Internet DRAFT - draft-ietf-grow-yang-bgp-communities
draft-ietf-grow-yang-bgp-communities
Network Working Group M. Pels
Internet-Draft RIPE NCC
Intended status: Informational 22 February 2024
Expires: 25 August 2024
YANG Module for BGP Communities
draft-ietf-grow-yang-bgp-communities-01
Abstract
This document defines a YANG data model for the structured
specification of BGP communities. The model provides operators with
a way to publish their locally defined BGP communities in a
standardised format.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 25 August 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Tree view . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Data elements . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. The "serial" leaf . . . . . . . . . . . . . . . . . . . . 6
5.2. The "uri" leaf . . . . . . . . . . . . . . . . . . . . . 6
5.3. The "description" leaf . . . . . . . . . . . . . . . . . 6
5.4. The "contacturl" leaf . . . . . . . . . . . . . . . . . . 6
5.5. The "contacts" list . . . . . . . . . . . . . . . . . . . 6
5.5.1. The "emailaddress" leaf . . . . . . . . . . . . . . . 6
5.5.2. The "name" leaf . . . . . . . . . . . . . . . . . . . 6
5.5.3. The "role" leaf . . . . . . . . . . . . . . . . . . . 7
5.5.4. The "organization" leaf . . . . . . . . . . . . . . . 7
5.5.5. The "organizationalunit" leaf . . . . . . . . . . . . 7
5.6. The "regular" list . . . . . . . . . . . . . . . . . . . 7
5.6.1. The "name" leaf . . . . . . . . . . . . . . . . . . . 7
5.6.2. The "category" leaf . . . . . . . . . . . . . . . . . 7
5.6.3. The "description" leaf . . . . . . . . . . . . . . . 7
5.6.4. The "globaladmin" leaf . . . . . . . . . . . . . . . 7
5.6.5. The "localadmin" container . . . . . . . . . . . . . 8
5.7. The "extended" list . . . . . . . . . . . . . . . . . . . 9
5.7.1. The "name" leaf . . . . . . . . . . . . . . . . . . . 9
5.7.2. The "category" leaf . . . . . . . . . . . . . . . . . 9
5.7.3. The "description" leaf . . . . . . . . . . . . . . . 9
5.7.4. The "type" leaf . . . . . . . . . . . . . . . . . . . 9
5.7.5. The "subtype" leaf . . . . . . . . . . . . . . . . . 9
5.7.6. The "asn" leaf . . . . . . . . . . . . . . . . . . . 10
5.7.7. The "asn4" leaf . . . . . . . . . . . . . . . . . . . 10
5.7.8. The "localadmin" container . . . . . . . . . . . . . 10
5.8. The "large" list . . . . . . . . . . . . . . . . . . . . 10
5.8.1. The "name" leaf . . . . . . . . . . . . . . . . . . . 10
5.8.2. The "category" leaf . . . . . . . . . . . . . . . . . 11
5.8.3. The "description" leaf . . . . . . . . . . . . . . . 11
5.8.4. The "globaladmin" leaf . . . . . . . . . . . . . . . 11
5.8.5. The "localdatapart1" container . . . . . . . . . . . 11
5.8.6. The "localdatapart2" container . . . . . . . . . . . 12
6. Type definitions . . . . . . . . . . . . . . . . . . . . . . 12
6.1. The "two-octet-as-number" data type . . . . . . . . . . . 12
6.2. The "community-name" data type . . . . . . . . . . . . . 12
6.3. The "community-category" data type . . . . . . . . . . . 12
6.4. The "community-description" data type . . . . . . . . . . 12
6.5. The "localadmin-format" data type . . . . . . . . . . . . 13
6.6. The "field-name" data type . . . . . . . . . . . . . . . 13
6.7. The "field-pattern" data type . . . . . . . . . . . . . . 13
6.8. The "field-description" data type . . . . . . . . . . . . 13
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7. Operational guidelines . . . . . . . . . . . . . . . . . . . 13
7.1. Publishing guidelines . . . . . . . . . . . . . . . . . . 13
7.2. Parsing guidelines . . . . . . . . . . . . . . . . . . . 13
8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 14
