Currently Used Terminology in Global Routing Operations
draft-ietf-grow-routing-ops-terms-01

Global Routing Operations                                      T. Fiebig
Internet-Draft                                                   MPI-INF
Intended status: Informational                                W. Tremmel
Expires: 10 April 2026                                            DE-CIX
                                                          7 October 2025

        Currently Used Terminology in Global Routing Operations
                  draft-ietf-grow-routing-ops-terms-01

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
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 10 April 2026.

Copyright Notice

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   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.

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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 . . . . . . . . . . . . . . . . .   8
     4.3.  Routing Terms . . . . . . . . . . . . . . . . . . . . . .  10
     4.4.  Security Terms  . . . . . . . . . . . . . . . . . . . . .  12
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

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 acronyms are commonly used in the context of global
   routing operations:

   ACL:
      Access Control List

   ASN:
      Autonomous System Number

   CE:
      Customer Edge Router

   DFZ:
      Default Free Zone

   GRT:
      Global Routing Table

   IRR:
      Internet Routing Registry

   IXP:
      Internet Exchange Point

   LIR:
      Local Internet Registry

   NIR:
      National Internet Registry

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   RIR:
      Regional Internet Registry

   NLRI:
      Network Layer Reachability Information

   OTC:
      Only To Customer BGP Attribute

   P:
      Provider Router

   PE:
      Provider Edge Router

   PMTUD:
      Path MTU Discovery

   uRPF:
      Unicast Reverse Path Forwarding

   VRF:
      Virtual Routing and Forwarding

   RPKI:
      Resource Public Key Infrastructure

   ROA:
      Route Origin Authorization

   ROV:
      Route Origin Validation

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.

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   Autonomous System:
      A connected group of one or more IP prefixes run by one or more
      network operators which has a SINGLE and CLEARLY DEFINED routing
      policy.

   Autonomous System Number:
      A 32-bit number uniquely identifying an Autonomous System.

   AS Confederation Identifier:
      {is according to [RFC5065] an externally visible autonomous system
      number that identifies a BGP confederation as a whole.

   Bidirectional Forwarding Detection:
      BFD is a protocol to check if a configured neighbor is alive.  For
      this packets are sent quite rapidly between two systems (rapidly
      means in the 100ms time range), if no packets are received from
      the neighbor for a given time, the neighbor is considered to be no
      longer reachable which is then signaled to other protocols like
      BGP.  BFD is defined in [RFC5880], its application on IPv4 and
      IPv6 is defined in [RFC5881].  [RFC5882] is about the general
      application of BFD and [RFC5883] describes BFD on multihop paths.}

   BGP Path Attribute:
      BGP update messages for prefixes contain not only the AS-Path but
      also other attributes.  BGP Path Attributes fall into four
      different categories: well-known mandatory, well-known
      discretionary, optional transitive, optional non-transitive.

   Well-known mandatory BGP Path Attribute:
      A BGP Path Attribute that needs to be understood by all BGP
      implementations and must be included in all NLRI.

   Well-known discretionary BGP Path Attribute:
      A BGP Path Attribute that needs to be understood by all BGP
      implementations but is not required to be included in NLRI.

   Optional transitive BGP Path Attribute:
      Optional transitive BGP Path Attributes are not required to be
      present in NLRI, do not have to be understood by all
      implementations, but should remain in BGP messages and should
      forwarded to other BGP speakers, even if their semantics are not
      understood by an implementation.

   Optional non-transitive BGP Path Attribute:
      Optional non-transitive BGP Path Attributes are similar to
      Optional transitive BGP Path Attributes, but must not be included
      in NLRI send to external BGP speakers.

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   Enhanced Interior Gateway Routing Protocol:
      EIGRP is a IGP defined by Cisco in the 1980s to distribute routing
      information within a network.  It was later openly specified in
      [RFC7868].

   Exterior Gateway Protocol:
      EGP was a predecessor to BGP.  First defined 1982 in [RFC827] it
      became obsolete once BGP was widely used (around 1994).
      Additionally, as a general term, it is used for protocols used to
      exchange routing information between ASes.  In that meaning, BGP
      is currently the only EGP.

   Interior Gateway Protocol:
      An IGP is a protocol running inside an Autonomous System to
      distribute the IP addresses of router interfaces.

