Generic Connection Admission Control (GCAC) Algorithm Specification for IP/MPLS Networks

This document presents a generic connection admission control (GCAC) reference model and algorithm for IP-/MPLS-based networks. Service provider (SP) IP/MPLS networks need an MPLS GCAC mechanism, as one motivational example, to reject Voice over IP (VoIP) calls when additional calls would adversely affect calls already in progress. Without MPLS GCAC, connections on congested links will suffer degraded quality. The MPLS GCAC algorithm can be optionally implemented in vendor equipment and deployed by service providers. MPLS GCAC interoperates between vendor equipment and across multiple service provider domains. The MPLS GCAC algorithm uses available standard mechanisms for MPLS-based networks, such as RSVP, Diffservaware MPLS Traffic Engineering (DS-TE), Path Computation Element (PCE), Next Steps in Signaling (NSIS), Diffserv, and OSPF. The MPLS GCAC algorithm does not include aspects of CAC that might be considered vendor proprietary implementations, such as detailed path selection mechanisms. MPLS GCAC functions are implemented in a distributed manner to deliver the objective Quality of Service (QoS) for specified QoS constraints. The objective is that the source is able to compute a source route with high likelihood that via-elements along the selected path will in fact admit the request. In some cases (e.g., multiple Autonomous Systems (ASes)), this objective cannot always be met, but this document summarizes methods that partially meet this objective. MPLS GCAC is applicable to any service or flow that must meet an objective QoS (delay, jitter, packet loss rate) for a specified quantity of traffic. Ash & McDysan Experimental [Page 1] RFC 6601 GCAC Algorithm for IP/MPLS Networks April 2012 Status of This Memo This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation. This document defines an Experimental Protocol for the Internet community. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6601.