8.1. YANG Namespace Registration . . . . . . . . . . . . . . . 14
8.2. YANG Module Registration . . . . . . . . . . . . . . . . 14
8.3. YANG SID Allocation . . . . . . . . . . . . . . . . . . . 14
9. Security considerations . . . . . . . . . . . . . . . . . . . 15
10. Normative References . . . . . . . . . . . . . . . . . . . . 15
11. Informative References . . . . . . . . . . . . . . . . . . . 16
Appendix A. YANG Module . . . . . . . . . . . . . . . . . . . . 16
Appendix B. JSON Examples . . . . . . . . . . . . . . . . . . . 26
B.1. RFC8195 Selective NO_EXPORT definition . . . . . . . . . 26
B.2. RFC4384 Data Collection definition . . . . . . . . . . . 28
Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 29
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction
ISP operators use BGP communities[RFC1997][RFC4360][RFC8092] to add
information to prefix announcements or to let customers influence
routing behaviour inside the network of the ISP. Each ISP defines
for itself which BGP communities to support and how the structure of
these communities should be interpreted. This document provides a
YANG[RFC7950] module for describing the structure and meaning of BGP
communities, Extended BGP communities and Large BGP communities. ISP
operators can use this to publish their community definitions in a
standardised format.
2. Terminology
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.
3. Rationale
ISP operators may define various BGP communities that have local
significance inside of their network. These communities could be
used to add miscellaneous information to a prefix announcement. For
example, a community "64501:1:528" may signify that AS64501 is
originating a prefix from a point of presence in The Netherlands (ISO
3166-1 code 528). Alternatively, communities could be used to allow
customers of an ISP to control routing behavior of their prefixes
inside the ISP. For example, a community "64501:4:64498" attached to
a prefix advertised to AS64501 by a customer may be interpreted by
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AS64501 to mean that this prefix must not be propagated to AS64498.
For both use cases it is necessary for the ISP to communicate the
meaning of their locally defined communities to others. Currently
this is typically done by publishing a list of communities on a web
page, or as a remark inside an autnum object in the Internet Routing
Registry. This makes it cumbersome to determine if and where an ISP
publishes community information. The lack of a well-defined
structure makes it hard to develop tools for parsing community
information.
The purpose of the YANG model defined in this document is to provide
a standardized format for publishing community definitions. These
definitions help applications to interpret the structure and purpose
of BGP communities. For example, looking glasses may use the
published definitions to parse communities seen in BGP announcements
and display their meaning. Another potential use case is in
generating routing policy configurations based on community
definitions published by an upstream ASN. This could be done
automatically using external tooling to generate router
configurations, or inside a router's command-line interface by
importing the definitions and providing the CLI-user with available
choices for manual configuration.
Note that this document only describes a model for the publishing
format of community definitions. The publishing location and
publishing mechanism used are outside the scope of this
specification.
4. Tree view
The following tree diagram provides an overview of the ietf-bgp-
communities.yang data model.
