uch as the power industry. This chapter examines the main issues that need to be addressed when using a packet-based transport to carry a timing signal across a wide-area network (WAN). In most cases, this means using some form of PTP to carry that signal, although there are other packet-based techniques that are covered. This chapter is where all the theory from the previous chapters comes together SO that you can see how to design and implement a timing solution using the transport network. This chapter is not spe- cific to the mobile or 5G use case, and the lessons largely apply to any deployment with similar characteristics and performance targets. "Chapter 11. 5G Timing Solutions", covers the more specific aspects of the 4G and 5G synchroniz- ation deployments, but the basic tenets are covered here first. In some areas where there is repetition between the mobile and non-mobile case, this chapter may refer to more details in other chapters (especially Chapter 11). Some portions of this chapter are more quantitative, but others are much more qualitative. If the mathematics is not important to you, then feel free to breeze over it-you should not feel it will pre- vent you from being able to successfully deploy a timing transport network. 9.1 Deployment and Usage This chapter deals with the aspects of designing a network to carry timing using a packet-based method. Mostly this means using some form of PTP, although there are also other packet-based methods that can carry frequency, phase, and time. For the case of phase/time, this chapter focuses on PTP, but it covers other options to carry frequency via packets. The engineer should consider the options available to deploy a timing solution as summarized in Table 9-1. The section "Solution Options" in Chapter 11 covers the trade-offs between these options in a little more detail and details the advantages of each (in a mobile setting). Table 9-1 Timing Methods for Different Synchronization Types Method Frequency- PhaseSync TimeSync Precision time protocol (1588