ALTO Performance Cost Metrics
Huawei
Yale University
Huawei
Huawei
Nokia Bell Labs
Cost metric is a basic concept in Application-Layer Traffic Optimization (ALTO), and is used in basic services including both the cost map service and the endpoint cost service. Different applications may use different cost metrics, but the ALTO base protocol documents only one single cost metric, i.e., the generic "routingcost" metric; see Sec. 14.2 of ALTO base specification [RFC7285]. Hence, if the resource consumer of an application prefers a resource provider that offers low-delay delivery to the resource consumer, the base protocol does not define the cost metric to be used. ALTO cost metrics can be generic metrics and this document focuses on network performance metrics, including network delay, jitter, packet loss, hop count, and bandwidth. These metrics can be derived and aggregated from routing protocols with different granularity and scope, such as BGP-LS, OSPF-TE and ISIS-TE, or from end-to-end traffic management tools. These metrics may then be exposed by an ALTO Server to allow applications to determine "where" to connect based on network performance criteria. Additional cost metrics may be documented in other documents.