--- 1/draft-ietf-grow-large-communities-usage-01.txt 2017-02-16 12:13:48.114532930 -0800 +++ 2/draft-ietf-grow-large-communities-usage-02.txt 2017-02-16 12:13:48.142533596 -0800 @@ -1,23 +1,24 @@ Global Routing Operations J. Snijders -Internet-Draft NTT -Intended status: Informational M. Schmidt -Expires: June 10, 2017 i3D.net - December 7, 2016 +Internet-Draft J. Heasley +Intended status: Informational NTT +Expires: August 20, 2017 M. Schmidt + i3D.net + February 16, 2017 - Usage of Large BGP Communities - draft-ietf-grow-large-communities-usage-01 + Usage of BGP Large Communities + draft-ietf-grow-large-communities-usage-02 Abstract - Examples and inspiration for operators on how to use Large BGP + Examples and inspiration for operators for the use of BGP Large Communities. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. Status of This Memo @@ -27,25 +28,25 @@ 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 http://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 June 10, 2017. + This Internet-Draft will expire on August 20, 2017. Copyright Notice - Copyright (c) 2016 IETF Trust and the persons identified as the + Copyright (c) 2017 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. 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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as @@ -74,173 +75,175 @@ 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 8.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction - Large BGP Communities [I-D.ietf-idr-large-community] provide a - mechanism to signal opaque information between Autonomous Systems. - This document presents a set of examples on how Large BGP Communities - could be implemented by an operator to achieve various goals. This - document draws from experience in Operational Communities such as - NANOG [1] and NLNOG [2]. + BGP Large Communities [RFC8092] provide a mechanism to signal opaque + information between Autonomous Systems. This document presents a set + of examples of how Large BGP Communities could be employed by an + operator to achieve various goals. This document draws from + experience in Operational Communities such as NANOG [1] and NLNOG + [2]. - The opaque nature of Large BGP Communities allows for rapid + The opaque nature of BGP Large Communities allows for rapid deployment of new features or changes to the product. Operators are - encouraged to publicly publish an up to date version of their routing - policy in which they document what each Large BGP Community means. + encouraged to publicly publish and maintain documentation of the + purpose of each Large BGP Community, both informational and action, + that they support or are visible in looking glasses. 2. The Generic Design Pattern - Large BGP Communities are composed of a 4-octet Global Administrator - field followed by two 4-octet Local Data fields. The design pattern - described in this document uses a "ASN:Function:Parameter"-approach - to fill the three fields. + BGP Large Communities are composed of a 4-octet Global Administrator + field followed by two 4-octet Local Data fields. Large BGP + Communities are compose three 4-octet fields. The first is the + Global Administrator field, whose value is the ASN of AS that has + defined the meaning of the remaining two 4-octet fields, the Local + Data fields. This document describes an approach defining these + fields as "ASN:Function:Parameter"-approach to fill the three fields. - In deployments of both BGP Communities [RFC1997] and Large BGP - Communities, two categories of Communities are recognised: + In deployments of both BGP Communities [RFC1997] and BGP Large + Communities, two categories of Communities exist: o Informational Communities o Action Communities - For each context ideas are provided regarding the contents of each of - the three fields in Large BGP Communities. + For each, ideas are provided regarding the contents of each of the + three fields in BGP Large Communities. Throughout the document a topology of four Autonomous Systems is used to illustrate the usage of Communities in the following configuration: AS 65551 | ^ | AS 64497 / \ ^ \ / ^ AS 64498 \ | | `<->- AS 64499 - AS 64497 obtains transit services from AS 65551. AS 64497 provides - transit services to both AS 64498 and AS 64499. AS 64498 and AS - 64499 maintain a peering relation in which they only exchange their - customer routes. + AS 64497 obtains transit services from AS 65551, a 32-bit ASN. AS + 64497 provides transit services to both AS 64498 and AS 64499. AS + 64498 and AS 64499 maintain a peering relationship in which they only + exchange their customer routes. 2.1. Informational Communities - Informational Communites serve as markers regarding the origin of the - route announcement, the relation with the EBGP neighbor or for + Informational Communites are labels for attributes such as origin of + the route announcement, the relation with the EBGP neighbor or for instance the intended propagation audience. Informational Communities also assist in network operations such as debugging. The Global Administrator field is set to the ASN which is marking the - routes with the Informational Communities. As an example: on a route - which AS 64497 announces to AS 64498, AS 64497 might add the Large - BGP Community 64497:100:31 to signal to AS 64498 that the route was - learned in the Netherlands. + routes with the Informational Communities. For example, AS 64497 + might add a community with the GA 64497 to a route learned from an + iBGP or eBGP peer that means that the route was learned from or + originated by a device in the Netherlands. In general the intended audience of Informational Communities are - downstream networks, but any adjacent Autonomous System could benefit - from receiving these communities. + downstream networks and the Global Administrator itself, but any + Autonomous System could benefit from receiving these communities. 