have full control over whether or not the control plane is turned on, so the switching function can be utilized independent of the control plane if so desired.

“Once the intelligent switching network elements are in place, turning on and managing the control-plane technology is a relatively trivial process,” he says.

One caveat to the above, he notes: while there are no significant challenges or hurdles involved, network operators do have to put in an appropriate amount of pre-planning to formulate new service frameworks that allow them to fully leverage the capabilities of the control plane.

“Whereas in the past operators may only have had two service classes – protected and non-protected circuits – the addition of an intelligent control plane means an operator has a multitude of new service-class options, including multiple failure protection, mesh restoration services, best-effort services, constraints-based circuit routing, Optical VPNs, etc,” he says. l

OTN switching isn’t the only option being proposed for optical transport evolution. Some players

are proposing ditching OTN completely in favor of a pure IP or MPLS solution with colored optics feeding into a simple WDM line system (similar to the concept of IPoDWDM architectures proposed in the early ‘00s).

However, Andrew Schmitt, principal analyst for optical at Infonetics, is skeptical that pure MPLS-based optical transport will gain much traction with carriers, if only because right now, the only ones expressing interest in it are a “small circle of specialty operators with straightforward all-packet networks with no need for multiple services.”

Outside of that, he said in a recent Infonetics report on OTN switching, “Our discussions with service providers indicate that the transport layer – specifically with OTN switching – is and will continue to be a fundamental part of future network architecture.”

Among the reservations expressed by operators, Infonetics reports, is the fact that structurally, they treat (and operate) MPLS data and optical transport functions as separate hardware functions in the core network, and swapping OTN for MPLS would require updating or replacing fundamental transport OSS, processes, training and skill sets. Also, pure MPLS “provides no means to partition, share or protect a transport network that contains transparent wavelength services.”

It doesn’t help that MPLS standards for transport such as MPLS-TP “have not made as much progress as the industry hoped and will require a few more years of work,” the Infonetics report says.

Schmitt does note that there may be some future interest in deploying a hybrid MPLS and OTN solution, “but today all 100-Gbps WDM networks are being built using OTN transport, and as service providers build out these networks, most plan to employ OTN switching, which eventually will underpin the efficient convergence of packet and optical transport functionality into a single network layer.” l

MPLS-TP won’t replace OTN – Infonetics

Next-Gen Optical Insights: The benefits of OTN switching are clear – what does an intelligent optical control plane bring to the table that wasn’t already there?

Anthony McLachlan: OTN by definition provides a next-generation bearer protocol for managing information flow across a transport network through multiplexing, switching, management and supervision of optical channels carrying client signals. As a next-generation technology, it does these functions well above and beyond those supported by legacy SDH/Sonet, for example supporting rates such as 40 and 100 Gbps.

OneConnect, on the other hand, is an intelligent control-plane technology – a distributed software intelligence embedded into each of Ciena’s optical network elements, be it transport or switching platforms, to provide network automation, resilience and service flexibility across the entire network. It additionally provides advanced services such as tiered service-levels, Optical VPN [O-VPN] services and dynamic capacity services.

What trends are driving the need for an intelligent optical control plane?

Broadly, there are two key trends driving the need for an intelligent optical control plane. The first is capex and opex challenges, which are driving network operators to optimize and automate as much of their networks as possible. An intelligent optical control plane provides network-wide service visibility for optimum capacity utilization, and enables network automation not only for network

Ciena VP and GM for Asia Pacific Anthony McLachlan explains how

intelligent control-plane technology will take OTN to the next level with

unprecedented network automation, resilience and service flexibility

across the entire network

provisioning, but also and especially for network survival in the event of failures anywhere in the network through automated restoration.

The second trend driving this is the need for revenue growth and service differentiation. Network operators are constantly on the lookout for capabilities that allow them to offer new services or to differentiate their service offerings from other service providers. An intelligent optical control

One plane to rule them all

Q&A


Ciena’s McLachlan

One plane to rule them all

plane offers customers the ability and flexibility of tailoring individual networks with new and differentiated service capabilities and classes.

What kinds of gains and benefits can operators realize from implementing this?

The bandwidth savings vary from operator to operator, but can be quite substantial. Traditional ring-based architectures designed to withstand single fiber cuts or single line-port failures waste as much as 50% of available network capacity in order to survive such network failures. Moving to a mesh-based architecture with an intelligent control plane allows a network operator to use any spare capacity to generate additional best-effort service revenues. And in the event of fiber, port or nodal failures, it’s able to preempt higher-class services to provide service survival across failures.

Significant network opex savings can be realized by giving the network the ability to auto-discover resources, dramatically simplifying provisioning through A-to-Z point-and-click provision, and automate network restoration in the events of single or multiple network failures. Network operators can benefit from more than 40% bandwidth savings for service restoration.

