T E C H N O L O G Y W H I T E P A P E R Packet-Optical Ethernet Business Access Networks Services without boundaries Ethernet has rapidly become the technology of choice for service providers supporting enterprise networks and services. But business customers are demanding increased bandwidth with more flexibility and differentiated service quality at lower costs. As a result, service providers are faced with many overlapping and conflicting challenges when trying to meet the demands of their business customers. This paper explains how Packet-Optical Ethernet business networks have evolved and how new solutions are able to overcome the limitations of Ethernet access in the last mile, in terms of physical delivery infrastructure, manageability, operations, administration and maintenance (OAM) and intelligent demarcation.
Table of contents 1 Introduction 1 Market drivers and challenges 3 Packet-Optical Transport and Ethernet business networks 4 Carrier Ethernet and the MEF 5 The evolution of Packet-Optical Ethernet business access services 6 Alcatel-Lucent Next-generation Packet-Optical Ethernet business access solutions 8 Conclusion 8 Acronyms
Introduction Enterprises have growing bandwidth, reach and reliability requirements for their voice, data and video traffic. They are also deploying new applications to meet crucial business objectives, such as increasing efficiency and reducing costs. The challenges for service providers are to deliver higher speed access for business services, provide connectivity to more enterprise sites wherever they are located and to do this without significant increases in cost and complexity. Ethernet has rapidly become the technology of choice for service providers supporting enterprise networks and services. It offers the ability to provide a single ubiquitous technology for multiple service types, and it is the technology of choice for transporting IP-based applications. Ethernet also provides the bandwidth, flexibility, service transparency and low cost requirements needed for today s packet-orientated business services. Thanks to the efforts of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T), the Institute of Electrical and Electronics Engineers (IEEE), and the Metro Ethernet Forum (MEF), the limitations of traditional LAN-based Ethernet in terms of scalability, reliability, Quality of Service (QoS) and manageability have been solved. This has allowed the widespread deployment of network solutions using Ethernet, or Carrier Ethernet as the MEF defines this new, more robust Ethernet. Market drivers and challenges Service providers have many overlapping and conflicting challenges when trying to meet the demands of their business customers. Business customers are demanding increased bandwidth with more flexibility and differentiated service quality at lower costs: Higher bandwidth services with far better granularity than those provided by traditional private line (E1/T1 or E3/T3) or frame relay Ubiquitous connectivity and capabilities to all of their sites, regardless of existing infrastructure (copper, fiber) Service quality at least as good as today s networks in terms of security, availability, latency and latency variation Ability to pay for differentiated service quality and to monitor and confirm, in real time, that service level agreements (SLAs) for their services are being met (pay for extremely low latency and latency variation for some services and best effort for other services) Consolidation of data and centralization of switching to move the switching capability from the customer to the service provider (customers want their hub sites provided with a single trunk that consolidates and routes all traffic to/from remote sites, rather than a link per site as required with traditional solutions) Near instantaneous service turn-up for new services to existing sites Connectivity to new sites extremely rapidly (days rather than weeks) Overall service package costs that are less than with traditional private line services At the same time service providers have to deal with: Cannibalization of revenue streams from their existing service products, while trying to migrate to new service products Maximizing return on investment (ROI) on the evolution of their network from circuit to packet, while continuing to maximize the ROI from their embedded networks Packet-Optical Ethernet Business Access Networks Technology White Paper 1
