Global Routing Operations T. Fiebig
Internet-Draft MPI-INF
Intended status: Informational 2 October 2024
Expires: 5 April 2025
Currently Used Terminology in Global Routing Operations
draft-fiebig-grow-routing-ops-terms-02
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
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This Internet-Draft will expire on 5 April 2025.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Providing input on the draft: . . . . . . . . . . . . . . 2
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Scope of the Document . . . . . . . . . . . . . . . . . . . . 3
3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Used Terminology by Topic . . . . . . . . . . . . . . . . . . 4
4.1. General Terms . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Neighbor Relation Terms . . . . . . . . . . . . . . . . . 5
4.3. Routing Terms . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Security Terms . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
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
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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
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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.
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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.
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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.
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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
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<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,
May 2017, <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,
February 2015, <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, May 2022,
<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, 29 August 2023,
<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
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* Job Snijders
* Berislav Todorovic
Author's Address
Tobias Fiebig
Max-Planck-Institut fuer Informatik
Campus E14
66123 Saarbruecken
Germany
Phone: +49 681 9325 3527
Email: tfiebig@mpi-inf.mpg.de
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