Additionally, an intelligent optical control plane provides the ability for the operator to either manually or automatically route circuits over the network based on specific criteria, be it latency, route distance or cost. This allows an operator to offer tiered service classes to various customers depending on their specific SLA requirements, such as for strict latency or costs. It’s also worth nothing that, as the control plane is not in the circuit’s bearer path, it doesn’t add any additional latency to the network.

You mentioned O-VPN earlier – what is that, and what kind of possibilities can it enable?

O-VPN provides a secure, high-bandwidth network virtualization capability that enables virtually private networks across a shared mesh infrastructure of OneConnect-enabled platforms. The O-VPN connects end-user sites with a flexible, managed virtual infrastructure over fractional,

single or multiple transparent optical wavelength connections with a wide variety of client interfaces (including Ethernet, OTN, Sonet, SDH, SAN and video).

Moreover, O-VPNs provide a virtual infrastructure for end-users to manage their own site-to-site connections, bandwidth allocation and circuit protection options within the O-VPN domain – or, optionally, have the service provider manage this process on the customer’s behalf.

O-VPNs can provide dedicated bandwidth to connect multiple end-user sites in a mesh configuration with multiple parallel line rates available, and still maintain full separation in user traffic and restoration bandwidth. Full visibility of the network and optional control over provisioning, protection and bandwidth on demand can be provided over a secure, web-based customer portal.

How does OneConnect handle migration situations where carriers are running both Sonet/SDH and OTN?

OneConnect has the ability to independently and simultaneously run two control planes, one for SDH/Sonet, and the other for OTN. Typical migration scenarios don’t necessarily require the function of a control plane. For example, encapsulating SDH payloads within an OTN frame is a basic capability supported by OTN that does not require invoking any control-plane functions.

However, Ciena’s OneConnect solution does provide additional migration support for customers wishing to gracefully evolve from existing SDH networks to an OTN-based one, through a technology that allows customers to flexibly groom SDH circuits while being encapsulated into OTN frames.

How would this work in multi-vendor situations?Multi-vendor support on a control-plane level

is provided through full OIF standards compliant UNI and NNI interface support, while multi-vendor support within the bearer circuits – either SDH/Sonet or OTN – is provided by full standards compliance with appropriate ITU standards. l


The telecommunications service provider market has embraced IP, MPLS, and Ethernet control plane solutions to deliver service flexibility with operational

simplification. Ciena has successfully delivered on this operational paradigm to deploy intelligent optical networks in many of the world’s leading service provider networks. Ciena solutions are based on a suite of signaling and routing protocols that enable an optical Ethernet network to react to service requests by allocating network resources automatically, end-to-end, across single- or multi-technology vendor networks.

The benefits of an optical Ethernet control plane have been field-proven in customer networks. Service provider analyses of Operating Expenses (OPEX) and Capital Expenditure (CAPEX) show significant savings from deployment of an intelligent network based on Ciena’s CoreDirector® FS Multiservice Optical Switch, 6500 Packet-Optical Platform, and 5400 Family. Networks built with these products demonstrate increased efficiency in network resource utilization with automated equipment and resource-inventory update processes and provisioning. Service providers save on operational costs, reduce service-provisioning and/or change intervals from months to minutes, and maximize revenue generated by the network.

Ciena’s leadership in control plane solutions has been extended across Layers 0, 1, and 2 with the products to deliver CAPEX and OPEX benefits to the DWDM, TDM and packet applications supported on these platforms, as shown in Figure 1. The control

planes are fully standards-compliant with optional extensions to provide value-added functionality requested by customers. The control plane at each layer operates independently but can also work across multiple layers where information sharing preserves or enables superior functionality.

This white paper examines one element of the Ciena optical Ethernet control plane strategy: The networking dividends delivered by the 5400, 6500 and CoreDirector FS intelligent TDM networks through OTN and SONET/SDH control plane functionality.

Layer One Control PlaneCiena was among the first to deploy control

plane-based automated discovery and topology successfully in Dense Wavelength Division Multiplexing (DWDM) systems and optical cross-connects. The innovative control plane functionality, hardened with over 10 years field experience and scaling to networks of 600+ nodes places Ciena well ahead of the competition for robust and reliable optical control plane software. The integration of this proven control plane into the 5400 and 6500 platforms, combined with the widely deployed CoreDirector FS, provides Ciena’s customers with a highly scalable intelligent optical switching portfolio supporting routing and signaling for automated service provisioning and mesh restoration. It is the most widely deployed optical control plane in networks today, with a rich carrier-class feature set and field-proven six-9s reliability.

Intelligent optical control plane architecture

White paper



Optical Switch Product Overview

5400 FamilyThe 5400 Family consists of two form factors:

the 5410 Reconfigurable Switching System, a 10-slot half-rack shelf initially providing 1.2 Tb/s per node; and the 5430 Reconfigurable Switching System, a 30-slot full-rack RU shelf initially providing 3.6 Tb/s per node. The 5400 Family shares common line modules providing GE rates from 1 to 100 Gb/s, SONET/SDH from 155 Mb/s to 10 Gb/s, and OTN switching from ODU-0 through ODU-4, including ODUflex. Each OTN/SONET/SDH card provides 120 Gb/s of I/O at both the faceplate and to the fabric. The platform supports both standard short-reach optics as well as advanced coherent DWDM interfaces that are fully integrated with Ciena’s optical line systems.