   IS-IS:
      The Intermediate System to Intermediate System protocol is an IGP
      running directly on top of layer 2.  It is used to distribute
      interface addresses within a network

   Local Internet Registry:
      An LIR is an organzation/company which receives IP address
      resources or Autonomous System Numbers as an allocation from a
      Regional Internet Registry and assigns these resources to end
      users.

   Open Shortest Path First:
      OSPF is a link state routing protocol.  It is used as an IGP.

   Regional Internet Registry:
      An RIR is an entity responsible for allocating IP addresses and AS
      numbers to NIRs and LIRs.  At the moment, currently, the five RIRs
      are Afrinic, APNIC, ARIN, LACNIC, and RIPE NCC, each being
      responsible for a different region.

   Routing Information Protocol:
      RIP is an old and by now obsolete protocol which was used to
      distribute routing information.  RIP is no longer in use

   RIPE:
      Is shorthand for Réseaux IP Européens, which is the community of
      network operators in the RIPE NCC's service region.  See also RIPE
      NCC.

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   RIPE NCC:
      The RIPE NCC, sometimes also just called the NCC, is the RIR for
      75 countries spanning Europe, parts of central Asia, and the
      Middle East.

   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.

   Customer Edge (CE) Router:
      Router at the customer's premises, may be connected to PE routers.

   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.

   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 carry default routes.

   Round Trip Time:
      The Round Tripe TIme between two hosts is the time measured in
      seconds or milliseconds it takes from sending out a packet until
      receiving a reply.

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   TCP:
      The Transmission Control Protocol is part of the TCP/IP protocol
      stack.  It is a connection oriented protocol taking care that
      everything which is sent is also received.

   MD5:
      MD5 is a by now obsolete hashing algorithm, used to generate a
      checksum on given data.  However, it is still regularly used to
      secure BGP sessions, even though it should be replaced by now.

   Time To Live:
      The TTL is a counter in the IP header which is decreased every
      time a packet is forwarded by a router.  If this counter hits
      zero, the packet is discarded and an ICMP Time Exceeded message is
      sent back to the originator of the packet.

4.2.  Neighbor Relation Terms

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

   AS Confederation:
      According to [RFC5065] a collection of autonomous systems
      represented and advertised as a single AS number to BGP speakers
      that are not members of the local BGP confederation.

   ICMP:
      Internet Control Message Protocol - this protocol is used to
      signal errors when forwarding packets.

   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.

   Network edge:
      Last routers under the control of an operator connected to routers
      of other networks.

   Mutual Transit:
      When two directly connected ASes both advertise a BGP fulltable to
      each other.  (See: [I-D.ietf-sidrops-aspa-verification])

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   Upstream Provider / Transit Provider:
      In a direct relationship between two ASes the one announcing
      either the full BGP routing table to the other or allowing the
      otherto point a default route to itself.  (See: [RFC9234], also
      known as the provider in a customer-provider relationship.)

   Downstream Customer:
      In a direct relationship between two ASes the one receiving a full
      BGP from the other or pointing a default route to the other.
      (See: [RFC9234], also known as the customer 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

   Provider (P) Router:
      A router with the core of a provider's network, usually implying
      the use of MPLS within the provider's network.  Connected to other
      P and PE routers.

   Provider Edge (PE) Router:
      Like Network Edge, usually implying the use of MPLS within the
      provider's network.  Connected to other PE, P, and CE routers.

   Providing Transit:
      Forwarding packets destined for addresses in an advertised prefix,
      while advertising a full BGP table or default route to the
      neighbor.

   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:
      Inserting a prefix with an empty AS-Path into the BGP table of an
      operator.  Once the prefix gets announced to neighboring ASes, the
      AS of the originating operator is added.

   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.

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   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.

   Route Reflector:
      A Route Reflector is an iBGP speaker which sends all prefixes it
      receives out to its Route Reflector Clients.  It is a central
      component for network designs that do not use a full mesh for iBGP
      speakers.

   Route Reflector Client:
      A Route Reflector CLient an iBGP speaking node with usually only
      one iBGP connection to a Route Reflector.

   Default Route:
      The default route is a route which covers every destination for
      which there is no specific route in the routing table.  The
      destination of the default-route is often called the default
      destination or the gateway of last resort.

