Global Routing OperationsInternet Engineering Task Force (IETF) J. SnijdersInternet-DraftRequest for Comments: 8195 J. HeasleyIntended status:Category: Informational NTTExpires: October 21, 2017ISSN: 2070-1721 M. Schmidt i3D.netApril 19,June 2017 Use of BGP Large Communitiesdraft-ietf-grow-large-communities-usage-07Abstract This document presents examples and inspiration foroperator'soperator application of BGP Large Communities. Based on operational experience with BGPCommunties,Communities, this document suggests logical categories of BGP Large Communities and demonstrates an orderly manner of organizing community values within them to achieve typical goals in routing policy. Any operator can consider using the concepts presented as the basis for their own BGP Large Communities repertoire. Status of This Memo ThisInternet-Draftdocument issubmitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documentsnot an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Engineering Task Force (IETF).Note that other groups may also distribute working documents as Internet-Drafts. The listIt represents the consensus ofcurrent Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents validthe IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are amaximumcandidate for any level of Internet Standard; see Section 2 of RFC 7841. Information about the current status ofsix monthsthis document, any errata, and how to provide feedback on it may beupdated, replaced, or obsoleted by other documentsobtained atany 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 October 21, 2017.http://www.rfc-editor.org/info/rfc8195. Copyright Notice 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 described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. The Design Overview . . . . . . . . . . . . . . . . . . . . . 3 2.1. Informational Communities . . . . . . . . . . . . . . . . 4 2.2. Action Communities . . . . . . . . . . . . . . . . . . . 4 3. Examples of Informational Communities . . . . . . . . . . . . 5 3.1. Location . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1.1. An ISO 3166-1 Numeric Function . . . . . . . . . . . 5 3.1.2.AnA UN M.49 Region Function . . . . . . . . . . . . . . 5 3.2. Relation Function . . . . . . . . . . . . . . . . . . . . 6 3.3. Combining Informational Communities . . . . . . . . . . . 6 4. Examples of Action Communities . . . . . . . . . . . . . . . 7 4.1. Selective NO_EXPORT . . . . . . . . . . . . . . . . . . . 7 4.1.1.ASN BasedASN-Based Selective NO_EXPORT . . . . . . . . . . . . 7 4.1.2.Location BasedLocation-Based Selective NO_EXPORT . . . . . . . . . 7 4.2. Selective AS_PATH Prepending . . . . . . . . . . . . . . 8 4.2.1.ASN BasedASN-Based Selective AS_PATH Prepending . . . . . . . 8 4.2.2.Location BasedLocation-Based Selective AS_PATH Prepending . . . . . 9 4.3. Manipulation of the LOCAL_PREF Attribute . . . . . . . . 9 4.3.1. Global Manipulation of LOCAL_PREF . . . . . . . . . . 10 4.3.2.Region BasedRegion-Based Manipulation of LOCAL_PREF . . . . . . . 10 4.3.3. Note of Caution for LOCAL_PREF Functions . . . . . . 11 4.4. Route Server Prefix Distribution Control . . . . . . . . 11 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 7.Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 8.References . . . . . . . . . . . . . . . . . . . . . . . . . 138.1.7.1. Normative References . . . . . . . . . . . . . . . . . . 138.2.7.2. Informative References . . . . . . . . . . . . . . . . . 138.3. URIs .Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .1413 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 1. Introduction BGP Large Communities [RFC8092] provide a mechanism to signal opaque information between and within Autonomous Systems(ASs).(ASes). In very much the same way that [RFC1998] provides a concrete real-world application for[RFC1997] communities,BGP Communities [RFC1997], this document presents examples of how operators might utilize BGP Large Communities to achieve various goals. This document draws on the experience of operator communities such asNANOG [1]the North American Network Operators' Group (NANOG) <https://www.nanog.org/> andNLNOG [2].the Netherlands Network Operator Group (NLNOG) <https://nlnog.net/>. 