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BGP peering configuration We propose an API standard for BGP Peering, also known as interdomain interconnection through global Internet Routing. This API offers a standard way to request public (settlement-free) peering, verify the status of a request or BGP session, and list potential connection locations. The API is backed by PeeringDB OIDC, the industry standard for peering authentication. We also propose future work to cover private peering, and alternative authentication methods. About This Document The latest revision of this draft can be found at . Status information for this document may be found at . Source for this draft and an issue tracker can be found at .

Introduction The Peering API is a mechanism that allows networks to automate interdomain interconnection between two Autonomous Systems (AS) through the Border Gateway Protocol 4 (). Using the API, networks will be able to automatically request and accept peering interconnections between Autonomous Systems in public or private scenarios in a time faster than it would take to configure sessions manually. By speeding up the peering turn-up process and removing the need for manual involvement in peering, the API and automation will ensure that networks can get interconnected as fast, reliably, cost-effectively, and efficiently as possible. As a result, this improves end-user performance for all applications using networks interconnection supporting the Peering API.

Business Justification By using the Peering API, entities requesting and accepting peering can significantly improve the process to turn up interconnections by:

• Reducing in person-hours spent configuring peering
• Reducing configuration mistakes by reducing human interaction
• And by peering, reducing network latency through expansion of interconnection relationships

Conventions and Definitions All terms used in this document will be defined here:

• Initiator: Network that wants to peer
• Receiver: Network that is receiving communications about peering
• Configured: peering session that is set up on one side
• Established: session is already defined as per BGP-4 specification

Security Considerations As peering connections exchange real Internet traffic, this API requires a security component to verify that the requestor is authorized to operate the interconnection on behalf of such AS. In this initial proposal, the API follows an authorization model based on OpenID Connect and OAuth 2.0 () where the Authorization Server is PeeringDB. The choice of OpenID Connect is to use the standardized token exchange format based on JSON Web Tokens () which allows interoperation with existing web-based application flows. JWT tokens also supply sufficient claims to implement receiver-side authorization decisions when used as bearer access tokens () and for which best common practices also exist (). After further discussion, the authors decided to offer alternate authentication options to accommodate the security concerns of different parties. As peers may require varying security standards, this document proposes to support PeeringDB OIDC as the base requirement, with optional security extensions in addition (RPKI () or alternative OIDC Authorization Servers, for example). This document hopes that, through the RFC process, the Working Group can come to a consensus on a base "authorization standard," to ease adoption for peering participants. Of particular interest is RPKI. PeeringDB OIDC allows the API to identify who the requesting party is, while RPKI-signing allows such requesting party to prove that they own some of the Internet-assigned resources referenced in the request. This combination provides a low entry barrier to create an identity federation across the participating ASs' API with a stronger guarantee of resource ownership against potential for misattribution and repudiation. The authors recognize that not all partners have the time or engineering resources to support all authorization standards, so the API reference implementations will offer an extensible security mechanism to meet varying identity and security requirements. For RPKI-based authentication, this document refers to RPKI Signed Checklists (RSCs) (). The Peering API does not enforce any kind of peering policy on the incoming requests. It is left to the server implementation to enforce the AS-specific peering policy. The authors encourage each peer to consider the needs of their peering policy and implement request validation as desired.

Audience The Peering API aims to simplify peering interconnection configuration. To that end, the API can be called by either a human or some automation. A network engineer can submit API requests through a client-side tool, and configure sessions by hand or through existing tooling. Alternately, an automated service can request BGP sessions through some trigger or regularly scheduled request (for example, upon joining a new peering location, or through regular polling of potential peers). That automated client can then configure the client sessions through its own tooling. For ease of exchanging peering requests, the authors suggest peers to maintain both a client and a server for the API. Toward the goal of streamlining peering configuration, the authors encourage peers to automate their network configuration wherever possible, but do not require full automation to use this API.

Protocol The Peering API follows the Representational State Transfer () architecture where sessions, locations, and maintenance events are the resources the API represents and is modeled after the OpenAPI standard . Using the token bearer model (), a client application can request to add or remove peering sessions, list potential interconnection locations, and query for upcoming maintenance events on behalf of the AS resource owner.