   Blackholing:
      As a general term, blackholing refers to packets silently being
      dropped, i.e., without the sender being notified via an ICMP or
      ICMP6 message.  For the additional meaning in the context of
      network security, please see below.

   Multi Exit Discriminator:
      MED is a metric in BGP which is used to signal neighbor to which
      an AS has multiple links via which path inbound traffic for a
      prefix is preferred.

   Local Preference:
      The local preference is the first evaluated BGP Attribute in best
      path selection selection process when comparing multiple NLRI for
      the same prefix.  It is an integer value, and NLRI with a higher
      local preference will be preferred.  It is redistributed via iBGP
      inside an Autonomous System}

   Router:
      Generally a term for a system forwarding network traffic on Layer
      3.  In the context of BGP, this usually refers to a BGP speaker.

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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.

   ROA:
      Route Origin Authorization - a cryptographically signed record in
      the RPKI which defines how a prefix can be announced, it defines
      the originating Autonomous System and the maximum prefix length.

   RPKI:
      Resource Public Key Infrastructure is a framework of certificates
      and ROA which enables resource holders to cryptographically prove
      that a resource is theirs and to define how it can be announced
      via BGP.

   RPKI validator:
      An RPKI validator is a piece of software that fetches RPKI
      certificates and ROAs from from RPKI publication points, checks
      the signatures of the certificates and ROAs.

   RTR Protocol
      The RPKI to Router Protocol is used to communicate a validator's
      view on the RPKI to routers, providing and maintaining a list of

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      certified prefixes and their allowed originating AS numbers.  RTR
      may be an independent daemon, or can also be integrated in an RPKI
      validator.

   DDOS:
      A distributed denial of service (DDOS) attack is an attack against
      a system via the Internet.  The attacker uses multiple (sometimes
      millions of) network sources to send more traffic towards the
      attacked system than it can handle.  Collateral damage is quite
      often the network infrastructure to which the attacked system is
      connected to.

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, 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

   [RFC827]   Rosen, E., "Exterior Gateway Protocol (EGP)", RFC 827,
              DOI 10.17487/RFC0827, October 1982,
              <https://www.rfc-editor.org/info/rfc827>.

   [RFC5065]  Traina, P., McPherson, D., and J. Scudder, "Autonomous
              System Confederations for BGP", RFC 5065,
              DOI 10.17487/RFC5065, August 2007,
              <https://www.rfc-editor.org/info/rfc5065>.

   [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
              <https://www.rfc-editor.org/info/rfc5880>.

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   [RFC5881]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
              DOI 10.17487/RFC5881, June 2010,
              <https://www.rfc-editor.org/info/rfc5881>.

   [RFC5882]  Katz, D. and D. Ward, "Generic Application of
              Bidirectional Forwarding Detection (BFD)", RFC 5882,
              DOI 10.17487/RFC5882, June 2010,
              <https://www.rfc-editor.org/info/rfc5882>.

   [RFC5883]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD) for Multihop Paths", RFC 5883, DOI 10.17487/RFC5883,
              June 2010, <https://www.rfc-editor.org/info/rfc5883>.

   [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>.

   [RFC7868]  Savage, D., Ng, J., Moore, S., Slice, D., Paluch, P., and
              R. White, "Cisco's Enhanced Interior Gateway Routing
              Protocol (EIGRP)", RFC 7868, DOI 10.17487/RFC7868, May
              2016, <https://www.rfc-editor.org/info/rfc7868>.

   [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-23, 23 September 2025,
              <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

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   *  Jeff Haas

   *  Nick Hilliard

   *  Geng Nan

   *  Martin Pels

   *  Job Snijders

   *  Berislav Todorovic

   *  Maximilian Wilhelm

   *  Emile Aben

Authors' Addresses

   Tobias Fiebig
   Max-Planck-Institut fuer Informatik
   Campus E14
   66123 Saarbruecken
   Germany
   Phone: +49 681 9325 3527
   Email: tfiebig@mpi-inf.mpg.de

   Wolfgang Tremmel
   DE-CIX Management GmbH
   Lindleystr. 12
   60314 Frankfurt
   Germany
   Phone: +49 69 1730 902 0
   Email: wolfgang.tremmel@de-cix.net

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