Potential escalation in operating expenditures (OPEX) due to the increased complexity of the technology for new services types and the increased complexity of the management requirements demanded by customers An unpredictable growth model because it is becoming increasingly difficult to predict when and where customers will want new or higher bandwidth services Ethernet is designed to transport IP. It also provides the ability to address flexible bandwidth needs with a cheap, ubiquitous customer interface. Carrier Ethernet, as defined by the MEF, extends Ethernet with the service quality capabilities demanded by business customers. Fiber is the natural technology of choice to deliver Carrier Ethernet business services. However, fiber is not widely available in many last mile access networks where copper continues to dominate. According to Vertical Systems, in 2007 the vast majority of business sites in the U.S. and Europe had no access to fiber, with small and medium business sites disproportionately underserved compared to large business sites. 1 Businesses in the same buildings within major metropolitan areas are most likely to have access to fiber, whereas businesses in smaller buildings and in less populated areas are the least likely to have access to fiber. Where business sites are not fiber-connected, service providers may opt to build fiber out to the building, if this makes sense commercially. Alternatively they would like the option to deliver Ethernet business services over existing copper infrastructures. This has prompted an increased interest in dedicated platforms that deliver Ethernet business access over copper, such as Ethernet over bonded copper and Ethernet over TDM access circuits. At the same time as placing demands on the access network, the change in the service provider product mix from traditional E1/T1-based business services to Ethernet-based business services makes it increasingly commercially viable to move to an all packet or hybrid packet/optical transport infrastructure. In making the move to a packet-based transport infrastructure for business services, business customers are still demanding the same transport capabilities. Therefore, the packet transport solution must provide security, availability, manageability, low latency and resiliency that, at a minimum, matches what is provided today by SDH/SONET options. Multi-Protocol Label Switching (MPLS) is the technology of choice for packet transport. MPLS Transport Profile (MPLS-TP) and its ITU-T standard counterpart Transport-MPLS (T-MPLS) extend MPLS to provide connection-oriented transport that is suitable for transporting packet and TDM services over optical networks. Key attributes of T-MPLS/MPLS-TP are OAM and resiliency features that ensure the capabilities needed for today s service environment scalable operations, high availability, performance monitoring and multi-domain support. In addition to the OAM and resiliency capabilities provided by T-MPLS/MPLS-TP, business customers and service providers alike are starting to demand a clear demarcation device an Ethernet Demarcation Device (EDD) between the customer s network and the service provider network. The EDD provides strong OAM and SLA management capabilities that allow the service provider to test, monitor and assure services all the way to the customer s premises. It creates a clear network and service demarcation point between the service provider s and the customer s networks, and helps to provide end-to-end visibility all the way to the customer s premises. It also ensures that the service provider can isolate the customer s network when testing and monitoring the end-to-end network connection and service to eliminate diagnostic errors caused by customer activities. 1 Got Business Fiber?, Vertical Systems Group STATFlash, 2008. 2 Packet-Optical Ethernet Business Access Networks Technology White Paper
Packet-Optical Transport and Ethernet business networks Ethernet business networks are built with two components that must integrate together seamlessly: the Ethernet transport network and the Ethernet business access network. In the Ethernet transport network, Packet-Optical Transport plays a key role. It allows service providers to evolve their core networks to provide transport solutions for the new packet based services. Packet-Optical Transport solutions simultaneously support SDH/SONET and Carrier Ethernet transport. This simultaneous support allows service providers to evolve their networks from circuit to packet at the rate that they want, only moving to pure packet when the business model is right (Figure 1). Figure 1. Packet-Optical Transport Packet Three separate platforms Purpose-built convergence platform TDM WDM Packet-optical transport In the Ethernet business access network, Packet-Optical Transport allows service providers to support a mix of traditional private line services and Ethernet business services, with both SDH/SON- ET and Ethernet used to provide business services. This approach allows service providers to evolve their business services product portfolio from E1/T1-based services to Ethernet-based services at the rate that suites them. It also allows them to select the best transport solution for their product mix: SDH/SONET, Ethernet or a hybrid approach. In addition, in the last mile (the physical connection between the customer premises equipment (CPE) and the transport network) Packet-Optical Transport solutions give service providers the flexibility to embrace all physical access technologies: fiber, copper (using Ethernet over Plesiochronous Digital Hierarchy (PDH)), or integration with packet microwave devices where neither fiber or copper is available. End-to-end across the Ethernet business network, Packet-Optical Transport provides the QoS, OAM, and manageability to guarantee end-to-end service