Enhanced AS Loop Detection for BGP
draft-chen-grow-enhanced-as-loop-detection-03

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Last updated 2019-11-04
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Network Working Group                                            H. Chen
Internet-Draft                                             China Telecom
Intended status: Best Current Practice                             D. Ma
Expires: May 7, 2020                                                ZDNS
                                                                   Y. Gu
                                                               S. Zhuang
                                                                 H. Wang
                                                                  Huawei
                                                        November 4, 2019

                   Enhanced AS Loop Detection for BGP
             draft-chen-grow-enhanced-as-loop-detection-03

Abstract

   Misconfiguration and malicious manipulation of BGP AS_Path may lead
   to route hijack.  This document proposes to enhance the BGP Inbound/
   Outbound route processing in the case of detecting an AS loop.  Two
   options are proposed for the enhancement, a) a local check at the
   device; b) data collection/analysis at the remote network controller/
   server.  Both approaches are beneficial for route hijack detection.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

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

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   This Internet-Draft will expire on May 7, 2020.

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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
   (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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Forged AS_PATH Examples . . . . . . . . . . . . . . . . . . .   3
     3.1.  AS Loop Detected at Inbound Processing  . . . . . . . . .   3
     3.2.  AS Loop Detected at Outbound Processing . . . . . . . . .   4
   4.  Enhancement to BGP Inbound/Outbound Processing  . . . . . . .   5
     4.1.  Enhancement for AS Loop Detected at Inbound Process . . .   5
     4.2.  Enhancement for AS Loop Detected at Outbound Process  . .   5
   5.  BMP extension for AS Loop Detection . . . . . . . . . . . . .   6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The Border Gateway Protocol (BGP) [RFC4271], as an inter-Autonomous
   (AS) routing protocol, is used to exchange network reachability
   information between BGP systems.  As a distance-vector based
   protocol, special mechanism is designed for BGP to avoid routing
   loop.  As stated in Section 9.1.2. of RFC4271:

      ...

      If the AS_PATH attribute of a BGP route contains an AS loop, the
      BGP route should be excluded from the Phase 2 decision function.
      AS loop detection is done by scanning the full AS path (as
      specified in the AS_PATH attribute), and checking that the
      autonomous system number of the local system does not appear in
      the AS path.  Operations of a BGP speaker that is configured to

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      accept routes with its own autonomous system number in the AS path
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