Internet-Draft BGP TERMS October 2024
Fiebig Expires 5 April 2025 [Page]
Workgroup:
Global Routing Operations
Internet-Draft:
draft-fiebig-grow-routing-ops-terms-02
Published:
Intended Status:
Informational
Expires:
Author:
T. Fiebig
MPI-INF

Currently Used Terminology in Global Routing Operations

Abstract

Operating the global routing ecosystem entails a divers set of interacting components, while operational practice evolved over time. In that time, terms emerged, disappeared, and sometimes changed their meaning.

To aid operators and implementers in reading contemporary drafts, this document provides an overview of terms and abbreviations used in the global routing operations community. The document explicitly does not serve as an authoritative source of correct terminology, but instead strives to provide an overview of practice.

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 5 April 2025.

1. Introduction

The practical operation of the global routing ecosystem entails a divers set of interacting components, while operational practice evolved over time. In that time, terms emerged, disappeared, and sometimes changed their meaning.

To aid operators and implementers in reading contemporary drafts, this document provides an overview of terms and abbreviations used in the global routing operations community.

1.1. Providing input on the draft:

While this draft is being edited, you may provide suggestions for additional abbreviations and terms to be included at:

https://files.measurement.network/apps/forms/s/CMXjrtCPD8QyG6CAWmSLmg4y

1.2. 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.

2. Scope of the Document

This document is explicitly descriptive, i.e., provides a collection of terms that are currently being used along with the context and definitions with which their use was observed. It is not an authoritative source of terminology, and only provides a snapshot of how certain terms have been used at the time of publication. As such, any terms and summaries in this document are subject to change.

3. Acronyms

The following acronymes are commonly used in the context of global routing operations:

ACL:
Access Control List
ASN:
Autonomous System Number
DFZ:
Default Free Zone
GRT:
Global Routing Table
IRR:
Internet Routing Registry
IXP:
Internet Exchange Point
LIR:
Local Internet Registry
NIR:
National Internet Registry
RIR:
Regional Internet Registry
NLRI:
Network Layer Reachability Information
OTC:
Only To Customer BGP Attribute
PMTUD:
Path MTU Discovery
uRPF:
Unicast Reverse Path Forwarding

4. Used Terminology by Topic

This section describes terms used in the context of global routing operations, grouped by topic. Terms may have a different meaning depending on the context in which they are used. Hence, terms may appear in multiple subsections with different descriptions..

4.1. General Terms

This section describes general terms used in the context of global routing operations, regardless of context.

Operator:
Individual, group of people, or organizational unit responsible for operating BGP speakers, i.e., making administrative changes, as well as defining and setting policies for all BGP speakers within an organization.
Router:
In this document, router always refers to a BGP speaker.
Global Routing Table:
The set of all routes for an address family that have been announced to external BGP Neighbors.
Route Selection:
The process when a BGP speaker applies the locally configured policy to select the best route from multiple available options according to that policy.
Network Layer Reachability Information:
General description for network reachability information. In the context of BGP, this usually refers to the complete set of information (prefix, next-hop, attributes, etc.) contained in a BGP update message.
Default Free Zone:
Part of the Internet where routers do not cary default routes.

4.2. Neighbor Relation Terms

This section lists terms used to describe relationships between different ASes.

Cone:
The set of ASes who are either direct downstreams of an AS, or in the cone of any of those ASes; Depending on the context this also includes the joint set of prefixes that may be originated by ASes in a cone.
Downstream:
In a direct relationship between two ASes the one receiving upstream from the other. (See: [RFC9234], also known as the customer in a customer-provider relationship.)
Mutual Transit:
When two directly connected ASes both advertise a BGP fulltable to each other. (See: [I-D.ietf-sidrops-aspa-verification])
Upstream:
In a direct relationship between two ASes the one providing upstream to the other. (See: [RFC9234], also known as the provider in a customer-provider relationship.)
Peer:
Two directly connected ASes who only advertise routes they originate or learned from their downstreams to each other. (See: [RFC9234])
Providing Transit:
Forwarding packets destined for addresses in an advertised prefix, while advertising a full BGP table or default route to the neighbor.
Providing Upstream:
See: Providing Transit
Depeering:
Removing sessions with a neighboring AS.
Neighbor:
An AS to which an established BGP session exists.

