LOOPS (Localized Optimization of Path Segments) Problem Statement and Opportunities
draft-li-tsvwg-loops-problem-opportunities-01

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TSVWG                                                              Y. Li
Internet-Draft                                                   X. Zhou
Intended status: Informational                                    Huawei
Expires: September 12, 2019                               March 11, 2019

 LOOPS (Localized Optimization of Path Segments) Problem Statement and
                             Opportunities
             draft-li-tsvwg-loops-problem-opportunities-01

Abstract

   Various overlay tunnels are used in networks including WAN,
   enterprise campus and others.  End to end paths are partitioned into
   multiple segments using overlay tunnels to achieve better path
   selection, lower latency and so on.  Traditional end-to-end transport
   layers respond to packet loss slowly especially in long-haul
   networks: They either wait for some signal from the receiver to
   indicate a loss and then retransmit from the sender or rely on
   sender's timeout which is often quite long.

   LOOPS (Localized Optimization of Path Segments) attempts to provide
   non end-to-end local based in-network recovery to achieve better data
   delivery by making packet loss recovery faster.  In an overlay
   network scenario, LOOPS can be performed over the existing, or
   purposely created, overlay tunnel based path segments.

   This document illustrates the slow packet loss recovery problems
   LOOPS tries to solve in some use cases and analyzes the impacts when
   local in-network recovery is employed as a LOOPS mechanism.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on September 12, 2019.

Li & Zhou              Expires September 12, 2019               [Page 1]
Internet-Draft        LOOPS Problem & opportunities           March 2019

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Cloud-Internet Overlay Network  . . . . . . . . . . . . . . .   5
     2.1.  Tail Loss or Loss in Short Flows  . . . . . . . . . . . .   7
     2.2.  Packet Loss in Real Time Media Streams  . . . . . . . . .   7
     2.3.  Packet Loss and Congestion Control in Bulk Data Transfer    8
     2.4.  Multipathing  . . . . . . . . . . . . . . . . . . . . . .   8
   3.  Features and Impacts to be Considered for LOOPS . . . . . . .   9
     3.1.  Local Recovery and End-to-end Retransmission  . . . . . .  10
       3.1.1.  OE to OE Measurement, Recovery and Multipathing . . .  12
     3.2.  Congestion Control Interaction  . . . . . . . . . . . . .  12
     3.3.  Overlay Protocol Extensions . . . . . . . . . . . . . . .  14
     3.4.  Summary . . . . . . . . . . . . . . . . . . . . . . . . .  14
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   6.  Informative References  . . . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  17

1.  Introduction

   Overlay tunnels are widely deployed for various networks, including
   long haul WAN interconnection, enterprise wireless access networks,
   etc.  The end to end connection is partitioned into multiple path
   segments using overlay tunnels.  This serves a number of purposes,
   for instance, selecting a better path over the WAN or delivering the
   packets over heterogeneous network, such as enterprise access and
   core networks.

   A reliable transport layer normally employs some end-to-end
   retransmission mechanisms which also address congestion control
   [RFC0793] [RFC5681].  The sender either waits for the receiver to
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