delivery at the appropriate quality levels. At the Ethernet layer, Ethernet OAM provides end-to-end service monitoring and service assurance. Standards-based OAM, such as IEEE 802.3ah Link OAM, 802.1ag Connectivity Fault Management, and ITU-T Y.1731 Ethernet Service OAM performance and monitoring, provide the capabilities to fulfill these requirements. At the transport layer, transport OAM is essential to provide and guarantee a highly available, resilient, manageable transport network. For Ethernet over SDH/SONET (EoS), the transport layer uses the trusted SDH/SONET mechanisms. As service providers evolve to Packet-Optical networks using T-MPLS/MPLS-TP as the transport layer, OAM capabilities are required for T-MPLS/MPLS-TP that allow the network to be managed consistently with SDH/SONET, Optical Transport Network (OTN) and Wave Division Multiplexing (WDM). Packet-Optical Ethernet Business Access Networks Technology White Paper 3
The final component required to provide end-to-end Ethernet business services is the management solution. When architected and implemented well, the management solution should help reduce operations complexity by streamlining and automating provisioning. When integrated with the OAM capabilities it allows service providers to rapidly deploy new services to new customers with the confidence that they can offer and guarantee the SLAs demanded by their customers. The Packet-Optical management solution has the advantage that it is an extension of the currently deployed, well understood Optical Management Systems. This means that as Ethernet service capabilities are added to the network, the existing business systems, procedures and processes can continue to be used with no need for extensive re-training or testing. In addition integration with existing northbound operations support system (OSS) remains intact with no need for expensive re-testing and re-integration. Carrier Ethernet and the MEF The MEF is a global industry alliance responsible for developing technical specifications, implementation agreements and certification programs to promote interoperability and deployment of Carrier Ethernet services worldwide. Carrier Ethernet is a concept developed and promoted by the MEF with the purpose of aiding and accelerating the deployment of Ethernet services. It is LAN-based Ethernet enhanced with five attributes (Figure 2). Figure 2. Carrier Ethernet as defined by MEF Carrier Ethernet attributes Carrier Ethernet Carrier Ethernet is a ubiquitous, standardized, carrierclass service defined by five attributes that distinguish Carrier Ethernet from familiar LAN-based Ethernet. It provides the compelling business benefit of the Ethernet cost model to achieve significant savings. Standardized services Scalability Service management Reliability Quality of service Specification test procedures and certification programs are increasingly important activities of the MEF: MEF 9 defines the requirements and corresponding test procedures that determine the readiness of Metro Ethernet Network (MEN) and Metro Ethernet equipment to deliver various Ethernet services, such as Ethernet Line (E-Line) and Ethernet LAN (E-LAN) services. MEF 14 defines the requirements and corresponding test procedures for service performance and bandwidth profile service attributes that may be specified as part of a Service Level Specification (SLS) for an Ethernet service. MEF 18 defines the requirements and corresponding test procedures for circuit emulation services over Ethernet. 4 Packet-Optical Ethernet Business Access Networks Technology White Paper
New MEF abstract test suites recently published include: MEF 19 for Type 1 MEF 21 for T Type 2 Link OAM In the process of being defined are abstract test suites for compliance to MEF Type 1 and Type 2. MEF certification is becoming a standard requirement both for products from equipment vendors and Ethernet services offered by service providers. Certification assures service providers that equipment supplied by vendors can deliver MEF-compliant services, and assures business customers that services they buy from service providers are compliant with MEF specifications. The evolution of Packet-Optical Ethernet business access services The Packet-Optical Carrier Ethernet business services market, which initially used EoS transport technology, has grown rapidly over recent years. Services such as Ethernet Private Line, Ethernet Virtual Private Line, Ethernet Hub n Spoke and simple Ethernet multipoint all using EoS have been mass deployed by service providers for their business customers (Figure 3). Figure 3. Ethernet service types defined by the MEF E-LINE service E-LAN service E-tree service Leaf Root Leaf Leaf Ethernet private line Ethernet multipoint Ethernet hub n spoke These services have rapidly replaced traditional services like private line. This is due to the greater bandwidth flexibility and improved bandwidth granularity at lower cost provided by Ethernet allied to security, availability, manageability, low latency and resiliency demanded by customers, provided by the underlying SDH/SONET transport, and augmented with