A Survey on Research on the Application-Layer Traffic Optimization (ALTO) Problem
RFC 6029
Internet Research Task Force (IRTF) I. Rimac
Request for Comments: 6029 V. Hilt
Category: Informational M. Tomsu
ISSN: 2070-1721 V. Gurbani
Bell Labs, Alcatel-Lucent
E. Marocco
Telecom Italia
October 2010
A Survey on Research on
the Application-Layer Traffic Optimization (ALTO) Problem
Abstract
A significant part of the Internet traffic today is generated by
peer-to-peer (P2P) applications used originally for file sharing, and
more recently for real-time communications and live media streaming.
Such applications discover a route to each other through an overlay
network with little knowledge of the underlying network topology. As
a result, they may choose peers based on information deduced from
empirical measurements, which can lead to suboptimal choices. This
document, a product of the P2P Research Group, presents a survey of
existing literature on discovering and using network topology
information for Application-Layer Traffic Optimization.
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 Research Task Force
(IRTF). The IRTF publishes the results of Internet-related research
and development activities. These results might not be suitable for
deployment. This RFC represents the consensus of the Peer-to-Peer
Research Group of the Internet Research Task Force (IRTF). Documents
approved for publication by the IRSG are not a candidate for any
level of Internet Standard; see Section 2 of RFC 5741.
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/rfc6029.
Rimac, et al. Informational [Page 1]
RFC 6029 ALTO Survey October 2010
Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Survey of Existing Literature . . . . . . . . . . . . . . . . 4
2.1. Application-Level Topology Estimation . . . . . . . . . . 5
2.2. Topology Estimation through Layer Cooperation . . . . . . 8
2.2.1. P4P Architecture . . . . . . . . . . . . . . . . . . . 9
2.2.2. Oracle-Based ISP-P2P Collaboration . . . . . . . . . . 9
2.2.3. ISP-Driven Informed Path Selection (IDIPS) Service . . 10
3. Application-Level Topology Estimation and the ALTO Problem . . 10
4. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1. Coordinate Estimation or Path Latencies? . . . . . . . . . 12
4.2. Malicious Nodes . . . . . . . . . . . . . . . . . . . . . 12
4.3. Information Integrity . . . . . . . . . . . . . . . . . . 12
4.4. Richness of Topological Information . . . . . . . . . . . 13
4.5. Hybrid Solutions . . . . . . . . . . . . . . . . . . . . . 13
4.6. Negative Impact of Over-Localization . . . . . . . . . . . 13
5. Security Considerations . . . . . . . . . . . . . . . . . . . 14
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
7. Informative References . . . . . . . . . . . . . . . . . . . . 14
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RFC 6029 ALTO Survey October 2010
1. Introduction
A significant part of today's Internet traffic is generated by peer-
to-peer (P2P) applications, used originally for file sharing, and
more recently for real-time multimedia communications and live media
streaming. P2P applications pose serious challenges to the Internet
infrastructure; by some estimates, P2P systems are so popular that
they make up anywhere between 40% and 85% of the entire Internet
traffic [Karagiannis], [LightReading], [LinuxReviews], [Parker],
[Glasner].
P2P systems ensure that popular content is replicated at multiple
instances in the overlay. But perhaps ironically, a peer searching
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