LOOPS Generic Information Set
draft-welzl-loops-gen-info-04
TSVWG M. Welzl
Internet-Draft University of Oslo
Intended status: Standards Track C. Bormann, Ed.
Expires: 14 January 2021 Universität Bremen TZI
13 July 2020
LOOPS Generic Information Set
draft-welzl-loops-gen-info-04
Abstract
LOOPS (Local Optimizations on Path Segments) aims to provide local
(not end-to-end but in-network) recovery of lost packets to achieve
better data delivery in the presence of losses.
[I-D.li-tsvwg-loops-problem-opportunities] provides an overview over
the problems and optimization opportunities that LOOPS could address.
The present document is a strawman for the set of information that
would be interchanged in a LOOPS protocol, without already defining a
specific data packet format.
The generic information set needs to be mapped to a specific
encapsulation protocol to actually run the LOOPS optimizations. A
companion document contains a sketch of a binding to the tunnel
encapsulation protocol Geneve [I-D.ietf-nvo3-geneve].
Status of This Memo
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Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
Welzl & Bormann Expires 14 January 2021 [Page 1]
Internet-Draft LOOPS July 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
2. Challenges . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1. No Access to End-to-End Transport Information . . . . . . 6
2.2. Path Asymmetry . . . . . . . . . . . . . . . . . . . . . 6
2.3. Reordering vs. Spurious Retransmission . . . . . . . . . 6
2.4. Informing the End-to-End Transport . . . . . . . . . . . 7
3. Simplifying assumptions . . . . . . . . . . . . . . . . . . . 8
4. LOOPS Architecture . . . . . . . . . . . . . . . . . . . . . 9
5. LOOPS Generic Information Set . . . . . . . . . . . . . . . . 10
5.1. Setup Information . . . . . . . . . . . . . . . . . . . . 10
5.2. Forward Information . . . . . . . . . . . . . . . . . . . 10
5.3. Reverse Information . . . . . . . . . . . . . . . . . . . 11
6. LOOPS General Operation . . . . . . . . . . . . . . . . . . . 12
6.1. Initial Packet Sequence Number . . . . . . . . . . . . . 12
6.1.1. Minimizing collisions . . . . . . . . . . . . . . . . 12
6.1.2. Optional Initial PSN procedure . . . . . . . . . . . 12
6.2. Acknowledgement Generation . . . . . . . . . . . . . . . 13
6.3. Measurement . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.1. Ingress-relative timestamps . . . . . . . . . . . . . 14
6.3.2. ACK generation . . . . . . . . . . . . . . . . . . . 15
6.4. Loss detection and Recovery . . . . . . . . . . . . . . . 15
6.4.1. Local Retransmission . . . . . . . . . . . . . . . . 15
6.4.2. FEC . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.5. Discussion . . . . . . . . . . . . . . . . . . . . . . . 16
7. Sketches of Bindings to Tunnel Protocols . . . . . . . . . . 16
7.1. Embedding LOOPS in Geneve . . . . . . . . . . . . . . . . 17
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
9. Security Considerations . . . . . . . . . . . . . . . . . . . 17
9.1. Threat model . . . . . . . . . . . . . . . . . . . . . . 17
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