next-generation features, such as Generic Framing Protocol (GFP), Virtual Concatenation (VCAT), and Link Capacity Adjustment Scheme (LCAS). The use of Ethernet over SDH/SONET technology in CPEs gives service providers an extremely simple migration path from their existing E1/T1-based private line services and allows them to reuse the embedded SDH/SONET transport networks. The EoS networks present Ethernet interfaces towards the customer and SDH/SONET interfaces (such as STM-1) towards the network. This means that when the service provider upgrades an existing private line service to Ethernet Private Line, the majority of the network remains unchanged as SDH/SONET transport, only the CPEs need to be Ethernet aware. This is illustrated in Figure 3, where the transport network can actually be any transport technology (for example, SDH/SONET, MPLS, etc.) and it is only the end points that need to be Ethernet aware and meet the Carrier Ethernet specifications. Packet-Optical Ethernet Business Access Networks Technology White Paper 5
More generally this approach has allowed service providers to deploy Ethernet business services extremely rapidly as all they need to do is deploy an Ethernet aware device called a Multi-Service Provisioning Platform (MSPP). In some cases all the service provider needs to do is add an EoS line card to an existing device to provide the Ethernet service. As the demand for Ethernet services increases and the number of traditional services decreases, a packet-orientated transport network becomes more cost-efficient than a circuit-orientated transport network. Hence, service providers are looking at how and when to migrate their existing transport network from circuit to packet. T-MPLS/MPLS-TP, based on the widely accepted and deployed MPLS technology, provide the transport OAM and protection capabilities required to replace the existing TDM transport network with a packet-optimized Packet-Optical Transport network. The Packet-Optical Transport approach offers service providers an evolutionary approach. It simultaneously supports existing TDM technology, SDH/SONET, and the newer Carrier Ethernet capabilities. What this means to service providers offering Ethernet business services is that they can fully leverage their SDH/SONET networks, processes and expertise with a seamless evolution to pure packet transport when they and their customers require this transition. Alcatel-Lucent Next-generation Packet-Optical Ethernet business access solutions Alcatel-Lucent has been leading the way in providing network solutions that allow service providers to support Optical Ethernet business services, initially with Ethernet Private Line and, more recently, with Ethernet Hub n Spoke and simple Ethernet multipoint services. Alcatel-Lucent equipment is used to provide the network for well over 100,000 Optical Ethernet business services in operation today. Alcatel-Lucent has also been a major player in the MEF since its inception, driving for a standardized approach for Ethernet that will allow equipment vendors, service providers and customers all to benefit from the advantages that a ubiquitous Ethernet solution offers. To support the next generation of Packet-Optical Transport, Alcatel-Lucent has introduced the 1850 Transport Service Switch (1850 TSS) portfolio (Figure 4). This portfolio allows service providers to support SDH/SONET, EoS, WDM and Packet-Optical simultaneously from the same network element. This simultaneous support gives service providers a simple evolution path as services migrate from predominantly TDM to predominantly packet services. Figure 4. The Alcatel-Lucent 1850 TSS portfolio 1850 TSS-320 320 Metro/regional 1850 TSS-160 160 Metro/access 1850 TSS-100 100 Capacity (Gb/s) 1350 OMS CPE/access 1850 TSS-40 40 1850 TSS-3 1850 TSS-5 5 3 6 Packet-Optical Ethernet Business Access Networks Technology White Paper
Business customers and service providers alike demand a clear, intelligent demarcation point/device between the customer s network and the service provider network that provides strong OAM capabilities. The Alcatel-Lucent 1850 Transport Service Switch (TSS-3) is the element of the 1850 TSS portfolio designed to provide these critical capabilities. The 1850 TSS-3 is a carrier-grade EDD. It offers the capabilities required to provide Packet-Optical Carrier Ethernet business access. In particular, it can support Ethernet service delivery over both copper and fiber, acting as an intelligent EDD with extensive, standards-compliant Ethernet OAM capabilities. Figure 5 shows the 1850 TSS-3 in an Ethernet-over-fiber configuration, providing intelligent Ethernet demarcation with the customer port on the TSS-3 being the demarcation point. The TSS-3 provides full fault diagnostics and monitoring, traffic rate limiting and Virtual LAN (VLAN) stacking from this demarcation point across the end-to-end network. Figure 5. Alcatel-Lucent 1850 TSS-3 providing Ethernet business access over fiber GigE/FEo with EFM OAM GigE/FEo with EFM OAM 1850 TSS-3 Carrier Ethernet Network 1850 TSS-3 Demarcation Demarcation The 1850 TSS-3 also provides Ethernet service aggregation, acting