for your timing network, the next section discusses the procurement of equipment and the request for proposal process. 12.2 Writing a Request for Proposal This section covers the process behind soliciting, selecting, and procuring the equipment needed to build a timing network. The mechanism that most businesses and operators utilize is some form of the request for proposal (RFP), whereby the buyer puts together a description of the current situ- ation and desired outcome, and vendors are invited to propose a comprehensive solution. The re- sponse to the RFP created by the vendor covers both commercial and technical aspects, with the technical part covering system performance and features. Normally, as part of the solicitation, the buyer supplies a detailed list of requirements posed as a series of questions asking the vendors' level of support for numerous features. The details of these RFP requirements range widely from a couple of sheets of paper to many thousands of detailed questions. The timing subset of an RFP requirements list can also vary from a few general questions to many hundreds, digging into every possible aspect of the proposed solution. Normally, these requirements are then classified as "mandatory," "optional," or "informational" as an indication of how much value the buyer places on that specific feature or behavior. The vendor then indicates its support for that requirement by providing an answer such as "Compliant," "Par- tially compliant," "Future roadmap," or "Not compliant." The conditions of some RFPs state that even a single "Not compliant" answer to a mandatory requirement eliminates the whole proposal without any future consideration! It should be obvious from the preceding section that timing is not just a software solution. The char- acteristics of a clock, especially performance, are mostly driven by the hardware. The selection of components such as the oscillator, PLL, and PHY is critically important. Equally, the timestamping accuracy, signal asymmetry, media type, environmental 