6500 FamilyThe 6500 Family features two form factors: a

14-slot 13RU shelf and a 32-slot 22RU half-rack shelf that will provide up to 1.6 Tb/s of switching. These network elements have been widely deployed for broadband 40/100G solutions providing a full range of Fibre Channel, Ethernet, SONET/SDH and OTN client interfaces. Their switching and control plane functionality enables the benefits of a dynamic networking solution to be extended from the core all the way through the metro and to the edge of customer networks.

CoreDirector FS Multiservice Optical Switch The CoreDirector FS provides 640 Gb/s of non-

blocking switching capacity in a single telco rack. CoreDirector FSCI, a smaller footprint, provides 160 Gb/s of non-blocking switching in half a telco rack. Both platforms offer the flexibility to support SONET/SDH, OTN, and Ethernet switching, and

groom and switch traffic in granularities from ~50 Mb/s to 10 Gb/s. CoreDirector FS and CoreDirector FSCI support a mix of SONET/SDH and OTN speeds, GbE and 10GbE; STM-1e electrical and tunable, pluggable ITU WDM interfaces. CoreDirector FS DWDM interfaces are completely interoperable with Ciena’s DWDM platforms as well as third-party transport systems.

Optical Control Plane Functionality Overview

An optical control plane allows transport networks to automate and distribute many functions formerly performed through the combination of centralized management systems and manual processes. As a result of this automation, the network reacts flexibly and supports rapid deployment of new services. In particular, the control plane supports the following features: • Auto-discovery:providesanaccuratepictureof

network topology and resource availability to make the network the database of record

• Auto-provisioning:increasesthespeedofservicesetup and tear down

• Auto-restoration:simplifiesfault-handlingbyimmediately restoring service with available resources, even after multiple failures

Policy, scalability, and performance needs usually dictate that a network be structured into different domains, separating the client and network at the User-to-Network Interface (UNI). Ciena’s control plane strategy supports a multi-domain architecture with standard UNI and External Network-to-Network Interface (E-NNI) points, as shown in Figure 2. In this model, client device A at the UNI requests a connection to client device



B, but receives no detailed topology information about which networks the connection must traverse. The connection may traverse single or multiple domains. The client device is aware only of its attachment to the ingress/egress Network Element (NE) of the optical network. However, each node within a domain is aware of the local topology and the clients attached to its local domain. The nodes within a domain are not aware of any nodes in another domain, nor are they aware of clients attached to another domain.

The control plane supports discovery of a node’s adjacent neighbor through an in-band exchange of discovery messages to detect the node’s local topology. The routing protocol distributes network topology and state information among all nodes within a local domain so the nodes may determine optimal routes based on an administrative policy defined by the user. The protocol supports typical routing functionality between all nodes and bandwidth advertisements (including automatic and flooding), capturing changes in available resources.

A distributed connection-signaling protocol allows connection setup and restoration throughout the network. In a Ciena switched optical network, for example, a single path computation command to the source node initiates a signaling sequence through the network to create a light path, or Sub-Network Connection (SNC), between any two nodes.

Ciena has developed its control plane to provide value-added intelligent functionality and implement extensions far beyond current Automatically Switched Optical Network (ASON) and Generalized Multi-Protocol Label Switching (GMPLS) internal control plane (I-NNI) standards. Value-added intelligent functionality available today includes: • FastMesh®:implementsmeshtopologyand

restoration, and can be deployed alone or concurrently with OTN or SONET/SDH line protection mechanisms. Thus, linear and ring

protection can be implemented concurrently with FastMesh restoration to provide the highest levels of service availability. FastMesh restores connections on an end-to-end basis and operates independently of underlying linear and ring protection schemes. Therefore, in addition to 50ms Automatic Protection Switching (APS) on the port or client level, the network also provides a framework for a multi-tiered protection hierarchy that uses the control plane to recover the network from catastrophic failures such as earthquakes, hurricanes and widespread power failures.

• LinkAggregation:allowsmultiplelinksbetweentwo nodes to be managed as a single link. Link aggregation supports intelligent network scaling, faster restoration times and network simplification.

• LocalSpanMeshRestoration(LSMR):supportsfaster restoration times in an intelligent network. In response to a failure event such as fiber breakage, the SNCs on that fiber normally are restored from their originating nodes using signaling functionality across the network. LSMR allows the SNCs to restore locally, between the nodes adjacent to the break, increasing the speed of service restoration.

• Crankback:providescontinuousSNCrestorationretries if the initial attempt is blocked. Each retry will seek alternative paths in the network using any available capacity, allowing restoration to function even in the presence of rapidly changing conditions and multiple failures.