2. The Design Overview BGP Large Communities are composed of three 4-octet fields. The first is the Global Administrator (GA) field, whose value is the Autonomous System Number (ASN) of the AS that has defined the meaning of the remaining two 4-octet fields, known as "Local Data Part 1" and "Local Data Part 2". This document describes an approach where the "Local Data Part 1" field contains a function identifier and the "Local Data Part 2" contains a parameter value. Using the canonical notation this format can be summarized as "ASN:Function:Parameter". +----------------------+---------------+ | RFC 8092 | this document | +----------------------+---------------+ | Global Administrator | ASN | | Local Data Part 1 | Function | | Local Data Part 2 | Parameter | +----------------------+---------------+ATable 1: Field Mapping The table above shows a mapping tableonbetween theuse offields in BGP Large Communitiesbetween[RFC8092] and this document.Table 1: Field MappingIn contemporary deployments of both BGP Communities [RFC1997] and BGP LargeCommunities,Communities [RFC8092], the function of a community can be divided into two categories: o Informational Communities o Action Communities Throughout thedocumentdocument, a topology of fourASsASes is used to illustrate the use of communities in the following configuration: AS 65551 | ^ | AS 64497 / \ ^ \ / ^ AS 64498 \ | | `<->- AS 64499 AS 64497 obtains transit services from (is a customer of) AS 65551, a 4-octet 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. The opaque nature of BGP Large Communities allows for rapid deployment of new features or changes to their routing policy that perform an action. Operators are encouraged to publicly publish and maintain documentation on the purpose of each BGP Large Community, bothinformationalInformational andaction,Action, that they support or that are visible in BGP RIBs. 2.1. Informational Communities Informational Communities are labels for attributes such as the origin of the route announcement, the nature of the relation with anEBGP neighborExternal BGP (EBGP) neighbor, or the intended propagation audience. Informational Communities can also assist in providing valuable information for day-to-day network operations such as debugging or capacity planning. The Global Administrator field is set to the ASNwhich labelsof the network that tags the routes with the Informational Communities. For example, AS 64497 might add a community with the GA 64497 to a route accepted from anIBGPInternal BGP (IBGP) or EBGP neighbor as a means of signaling that it was imported in a certain geographical region. In general, the intended audiences of Informational Communities are downstream networks and theGlobal AdministratorGA itself, but any AS could benefit from receiving these communities. 2.2. Action Communities Action Communities are added asa labellabels to request that a route be treated in a particular way within an AS. The operator of the AS defines a routing policy that adjusts path attributes based on the community. For example, the route's propagation characteristics, the LOCAL_PREF (local preference), thenext-hop,next hop, or the number of AS_PATH prepends to be added when it is received or propagated can be changed. The Global Administrator field is set to the ASNwhichthat has defined the functionality of that BGP Large Community and is the ASN that is expected to perform the action. For example, AS 64499 might label a route with a BGP Large Community containing GA 64497 to request that AS 64497 perform apre-definedpredefined action on that route. In general, the intended audience of Action Communities are transit providers taking action on behalf of a customer or theGlobal AdministratorGA itself, but any AS could take action if they choose and any AS could add an Action Community with the GA of a non-adjacent ASN. However, note that an Action Community could also beinformational.Informational. Its presence is an indicator that the GA may have performed the action and that an AS in the AS_PATH requested it. Operators are recommended to publish the relative order in which Action Communities (both BGP Communities and BGP Large Communities) are processed in their routing policy. 