LOOPS (Localized Optimizations on Path Segments) Problem Statement and Opportunities for Network-Assisted Performance Enhancement
draft-li-tsvwg-loops-problem-opportunities-03

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TSVWG                                                              Y. Li
Internet-Draft                                                   X. Zhou
Intended status: Informational                                    Huawei
Expires: January 8, 2020                                    M. Boucadair
                                                                  Orange
                                                                 J. Wang
                                                           China Telecom
                                                           July 07, 2019

 LOOPS (Localized Optimizations on Path Segments) Problem Statement and
       Opportunities for Network-Assisted Performance Enhancement
             draft-li-tsvwg-loops-problem-opportunities-03

Abstract

   In various network deployments, end to end forwarding paths are
   partitioned into multiple segments.  For example, in some cloud-based
   WAN communications, stitching multiple overlay tunnels are used for
   traffic policy enforcement matters such as to optimize traffic
   distribution or to select paths exposing a lower latency.  Likewise,
   in satellite communications, the communication path is decomposed
   into two terrestrial segments and a satellite segment.  Such long-
   haul paths are naturally composed of multiple network segments with
   various encapsulation schemes.  Packet loss may show different
   characteristics on different segments.

   Traditional transport protocols (e.g., TCP) 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.
   Non-congestive loss may make the TCP sender over-reduce the sending
   rate unnecessarily.  With the increase of end-to-end transport
   encryption (e.g., QUIC), traditional PEP (performance enhancing
   proxy) techniques such as TCP splitting are no longer applicable.

   LOOPS (Local Optimizations on Path Segments) is a network-assisted
   performance enhancement over path segment and it aims to provide
   local in-network recovery to achieve better data delivery by making
   packet loss recovery faster and by avoiding the senders over-reducing
   their sending rate.  In an overlay network scenario, LOOPS can be
   performed over a variety of the existing, or purposely created,
   tunnel-based path segments.

Li, et al.               Expires January 8, 2020                [Page 1]
Internet-Draft        LOOPS Problem & opportunities            July 2019

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  The Problem . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Sketching a Work Direction: Rationale & Goals . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
   3.  Cloud-Internet Overlay Network  . . . . . . . . . . . . . . .   7
     3.1.  Tail Loss or Loss in Short Flows  . . . . . . . . . . . .   9
     3.2.  Packet Loss in Real Time Media Streams  . . . . . . . . .   9
     3.3.  Packet Loss and Congestion Control in Bulk Data Transfer   10
     3.4.  Multipathing  . . . . . . . . . . . . . . . . . . . . . .  10
   4.  Satellite Communication . . . . . . . . . . . . . . . . . . .  11
   5.  Branch Office WAN Connection  . . . . . . . . . . . . . . . .  13
   6.  Features and Impacts to be Considered for LOOPS . . . . . . .  14
     6.1.  Local Recovery and End-to-end Retransmission  . . . . . .  15
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