Neighbor Cache Entries on First-Hop Routers: Operational Considerations
draft-linkova-v6ops-nd-cache-init-01

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v6ops                                                         J. Linkova
Internet-Draft                                                    Google
Intended status: Informational                              July 5, 2019
Expires: January 6, 2020

Neighbor Cache Entries on First-Hop Routers: Operational Considerations
                  draft-linkova-v6ops-nd-cache-init-01

Abstract

   Neighbor Discovery (RFC4861) is used by IPv6 nodes to determine the
   link-layer addresses of neighboring nodes as well as to discover and
   maintain reachability information.  This document discusses how the
   neighbor discovery state machine on a first-hop router is causing
   user-visible connectivity issues when a new (not being seen on the
   network before) IPv6 address is being used.

Status of This Memo

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   This Internet-Draft will expire on January 6, 2020.

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   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Linkova                  Expires January 6, 2020                [Page 1]
Internet-DraNeighbor Cache Entries on First-Hop Routers: Oper  July 2019

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Potential Solutions . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  Do Nothing  . . . . . . . . . . . . . . . . . . . . . . .   5
       2.1.1.  Pros  . . . . . . . . . . . . . . . . . . . . . . . .   5
       2.1.2.  Cons  . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.2.  Change to the Registration-Based Neighbor Discovery . . .   5
     2.3.  Hosts Explicitly Advertizing Their GUAs Using Existing ND
           Mechanisms  . . . . . . . . . . . . . . . . . . . . . . .   6
       2.3.1.  Host Sending Unsolicited NA . . . . . . . . . . . . .   6
         2.3.1.1.  Pros  . . . . . . . . . . . . . . . . . . . . . .   7
         2.3.1.2.  Cons  . . . . . . . . . . . . . . . . . . . . . .   7
       2.3.2.  Host Sending NS to the Router Address from Its GUA  .   7
         2.3.2.1.  Pros  . . . . . . . . . . . . . . . . . . . . . .   7
         2.3.2.2.  Cons  . . . . . . . . . . . . . . . . . . . . . .   7
       2.3.3.  Host Sending Router Solicitation from its GUA . . . .   8
         2.3.3.1.  Pros  . . . . . . . . . . . . . . . . . . . . . .   8
         2.3.3.2.  Cons  . . . . . . . . . . . . . . . . . . . . . .   8
     2.4.  Initiating Hosts2Routers Communication  . . . . . . . . .   8
       2.4.1.  Pros  . . . . . . . . . . . . . . . . . . . . . . . .   9
       2.4.2.  Cons  . . . . . . . . . . . . . . . . . . . . . . . .   9
     2.5.  Tweaking Probing Algorithms . . . . . . . . . . . . . . .   9
     2.6.  Routers Buffering More Packets  . . . . . . . . . . . . .   9
       2.6.1.  Pros  . . . . . . . . . . . . . . . . . . . . . . . .  10
       2.6.2.  Cons  . . . . . . . . . . . . . . . . . . . . . . . .  10
   3.  Recommendations . . . . . . . . . . . . . . . . . . . . . . .  10
     3.1.  Avoiding Disruption . . . . . . . . . . . . . . . . . . .  10
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   The section 7.2.5 of [RFC4861] states: "When a valid Neighbor