Control Plane InteroperabilityCiena recognizes the importance of

interoperability in the control plane and has been an active organizer and supporter of control plane standards and interoperability efforts, meeting customer requirements and working to reduce customer risk. Ciena, together with Cisco®, founded the Optical Internet-working Forum (OIF), which gives vendors, service providers, and end-users an avenue for closely coordinated optical networking interoperability testing and specification work. Ciena has been an instrumental participant in the development of ASON standards by working with the International Telecommunications Union–Telecommunications Standardization Sector (ITU-T) Study Group 15, and has implemented ASON-based control protocols internally and at the UNI and E-NNI interfaces. Ciena is also a major contributor to Internet Engineering Task Force (IETF) IP and optical control plane integration standardization, co-authoring many IETF GMPLS specifications and providing coordination between OIF, ITU-T and IETF working groups.

Ciena has been a core participant in both ASON



and GMPLS interoperability testing through the OIF worldwide interoperability demos and the Isocore laboratory, and in open sessions with major optical switching vendors and leading IP/MPLS vendors such as Cisco and Juniper®. Ciena stands ready to support the convergence of IP/MPLS networks at the service level, and agile optical networks at the physical level. The OIF testing program – conducted at public locations such as OFC and ECOC as well as through sponsoring laboratories at AT&T®, China Telecom™, France Telecom®, NTT™, Telecom Italia™, T-Systems and Verizon™ – has tested interoperability of UNI interfaces between routers and optical switches, and E-NNI interfaces between different optical switch vendors.

Support for O-UNICiena has implemented the OIF’s O-UNI 1.0r2,

a subset of ITU-T Recommendation G.7713.2, as part of the CoreDirector FS product offer. Support for O-UNI allows subtended network elements, which also support O-UNI, to request the automatic setup or tear down of light paths across the 5400, 6500 and/or CoreDirector FS network. Automating request, setup and tear-down processes reduces operational costs and results in the ability to respond rapidly to service requests and generate additional revenue. The initial CoreDirector FS O-UNI implementation includes: • ResourceReservationProtocolwithTraffic

Engineering (RSVP-TE) for in- and out-of-band signaling

• ExtensionstoRSVP-TEforsignaling• Neighbordiscovery• SupportacrossallCoreDirectorFSSONET/SDH,

OTN and Ethernet optical interfaces • SupportforIPv4addressingwithpotential

extension to IPv6 and Network Service Access Point (NSAP)

• Handlingforbothnumberedandun-numberedlinks

• Mesh,ringorlinearCoreDirectorFStopologysupport Ciena O-UNI 1.0 software has been tested

successfully for interoperability with third-parties, both during industry interoperability demos and internally in Ciena development labs. An intelligent network can be deployed with O-UNI signaling to activate or deactivate light paths across a 5400, 6500 and/or CoreDirector FS network, providing a standards-based solution for future dynamic service instantiation requirements by edge devices.

Support for E-NNIThe Ciena optical control plane has proven

interoperability based on OIF E-NNI/ITU-T G.7713.2. The implementation of E-NNI expands the end-to-end automated provisioning capabilities of the intelligent optical network across disparate optical control domains. This expansion uses the ASON domain model to allow rapid, worldwide deployment of services across multiple service provider networks via a variety of vendor equipment.

CoreDirector FS, with E-NNI functionality, has participated in several OIF-sponsored interoperability events, proving successful interoperability with third-party products. The Ciena implementation of E-NNI includes:• SupportacrossallSONET/SDHandOTNoptical

interfaces• IPv4addressing,withpotentialextensiontoIPv6

and NSAP• Handlingforbothnumberedandun-numbered

links

Financial Benefits of Ciena Intelligent Optical NetworksA Ciena intelligent optical network:• Reducescostsfornetworkingequipment,space

and power • Improvesresourceutilizationandservice

availability via mesh networking • Reducesoperationcostsviaautomation

Ciena customer experience with deployment of a control plane-enabled mesh network has proven it will reduce CAPEX and OPEX significantly. For example, after deploying a CoreDirector FS intelligent network, AT&T achieved higher utilization and capital efficiency, a 44 percent reduction in required operating personnel, an 18 percent revenue increase ($500-600K) per network employee, and increased operational effectiveness.