2.2. Action Communities Action Communities are attached to routes to request non-default - behaviour in an adjacent Autonomous System. For instance, Action - Communities are used to change the route's propagation - characteristics, the route's LOCAL_PREF value or the amount of - AS_PATH prepends that should be added when exporting or importing a - route. + behaviour in this, a conferation or an external AS. Action + Communities could be used to change the route's propagation + characteristics, the LOCAL_PREFENCE or the number of AS_PATH prepends + to add when exporting or importing a route. The Global Administrator field is set to the ASN which is expected to - perform a non-default action upon receiving the route. For instance, - if AS 64499 would want to request AS 64497 to lower the - LOCAL_PREFERENCE below the default, AS 64499 could tag the route with - 64497:20:50. + perform the action. For instance, AS 64499 might add a Large + Community with the GA 64497 to signal AS 64497 to perform an action + upon that route. In general the intended audience of Action Communities is an upstream - provider. + provider, but realistically could be any AS willing to act upon it. 3. Examples of Informational Communities 3.1. Location AS 64497 can inform its downstream networks about the geographical - entity where AS 64497 learned a route by marking the route with Large - BGP Communities following one or a combination of the following + entity where AS 64497 learned a route by marking the route with BGP + Large Communities following one or a combination of the following schemes. 3.1.1. An ISO 3166-1 numeric function AS 64497 could assign a value of 1 to the first Local Data field to - designate the function of the parameter in the second Local Data - field as ISO-3166-1 numeric country identifiers. + designate the function of the second Local Data field as ISO-3166-1 + numeric country identifiers. +---------------------+-------------------------------------------+ - | Large BGP Community | Meaning | + | BGP Large Community | Description | +---------------------+-------------------------------------------+ | 64497:1:528 | Route learned in Netherlands | | 64497:1:392 | Route learned in Japan | | 64497:1:840 | Route learned in United States of America | +---------------------+-------------------------------------------+ - Example documentation for AS 64497 using Informational Communties + Example documentation for AS 64497 using Informational Communities describing the origin of routes using ISO 3166-1 numeric identifiers. Table 1: Information: ISO 3166-1 3.1.2. An UNSD region function AS 64497 could assign a value of 2 to the first Local Data field to designate the function of the parameter in the second Local Data field as an identifier for the macro geographical (continental) regions, geographical sub-regions, or selected economic and other groupings following a set of published identifiers by the United Nations Statistics Division [3]. +---------------------+-------------------------------+ - | Large BGP Community | Meaning | + | BGP Large Community | Description | +---------------------+-------------------------------+ | 64497:2:2 | Route learned in Africa | | 64497:2:9 | Route learned in Oceania | | 64497:2:145 | Route learned in Western Asia | | 64497:2:150 | Route learned in Europe | +---------------------+-------------------------------+ - Example documentation for AS 64497 using Informational Communties + Example documentation for AS 64497 using Informational Communities describing the origin of routes using numeric identifiers provided by the UN Statistics Division. Table 2: Information: Regions 3.2. Relation AS 64497 could assign a value of 3 to the first Local Data field to designate that the second Local Data field contains an identifier showing the relation with the EBGP neighbor from whom the route was received. +---------------------+-----------------------------------------+ - | Large BGP Community | Meaning | + | BGP Large Community | Description | +---------------------+-----------------------------------------+ | 64497:3:1 | Route learned from a customer | | 64497:3:2 | Route learned from a peering partner | | 64497:3:3 | Route learned from an upstream provider | +---------------------+-----------------------------------------+ - Example documentation for AS 64497 using Informational Communties + Example documentation for AS 64497 using Informational Communities describing the relation with the ASN from which the route was received. Table 3: Information: Relation 3.3. Combining Informational Communities Multiple Informational Communities can be tagged on a route, for example: a route learned in the Netherlands from a customer can contain both 64497:1:528 and 64497:2:150 and 64497:3:1. @@ -254,104 +257,104 @@ such as selectively not export routes learned from 64498 to certain EBGP neighbors of AS 64497. 