 network. However, a SP MPLS network should be considered a more secure network. A basic assumption for most cus- tomers is that a SP-provided MPLS network should be less vulnerable to a hacker snoop- ing packets or sending inappropriate ping messages, then the customers own network. This requirement for a secure IP network infrastructure is inherent for any SP that wants to offer a high-quality SIP trunking solution. In summary, a SP should ensure that it has a high-quality, reliable, and secure basic IP network infrastructure with low packet loss, jitter, and delay to deliver a high-quality SIP trunk solution. SIP trunks that act as replacements for TDM trunks have an expected "five nines" reliability, and SIP trunks used for enhanced services, such as video, have even more susceptibility to impairments than basic voice-only networks. SP Network-Customer Premise Equipment As SPs look to offer SIP trunks as a replacement service for TDM trunks, an important component can be lost. This component is the mandatory requirement for a physical con- nection at the customer premise. The ability for an SP to offer a SIP trunk service without any equipment physically at the customer premise has both a positive effect and a nega- tive effect. The positive effect is that the SP can deploy a service with less capital. As a result, this can lead to improved profitability; however, the negative effect is that without a physical presence at the customer, the capability to troubleshoot and determine quality on the customer premise, which existed in TDM networks, is lost without some type of CPE. Generally, CPE refers to physical hardware that is mandated, managed, and owned by the SP and enables it to monitor and control the experience down to the customer premise. The expectation is that any issue that occurs beyond the boundary of the CPE is an issue that the customer is responsible for, and any issue that occurs at the CPE or at any device owned by the SP is an issue the SP is responsible for. The type, complexity, and featur