BGP Maximum Prefix Limits
draft-sa-grow-maxprefix-02

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Global Routing Operations                                    J. Snijders
Internet-Draft                                        NTT Communications
Intended status: Standards Track                              M. Aelmans
Expires: September 9, 2019                              Juniper Networks
                                                           March 8, 2019

                       BGP Maximum Prefix Limits
                       draft-sa-grow-maxprefix-02

Abstract

   This document describes mechanisms to limit the negative impact of
   route leaks [RFC7908] and/or resource exhaustion in BGP [RFC4271]
   implementations.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 9, 2019.

Copyright Notice

   Copyright (c) 2019 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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   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Inbound Maximum Prefix Limits . . . . . . . . . . . . . . . .   2
     2.1.  Type A: Pre-Policy Inbound Maximum Prefix Limits  . . . .   3
     2.2.  Type B: Post-Policy Inbound Maximum Prefix Limits . . . .   3
   3.  Outbound Maximum Prefix Limits  . . . . . . . . . . . . . . .   3
   4.  Considerations for Operations with Multi-Protocol BGP . . . .   4
   5.  Considerations for soft thresholds  . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   5
   9.  Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION   5
   10. Appendix: Implementation Guidance . . . . . . . . . . . . . .   6
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     11.2.  Informative References . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   This document describes mechanisms to reduce the negative impact of
   certain types of misconfigurations and/or resource exhaustions in BGP
   [RFC4271] operations.  While [RFC4271] already described a method to
   tear down BGP sessions when certain thresholds are exceeded, some
   nuances in this specification were missing resulting in
   inconsistencies between BGP implementations.  In addition to
   clarifying "inbound maximum prefix limits", this document also
   introduces a specification for "outbound maximum prefix limits".

2.  Inbound Maximum Prefix Limits

   An operator MAY configure a BGP speaker to terminate its BGP session
   with a neighbor when the number of address prefixes received from
   that neighbor exceeds a locally configured upper limit.  The BGP
   speaker then MUST send the neighbor a NOTIFICATION message with the
   Error Code Cease and the Error Subcode "Threshold reached: Maximum
   Number of Prefixes Received", and MAY support other actions.
   Reporting when thresholds have been exceeded is an implementation
   specific consideration, but SHOULD include methods such as Syslog

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