 13.1 The Need to Reduce End-to-End Delivery Cost In Chapter 12 we suggested a brave new world in which telecom networks including mobile broadband networks would deliver social, political, intellectual, economic and possibly envi- ronmental value. However, this can only be achieved if the networks are financially sustainable. This might seem back to front, but in Chapter 21 we review a series of forecasts including our own that suggest that one consequence of the transition from telecom networks to information networks is that there will be a 30-fold increase in data volume over the next five years over mobile broadband networks and a threefold increase in value. This implies a substantial need to reduce end-to-end delivery cost. Backhaul costs presently represent 30% of this cost but are increasing over time. This cost of delivery is not just a function of volume but is also influenced by traffic mix and the degree of multiplexing gain that can be achieved. 13.1.1 Multiplexing Gain Multiplexing gain is a function of single users having variable bit rate requirements that are then averaged over multiple users. Some of the bits are not latency sensitive and can be buffered. Additionally, there may be more than one point-to-point routing option that provides additional multiplexing gain. Mobile broadband offered traffic is highly asynchronous (bursty). On the one hand, it could be argued that this makes multiplexing more rather than less effective. The counterargument is that bursty traffic remains bursty even after aggregation (persistent burstiness). What this means is that bursty traffic behaves in different ways and affected by the characteristics of the paths over which it travels. Generally, it can be stated that conversational, streamed and interactive traffic costs more to deliver than best effort and can be shown not to aggregate efficiently. The offered traffic can also be highly asymmetric. These characteristics together mean that backhaul has to be over provisioned in order to meet defined user QOS and