3. Examples of Informational Communities 3.1. Location An AS, AS 64497 in these examples, may inform other networks about the geographical region where AS 64497 imported a route by labeling it with BGP Large Communities following one of the following schemes or a combination of them. 3.1.1. An ISO 3166-1 Numeric Function AS 64497 could assign a value of 1 to the Function field to designate the content of the Parameter field as anISO-3166-1 [3]ISO 3166-1 numeric countryidentifier.identifier <https://www.iso.org/iso-3166-country-codes.html>. +---------------------+---------------------------------------------+ | BGP Large Community | Description | +---------------------+---------------------------------------------+ | 64497:1:528 | Route learned in the Netherlands | | 64497:1:392 | Route learned in Japan | | 64497:1:840 | Route learned in the United States of | | | America | +---------------------+---------------------------------------------+ExampleTable 2: Informational: ISO 3166-1 The table above shows example documentation for Informational Communities deployed by AS 64497 to describe the location where a route was imported using ISO 3166-1 numeric identifiers.Table 2: Information: ISO 3166-13.1.2.AnA UN M.49 Region Function AS 64497 could assign a value of 2 to the Function field to designate the content of the Parameter field as the M.49 numeric code published by the United Nations Statistics Division (UNSD)[4]<https://unstats.un.org/unsd/methodology/m49/> formacro geographicalmacro-geographical (continental) regions, geographical sub-regions, or selected economic and other groupings. +---------------------+-------------------------------+ | 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 | +---------------------+-------------------------------+ExampleTable 3: Informational: UNSD Regions The table above shows example documentation for Informational Communities deployed by AS 64497 to describe the location where a route was imported using M.49 numeric codes published by theUnited Nations Statistics Division. Table 3: Information: UNSD RegionsUNSD. 3.2. Relation Function An AS, AS 64497 in this example, could assign a value of 3 to the Function field to designate the content of the Parameter field as a number indicating whether the route originated inside its own network or was learned externally, and if learned externally, it might simultaneously characterize the nature of the relation with that specific EBGP neighbor. +---------------------+---------------------------------------+ | BGP Large Community | Description | +---------------------+---------------------------------------+ | 64497:3:1 | Route originated internally | | 64497:3:2 | Route learned from a customer | | 64497:3:3 | Route learned from a peering partner | | 64497:3:4 | Route learned from a transit provider | +---------------------+---------------------------------------+ExampleTable 4: Informational: Relation The table above shows example documentation for Informational Communities deployed by AS 64497 to describe the relation to the ASN from which the route was learned.Table 4: Information: Relation3.3. Combining Informational Communities A route may be labeled with multiple Informational Communities. For example, a route learned in the Netherlands from a customer might be labeled with communities 64497:1:528,64497:2:15064497:2:150, and 64497:3:2 at the same time. 4. Examples of Action Communities 4.1. Selective NO_EXPORT As part of an agreement, often a commercial transit agreement, between AS 64497 and AS 64498, AS 64497 might expose BGPtraffictraffic- engineering functions to AS 64498. One such BGPtraffic engineeringtraffic-engineering function could be selective NO_EXPORT, which is the selective filtering of a route learned from one AS, AS 64498, to certain EBGP neighbors of the GA, AS 64497. 4.1.1.ASN BasedASN-Based Selective NO_EXPORT AS 64497 could assign a value of 4 to the Function field to designate the content of the Parameter field as a neighboring ASN to which a route should not be propagated. +---------------------+---------------------------------+ | BGP Large Community | Description | +---------------------+---------------------------------+ | 64497:4:64498 | Do not export route to AS 64498 | | 64497:4:64499 | Do not export route to AS 64499 | | 64497:4:65551 | Do not export route to AS 65551 | +---------------------+---------------------------------+ExampleTable 5: Action: ASN NO_EXPORT The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGPtraffic engineeringtraffic-engineering functionwhichthat selectively prevents the propagation of routes to the neighboring ASN specified in the Parameter field.Table 5: Action: ASN NO_EXPORT4.1.2.Location BasedLocation-Based Selective NO_EXPORT AS 64497 could assign a value of 5 to the Function field to designate the content of the