June 1, 2011

Carrier Ethernet: Four Ways To Meet Backhaul Challenges

By Juan Prieto

The popularity and rapid growth of mobile-data services presents a potential revenue driver for mobile operators fighting rapidly declining average revenue per user (ARPU) for voice services. Mobile-data traffic volumes are sure to continue to grow at a breakneck pace, with Cisco predicting a compound annual growth rate for this traffic of 92 percent from 2010 to 2015. Unfortunately, without the right management approach, revenues from mobile data services cannot be counted on to do the same. Mobile operators must find ways to reduce backhaul operating expense (opex) to increase data-services revenue margins.

To realize the promise that growth in mobile-data services offers, operators are turning to Carrier Ethernet technology as the transport medium of choice for cost-effectively handling data traffic. Deploying an Ethernet-based backhaul network can drive down the “per-bit” cost of transporting data traffic as well as future-proofing for continually evolving mobile technologies.

Transitioning to an IP/MPLS-based mobile-backhaul plan eliminates the data-transfer bottleneck of such traditional backhaul technologies as TDM. This bottleneck otherwise would stand in the way of competitively offering mobile broadband or the burgeoning possibilities for value-added content on top of that mobile broadband, like mobile TV or video on demand.

While Carrier Ethernet offers numerous advantages when compared with legacy backhaul technologies that don’t scale in terms of cost benefits, mobile operators wanting to leverage these advantages must consider how to manage some key operational and engineering challenges Carrier Ethernet introduces. There are four major challenges that must be addressed in any Carrier Ethernet backhaul deployment to help ensure a rapid, trouble-free transition. Here are some thoughts on each of them:

1. Managing The Complexities

Carrier Ethernet introduces new complexities not faced with traditional TDM, including classes of service, VLANs, virtual circuits and MPLS tunnels. Engineering an end-to-end connection between a cell site and the upstream controller using Carrier Ethernet requires an orchestration of all of these entities because a modification of any one entity requires a deep and ongoing analysis of the others from a performance perspective. The transport teams that managed TDM backhaul need to be equipped with the right tools that can help assure and engineer all these new entities holistically.

2. Transport Assurance

In combination with native IP/Ethernet interfaces, pseudowire or circuit-emulation technologies are enabling operators to support legacy transport interfaces seamlessly over a pure Carrier Ethernet network. But transport connections to individual cell sites still are prone to multiple problems, ranging from weather to careless configuration changes.

Pseudowire monitoring empowers operators to track service performance over virtual tunnels, Ethernet virtual circuits, interfaces and VLANs — all of which are used to transport traditional technologies via Carrier Ethernet networks. To accomplish this monitoring, detailed visibility is needed into each of these entities ( i.e., per pseudowire, virtual circuit, interface, cell site, etc.) to help assure and engineer them holistically. As a result, the operations teams that managed performance of the legacy connectivity need new tools that can provide the availability and quality of emulated connections proactively over Carrier Ethernet. The capability to troubleshoot transport to each cell site in real time also is vital for comprehensive service management.

3. Quality Control

It can be anticipated that video will account for much of the rapid growth in data services predicted by Cisco as operators look to push their top-line revenue by introducing streaming-oriented and real-time, value-added applications. These applications are extremely sensitive to service-quality degradations, which likely will place tighter quality-of-service (QoS) demands on operators than faced with traditional voice traffic.

Meeting these strict end-to-end quality demands will be essential because mobile subscribers are notoriously susceptible to churn when they experience poor service quality. Achieving this high QoS will require the ability to measure and monitor at varied levels of traffic segregation. Additionally, if the Ethernet backhaul being deployed consists of equipment from multiple vendors, operators will benefit from a service assurance platform that can leverage vendor-specific instrumentation to portray the end-to-end quality of the Ethernet backhaul using vendor-agnostic key quality indicators.

4. Right-Sizing The Infrastructure

The traditional approach of over-sizing the network to meet growing mobile-data traffic demands would defeat the advantage of Carrier Ethernet as a more cost-effective technology. At the same time, cost-containment through careful sizing must be balanced against the need for a high quality of experience (QoE) to avoid churn. “Right-sizing” the network is required to ensure that costs are contained and QoE is preserved.

Right-sizing is complicated, however, by the fluctuating data-traffic patterns generated by mobile subscribers. Holidays and events, for example, can cause a sudden increase in subscribers’ messaging and browsing patterns. An accurate comprehension of these volatile traffic patterns requires deep analytics of traffic utilization. Such industry-proved concepts as “busy day” and “busy hour” designations are crucial in determining the worst stress levels of the backhaul network. Hourly baselines; engineering benchmarks; and accurate traffic forecasts based on historical monthly, quarterly and yearly analytics are indispensable to achieving the objective of right-sizing the network, and planning maintenance and engineering activities intelligently.

Being able to accomplish this down to every sub-element (interface, class of service and VLAN) requires industry-grade assurance tools that demonstrate proved scalability and performance. Moreover, right-sizing is an ongoing effort that relies on the ability to baseline end-to-end quality continuously over time. This is the only way to help ensure the chosen infrastructure sizing can meet service-quality expectations.

Leveraging The Advantages

Carrier Ethernet backhaul is an excellent choice for mobile operators seeking to capitalize on the potential revenue opportunities presented by the growth in mobile data services. To successfully leverage the advantages that Carrier Ethernet backhaul has to offer, operators will need service-assurance tools that address the operational and engineering challenges such a deployment involves. Backing up the business decision and technology choice to deploy a Carrier Ethernet backhaul with the right service-assurance solution is a prerequisite for successfully achieving the business objectives behind Ethernet backhaul and realizing the revenue potential mobile-data services offer.

Juan Prieto is product marketing manager at InfoVista. Contact him at jprieto@infovista.com.