Migrating from an existing ring-based network to a network built with Ciena mesh networking provides substantial economic benefit by reducing the overall capacity requirements of the network, as shown in Figure 3. This analysis demonstrated a 38 percent reduction in the number of 10G lines required in a service provider network when comparing an existing ring architecture to a planned mesh network. This represents substantial CAPEX savings for the service provider while preserving the service characteristics for the end-customer. The analysis shown in Figure 3 utilized the following high-level assumptions:



For Mesh Network• Line-sidenetworkisbasedentirelyonmesh

restoration • Networkcapacitysupports100percent

restoration for any single fiber bundle (fiber conduit) failure

For Ring Network• Line-sidenetworkisbasedentirelyonan

optimized four-fiber BLSR ring • Inoptimizedasymmetricalrings,workinglines

are placed only where traffic is required • Networkcapacitysupports100percent

protection for any single fiber bundle (fiber conduit) failure

• NotrafficisplacedonprotectionlinesIn addition to CAPEX reductions, customers

experience a significant reduction in service provisioning time when using mesh networks, as illustrated in the customer data shown in Figure 4. Increasing the network footprint caused a reduction in average service provisioning time, generating additional revenue for the customer. This is contrary to the experience of many non-control plane-enabled networks wherein increasing network

size drives additional complexity, and service provisioning times are actually increased.

Improving Resource Utilization and Service Availability Through Mesh Networking

Unlike traditional networks with line-level protection, Ciena intelligent mesh networks share protection bandwidth across multiple working services, eliminating the requirement for equal capacity on working and protection bandwidths and resulting in significant savings on network switching and transport equipment.

Because they can restore services with available spare bandwidth anywhere in the network, Ciena mesh networks provide higher service availability than existing line-level protection networks with field proven six-9s reliability. In addition to increased customer satisfaction and loyalty scores, high service availability can result in increased revenue for service providers, as shown in Figure 4. The chart in Figure 4 compares projected service reliability and availability in traditional and intelligent mesh-restored networks. While mesh-restored networks handle multiple failures easily, traditional ring




networks are designed to restore service quickly in the event of a single failure but usually cannot manage a second failure and require manual repair. Mesh restoration will restore any number of failures up to the point at which the network is partitioned, maximizing active, revenue-generating circuit time.

Reduced Operations Costs via Automation

The automation of operating functions – such as service provisioning, equipment inventory and topology updates – allows for reduced network operations manpower while enabling more rapid response to requests for new services, moves, adds and changes. This automated service-activation can increase revenue, as shown in Figure 6. The illustration captures the full lifecycle of the

circuit and shows the advantages of automated provisioning, compared to traditional approaches. Initially, circuit turn-up on the intelligent network is achieved one order of magnitude faster than on the traditional network, reducing the circuit’s idle time and generating revenue instead of maintenance costs. Subsequently, automated provisioning accelerates the tear-down process and reduces idle time until the circuit is available for re-use.

In addition to the increased revenue potential associated with faster service turn-up, automated database updates result in operational savings. Ciena control plane intelligence automatically updates equipment inventory and changes topology, ensuring database accuracy and eliminating additional work associated with human database-entry error. l

Summary

An intelligent control plane offers many capabilities and benefits that can lower costs dramatically, improve network reliability and increase customer satisfaction. Ciena – by virtue of its field-proven hardware and software – is the industry’s most advanced multiservice optical switch vendor with an unmatched OTN and SONET/SDH portfolio of products. Ciena’s instrumental participation in standards development for optical control plane technologies ensures the continued improvement of network cost structures, helping to sustain higher service margins. These technologies are available on the 5400 Family, 6500 Family, and CoreDirector FS. As a result of its leadership in intelligent optical Ethernet switching technologies, Ciena’s platforms have been deployed in service provider networks around the world, with proven financial benefits.

Ciena may from time to time make changes to the products or specifications contained herein without notice. © 2011 Ciena Corporation. All rights reserved. WP053 4.2011

Network traffic is growing at unprecedented rates. In the shadow of this growth, network operators and end-users alike are struggling to come to

terms with a high degree of uncertainty associated with what kind of bandwidth is needed, where it needs to go, when it should be delivered, and how it should scale.

This uncertainty comes in two flavors. First, at the level of detailed packet flows (micro-level changes), packet service dynamics require bandwidth response times in the order of milliseconds to seconds. Such packet-specific challenges are being addressed using flexible Layer 2 and Layer 3+ technologies such as IP, MPLS, Ethernet, and variations thereof. Second, at the level of high-bandwidth connections (macro-level changes), continuously changing aggregate traffic flows require network adaptability in the order of minutes to months to ensure high levels of network efficiency. The network that supports these macro-level changes must be able to accommodate a diverse array of client protocols and scale to enormous capacity levels while maintaining the highest levels of efficiency and responsive flexibility.

This paper describes how the powerful combination of Optical Transport Network (OTN) switching and the distributed control plane enables operators to turn their networks into intelligent infrastructure.

Network Evolution Today, two primary classes of traffic associated

with consumer and business networks are developing. While both carry packet-formatted services, they are treated differently in the network.

Consumer services make up the majority of total bandwidth connections in support of voice, video, and general Internet access. They are highly cost-sensitive and, consequently, return a relatively low profit margin to service providers. Aggregate connectivity for consumer services is fairly static, with trending network architectures using backhaul networks to aggregate multiple customers on a large backhaul connection, and then connect to a few consolidated data centers or service/application gateway locations scattered around the geographic communities of interest. Bandwidth-sharing through oversubscription of packet bandwidth is commonly used to maximize an operator’s return on investment.