Parameter field as an ISO 3166-1 numeric country identifier within which a labeled route is not propagated to EBGP neighbors. However, this might not prevent one of those EBGP neighbors from learning that route in another country and making it available in the country specified by the BGP Large Community. +-----------------+-------------------------------------------------+ | 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 the United | | | States of America | +-----------------+-------------------------------------------------+ExampleTable 6: Action: NO_EXPORT in Region The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGPtraffic engineeringtraffic-engineering functionwhichthat selectively prevents the propagation of routes to all EBGP neighbors in the geographical region specified in the Parameter field.Table 6: Action: NO_EXPORT in Region4.2. Selective AS_PATH Prepending As part of an agreement between AS 64497 and AS 64498, AS 64497 might expose BGPtraffic engineeringtraffic-engineering functions to AS 64498. One such BGPtraffic engineeringtraffic-engineering function could be selective prepending of the AS_PATH with AS 64497 to certaincertainEBGP neighbors of AS 64497. 4.2.1.ASN BasedASN-Based Selective AS_PATH Prepending AS 64497 could assign a value of 6 to the Function field to designate the content of the Parameter field as a neighboring ASN to which prepending of the AS_PATH with AS 64497 is requested on propagation of the route. Additional AS_PATH prepending functions might also be defined to support multiples of prepending, thatisis, two,threethree, or more prepends of AS 64497. +---------------------+------------------------------------------+ | BGP Large Community | Description | +---------------------+------------------------------------------+ | 64497:6:64498 | Prepend 64497 once on export to AS 64498 | | 64497:6:64499 | Prepend 64497 once on export to AS 64499 | | 64497:6:65551 | Prepend 64497 once on export to AS 65551 | +---------------------+------------------------------------------+ExampleTable 7: Action: Prepend to ASN The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGPtraffic engineeringtraffic-engineering functionwhichthat selectively prepends the AS_PATH with AS 64497 when propagating the route to the specified EBGP neighbor.Table 7: Action: Prepend to ASN4.2.2.Location BasedLocation-Based Selective AS_PATH Prepending AS 64497 could assign a value of 7 to the Function field to designate the content of the Parameter field as an ISO 3166-1 numeric country identifier to which the prepending of the AS_PATH with AS 64497 is requested on propagation of the route to all EBGP neighbors in that region.+------------------+------------------------------------------------++-----------------+-------------------------------------------------+ | 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 the United | | | States of America |+------------------+------------------------------------------------+ Example+-----------------+-------------------------------------------------+ Table 8: Action: Prepend in Region The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGPtraffic engineeringtraffic-engineering functionwhichthat selectively prepends the AS_PATH with AS 64497 when propagating the route to all EBGP neighbors in the geographical region specified in the Parameter field.Table 8: Action: Prepend in Region4.3. Manipulation of the LOCAL_PREF Attribute As part of an agreement between AS 64497 and AS 64498, AS 64497 might expose BGPtraffic engineeringtraffic-engineering functions to AS 64498. One such BGPtraffic engineeringtraffic-engineering function might allow AS 64498 to manipulate the value of the LOCAL_PREF attribute of routes learned from AS 64498 within AS 64497, even though the LOCAL_PREF attribute is non- transitive and is not propagated to EBGP neighbors. The LOCAL_PREF value of routes are locally significant within each AS and are impossible to list in this document. Instead, the typical LOCAL_PREF values could be classified as ahierarchyhierarchy, and a BGP Large Community functionexposedcould be exposed, allowing an EBGP neighbor to affect the LOCAL_PREF value within the specified GA. The following example list defines the classes of routes in the order of descending LOCAL_PREF value and assigns a function identifierwhichthat could be used in the Function field of a BGP Large Community. +----------+--------------------------------------------------------+ | Function | Preference Class | +----------+--------------------------------------------------------+ | 8 | Normal customer route | | 9 | Backup customer route | | 10 | Peering route | | 11 | Upstream transit route | | 12 | Fallback route, to be installed if no other path is | | | available | +----------+--------------------------------------------------------+ Table 9: Action: Preference Function Identifiers 4.3.1. Global Manipulation of LOCAL_PREF AS 64497 could place one of the previously defined Preference Function Identifiers in the Function field and set the value 0 in the Parameter field to designate that the LOCAL_PREF associated with that function identifier should be applied for that route throughout the whole AS. +---------------------+---------------------------------------------+ | BGP Large Community | Description | +---------------------+---------------------------------------------+ | 64497:9:0 | Assign LOCAL_PREF for a customer backup | | | route | | 64497:10:0 | Assign LOCAL_PREF for a peering route | | 64497:12:0 | Assign LOCAL_PREF for a fallback route | +---------------------+---------------------------------------------+ExampleTable 10: Action: Global LOCAL_PREF Manipulation The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGPtraffic engineeringtraffic-engineering functionwhichthat allows a BGP neighbor to globally manipulate the LOCAL_PREF attribute for the route within AS 64497.Table 10: Action: Global LOCAL_PREF Manipulation4.3.2.Region BasedRegion-Based Manipulation of LOCAL_PREF AS 64497 could place one of the previously defined Preference Function Identifiers in the Function field and useana UN M.49 numeric region identifier in the Parameter field to designate the geographical region within which the non-default LOCAL_PREF associated with that function identifier should be applied to the route. The value of the LOCAL_PREF attribute should not deviate from the default for that route class in any region not specified by one or more of these Action Communities. +--------------+----------------------------------------------------+ | BGP Large | Description | | Community | | +--------------+----------------------------------------------------+ | 64497:9:3 | Assign the LOCAL_PREF value equivalent to a | | | customer backup class route on BGP routers in the | | | North America region | | 64497:10:5 | Assign the LOCAL_PREF value equivalent to a | | | peering class route on BGP routers in the South | | | America region | | 64497:12:142 | Assign the LOCAL_PREF value equivalent to a | | | fallback class route on BGP routers in the Asia | | | region | +--------------+----------------------------------------------------+ExampleTable 11: Action: Regional LOCAL_PREF Manipulation The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGPtraffic engineeringtraffic-engineering functionwhichthat allows a BGP neighbor to selectively manipulate the LOCAL_PREF attribute within AS 64497 in the geographical region specified in the Parameter field.Table 11: Action: Regional LOCAL_PREF Manipulation4.3.3. Note of Caution for LOCAL_PREF Functions The LOCAL_PREF attribute strongly influences the BGP Decision Process, which in turn affects the scope of route propagation. Operators should take special care when using Action Communities that decrease the LOCAL_PREF value, and the degree of preference, to a value below that of another route class. Some of the unintended BGP states that might arise as a result of thesetraffic engineeringtraffic-engineering decisions are described as "BGP Wedgies" in [RFC4264]. 4.4. Route Server Prefix Distribution Control RouteServersservers [RFC7947] use BGP to broker network reachability information among their clients. As not all route server clients may wish to interconnect with each other, the route server operator will usually implement a mechanism to allow each client to control the route server's export routing policy, as described in Section 4.6 of [RFC7948]. Onewidely-usedwidely used mechanism isa route server specifican adaption of"ASN Based"ASN-Based Selective NO_EXPORT" (Section4.1.1).4.1.1) that is specific to route servers. An example BGP Large Communities policywhichthat enables client- controlled prefix distribution for a route server operating as AS64497,64511 is outlined as follows: +-------------------+-----------------------------------------------+ | BGP Large | Description | | Community | | +-------------------+-----------------------------------------------+ |64497:13:peer-as64511:0:peer-as | Explicitly prevent announcement of route to | | | peer-as | |64497:14:peer-as64511:1:peer-as | Explicitly announce route to peer-as | |64497:13:064511:0:0 | Do not announce route to any peers by default | |64497:14:064511:1:0 | Announce route to all peers by default | +-------------------+-----------------------------------------------+ Table 12: Action: Route Server Prefix Distribution Control Multiple BGP Large Community values can be used together to implement fine-grained route distribution control. For example, route server client AS 64500 might wish to use a route server for interconnecting to all other clients except AS64510.64509. In this case, they would label all their outbound routes to the route server with64497:14:064511:1:0 (to announce to all clients by default) and64497:13:6451064511:0:64509 (to prevent announcement to AS64510).64509). Alternatively, route server client AS 64501 may have a selective routing policy and may wish to interconnect with only AS 64505 and AS 64506. This could be implemented by announcing routes labeled with64497:13:064511:0:0 (blocking all distribution by default) and64497:14:64505, 64497:14:6450664511:1:64505, 64511:1:64506 to instruct the route server to force announcement to those two ASNs. 5. Security Considerations Operators should note the recommendations in Section 11 ofBGP"BGP Operations andSecuritySecurity" [RFC7454] and handle BGP Large Communities with their ASN in the Global Administrator field similarly. In particular and in the same respect as BGP Communities [RFC1997], operators should becongnizantcognizant that any Large Community can be carried in a BGP UPDATE. Operators should recognize that BGP neighbors, particularly customers and customers of customers, may utilize communities defined by other BGP neighbors of the operator. They may wish to send routes withaction communitiesAction Communities and receive routes withinformational communitiesInformational Communities to or from these otherneighborsneighbors, and it is beneficial to all to permit this. 6. IANA ConsiderationsNone.This document does not require any IANA actions. 7.Acknowledgments The authors would like to gratefully acknowledge the insightful comments, contributions, critique and support from Adam Chappell, Jonathan Stewart, Greg Hankins, Nick Hilliard, Will Hargrave, Randy Bush, Shawn Morris, Jay Borkenhagen and Stewart Bryant. 8.References8.1.7.1. Normative References [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, <http://www.rfc-editor.org/info/rfc1997>. [RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454, February 2015, <http://www.rfc-editor.org/info/rfc7454>. [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, <http://www.rfc-editor.org/info/rfc8092>.8.2.7.2. Informative References [RFC1998] Chen, E. and T. Bates, "An Application of the BGP Community Attribute in Multi-home Routing", RFC 1998, DOI 10.17487/RFC1998, August 1996, <http://www.rfc-editor.org/info/rfc1998>. [RFC4264] Griffin, T. and G. Huston, "BGP Wedgies", RFC 4264, DOI 10.17487/RFC4264, November 2005, <http://www.rfc-editor.org/info/rfc4264>. [RFC7947] Jasinska, E., Hilliard, N., Raszuk, R., and N. Bakker, "Internet Exchange BGP Route Server", RFC 7947, DOI 10.17487/RFC7947, September 2016, <http://www.rfc-editor.org/info/rfc7947>. [RFC7948] Hilliard, N., Jasinska, E., Raszuk, R., and N. Bakker, "Internet Exchange BGP Route Server Operations", RFC 7948, DOI 10.17487/RFC7948, September 2016, <http://www.rfc-editor.org/info/rfc7948>.8.3. URIs [1] https://www.nanog.org [2] https://nlnog.net [3] https://www.iso.org/iso-3166-country-codes.html [4] https://unstats.un.org/unsd/methodology/m49/Acknowledgments The authors would like to gratefully acknowledge the insightful comments, contributions, critique, and support from Adam Chappell, Jonathan Stewart, Greg Hankins, Nick Hilliard, Will Hargrave, Randy Bush, Shawn Morris, Jay Borkenhagen, and Stewart Bryant. Authors' Addresses Job Snijders NTT Communications Theodorus Majofskistraat 100 Amsterdam 1065 SZ The Netherlands Email: job@ntt.net John Heasley NTT Communications 1111 NW 53rd Drive Portland, OR 97210 United States of America Email: heas@shrubbery.net Martijn Schmidt i3D.net Rivium 1e Straat 1 Capelle aan den IJssel 2909 LENLThe Netherlands Email: martijnschmidt@i3d.net