4.3. Routing Terms

This section describes terms specific to technical aspects of routing.

BGP Speaker:
A device exchanging routes with other BGP speakers using the BGP protocol
Full Table:
A routing table containing a route to all prefixes in the GRT but not the default route.
Exporting a Prefix:
Advertising a prefix to a neighbor.
Importing a Prefix:
Accepting a prefix advertised by a neighbor and considering it for route selection and import into the local AS' routing table.
Network edge:
Last routers under the control of an operator.
Originating a Prefix:
Anouncing a prefix with an empty AS-Path.
Propagating a Prefix:
Announcing a prefix with an non-empty AS-Path including other ASes than the announcing AS.
BGP Neighbor:
Also just 'Neighbor'. Two BGP speakers that exchange NLRI using the BGP protocol are neighbors.
Peer:
A BGP neighbor, if not used to describe a relationship.
Prepending:
Inserting an ASes into the AS_PATH multiple times to influence route selection.
Traffic Engineering:
Making changes to properties of imported and exported NLRI to influence route selection, and thereby the flow of traffic.
Converging:
Used to describe the process of a BGP speaker evaluating all routes and finding the preferred route for each visible prefix. Reconverging is often also used to describe an ongoing selection process reevaluating all routes sent by neighbors, e.g., after a loss of connectivity to one or multiple neighbors.

4.4. Security Terms

This section describes terms used in the context of routing security.

Route Flapping:
A route that is constantly announced and widthdrawn or otherwise sees constant change.
BGP Hijack / Route Hijack:
When an AS announces a route it is not authorized to announce with the intent of intercepting traffic towards the authorized origin.
Route Leak:
When an AS announces a route it is not authorized to announce without malicious intent.
Update Storm:
A continuous high volume stream of BGP Updates send to one or multiple neighbors.
Cascading Update Storm:
When an update storm traverses beyond directly connected neighbors.
Blackholing:
Announcing prefixes grouped by a specific community to inform all neighbors observing the announcement that traffic to the destination should be dropped.

5. IANA Considerations

This document does not require any IANA actions.

6. Security Considerations

This document describes currently used terminology and does not make recommendations. As such, it does not have security considerations.

7. References

7.1. Normative References

[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.

7.2. Informative References

[RFC7454]
Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454, , <https://www.rfc-editor.org/info/rfc7454>.
[RFC9234]
Azimov, A., Bogomazov, E., Bush, R., Patel, K., and K. Sriram, "Route Leak Prevention and Detection Using Roles in UPDATE and OPEN Messages", RFC 9234, DOI 10.17487/RFC9234, , <https://www.rfc-editor.org/info/rfc9234>.
[I-D.ietf-sidrops-aspa-verification]
Azimov, A., Bogomazov, E., Bush, R., Patel, K., Snijders, J., and K. Sriram, "BGP AS_PATH Verification Based on Autonomous System Provider Authorization (ASPA) Objects", Work in Progress, Internet-Draft, draft-ietf-sidrops-aspa-verification-17, , <https://datatracker.ietf.org/doc/html/draft-ietf-sidrops-aspa-verification-17>.

Acknowledgements

This document is based on [RFC7454] and we thank the original authors for their work.

We thank the following people for reviewing this draft and suggesting changes:

  • Gert Doerring
  • Jeff Haas
  • Nick Hilliard
  • Geng Nan
  • Martin Pels
  • Job Snijders
  • Berislav Todorovic

Author's Address

Tobias Fiebig
Max-Planck-Institut fuer Informatik
Campus E14
66123 Saarbruecken
Germany