By Ilan Seidner, Director of Marketing Communications
As published in Total Telecom on September 8
Carrier Ethernet is enjoying a meteoric rise in telecommunications today revolutionizing how fixed operators offer business services and how mobile operators manage the colossal backhaul challenge.
Central to its success has been its ability to transform the economics of carrier transport while also offering unmatched flexibility. This has resulted in a massive rise in operators' enterprise Carrier Ethernet services delivering more and more features and bandwidth at ever more competitive prices. At the same time, mobile operators have found that their backhaul costs are rendering their mobile broadband services unprofitable and are therefore turning to Carrier Ethernet. However, it also faces a number of challenges, such as demands for quality of service, traffic management, synchronization for real-time services and greater insight into faults.
Ethernet services for enterprises are booming. Enterprise customers are embracing Ethernet VPN services as these offer higher bandwidth rates, competitive pricing, flexibility, and scalability. From their end, carriers and service providers see an opportunity to enhance their business networking solutions portfolio with next-generation services that are cheaper to operate and combine added user value with quick return on investment and sustainable revenue potential.
The growth in popularity of business Ethernet services is closely linked to the level of maturity Ethernet technology has reached, enabling carriers to deliver and audit hard service level agreement (SLA) guarantees that satisfy exacting requirements from enterprise users.
Before they migrate all their corporate traffic to new Ethernet services, organizations will expect to be assured that they will receive the appropriate quality of service (QoS) and performance guarantees to support their critical applications. Enterprise users are expecting the same service consistency and reach that have been offered by legacy TDM, ATM and Frame Relay – a requirement that "best effort" Ethernet services were unable to fulfill. They also demand service differentiation to facilitate efficient operations and to meet their particular business needs, both current and future.
Carriers and service providers deploying business Ethernet services, therefore, must be prepared to deliver measurable and enforceable SLAs that detail commitments for user traffic handling, bandwidth and performance guarantees, user control protocols processing and availability, as well as for redundancy, response and repair times. This requires the installation of intelligent demarcation devices, or Ethernet network termination units (E-NTUs), at the customer premises to ensure end-to-end service control and efficient service provisioning from the service hand-off points. Such devices are ideally equipped with Ethernet SLA support tools, including advanced service delivery and service assurance capabilities.
Carrier Ethernet is a perfect fit for transporting 3G and LTE backhaul as it offers simplicity, scalability and cost-effectiveness. This will mandate the use of mobile demarcation devices (MDDs) to connect LTE elements with the backhaul network. MDDs must support a flexible selection of topologies and allow distributed intelligence at cell site and aggregation switches to efficiently handle tens of thousands of backhaul connections in LTE's flat architecture, while optimizing network resources. In addition, MDDs must enable cost-effective backhaul sharing with customized SLAs and differentiated QoS.
Originally, the introduction of 3G and subsequently HSPA was met by market conditions that dictated the decoupling of data traffic increases from flattening revenues. This resulted in the need to separate backhaul costs from capacity so that booming traffic rates could be delivered economically. LTE addresses this issue by specifying cost-effective packet switching as the native transport technology.
Nevertheless, high-volume "IP pipes" alone are not enough for backhaul providers to lower their total cost of ownership (TCO) in the access network and to meet operators' requirements for tight SLAs with guaranteed reliability and service quality. The need for intelligence in LTE backhaul is much greater than that of earlier generations due to additional challenges such as its X2 interface and many-to-many connectivity, as well as matters of architecture, network service functionalities, backhaul sharing, and voice traffic delivery.
Synchronization is widely recognized as one of mobile backhaul over packet's major challenges. This is because clocking data, which is transmitted natively over TDM, requires special attention in new packet switched networks (PSNs), which are asynchronous by nature and introduce packet delay variation (PDV) and packet loss. As far as mobile operators are concerned, the backhaul network must meet "SDH/SONET or better" performance levels to eliminate the risk of service disruptions, impaired cell hand-offs and excessive dropped calls. LTE, therefore, requires robust clock distribution to all network elements to ensure accurate handover.
The most popular methods today for ensuring synchronization over all-IP backhaul are based on the ITU-T Synchronous Ethernet (Sync-E) methodology and on the IEEE 1588-2008 standard. MDDs support clock transfer and enable substantive cost savings by eliminating the need for costly dedicated hardware or GPS installations. An advanced MDD will facilitate further savings by bridging different timing and synchronization technologies, for example, by employing 1588-2008 to receive the clock from the network then distributing it to the cell site using Sync-E. Such an MDD will provide backhaul suppliers with the ability to match different clocking technologies used by the transport network and the base stations, as well as help them avoid complete network upgrades with new hardware to support Sync-E end-to-end.
Transport providers offering clock distribution as a backhaul service stand to benefit greatly from MDDs that combine timing and synchronization with demarcation capabilities. Aside from their equipment consolidation benefits, MDDs help providers navigate through the intricacies of multi-operator clocking SLAs, including QoS, resource management, OAM, and security for the different entities located at the same site.
Evidently, Carrier Ethernet is transforming the economics and capabilities of fixed and mobile operators' offerings. However, the clear challenge for this, and indeed all, packet-based technologies is upholding network quality, something than manifests itself in the strict requirement for quality of service, traffic management, synchronization, OAM features, redundancy, and rapid restoration of Carrier Ethernet rings. The only way of overcoming this critical obstacle is by spreading intelligence to the edge of the network. This is perhaps set to become the mantra of the next generation of communications.
