With data traffic exploding at a rate of 400 percent to 800 percent annually worldwide and with the pending move toward LTE, mobile service providers face mounting pressure to have in place the necessary backhaul capacity to handle the traffic. But while we know wireless data applications and the resulting traffic will continue to proliferate, it is also clear the revenue mobile providers derive from this growth will not increase at that same pace.
The only way for mobile operators to maintain operating margins is to keep capital expenditures lower to eventually gain a lower cost per bit. Mobile operators are either upgrading their own backhaul network or going to their wholesale providers (wireline or cable operator) for higher capacity contracts. The wholesale providers are expected to offer stringent SLAs with customer reporting. In this competitive environment, time to market is key to gaining market share.
In light of these market dynamics, all signs are pointing to Carrier Ethernet technology as the technology of choice for next-generation mobile backhaul infrastructures. Compared to legacy TDM networks, Carrier Ethernet offers clear advantages in handling the explosive growth of traffic while reducing operational expenses. But while the evolution to Ethernet mobile backhaul might appear to be a straightforward migration strategy, it introduces significant challenges for mobile operators, including:
• Right-sizing the Ethernet backhaul infrastructure
• The need to guarantee the same end-to-end quality as traditional TDM
• The need to assure the performance of cell sites by monitoring Pseudowires emulating TDM & ATM technologies over Ethernet
• Managing the complexities associated with class of service and MPLS traffic engineering.
In a Carrier Ethernet environment, the traditional approach of over-sizing a network infrastructure to meet growing traffic demands becomes counterproductive because it defeats the purpose of Ethernet as a more flexible and scalable technology. Under-provisioning, on the other hand, would compromise end-to-end transport quality and cause other heartaches like sloppy synchronization in the radio access network (RAN). Customers who have signed up for expensive data service packages, especially those traveling on business, expect a certain quality of experience. If they don’t get it, they can become strong candidates for churn.
Providers will need to continuously baseline end-to-end quality over long periods of time to ensure that the chosen infrastructure sizing can meet service quality expectations while keeping up with new traffic patterns that may result from disruptive business decisions (e.g., the introduction of new and improved smartphones) or user and demographic behavior (e.g., being in Times Square on New Year’s Eve). Over time, analytics on traffic utilization data can be used to not only predict near- and long-term forecasts but also for establishing the right engineering limits for every sub-entity (ports, sub-interface, quality of service queues) that make up the backhaul network. Long-term analytics like hourly baselines and busy-hour analysis of end-to-end quality (leveraging Ethernet OAM standards) can help the operator determine if their “first pass” at the engineering limits indeed support their expectations for end-to-end quality. If not, the iteration should continue.
Furthermore, there are stringent quality benchmarks imposed by packet-based synchronization standards, like IEEE 1588v2 or adaptive clock recovery, to carry out the basic functions of a cellular network, such as cell-to-cell hand-offs. The RAN is critical to the delivery of voice and data services. Although operators embrace Carrier Ethernet to “future-proof” against explosive data growth and 4G networks, they still have to support their legacy 2G and even 3G radio networks (e.g., UMTS, HSPA, and HSPA+), which use legacy transmission standards like TDM or ATM. This is where pseudowire or circuit emulation technologies are enabling operators to seamlessly support legacy transmission interfaces over a pure Carrier Ethernet network. Nevertheless, transmission connections to individual cell sites are still prone to multiple problems ranging from weather to careless configuration changes. The operations teams that traditionally managed the legacy connectivity now need tools to assure the availability and quality of such emulated connections over Carrier Ethernet. In addition, the capability to troubleshoot transmissions to each cell site in real time is vital for comprehensive service management.
Last but not least, Carrier Ethernet, as compared with traditional TDM, brings more complex concepts. While T1 backhaul brought only channelization, Ethernet backhaul brings challenges such as the management of VLANs (for traffic separation), classes of service (for traffic prioritization), pseudowires, Ethernet virtual lines, Ethernet virtual LANs (for broadcast TV) and MPLS tunnels. And although the same transmission-engineering and transmission-operations teams are being entrusted with a far more sophisticated transmission medium (Carrier Ethernet), they also need the right set of assurance tools to measure and report the performance of these complex entities in a holistic manner. Engineering an end-to-end connection between a cell site and the upstream controller using Carrier Ethernet requires an orchestration of all these entities; therefore, a modification of any one entity requires a deep and ongoing analysis of the other entities from a performance perspective. And because the Ethernet backhaul being deployed may consist of multiple vendors, effective service assurance platforms should leverage vendor-specific instrumentation to portray the end-to-end quality of the Ethernet backhaul using vendor-agnostic key quality indicators.
While there will be challenges moving to a Carrier Ethernet infrastructure, enhanced monitoring of services can make sure there is no degradation of service quality. Even those mobile operators that go to a wholesaler for backhaul infrastructure look for a wholesaler who offers online reporting, or customer portals. In this way, the mobile provider can have a good understanding of the quality of services they are receiving. Wholesale operators thus need a system that can enable them to provide that visibility to their mobile operator clients while also bringing them the same operational and engineering benefits as described above.
The right Ethernet-based performance management and assurance system can help mobile service providers and wholesale operators rise to meet the challenges they face today. Mobile operators should seek a solution that provides proactive performance management and reporting capabilities across a multi-vendor Carrier Ethernet environment and mobile domain.
Ranga Thittai is product manager for InfoVista
Filed Under: Infrastructure
