Packet-based mobile backhaul is one of the hottest topics discussed in our industry – since quite a few years in fact. And it will keep us busy for a couple of more years. Initially driven by the requirement for increased network capacity and the business challenge to reduce backhaul costs dramatically, the drivers and requirements now have changed with the roll-out of LTE in many mobile operator networks and the migration to the Evolved Packet Core (EPC).

Not surprisingly, initial Ethernet-based backhaul services have been simple since the mobile network topology and technology did not change. Mobile network operators predominantly asked for point-to-point connectivity linking their cell towers to the radio access network controllers. Nothing fancy – single class of service, dedicated capacity with no oversubscription, hub-and-spoke topology and little emphasis on timing distribution, though service availability and assurance have been a strong requirement from day one. In other words: a replacement solution for TDM services providing more capacity at lower cost.

With LTE and the introduction of the EPC this has changed. LTE has been designed from scratch as an IP-based technology, architecting concepts, topologies and functions from a packet-based perspective. Intelligence has now moved further down into the base stations and is distributed across nodes. Base stations now communicate with multiple instances in the mobile core and even with each other. Resiliency is achieved by organized resource clusters with dynamic allocation, quality of service differentiation becomes available on the air interface, the control plane is now completely separated from the data plane and many more innovations. The mobile network developed into a much more virtual world also from a backhaul perspective, with stricter requirements on transmission latencies and an ever increasing demand for bandwidth. With the addition of active capacity enhancement functionality such as coordinated multi-point transmission and inter-cell interference coordination, the demand for highly accurate network synchronization has increased substantially as well.

These changes have a significant impact on the backhaul network. The connections between base stations and the EPC need to support seamlessly these new LTE-driven requirements. Providers of mobile backhaul services are now asked to deliver more intelligent and value-added services to their customers – a distinct departure from the transport-centric wholesale offering as we have seen it in the past. Carrier Ethernet networks finally will be challenged also from mobile backhaul. Many features already built into business service offerings now find their way into mobile backhaul – multiple service classes with quality of service differentiation, multi-point connectivity, strict priority forwarding for lowest latency, end-to-end configuration and service management and a lot more. Last but not least, the distribution of synchronization information for frequency and time alignment needs to be architected into the backhaul network to achieve highest accuracy, reliability and operational simplicity.

That’s Mobile Backhaul 2.0 – it will challenge most backhaul providers to deliver such intelligent and versatile services with the same quality of service and at the same speed as mobile operators have experienced with the initial transport-centric Ethernet backhaul offerings. With Carrier Ethernet, the tools are in place. We will finally start using them across all applications.