as a carrier-class Ethernet switch, accepting multiple inputs from the customer side and aggregating them for onward transmission on the network side. The TSS-3 supports Rapid Spanning Tree Protocol (RSTP), Link Aggregation or Ethernet 1:1 port protection (sub-50 ms) to provide for network-side redundancy in single homing, dual homing or ring topologies. For transmission over longer distances than are possible with copper lines, the TSS-3 provides Ethernet extension where the electrically-based FE or GigE on the customer port is converted to optical Ethernet for transmission into the service provider network. Figure 6 shows the 1850 TSS-3 in an Ethernet over PDH (EoPDH) configuration, providing Ethernet demarcation with the customer port on the 1850 TSS-3 being the demarcation point. In this configuration, there is a pre-existing copper connection capable of carrying one or more E1/DS1 channel(s) or E3/DS3 channel(s) connected to a legacy TDM network. By inserting the 1850 TSS-3 into the copper connection, EoPDH is established. Ethernet packets are mapped to the PDH lines using a standards-compliant mapping mechanism (GFP/VCAT) with redundancy provided by PDH interface 1+1 protection or LCAS. If several E1/DS1 or E3/DS3 lines are available, they can be bonded together to create a higher-bandwidth uplink. Figure 6. Alcatel-Lucent 1850 TSS-3 providing Ethernet business access over copper Demarcation Customer Equipment Ethernet/ FE/GigE Service Provider Equipment 1850 TSS-3 Ethernet over E1/DS1 SDH/SONET Packet-Optical Ethernet Business Access Networks Technology White Paper 7
The 1850 TSS-3 supports the OAM tools that provide end-to-end service assurance to measure and report SLAs that are essential for Ethernet business access solutions. IEEE 802.3ah Ethernet in the first mile provides physical link layer OAM for monitoring and troubleshooting a point-to-point fullduplex link. It is particularly valuable in the first/last-mile connection to the network demarcation or CPE device where most link failures typically occur. IEEE 802.1ag Connectivity Fault Management provides end-to-end network OAM and Ethernet service management. 802.1ag also provides capabilities for connectivity verification, and detection and isolation of connectivity failures. Y.1731 Ethernet Service OAM is complementary to and a superset of IEEE 802.1ag. The ITU-T developed Y.1731 in cooperation with the IEEE, defining further VLAN-based service transport OAM functionality. Several of the additional features offer performance monitoring capabilities, such as loss and delay measurement. The 1850 TSS-3 features a hardware-based Y.1731 implementation for highly accurate service measurements. This contrasts with competing software-based Y.1731 implementations that can lack the accuracy needed for strong SLA support required by demanding customers. The Alcatel-Lucent 1350 Optical Management System (OMS) is an advanced optical management system that provides the functionality to fully manage new packet-based networks as well as traditional SDH/SONET networks. It provides automation and optimized workflows to allow simple endto-end provisioning across the entire network. And for easy integration into the OSS and business support system (BSS) ecosystem there are comprehensive, standards-based compliant interfaces. Conclusion The Alcatel-Lucent 1850 TSS-3 goes beyond simple media conversion and physical presence, providing a rich mix of connectivity and network services. It offers diagnostics, service monitoring, protection, QoS, rate limiting and VLAN stacking for MEF-compliant Ethernet services. With all these features, service differentiation becomes possible and time-sensitive traffic is given precedence. Finally, a variety of redundancy schemes are available, depending upon the application chosen. All this makes the Alcatel-Lucent 1850 TSS-3 a leading intelligent Ethernet demarcation device for Ethernet business services. Acronyms BSS business support system MSPP Multi-Service Provisioning Platform CPE customer premises equipment OAM operations, administration and maintenance EDD Ethernet Demarcation Device OPEX operating expenditures E-LAN Ethernet LAN OSS operations support system E-Line Ethernet Line PDH Plesiochronous Digital Hierarchy EoS Ethernet over SDH/SONET QoS Quality of Service EoPDH Ethernet over PDH ROI return on investment GFP Generic Framing Protocol RSTP Rapid Spanning Tree Protocol IEEE Institute of Electrical and Electronics Engineers SDH Synchronous Digital Hierarchy IP Internet Protocol SLA Service Level Agreement ITU-T LAN LCAS MEF MEN MPLS MPLS-TP International Telecommunication Union Telecommunication Standardization Sector Local Area Network Link Capacity Adjustment Scheme Metro Ethernet Forum Metro Ethernet Network Multi-Protocol Label Switching MPLS Transport Profile SLS SONET TDM T-MPLS VCAT VLAN WDM Service Level Specification Synchronous Optical Network Time Division Multiplexing Transport-MPLS Virtual Concatenation Virtual LAN Wave Division Multiplexing 8 Packet-Optical Ethernet Business Access Networks Technology White Paper
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