ALTO Performance Cost Metrics
ALTO Working Group Q. Wu
Intended status: Standards Track Y. Yang
Expires: January 13, 2021 Yale University
Nokia Bell Labs
July 12, 2020
ALTO Performance Cost Metrics
Cost metric is a basic concept in Application-Layer Traffic
Optimization (ALTO), and is used in basic ALTO services including
both the cost map service and the endpoint cost service.
Different applications may use different cost metrics, but the ALTO
base protocol [RFC7285] defines only a single cost metric, i.e., the
generic "routingcost" metric; see Sec. 14.2 of [RFC7285]. Hence, if
the ALTO client of an application wants to issue a cost map or an
endpoint cost request to determine the resource provider that offers
better delay performance (i.e., low-delay) to a resource consumer,
the base protocol does not define the cost metric to be used.
This document addresses the issue by introducing network performance
metrics, including network delay, jitter, packet loss rate, hop
count, and bandwidth. The ALTO server may derive and aggregate such
performance metrics from routing protocols such as BGP-LS, OSPF-TE
and ISIS-TE, or from end-to-end traffic management tools, and then
expose the information to allow applications to determine "where" to
connect based on network performance criteria.
There are multiple sources to derive the performance metrics. For
example, whether the metric reported is an estimation based on
measurements or it is a service-level agreement (SLA) can define the
meaning of the performance metric. Hence, an application may need
additional contextual information beyond the metric value. This
document introduces an additional "cost-context" field to the ALTO
"cost-type" field to convey such information.
Wu, et al. Expires January 13, 2021 [Page 1]
Internet-Draft ALTO Performance Cost Metrics July 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Performance Metric Attributes . . . . . . . . . . . . . . . . 5
2.1. Performance Metric Context: cost-context . . . . . . . . 6
2.2. Performance Metric Statistics . . . . . . . . . . . . . . 8
3. Packet Performance Metrics . . . . . . . . . . . . . . . . . 9
3.1. Cost Metric: One-Way Delay (delay-ow) . . . . . . . . . . 9
3.1.1. Base Identifier . . . . . . . . . . . . . . . . . . . 10
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