This document describes the use of the Common Open Policy Service (COPS) protocol for supporting Service Level Specification (SLS) negotiation. The [SLS-FRW-TEQ] document has presented the need of a Service Level Specification (SLS). Different works [SLS-TEQ], [SLS- AQU], [SLS-INTER] have defined some SLSs for CPE-PE interface and inter-domain QoS negotiation. The COPS protocol [COPS] has been defined by the IETF Resource Allocation Protocol (RAP) WG [RAP] and will be used in this memo to communicate SLS information from the client to the network provider.