Business services, on the other hand, define fewer of the total service connections. However, because business bandwidth requires high performance guarantees, these services typically return a higher profit margin to the service provider. In addition to requiring connectivity to voice, video, and general Internet services for the consumer, business services require private, dedicated, and robust connectivity to support the private (or third-party) networks built across the business connection. As a result, business services define a more uncertain and arbitrary meshed connectivity pattern that must offer Service Level Agreement (SLA) guarantees associated with availability, latency, and packet loss.

Addressing network uncertainty with an intelligent infrastructure

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Intelligent Switched OTN Intelligent switched OTN combines the

layered and flexible network architecture of OTN (per ITU-T G.709) with high-capacity Dense Wavelength Division Multiplexing (DWDM) and the responsive Automatically Switched Optical Network (ASON) control plane (per ITU-T G.8080). Intelligent switched OTN is applicable to both consumer and business networks as a common, managed, and efficient infrastructure substrate upon which any client service network may be built. In addition, when applied specifically to retail and wholesale business networks, it also acts as a service platform for dedicated high-bandwidth private-line connectivity.

What kind of bandwidth? OTN was standardized as a deterministic

layered architecture based on the well-understood client-server approach to networking. Because of this foundation, any client protocol may be carried transparently within an OTN container without impacting the native characteristics of the client service. As a result, popular packet protocols such as IP, MPLS, or Ethernet may be carried across an OTN network without hindrance. In addition, OTN can carry less-mainstream networking technologies – such as Fibre Channel, ESCON®, or dedicated video protocols like Standard-Definition or High-Definition SDI (SD-SDI, HD-SDI) – while supporting legacy SONET or SDH network connections.

Because of this ability to map many different clients transparently to a common networking technology, OTN is the perfect multiservice networking platform for an uncertain future. As shown in Figure 1, multiple disparate client networks operating with different data rates, protocols, and timing sources may be multiplexed together on a single wavelength, using OTN’s digital hierarchy to achieve maximum utilization of the valuable optical network infrastructure.

This client flexibility makes OTN an ideal

transition platform for evolving networks away from legacy SONET/SDH toward new, packet-oriented solutions based on Carrier Ethernet. In fact, recent updates to the G.709 standard have defined OTN data rates that align with Ethernet, Gigabit Ethernet (GbE), 10GbE, 40GbE, and 100GbE physical interfaces – making Ethernet and OTN close partners for the next generation of networking growth.

This alignment with Ethernet is important for the support of dedicated Ethernet Private Line (EPL) business services. Private GbE and 10GbE connections are growing in popularity for retail and wholesale services respectively, and a switched OTN network is the ideal platform upon which to deliver native Ethernet frames transparently and securely. When implemented with an intelligent control plane, these private lines may be offered with varying classes of service that provide different degrees of survivability (and therefore availability) such as unprotected, restorable, protected, and protected with additional mesh restoration. In fact, over the past few years, the introduction of control plane-enabled mesh restoration in large switched networks has been shown to increase connection availability to over 99.9999% (six-9s) uptime.

In a static network environment where connectivity is known a priori, the use of fixed point-to-point muxponder technology might be an adequate solution to achieve high levels of network efficiency. However, as traffic demands increase and business services proliferate, a switched implementation will be necessary to adapt to changing traffic patterns and accommodate the uncertainty of new service locations.

Where is bandwidth needed? The separation of client port rate from the

underlying DWDM line rate allows network operators to do more than simple multiplexing. A switched OTN layer allows an operator to partition the underlying DWDM capacity into different topological links in support of different client networks. In essence, OTN enables the creation of multiple independent overlay networks with different geographical termination points, within the context of a single managed server layer.

Clearly, with client networks typically operating at rates ranging from 1 Gb/s to 10 Gb/s, and sophisticated coherent DWDM technologies driving optical channel line rates to 100 Gb/s today – with plans to extend to 400 Gb/s and 1 Tb/s in the foreseeable future – the ability to partition the capacity of optical resources has become increasingly relevant. By taking advantage of economies of scale achieved through enormous growth in data center and enterprise markets, client devices can benefit from the use of low-cost GbE



and 10GbE ports as their interface of choice on a single, consistent, high-speed optical platform.

In metro networks where there are many different client service offerings supporting consumer and business applications, switched OTN provides the ability to combine different public and private network topologies on a common managed server layer. This capability maximizes network efficiency and allows the network operator to address the need for new bandwidth demand flexibly between new service endpoints (for example, new private GbE or 10GbE Ethernet Private Line) or update existing bandwidth demands on existing connections (for example, adding bandwidth to a client’s existing Link Aggregation (LAG) bundle). In an IP network, for instance, a switched OTN layer can enable the turn-up of a new Provider Edge (PE)-to-Provider (P) router connection using a GbE or 10GbE link. With switched OTN, the peering of PE-to-P need not be constrained by geographical or physical adjacency, allowing the network operator the flexibility to make smart choices about how to design a client IP network and which routers to define as adjacent peers.

