 QOE expectations. This increases capital and operational cost. However, we have also stated in previous chapters that although best-effort traffic can be used to increase delivery bandwidth utilisation this is only achieved by buffering that itself introduces cost. Making Telecoms Work: From Technical Innovation to Commercial Success, First Edition. Geoff Varrall. © 2012 John Wiley & Sons, Ltd. Published 2012 by John Wiley & Sons, Ltd. Making Telecoms Work Backhaul strictly defined is a delivery network not a buffered network. Buffering will be applied at the edge of the network. Delivery options include point-to-point microwave, point- to-multipoint microwave, multipoint to multipoint microwave also known as mesh networks, free-space optics, fibre, cable and copper. Many markets are growing at a rate where traditional fibre or copper backhaul cannot be deployed fast enough. Point-to-point or point-to-multipoint microwave or free-space optic links are alternative options. These offer deployment time scale advantage and easy through- life reconfigurability but have different optimum fiscal- and energy-efficiency thresholds that are dependent on the technology and topology used and the characteristics of the offered traffic. In addition to the offered traffic mix, the trade off points for each option will be determined by network density, local geography, the mix between urban and rural coverage and local economic and business model considerations. The assumption is that future peak and average throughput requirements can be met either by more aggressive deployment of higher-order modulation schemes into existing bands and/or by implementing links in unlicensed or lightly licensed spectrum at 60, 70 and 80 GHz. 13.2 Microwave-Link Economics Microwave-link economics and the choice of channel bandwidth and modulation schemes are also influenced directly and indirectly by spectral allocation and regulatory policy. A typical licensed spectrum product offer from a vendor such as Ericsson includes options at 6, 8, 11, 1