Application-Layer Traffic Optimization (ALTO) Cost Calendar
RFC 8896

Document Type RFC - Proposed Standard (November 2020; No errata)
Authors Sabine Randriamasy  , Y. Yang  , Qin Wu  , Deng Lingli  , Nico Schwan 
Last updated 2020-11-06
Replaces draft-randriamasy-alto-cost-calendar
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Stream WG state Submitted to IESG for Publication (wg milestone: Jul 2020 - Submit cost property... )
Document shepherd Vijay Gurbani
Shepherd write-up Show (last changed 2020-01-24)
IESG IESG state RFC 8896 (Proposed Standard)
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Consensus Boilerplate Yes
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Responsible AD Mirja K├╝hlewind
Send notices to Vijay Gurbani <>
IANA IANA review state Version Changed - Review Needed
IANA action state No IANA Actions

Internet Engineering Task Force (IETF)                    S. Randriamasy
Request for Comments: 8896                               Nokia Bell Labs
Category: Standards Track                                        Y. Yang
ISSN: 2070-1721                                          Yale University
                                                                   Q. Wu
                                                                 L. Deng
                                                            China Mobile
                                                               N. Schwan
                                                      Thales Deutschland
                                                           November 2020

      Application-Layer Traffic Optimization (ALTO) Cost Calendar


   This document is an extension to the base Application-Layer Traffic
   Optimization (ALTO) protocol.  It extends the ALTO cost information
   service so that applications decide not only 'where' to connect but
   also 'when'.  This is useful for applications that need to perform
   bulk data transfer and would like to schedule these transfers during
   an off-peak hour, for example.  This extension introduces the ALTO
   Cost Calendar with which an ALTO Server exposes ALTO cost values in
   JSON arrays where each value corresponds to a given time interval.
   The time intervals, as well as other Calendar attributes, are
   specified in the Information Resources Directory and ALTO Server

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
     1.1.  Some Recent Known Uses
     1.2.  Terminology
   2.  Requirements Language
   3.  Overview of ALTO Cost Calendars and Terminology
     3.1.  ALTO Cost Calendar Overview
     3.2.  ALTO Cost Calendar Information Features
     3.3.  ALTO Calendar Design Characteristics
       3.3.1.  ALTO Cost Calendar for All Cost Modes
       3.3.2.  Compatibility with Legacy ALTO Clients
   4.  ALTO Calendar Specification: IRD Extensions
     4.1.  Calendar Attributes in the IRD Resource Capabilities
     4.2.  Calendars in a Delegate IRD
     4.3.  Example IRD with ALTO Cost Calendars
   5.  ALTO Calendar Specification: Service Information Resources
     5.1.  Calendar Extensions for Filtered Cost Maps (FCM)
       5.1.1.  Calendar Extensions in Filtered Cost Map Requests
       5.1.2.  Calendar Extensions in Filtered Cost Map Responses
       5.1.3.  Use Case and Example: FCM with a Bandwidth Calendar
     5.2.  Calendar Extensions in the Endpoint Cost Service
       5.2.1.  Calendar-Specific Input in Endpoint Cost Requests
       5.2.2.  Calendar Attributes in the Endpoint Cost Response
       5.2.3.  Use Case and Example: ECS with a routingcost Calendar
       5.2.4.  Use Case and Example: ECS with a Multi-cost Calendar
               for routingcost and owdelay
   6.  IANA Considerations
   7.  Security Considerations
   8.  Operational Considerations
   9.  References
     9.1.  Normative References
     9.2.  Informative References
   Authors' Addresses

1.  Introduction

   The base Application-Layer Traffic Optimization (ALTO) protocol
   specified in [RFC7285] provides guidance to overlay applications that
   need to select one or several hosts from a set of candidates able to
   provide a desired resource.  This guidance is based on parameters
   that affect performance and efficiency of the data transmission
   between the hosts, such as the topological distance.  The goal of
   ALTO is to improve the Quality of Experience (QoE) in the application
   while optimizing resource usage in the underlying network
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