The present disclosure generally pertains to systems and methods for providing service admission control in telecommunication networks. In one exemplary embodiment, a system comprises a network access control (SAC) element that is coupled to at least one node of a network segment. The SAC element communicates with each network node within the network segment to discover its configuration and capacity. The SAC element also stores information indicative of performance requirements, such as terms of SLAs pertaining to traffic that passes through the network segment. When a new service is to be added, the SAC element receives information indicative of the new service and its requirements, such as the SLA terms for the new service. The SAC element then automatically determines whether the network segment has sufficient capacity to add the new service without violating the SLAs of any of the services using the network segment. The SAC element then provides an output indicating whether the new service can be so added. Accordingly, the SAC element can be used to ensure SLA compliance.