module: draft-ietf-grow-yang-bgp-communities
+--rw bgp-communities
+--rw serial uint32
+--rw uri? inet:uri
+--rw description? string
+--rw contacturl? inet:uri
+--rw contacts* [emailaddress]
| +--rw emailaddress inet:email-address
| +--rw name? string
| +--rw role? string
| +--rw organization? string
| +--rw organizationalunit? string
+--rw regular* [name]
| +--rw name community-name
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| +--rw category? community-category
| +--rw description? community-description
| +--rw globaladmin two-octet-as-number
| +--rw localadmin
| +--rw format? localadmin-format
| +--rw fields* [name]
| +--rw name field-name
| +--rw length? uint8
| +--rw pattern field-pattern
| +--rw description? field-description
+--rw extended* [name]
| +--rw name community-name
| +--rw category? community-category
| +--rw description? community-description
| +--rw type uint8
| +--rw subtype uint8
| +--rw (globaladmin)
| | +--:(asn)
| | | +--rw asn? two-octet-as-number
| | +--:(asn4)
| | +--rw asn4? inet:as-number
| +--rw localadmin
| +--rw format? localadmin-format
| +--rw fields* [name]
| +--rw name field-name
| +--rw length? uint8
| +--rw pattern field-pattern
| +--rw description? field-description
+--rw large* [name]
+--rw name community-name
+--rw category? community-category
+--rw description? community-description
+--rw globaladmin inet:as-number
+--rw localdatapart1
| +--rw format? localadmin-format
| +--rw fields* [name]
| +--rw name field-name
| +--rw length? uint8
| +--rw pattern field-pattern
| +--rw description? field-description
+--rw localdatapart2
+--rw format? localadmin-format
+--rw fields* [name]
+--rw name field-name
+--rw length? uint8
+--rw pattern field-pattern
+--rw description? field-description
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Figure 1
5. Data elements
The BGP Communities YANG Module contains the elements described in
this section. The full contents of the module can be found in
Appendix A. Several elements in this module use data types from
[I-D.ietf-netmod-rfc6991-bis]. These data types are represented with
the prefix "inet".
5.1. The "serial" leaf
A required value of type "uint32", containing the version number for
the community set. This value wraps and should be compared using
sequence space arithmetic.
5.2. The "uri" leaf
An optional value of type "inet:uri", describing the publication
point for the community set.
5.3. The "description" leaf
An optional value of type "string" with a maximum length of 65535,
providing information about the specified set of communities.
5.4. The "contacturl" leaf
An optional value of type "inet:uri", describing a webpage where
maintainer contact information may be found.
5.5. The "contacts" list
A list of objects defining contact information for the maintainer(s)
of the community set. Each object contains the following elements.
5.5.1. The "emailaddress" leaf
A required value of type "inet:email-address", containing the e-mail
address of the contact.
5.5.2. The "name" leaf
An optional value of type "string" with a maximum length of 255,
containing the name of the contact.
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5.5.3. The "role" leaf
An optional value of type "string" with a maximum length of 255,
describing the role of the contact.
5.5.4. The "organization" leaf
An optional value of type "string" with a maximum length of 255,
containing the organization of the contact.
5.5.5. The "organizationalunit" leaf
An optional value of type "string" with a maximum length of 255,
containing the organizational unit of the contact.
5.6. The "regular" list
A list of objects defining Regular ([RFC1997]) BGP communities. Each
object contains the following elements.
5.6.1. The "name" leaf
A required value of type "community-name", containing the name of
this community.
The structure of the "community-name" type is defined in Section 6.2.
5.6.2. The "category" leaf
An optional value of type "community-category", containing the
category of this community.
The structure of the "community-category" type is defined in
Section 6.3.
5.6.3. The "description" leaf
An optional value of type "community-description", containing a
description of this community.
The structure of the "community-description" type is defined in
Section 6.4.
5.6.4. The "globaladmin" leaf
A required value of type "two-octet-as-number", containing the
Autonomous Sytem Number set in the Global Administrator part of this
community.
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The structure of the "two-octet-as-number" type is defined in
Section 6.1.
5.6.5. The "localadmin" container
A group of elements that describe the Local Administrator part of the
community. This object contains the following elements.
5.6.5.1. The "format" leaf
An optional value of type "localadmin-format", describing the
encoding format in which fields are to be parsed (see Section 7.2).
The structure of the "localadmin-format" type is defined in
Section 6.5. If this leaf is not defined, the default "decimal"
encoding is assumed.
5.6.5.2. The "fields" list
A list of objects that together form the Local Administrator part of
the community. The combined length values of all fields MUST NOT
exceed the maximum length of the Local Administrator part of the
community.
5.6.5.2.1. The "name" leaf
A required value of type "field-name", containing the name of the
field.
The structure of the "field-name" type is defined in Section 6.6.
