Critical Capabilities for U.S. Wireline Telecom Services is a research document that evaluates major U.S. network service providers (NSPs) based on seven critical capabilities for wireline voice and data services. Execution and quality of service have become key differentiators as pricing becomes more consistent. Providers are starting to offer Ethernet services in response to demand, but offerings remain immature. The document provides recommendations for network managers to focus on tier 1 providers for full service bundles or tier 2 for select capabilities and better customer support.