In core networks, the switched OTN helps to optimize aggregate connectivity between serving areas by defining a core topology with the appropriate levels of grooming and express “bypass,” and then adapting the size and connectivity of OTN connections to changes in macro-level traffic conditions. It is important to note that, to maintain lowest cost-per-bit performance in a network, the size and topology of connections will need to change with time – even if the service endpoints do not change. A network operator is continually faced with the decision of whether to groom traffic at the client layer or express traffic at the server layer to a final destination. As traffic demand grows between sets of locations, support of an aggregate connection that previously may have been served at lowest cost with a groomed architecture may become more cost-effective with an express (bypass) solution.

When is bandwidth required? Capacity partitioning and multiplexing of

different client networks are streamlined through the use of the distributed control plane. The control plane provides a means to respond to the temporal uncertainty of the network and allows an operator to quickly define and, over time, redefine the topological connectivity and associated client link bandwidth for each of the client networks. In addition, the control plane provides a mechanism to share bandwidth rapidly across the OTN network for improved efficiency and cost savings, and enables timely mesh restoration in response to network failures for super-high-availability connectivity.

In addition to enabling rapid turn-up of new connections and the timely addition of bandwidth to existing connections, the control plane helps network operators maintain the lowest cost-per-bit operation over longer timescales by working closely with network planning systems. The control plane allows the OTN network to adapt to changing client bandwidth demands and respond to local bandwidth hot spots as the network evolves.

Using the same example introduced above, as the number of client services on a network grows, the most cost-efficient approach to carrying the service traffic changes over time, resulting in a need to change a client network topology.

In the beginning, when a network is lightly loaded, a network operator should take advantage of frequent aggregation and grooming in order to maintain efficient fill of transmission links. However, when the aggregate traffic demand on the network grows, frequent grooming may no longer be necessary at many switching or routing locations. Instead, expressing aggregate blocks of traffic from an aggregation point to a common destination becomes more economical. When this happens, reorganizing how traffic is forwarded through the network becomes necessary, using a method similar to the defragmentation of a computer hard disk. By monitoring traffic flows and resource usage with the control plane, a network planner can determine when a bandwidth threshold has been crossed and then choose to update the client network topology to reflect the change in traffic pattern. The use of OTN or DWDM links to carry traffic past intermediate “transit” routers is a good example of reorganizing a client topology over time to improve network costs.

From an optical service perspective, the application of the control plane to business private line services not only allows rapid service provisioning and differentiated class of service, but also enables the definition of new service types. A good example of a new control plane enabled service is the Layer 1 Virtual Private Network (VPN), based on optical mesh connectivity. In this service, a business customer purchases multiple interfaces to the network and uses control plane signaling to define (and redefine) OTN bandwidth connectivity between components of its personal interface group, within bandwidth and connectivity boundaries pre-defined with the service provider.

How does bandwidth scale? Today’s enormous growth in network traffic is

being fueled by the combination of high-bandwidth applications, such as video, with unprecedented levels of interconnectivity. A switched OTN network is capable of scaling to absorb this growth efficiently in all key areas of data, management, and control



plane operation. At the data plane level, OTN originally was

designed to deal with large bandwidth connections, and therefore combines the flexibility of transparent digital switching with the scalability of massive DWDM capacity. Originally specified to manage wavelengths, OTN’s structure was built around the use of efficient Forward Error Correction (FEC). Today, the G.709 standard includes a data rate for 100 Gb/s and will continue to scale to higher rates, aligning comfortably with the new breed of coherent DWDM system technologies. SONET and SDH cannot accomplish this scalability, as their maximum rate is limited to 40 Gb/s. Combined with a digital multiplexing hierarchy that is compatible with client data rates, OTN’s data plane provides the most efficient way to scale multiple client networks across a common DWDM infrastructure. This value is highlighted in Figure 2, where analysis of a real North American backbone network demonstrated over 70 percent additional bandwidth efficiency improvement with intelligent OTN switching when compared to today’s 10G solution.

At the management plane level, OTN provides overhead to monitor the health of aggregate client connections across high-bandwidth link segments, end-to-end client paths, and multiple network operator domains, using nested tandem connection monitoring techniques. Error monitoring, alarms, and signal information are all handled in a hierarchical manner to accommodate a high degree of scaling.

At the control plane level, the ASON architecture supports indefinite scaling through the use of administrative control domains separated across External Network-to-Network Interfaces (E-NNIs). Within each administrative control

domain, today’s Internal Network-to-Network Interfaces Interfaces (I-NNIs) scale to ~1,000 nodes, support over 100,000 connections, and are expected to continue to grow.

The User’s PerspectiveIntelligent Infrastructure, based on switched

OTN and control plane, clearly provides flexible and adaptable capabilities to address a changing and growing network environment. This section looks briefly at the solution from the perspective of network operators and end-users (clients).

