Most large enterprises buy telecom services from multiple service providers even when the bulk of their telecom spending is on managed services or is outsourced. The main reasons for multi-sourcing telecom services are: 1) to benchmark and lower telecom costs, and 2) to reduce risk. This multi-sourced environment has led the majority of enterprises towards a mixed approach to telecom services vendor management (VM): vendor management is centralized at the corporate level for international network and telecom services and distributed to the local business units for local access and telephony services. The biggest challenges with respect to managing multiple telecom services providers relate to establishing clear service responsibility boundaries and getting consistent billing and SLA reporting. Key to successful, effective, multivendor telecom vendor management are relationship-oriented practices that foster good communication and mutual respect.