5.6.5.2.2. The "length" leaf
An optional value of type "uint8", containing the length of the
field. If the expected field format (Section 5.6.5.1) is "decimal",
this is a number of digits. In case the expected field format is
"binary", this is a number of bits.
If this leaf is not defined, the length is assumed to be the maximum
allowed length of the entire field list. In this case the field list
MUST NOT contain more than one element.
5.6.5.2.3. The "pattern" leaf
A required value of type "field-pattern", containing a pattern used
for matching the field's contents.
The structure of the "field-pattern" type is defined in Section 6.7.
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5.6.5.2.4. The "description" leaf
An optional value of type "field-description", containing a
description of the pattern. This description can be used to provide
meaning to specific values for a field.
The structure of the "field-description" type is defined in
Section 6.8.
5.7. The "extended" list
A list of objects defining Extended ([RFC4360]) BGP communities.
Two-Octet and Four-Octet AS Specific communities are supported by
this specification. Each object contains the following elements.
5.7.1. The "name" leaf
A required value of type "community-name", containing the name of
this community.
The structure of the "community-name" type is defined in Section 6.2.
5.7.2. The "category" leaf
An optional value of type "community-category", containing the
category of this community.
The structure of the "community-category" type is defined in
Section 6.3.
5.7.3. The "description" leaf
An optional value of type "community-description", containing a
description of this community.
The structure of the "community-description" type is defined in
Section 6.4.
5.7.4. The "type" leaf
A required value of type "uint8", containing the high-order Type of
the community.
5.7.5. The "subtype" leaf
A required value of type "uint8", containing the low-order Sub-Type
of the community.
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5.7.6. The "asn" leaf
For Two-Octet AS Specific communities: A required value of type "two-
octet-as-number", containing the Autonomous Sytem Number set in the
Global Administrator part of this community.
The structure of the "two-octet-as-number" type is defined in
Section 6.1.
5.7.7. The "asn4" leaf
For Four-Octet AS Specific communities: A required value of type
"inet:as-number", containing the Autonomous Sytem Number set in the
Global Administrator part of this community.
5.7.8. The "localadmin" container
A group of elements that describe the Local Administrator part of the
community. This object contains the following elements.
5.7.8.1. The "format" leaf
An optional value of type "localadmin-format", describing the
encoding format in which fields are to be parsed (see Section 7.2).
The structure of the "localadmin-format" type is defined in
Section 6.5. If this leaf is not defined, the default "decimal"
encoding is assumed.
5.7.8.2. The "fields" list
A list of objects that together form the Local Administrator part of
the community. The combined length values of all fields MUST NOT
exceed the maximum length of the Local Administrator part of the
community.
The supported leafs in this list are identical to those described in
Section 5.6.5.2.
5.8. The "large" list
A list of objects defining Large ([RFC8092]) BGP communities. Each
object contains the following elements.
5.8.1. The "name" leaf
A required value of type "community-name", containing the name of
this community.
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The structure of the "community-name" type is defined in Section 6.2.
5.8.2. The "category" leaf
An optional value of type "community-category", containing the
category of this community.
The structure of the "community-category" type is defined in
Section 6.3.
5.8.3. The "description" leaf
An optional value of type "community-description", containing a
description of this community.
The structure of the "community-description" type is defined in
Section 6.4.
5.8.4. The "globaladmin" leaf
A required value of type "inet:as-number", containing the Autonomous
Sytem Number set in the Global Administrator part of this community.
5.8.5. The "localdatapart1" container
A group of elements that describe the Local Data Part 1 section of
the community. This object contains the following elements.
5.8.5.1. The "format" leaf
An optional value of type "localadmin-format", describing the
encoding format in which fields are to be parsed (see Section 7.2).
The structure of the "localadmin-format" type is defined in
Section 6.5. If this leaf is not defined, the default "decimal"
encoding is assumed.
5.8.5.2. The "fields" list
A list of objects that together form the Local Data Part 1 section of
the community. The combined length values of all fields MUST NOT
exceed the maximum length of the "Local Data Part 1" section of the
community.
