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