Application-Layer Traffic Optimization (ALTO) Deployment Considerations
RFC 7971

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Internet Engineering Task Force (IETF)                    M. Stiemerling
Request for Comments: 7971                          Hochschule Darmstadt
Category: Informational                                        S. Kiesel
ISSN: 2070-1721                                  University of Stuttgart
                                                               M. Scharf
                                                                   Nokia
                                                               H. Seidel
                                                                  BENOCS
                                                              S. Previdi
                                                                   Cisco
                                                            October 2016

Application-Layer Traffic Optimization (ALTO) Deployment Considerations

Abstract

   Many Internet applications are used to access resources such as
   pieces of information or server processes that are available in
   several equivalent replicas on different hosts.  This includes, but
   is not limited to, peer-to-peer file sharing applications.  The goal
   of Application-Layer Traffic Optimization (ALTO) is to provide
   guidance to applications that have to select one or several hosts
   from a set of candidates capable of providing a desired resource.
   This memo discusses deployment-related issues of ALTO.  It addresses
   different use cases of ALTO such as peer-to-peer file sharing and
   Content Delivery Networks (CDNs) and presents corresponding examples.
   The document also includes recommendations for network administrators
   and application designers planning to deploy ALTO, such as
   recommendations on how to generate ALTO map information.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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 7841.

   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/rfc7971.

Stiemerling, et al.           Informational                     [Page 1]
RFC 7971             ALTO Deployment Considerations         October 2016

Copyright Notice

   Copyright (c) 2016 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
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   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................4
   2. General Considerations ..........................................4
      2.1. ALTO Entities ..............................................4
           2.1.1. Baseline Scenario ...................................4
           2.1.2. Placement of ALTO Entities ..........................6
      2.2. Classification of Deployment Scenarios .....................8
           2.2.1. Roles in ALTO Deployments ...........................8
           2.2.2. Information Exposure ...............................11
           2.2.3. More-Advanced Deployments ..........................12
   3. Deployment Considerations by ISPs ..............................15
      3.1. Objectives for the Guidance to Applications ...............15
           3.1.1. General Objectives for Traffic Optimization ........15
           3.1.2. Inter-Network Traffic Localization .................16
           3.1.3. Intra-Network Traffic Localization .................17
           3.1.4. Network Offloading .................................18
           3.1.5. Application Tuning .................................19
      3.2. Provisioning of ALTO Topology Data ........................20
           3.2.1. High-Level Process and Requirements ................20
           3.2.2. Data Collection from Data Sources ..................21
           3.2.3. Partitioning and Grouping of IP Address Ranges .....24
           3.2.4. Rating Criteria and/or Cost Calculation ............25
      3.3. ALTO Focus and Scope ......................................29
           3.3.1. Limitations of Using ALTO beyond Design