The supported leafs in this list are identical to those described in
Section 5.6.5.2.
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5.8.6. The "localdatapart2" container
A group of elements that describe the Local Data Part 2 section of
the community. This object contains the following elements.
5.8.6.1. The "format" leaf
An optional value of type "localadmin-format", describing the
encoding format in which fields are to be parsed (see Section 7.2).
The structure of the "localadmin-format" type is defined in
Section 6.5. If this leaf is not defined, the default "decimal"
encoding is assumed.
5.8.6.2. The "fields" list
A list of objects that together form the Local Data Part 2 section of
the community. The combined length values of all fields MUST NOT
exceed the maximum length of the "Local Data Part 2" section of the
community.
The supported leafs in this list are identical to those described in
Section 5.6.5.2.
6. Type definitions
Several of the elements defined in Section 5 use custom data types.
These data types are defined here.
6.1. The "two-octet-as-number" data type
A Two-Octet Autonomous System Number, as defined in [RFC1930].
6.2. The "community-name" data type
A string specifying the name of a BGP community. Names may be up to
255 characters long and MUST NOT contain spaces or tabs.
6.3. The "community-category" data type
An enum specifying the category of a BGP community. Possible
categories are "informational" and "action", as described in
[RFC8195].
6.4. The "community-description" data type
A string specifying the description of a BGP community. Descriptions
may be up to 65535 characters long.
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6.5. The "localadmin-format" data type
An enum specifying the encoding for a localadmin/localdata field.
Possible encodings are "decimal" for decimal numbers and "binary" for
bit strings.
6.6. The "field-name" data type
A string specifying the name of a BGP community localadmin/localdata
field. Names may be up to 255 characters long and MUST NOT contain
spaces or tabs.
6.7. The "field-pattern" data type
A string specifying the pattern of a BGP community localadmin/
localdata field. Patterns may be up to 4095 characters long and are
described as POSIX Extended Regular Expressions (see
[IEEE.1003-2.1992], section 2.8.4).
6.8. The "field-description" data type
A string specifying the description of a BGP community localadmin/
localdata field. Descriptions may be up to 65535 characters long.
7. Operational guidelines
7.1. Publishing guidelines
Operators SHOULD only publish BGP community definitions for networks
they control. This may include communities where the Global
Administrator field contains a private ASN, if this community has a
local meaning inside the network of the publisher.
When publishing community definitions with overlapping field
patterns, these definitions MUST be ordered from most to least
preferred. This ensures parsers can perform deterministic matching
(see Section 7.2). For example, a definition for a single community
"64500:123" needs to be specified before a definition that matches a
covering range of communities "64500:*".
7.2. Parsing guidelines
A published BGP community definition can be used by parsers to
display information about a received community. If a received
community matches multiple published community definitions, the first
matching definition in the published order takes precedence.
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Parsers that use published community definitions from multiple
operators SHOULD NOT attempt to match received communities where the
Global Administrator field contains a private ASN, unless they have
some method to determine which published definition is the
authoritative one.
By default, communities are compared using the decimal representation
of the fields. If "format" for a Local Administrator or Local Data
Part is set to "binary", the fields in the received community are
converted to strings of zeros and ones before comparison.
Applications that parse these community definitions SHOULD reject
objects that do not comply with the rules described in this document.
Furthermore, parsers SHOULD check that the sum of the specified Local
Administrator or Local Data Part field lengths in each community
definition does not exceed the local part size of the specified
community type. For example, a Regular BGP community definition with
format "decimal" containing a field of length 4 and a field of length
2 would be illegal, as the Local Administrator field has a maximum
length of 65535 (5 digits).
