runk offering: Determine what SP SIP trunk offerings are available. Determine the exact capabilities and terms each SP SIP trunk offering includes. Determine how your network interacts or interconnects with the SP network. At the moment, SIP trunk offerings vary considerably more than PRI offerings; therefore, they require careful evaluation. It is good practice to do a side-by-side comparison of your existing PRI offering to the features that would be available on a SIP trunk. These will not be equal, but they will give you the information to decide what features are most important and what you can live without. During the evaluation of a SIP Trunk offering step, work through the following activities and address each one to the satisfaction of your organization's expectations: Assess SIP trunk provider offerings. Determine the availability of TDM-equivalent features. Determine geographic coverage. Assess DID porting realities. Determine call load balancing and failover routing. Determine emergency call handling. Determine the physical delivery of the SIP trunk. Chapter 11: Deployment Steps and Best Practices 249 Determine network demarcation. Agree on monitoring and troubleshooting procedures. Assess SIP Trunk Provider Offerings Approach SPs with offerings in your geographical area and, based on their responses, rank the top one or two providers to engage in the next round of discussions. Finally, select the top contender (or sometimes two contenders for larger enterprises that require either redundancy or alternate least-cost options for their traffic). Chapter 9 details Request for Proposal (RFP) type questions to use to evaluate an SPs offering. Use this information as a guide to draw up your own list of questions to evalu- ate different offerings. Determine the Availability of TDM-Equivalent Features At this time in the industry, you cannot assume that SIP trunks offer the exact same fea- tures as you would expect on a PRI, even though current SIP trunk offerings are market- ed primarily as PSTN replacement 