urately gather realistic feedback from the pilot participants. Most pilot implementations are typically more than one month in duration. Ensure that you have well-defined method to provide feedback on the quality and issues with a SIP trunk from the end-user community. Note both the reproducible issues, such as the inability to call to specific numbers, and the transient issues, such as low quality audio on a specific phone call. Both reproducible and transient issues are important to understand the quality of a specific SP. Implement an outgoing calling method via the use of a special dial pattern. For example, have end users dial an 8 in front of PSTN numbers, instead of the tradi- tional 9 when making outbound calls using the trial SIP trunk. This ensures end users of both a backup method of calling via TDM if the SIP trunk fails and an easy way to compare the call quality and experience of calls made from a SIP trunk ver- sus those made from a TDM trunk. Add incoming calling numbers before porting existing numbers. Adding an incoming number and having these ring at existing or new phones helps to isolate any issues with the pilot from issues with the production system. Port DID numbers of support staff as a method to ensure that the porting process occurs smoothly and is well understood and documented. Porting DID numbers of Chapter 3: Transitioning to SIP Trunks 37 all the participants in the pilot should eventually be undertaken, but this can be a long process and should be planned to not affect mission-critical work if porting of numbers is delayed. Test various types of calls, by calling various locations and systems, including International locations: Ask what cadence of ring-back tone is heard and what type of caller ID is displayed. Different international mobile and international land lines should be called to effectively test the provided SIP trunk service. Compare issues to when calling via a TDM trunk to the same number. Cellular phones: Ask the called party if a distinct difference exists between 