8. IANA considerations
8.1. YANG Namespace Registration
This document registers the following XML namespace URN in the "IETF
XML Registry", following the format defined in [RFC3688]:
TODO
8.2. YANG Module Registration
This document registers the following YANG module in the "YANG Module
Names" registry [RFC6020]:
TODO
8.3. YANG SID Allocation
This document registers the following entry in the "IETF YANG SID"
registry [I-D.ietf-core-sid]:
TODO
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9. Security considerations
The YANG module described in this document may be used to specify BGP
community definitions in different encoding formats, such as XML,
JSON or CBOR. Applications that parse these community definitions
SHOULD reject objects that do not comply with the rules described in
this document. Furthermore, parsers SHOULD check that the sum of the
specified Local Administrator or Local Data Part field lengths in
each community definition does not exceed the local part size of the
specified community type.
10. Normative References
[I-D.ietf-core-sid]
Veillette, M., Pelov, A., Petrov, I., Bormann, C., and M.
Richardson, "YANG Schema Item iDentifier (YANG SID)", Work
in Progress, Internet-Draft, draft-ietf-core-sid-24, 22
December 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-core-sid-24>.
[I-D.ietf-netmod-rfc6991-bis]
Schönwälder, J., "Common YANG Data Types", Work in
Progress, Internet-Draft, draft-ietf-netmod-rfc6991-bis-
15, 23 January 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
rfc6991-bis-15>.
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System (AS)",
BCP 6, RFC 1930, DOI 10.17487/RFC1930, March 1996,
<https://www.rfc-editor.org/info/rfc1930>.
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities
Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
<https://www.rfc-editor.org/info/rfc1997>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
February 2006, <https://www.rfc-editor.org/info/rfc4360>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8092] Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas,
I., and N. Hilliard, "BGP Large Communities Attribute",
RFC 8092, DOI 10.17487/RFC8092, February 2017,
<https://www.rfc-editor.org/info/rfc8092>.
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11. Informative References
[IEEE.1003-2.1992]
Institute of Electrical and Electronics Engineers,
"Information Technology - Portable Operating System
Interface (POSIX) - Part 2: Shell and Utilities (Vol. 1)",
IEEE Standard 1003.2, IEEE 1003.2-1992, IEEE ieee-1003-2,
1992.
[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>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC4384] Meyer, D., "BGP Communities for Data Collection", BCP 114,
RFC 4384, DOI 10.17487/RFC4384, February 2006,
<https://www.rfc-editor.org/info/rfc4384>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>.
[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>.
[RFC8195] Snijders, J., Heasley, J., and M. Schmidt, "Use of BGP
Large Communities", RFC 8195, DOI 10.17487/RFC8195, June
2017, <https://www.rfc-editor.org/info/rfc8195>.
[RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
"Handling Long Lines in Content of Internet-Drafts and
RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
<https://www.rfc-editor.org/info/rfc8792>.
Appendix A. YANG Module
This section contains the complete YANG module defined in this
document.
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module draft-ietf-grow-yang-bgp-communities {
yang-version 1.1;
namespace "urn:to-be-defined";
prefix bgpcomm;
import ietf-inet-types {
prefix inet;
revision-date 2021-02-22;
reference
"draft-ietf-netmod-rfc6991-bis-15: Common YANG Data Types";
}
organization
"IETF GROW Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/grow/>
WG List: <mailto:grow@ietf.org>
Author: Martin Pels
<mailto:mpels@ripe.net>";
description
"This module describes a structure for BGP Communities";
revision "2024-02-21" {
description
"Added data types and string restrictions.
Added category leaf.";
reference
"RFC YYYY: YANG Module for BGP Communities
RFC-EDITOR: please update YYYY with this RFC ID";
}
revision "2023-08-01" {
description
"Initial version.";
reference
"draft-ietf-grow-yang-bgp-communities-00";
}
typedef two-octet-as-number {
type uint16;
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description
"This type represents autonomous system numbers, which
identify an Autonomous System (AS).