Network Operator’s Perspective Network planning, operations, and sales teams

all benefit from the switched OTN network. From the perspective of a network operator, the intelligent switched OTN network provides: (1) the most efficient way to address capital and operational cost challenges associated with unpredictable scaling; and (2) a new revenue opportunity in support of high-bandwidth business services.

By combining and operating many different clients across a single switched infrastructure, the network operator adapts flexibly to any client network needs. Metro backhaul, metro core, and inter-city core networks all benefit from CAPEX savings achieved through improved sharing of underlying optical capacity.

From a control and management perspective, control plane discovery and routing protocols define the network as the operator’s database of record, enabling an accurate and timely view of what resources exist in the network and how they are being used. The addition of control plane path computation and signaling automates the provisioning and restoration processes, speeding up the time to turn up a new service or restore an existing service when faced with network failure. In addition, the operator receives a rich and consistent suite of OAM capabilities that allow monitoring of network health on a number of levels – from end-to-end path, to individual sections, to tandem connections at multiple nested levels. The operator benefits from the ability to track the performance of multiple client networks against agreed-upon SLAs within his or her own network and across external network domains.

Finally, with anticipated growth in demand for private GbE or 10GbE connections, new revenue opportunities are made possible through the delivery of dedicated private line business services across the same, common infrastructure used for consumer traffic.

End-User’s (Client’s) Perspective An end-user (or client) of the switched

OTN network benefits from the efficiency and



responsiveness gained by the network operator. Improved network efficiency translates into lower cost per bit and a more competitive service offering to the client, while different class-of-service offerings translate into a greater selection of service choices. Client protocol transparency results in confidence that the network operator will not interfere with the client’s native functionality. In addition, the responsiveness of the switched OTN control plane provides the end-user with fast time to service for new or additional bandwidth requests.

Because the switched OTN network is efficient, robust, responsive, and adaptable, the end-user is left to focus on private concerns, free from the uncertainty of ever-changing underlying transport network challenges.

Ciena’s PerspectiveReducing CAPEX and OPEX, automating

network operations for increased survivability and accelerated service turn-up, and broadening the network operator’s service and application scope are key elements of Ciena’s vision and strategy in turning the network into a dynamic, revenue-generating, and intelligent infrastructure asset. Ciena’s vision and product development strategies have been in line with market needs to develop cost-effective, complete, and efficient OTN transport and switching platforms to address each network operator’s business requirements. Ciena’s WaveLogic™ Coherent Optical Processors unlock network capacity to 100G and beyond, without requiring network reengineering or massive capital investment, while Ciena’s OTN switching platforms and intelligent control plane have proven to change service economics and set a new benchmark in network survivability.

Ciena’s intelligent infrastructure solution is based on its industry-leading Packet-Optical Transport and Packet-Optical Switching platforms – namely, the 5400 and 6500 Family products. These products share a common, scalable, and intelligent OTN switching and control plane feature set to deliver a multi-domain solution for metro and core networks. In addition, Ciena’s OneControl

Unified Network Management System provides true multi-layer, cross-domain management required for realizing an intelligent infrastructure.

Ciena’s 5430 Reconfigurable Switching System is the industry’s first multi-terabit packet-optical switching platform that transforms networks into scalable, flexible, cost-reduced, and service-enabling infrastructures that can meet the monumental traffic growth challenges of the 21st century. The system features a switch fabric capable of switching SONET/SDH/OTN/packet, an intelligent multi-layer optical control plane, and a compact design with 3.6 Tb/s of switching capacity in a single bay, scalable to 15 Tb/s and beyond.

Architected for network modernization, Ciena’s 6500 Packet-Optical Platform converges comprehensive Ethernet, TDM, and WDM capabilities in one platform for cost-effective delivery of emerging and existing services, from the access edge to the backbone core. Boasting years of coherent deployment experience, 40G/100G solutions equipped with WaveLogic scale the capacity and reach of existing networks with operational simplicity. The system also features electronic dispersion compensation and supports directionless and colorless ROADM functionality, which combine with intelligent automation and OTN switching to maximize both the bandwidth efficiency and flexibility of the overall network.

OneControl unites the control of Ciena’s Carrier Ethernet Solutions, Packet-Optical Transport, and Packet-Optical Switching portfolios under a single management. With its unique toolset of comprehensive management features, OneControl puts the control of critical networks at the operator’s fingertips. The unified GUI and common management model enables NOC operators to deploy new service offerings that cut across access, metro, and core domains, and network protocol layers to ensure efficient use of critical network assets and bandwidth optimization. Once enabled, OneControl provides visualization of the complete end-to-end service multi-layer correlation, which aids in proactive root cause analysis and troubleshooting. l


Ciena may from time to time make changes to the products or specifications contained herein without notice. © 2011 Ciena Corporation. All rights reserved. WP053 4.2011

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