results on which to base your production serv- ice decision. It is recommended that this time is at least 3 months. 254 SIP Trunking Install and Configure the Service Work with your selected SP to install the physical delivery and CPE for the SIP trunk. Do the configuration changes on your call agent and border element to enable a test call capability to and from the SIP trunk. Ensure that monitoring tools and capabilities are turned on to determine the outcome of the tests that are to follow. Define a Clear Test Plan and Execute the Test Plan Write an explicit test plan for the capabilities and services that you expect the SIP trunk to perform correctly before live calls from your pilot community can be placed on the trunk. A suggested outline of such a test plan is provided in the following list: Circuit acceptance test cases SP Layer 2 connection SP Layer 3 connection SP reachability and routing Connectivity test cases Registration sequence Session refresh Basic outbound/inbound call completion Management access Call accounting Voice quality Stability and duration Restart SIP application (call flow) test cases Caller ID Codec negotiation Call hold/resume Call forward to voice mail Call forward back to the PSTN Call transfer Single number reach Chapter 11: Deployment Steps and Best Practices 255 Call modifications due to mobility features Ad-hoc conference IVR interaction FAX, Mode, TTY Emergency/911 Call types (local, long distance, international) Monitoring and failover test cases SIP trunk monitoring and alerting on overload or failure Layers 1, 2, 3, 4 failover scenarios Execute the test plan and address any issues that arise. Make the necessary configuration changes. Make troubleshooting changes to determine where the fault lies. It is often good practice to collect IP call traces of working call flows. This might reduce debugging time later during production service if call behavior changes or problems crop up. After a satisfactorily working setup is reached, document the configurations of your call agent