Autonomous system numbers were originally limited to 16
bits. BGP extensions have enlarged the autonomous system
number space to 32 bits. The two-octet-as-number type uses
an uint16 base type for use cases where the enlarged number
space is not supported.";
reference
"RFC 1930: Guidelines for creation, selection, and registration
of an Autonomous System (AS)";
}
typedef community-name {
type string {
length 1..255;
pattern "[^ \t\n[:cntrl:]]+";
}
description
"This type restricts values for the name of a BGP community.";
}
typedef community-category {
type enumeration {
enum informational {
value 0;
description
"Informational community";
}
enum action {
value 1;
description
"Action community";
}
}
description
"This type restricts values for the category of a BGP community.";
}
typedef community-description {
type string {
length 1..65535;
pattern "[[:print:]]+";
}
description
"This type restricts values for the description of a BGP
community.";
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}
typedef localadmin-format {
type enumeration {
enum decimal {
value 0;
description
"Decimal number string";
}
enum binary {
value 1;
description
"Bit string";
}
}
description
"This type defines the format options for a BGP community
localadmin/localdata field encoding";
}
typedef field-name {
type string {
length 1..255;
pattern "[^ \t\n[:cntrl:]]+";
}
description
"This type restricts values for the name leaf of a BGP community
localadmin/localdata field.";
}
typedef field-pattern {
type string {
length 1..4095;
pattern "[-0-9.,*?^$+|(){}\\[\\]]+";
}
description
"This type restricts values for the pattern leaf of a BGP
community localadmin/localdata field. Patterns are
described as POSIX Extended Regular Expressions";
reference
"IEEE 1003.2-1992: Information Technology - Portable
Operating System Interface (POSIX) - Part 2: Shell and
Utilities (Vol. 1)";
}
typedef field-description {
type string {
length 1..65535;
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pattern "[[:print:]]+";
}
description
"This type restricts values for the description leaf of a BGP
community localadmin/localdata field.";
}
grouping localadmin-fields {
list fields {
ordered-by user;
key "name";
leaf name {
type field-name;
mandatory true;
description
"The name of the field";
}
leaf length {
type uint8;
description
"Length of the field";
}
leaf pattern {
type field-pattern;
mandatory true;
description
"Regular Expression describing the expected contents of
the field";
}
leaf description {
type field-description;
description
"A text description of the field contents";
}
}
}
container bgp-communities {
leaf serial {
type uint32;
mandatory true;
description
"Version number of the community set";
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}
leaf uri {
type inet:uri;
description
"Publication point for the community set";
}
leaf description {
type string {
length 1..65535;
pattern "[[:print:]]+";
}
description
"A description for the community set";
}
leaf contacturl {
type inet:uri;
description
"A reference to a webpage with maintainer contact information";
}
list contacts {
key "emailaddress";
leaf emailaddress {
type inet:email-address;
description
"Maintainer contact e-mail address";
}
leaf name {
type string {
length 1..255;
pattern "[[:print:]]+";
}
description
"Maintainer contact name";
}
leaf role {
type string {
length 1..255;
pattern "[[:print:]]+";
}
description
"Maintainer contact role";
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}
leaf organization {
type string {
length 1..255;
pattern "[[:print:]]+";
}
description
"Maintainer contact organization";
}
leaf organizationalunit {
type string {
length 1..255;
pattern "[[:print:]]+";
}
description
"Maintainer contact organizational unit";
}
}
list regular {
key "name";
leaf name {
type community-name;
mandatory true;
description
"Community name";
}
leaf category {
type community-category;
description
"Category of the community";
}
leaf description {
type community-description;
description
"Description for the community";
}
leaf globaladmin {
type two-octet-as-number;
mandatory true;
description
"Global Administrator field";
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}
container localadmin {
leaf format {
type localadmin-format;
default decimal;
description
"Format used for parsing localadmin fields";
}
uses localadmin-fields;
}
description