4.1.1. Peer ASN Based Selective NO_EXPORT AS 64497 might assign function identifier 4 to allow preventing propagation of routes to the ASN listed in the second Local Data field. +---------------------+---------------------------------+ - | Large BGP Community | Meaning | + | BGP Large Community | Description | +---------------------+---------------------------------+ | 64497:4:2914 | Do not export route to AS 2914 | | 64497:4:7018 | Do not export route to AS 7018 | | 64497:4:65551 | Do not export route to AS 65551 | +---------------------+---------------------------------+ - Example documentation for AS 64497 offering Action Communties to + Example documentation for AS 64497 offering Action Communities to limit propagation of routes based on the Peer ASN described in the third field. Table 4: Action: Peer ASN NO_EXPORT 4.1.2. Location Based Selective NO_EXPORT AS 64497 might assign function identifier 5 to allow its customers to request selectively not exporting routes on EBGP sessions within a certain geographical area. This example follows the ISO 3166-1 numeric encoding. +------------------+------------------------------------------------+ - | Large BGP | Meaning | + | BGP Large | Description | | Community | | +------------------+------------------------------------------------+ | 64497:5:528 | Do not export to EBGP neighbors in the | | | Netherlands | | 64497:5:392 | Do not export to EBGP neighbors in Japan | | 64497:5:840 | Do not export to EBGP neighbors in United | | | States of America | +------------------+------------------------------------------------+ - Example documentation for AS 64497 offering Action Communties to + Example documentation for AS 64497 offering Action Communities to trigger NO_EXPORT on routes only when propagating the route to a certain geographical region. Table 5: Action: NO_EXPORT in Region 4.2. Selective AS_PATH Prepending As part of the commercial agreement between AS 64497 and AS 64498, AS 64497 might offer AS 64498 certain BGP Traffic Engineering features such as selectively prepending the AS_PATH with 64497's ASN to certain EBGP neighbors of AS 64497. 4.2.1. Peer ASN Based Selective AS_PATH Prepending AS 64497 might assign function identifier 6 to allow prepending the AS_PATH on propagation of routes to the ASN listed in the second Local Data field. +---------------------+------------------------------------------+ - | Large BGP Community | Meaning | + | BGP Large Community | Description | +---------------------+------------------------------------------+ | 64497:6:2914 | Prepend 64497 once on export to AS 2914 | | 64497:6:7018 | Prepend 64497 once on export to AS 7018 | | 64497:6:65551 | Prepend 64497 once on export to AS 65551 | +---------------------+------------------------------------------+ - Example documentation for AS 64497 offering Action Communties to + Example documentation for AS 64497 offering Action Communities to trigger prepending of the AS_PATH only when propagating the route to a certain Peer ASN. Table 6: Action: Prepend to Peer ASN 4.2.2. Location Based Selective AS_PATH Prepending AS 64497 might assign function identifier 7 to allow prepending of the AS_PATH on propagation of routes to on any EBGP neighbor's interconnection in the geographical entity listed in the second Local Data field. This example follows the ISO 3166-1 numeric regions codes in the Local Data 2 field. +------------------+------------------------------------------------+ - | Large BGP | Meaning | + | BGP Large | Description | | Community | | +------------------+------------------------------------------------+ | 64497:7:528 | Prepend once to EBGP neighbors in the | | | Netherlands | | 64497:7:392 | Prepend once to EBGP neighbors in Japan | | 64497:7:840 | Prepend once to EBGP neighbors in United | | | States of America | +------------------+------------------------------------------------+ - Example documentation for AS 64497 offering Action Communties to + Example documentation for AS 64497 offering Action Communities to trigger prepending of the AS_PATH only when propagating the route to a certain geographical region. Table 7: Action: Prepend in Region 4.3. Location based manipulation of LOCAL_PREF In some cases, it can be desirable for an autonomous system to allow adjacent Autonomous Systems to directly influence the degree of preference associated with a route, usually expressed within the @@ -397,21 +400,21 @@ +----------+-----------------------------------------------+ Table 8: Action: Preference Function Identifiers Once established, these route preference setting functions can be linked with a scoping operand such as per-peer or per-location based identifiers in order to provide AS64497's customers with a comprehensive and rich toolset to influence route preference. +--------------------+----------------------------------------------+ - | Large BGP | Meaning | + | BGP Large | Description | | Community | | +--------------------+----------------------------------------------+ | 64497:15:528 | Set as peer route in Netherlands | | 64497:19:840 | Set as backup route in United States of | | | America | +--------------------+----------------------------------------------+ Table 9: Action: Regional Preference Communities Since the degree of preference influences BGP best path selection @@ -425,63 +428,71 @@ BGP Operations and Security [RFC7454]. 6. IANA Considerations None. 7. Acknowledgements The authors would like to gratefully acknowledge the insightful comments, contributions, critique and support from John Heasley, Adam - Chappell and Jonathan Stewart. + Chappell, Jonathan Stewart, and Will Hargrave. 8. References 8.1. Normative References - [I-D.ietf-idr-large-community] - Heitz, J., Snijders, J., Patel, K., Bagdonas, I., and N. - Hilliard, "BGP Large Communities", draft-ietf-idr-large- - community-11 (work in progress), December 2016. - [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4264] Griffin, T. and G. Huston, "BGP Wedgies", RFC 4264, DOI 10.17487/RFC4264, November 2005, . [RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454, February 2015, . + [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, + . + 8.2. URIs [1] http://nanog.net [2] http://nlnog.net [3] http://unstats.un.org/unsd/methods/m49/m49regin.htm Authors' Addresses Job Snijders NTT Communications Theodorus Majofskistraat 100 Amsterdam 1065 SZ - NL + The Netherlands Email: job@ntt.net + John Heasley + NTT Communications + 12160 NW Coleman Drive + Portland, OR 97229 + United States of America + + Email: heas@shrubbery.net + Martijn Schmidt i3D.net Rivium 1e Straat 1 Capelle aan den IJssel 2909 LE NL Email: martijnschmidt@i3d.net