Multi-Cost Application-Layer Traffic Optimization (ALTO)
RFC 8189
Internet Engineering Task Force (IETF) S. Randriamasy
Request for Comments: 8189 W. Roome
Category: Standards Track Nokia Bell Labs
ISSN: 2070-1721 N. Schwan
Thales Deutschland
October 2017
Multi-Cost Application-Layer Traffic Optimization (ALTO)
Abstract
The Application-Layer Traffic Optimization (ALTO) protocol, specified
in RFC 7285, defines several services that return various metrics
describing the costs between network endpoints.
This document defines a new service that allows an ALTO Client to
retrieve several cost metrics in a single request for an ALTO
filtered cost map and endpoint cost map. In addition, it extends the
constraints to further filter those maps by allowing an ALTO Client
to specify a logical combination of tests on several cost metrics.
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
https://www.rfc-editor.org/info/rfc8189.
Randriamasy, et al. Standards Track [Page 1]
RFC 8189 Multi-Cost ALTO October 2017
Copyright Notice
Copyright (c) 2017 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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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.
Randriamasy, et al. Standards Track [Page 2]
RFC 8189 Multi-Cost ALTO October 2017
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Overview Of Approach . . . . . . . . . . . . . . . . . . . . 6
3.1. Multi-Cost Data Format . . . . . . . . . . . . . . . . . 6
3.2. Compatibility with Legacy ALTO Clients . . . . . . . . . 7
3.3. Filtered Multi-Cost Map Resources . . . . . . . . . . . . 7
3.4. Endpoint Cost Service Resources . . . . . . . . . . . . . 8
3.5. Full Cost Map Resources . . . . . . . . . . . . . . . . . 8
3.6. Extended Constraint Tests . . . . . . . . . . . . . . . . 8
3.6.1. Extended Constraint Predicates . . . . . . . . . . . 9
3.6.2. Extended Logical Combination of Predicates . . . . . 9
3.6.3. Testable Cost Types in Constraints . . . . . . . . . 9
3.6.4. Testable Cost Type Names in IRD Capabilities . . . . 10
3.6.5. Legacy ALTO Client Issues . . . . . . . . . . . . . . 10
4. Protocol Extensions for Multi-Cost ALTO Transactions . . . . 12
4.1. Filtered Cost Map Extensions . . . . . . . . . . . . . . 12
4.1.1. Capabilities . . . . . . . . . . . . . . . . . . . . 13
4.1.2. Accept Input Parameters . . . . . . . . . . . . . . . 14
4.1.3. Response . . . . . . . . . . . . . . . . . . . . . . 17
4.2. Endpoint Cost Service Extensions . . . . . . . . . . . . 17
4.2.1. Capabilities . . . . . . . . . . . . . . . . . . . . 17
4.2.2. Accept Input Parameters . . . . . . . . . . . . . . . 18
4.2.3. Response . . . . . . . . . . . . . . . . . . . . . . 19
5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.1. Information Resource Directory . . . . . . . . . . . . . 19
5.2. Multi-Cost Filtered Cost Map: Example #1 . . . . . . . . 21
5.3. Multi-Cost Filtered Cost Map: Example #2 . . . . . . . . 23
5.4. Multi-Cost Filtered Cost Map: Example #3 . . . . . . . . 24
5.5. Multi-Cost Filtered Cost Map: Example #4 . . . . . . . . 25
5.6. Endpoint Cost Service . . . . . . . . . . . . . . . . . . 26
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
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