"A list of objects defining Regular BGP Communities";
reference
"RFC1997: BGP Communities Attribute";
}
list extended {
key "name";
leaf name {
type community-name;
mandatory true;
description
"Community name";
}
leaf category {
type community-category;
description
"Category of the community";
}
leaf description {
type community-description;
description
"Description for the community";
}
leaf type {
type uint8;
mandatory true;
description
"Type Field";
}
leaf subtype {
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type uint8;
mandatory true;
description
"Sub-Type Field";
}
choice globaladmin {
mandatory true;
case asn {
leaf asn {
type two-octet-as-number;
description
"Two-Octet AS";
}
}
case asn4 {
leaf asn4 {
type inet:as-number;
description
"Four-Octet AS";
}
}
}
container localadmin {
leaf format {
type localadmin-format;
default decimal;
description
"Format used for parsing localadmin fields";
}
uses localadmin-fields;
}
description
"A list of objects defining Extended BGP Communities";
reference
"RFC4360: BGP Extended Communities Attribute";
}
list large {
key "name";
leaf name {
type community-name;
mandatory true;
description
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"Community name";
}
leaf category {
type community-category;
description
"Category of the community";
}
leaf description {
type community-description;
description
"Description for the community";
}
leaf globaladmin {
type inet:as-number;
mandatory true;
description
"Global Administrator field";
}
container localdatapart1 {
leaf format {
type localadmin-format;
default decimal;
description
"Format used for parsing localadmin fields";
}
uses localadmin-fields;
}
container localdatapart2 {
leaf format {
type localadmin-format;
default decimal;
description
"Format used for parsing localadmin fields";
}
uses localadmin-fields;
}
description
"A list of objects defining Large BGP Communities";
reference
"RFC8092: BGP Large Communities Attribute";
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}
}
}
Figure 2
Appendix B. JSON Examples
This section shows example use cases for the YANG module defined in
this document, using JSON[RFC7951] encoding.
B.1. RFC8195 Selective NO_EXPORT definition
A JSON definition for the example Large BGP community described in
[RFC8195], section 4.1.1 looks as follows.
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{
"draft-ietf-grow-yang-bgp-communities:bgp-communities": {
"serial": 2023080101,
"uri": "http://example.net/peering/communities",
"description": "BGP Community example for ASN-Based Selective \
NO_EXPORT",
"contacts": [
{
"emailaddress": "noc@example.net",
"name": "Example.net contact",
"role": "Administrative contact",
"organization": "Example.net",
"organizationalunit": "NOC"
}
],
"large": [
{
"name": "RFC8195-NOEXPORT-ASN",
"category": "action",
"description": "Do not export route to ASN",
"globaladmin": 65539,
"localdatapart1": {
"fields": [
{
"name": "Function",
"pattern": "4",
"description": "ASN-No-Export"
}
]
},
"localdatapart2": {
"fields": [
{
"name": "ASN",
"pattern": ".*"
}
]
}
}
]
}
}
Figure 3
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B.2. RFC4384 Data Collection definition
A JSON definition for the example Regular BGP community described in
[RFC4384], section 4 looks as follows.
NOTE: '\' line wrapping per [RFC8792]
{
"draft-ietf-grow-yang-bgp-communities:bgp-communities": {
"serial": 2023080101,
"uri": "http://example.net/peering/communities",
"description": "BGP Community example for Data Collection",
"contacturl": "https://example.net/contact",
"regular": [
{
"name": "RFC4384-ORIGIN-OC/FJ",
"description": "A national route over a terrestrial link from \
the Fiji Islands",
"globaladmin": 64497,
"localadmin": {
"format": "binary",
"fields": [
{
"name": "Region",
"length": 5,
"pattern": "00010",
"description": "OC"
},
{
"name": "Satellite",
"length": 1,
"pattern": "0"
},
{
"name": "Country",
"length": 10,
"pattern": "0011110010",
"description": "FJ"
}
]
}
}
]
}
}
Figure 4
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Appendix C. Acknowledgements
The author would like to thank Jeffrey Haas, Luuk Hendriks, Jasper
den Hertog, Teun Vink, Tom Petch and Dale Carder for contributing
ideas and feedback to this document.
Author's Address
Martin Pels
RIPE NCC
Netherlands
Email: mpels@ripe.net
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