Currently Used Terminology in Global Routing Operations
draft-fiebig-grow-routing-ops-terms-03
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Tobias Fiebig , Wolfgang Tremmel | ||
| Last updated | 2024-10-11 | ||
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draft-fiebig-grow-routing-ops-terms-03
Global Routing Operations T. Fiebig
Internet-Draft MPI-INF
Intended status: Informational W. Tremmel
Expires: 14 April 2025 DE-CIX
11 October 2024
Currently Used Terminology in Global Routing Operations
draft-fiebig-grow-routing-ops-terms-03
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 14 April 2025.
Copyright Notice
Copyright (c) 2024 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.
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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 Revised BSD License text as
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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 . . . . . . . . . . . . . . . . . . . . . . 9
4.4. Security Terms . . . . . . . . . . . . . . . . . . . . . 11
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 European, Russian, and Middle Eastern
region. See also RIPE NCC.
RIPE NCC:
The RIPE NCC, sometimes also just called the NCC, is the RIR for
the European, Russian, and Middle Eastern region.
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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.
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.
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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])
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.)
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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.
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
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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.
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.
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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.
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.
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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
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
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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>.
[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>.
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[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-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
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* Martin Pels
* Job Snijders
* Berislav Todorovic
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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