Example Request Flow The diagram below outlines the proposed API flow. | | | | | Provide auth code | |<---------------------------------------------------------| | | | | Send auth code to Peer | | |--------------------------------------------------------->| | | | | | Exchange auth code for token | | |----------------------------->| | | | | | Return token | | |<-----------------------------| | | | Peer determines permissions based on token | | | Send OK back to Initiator | |<--------------------------| Operations, loop until peering is complete. List Locations +-----------+ +-------+ | Initiator | | Peer | +-----------+ +-------+ | | | QUERY peering locations (peer type, ASN, auth code) | |----------------------------------------------------------->| | | | Reply with peering locations | | or errors (401, 406, 451, etc.) | |<-----------------------------------------------------------| Request session status +-----------+ +-------+ | Initiator | | Peer | +-----------+ +-------+ | | | QUERY request status using request ID & auth code | |----------------------------------------------------------->| | | | Reply with session status | | (200, 404, 202, etc.) | |<-----------------------------------------------------------| ]]>

AUTH First, the initiating OAuth2 Client is also the Resource Owner (RO) so it can follow the OAuth2 client credentials grant . In this example, the client will use PeeringDB OIDC credentials to acquire a JWT access token that is scoped for use with the receiving API. On successful authentication, PeeringDB provides the Resource Server (RS) with the client's email (for potential manual discussion), along with the client's usage entitlements (known as OAuth2 scopes), to confirm the client is permitted to make API requests on behalf of the initiating AS.

REQUEST

1. ADD SESSION (CLIENT BATCHED REQUEST)

• The initiator's client provides a set of:
  • Structure:
    1. Local ASN (receiver)
    2. Local IP
    3. Peer ASN (initiator)
    4. Peer IP
    5. Peer Type (public or private)
    6. MD5 (optional with encoding agreed outside of this specification)
    7. Location (Commonly agreed identifier of the BGP speaker, e.g. PeeringDB IX lan ID)
• The receiver's expected actions:
  • The server confirms requested clientASN in list of authorized ASNs.
  • Optional: checks traffic levels, prefix limit counters, other desired internal checks.

1. ADD SESSIONS (SERVER BATCHED RESPONSE)

• APPROVAL CASE
  • Server returns a list with the structure for each of the acceptable peering sessions. Note: this structure may also contain additional attributes such as the server generated session ID.
• PARTIAL APPROVAL CASE
  • Server returns a list with the structure for each of the acceptable peering sessions as in the approval case. The server also returns a list of sessions that have not deemed as validated or acceptable to be created. The set of sessions accepted and rejected is disjoint and the join of both sets matches the cardinality of the requested sessions.
• REJECTION CASE
  • Server returns an error message which indicates that all of the sessions requested have been rejected and the reason for it.

CLIENT CONFIGURATION The client then configures the chosen peering sessions asynchronously using their internal mechanisms. For every session that the server rejected, the client removes that session from the list to be configured.

SERVER CONFIGURATION The server configures all sessions that are in its list of approved peering sessions from its reply to the client.

MONITORING Both client and server wait for sessions to establish. At any point, client may send a "GET STATUS" request to the server, to request the status of the session (by session ID). The client will send a structure along with the request, as follows:

• structure:
  • Session ID
  • Local ASN (server)
  • Local IP
  • Peer ASN (client)
  • Peer IP
  • Peer Type
  • MD5 (optional, as defined above)
  • Location
  • Status

The server then responds with the same structure, with the information that it understands (status, etc).

COMPLETION If both sides report that the session is established, then peering is complete. If one side does not configure sessions within the server's acceptable configuration window (TimeWindow), then the server is entitled to remove the configured sessions and report "Unestablished" to the client.

API Endpoints and Specifications Each peer needs a public API endpoint that will implement the API protocol. This API should be publicly listed in peeringDB and also as a potential expansion of which could provide endpoint integration to WHOIS (). Each API endpoint should be fuzz-tested and protected against abuse. Attackers should not be able to access internal systems using the API. Every single request should come in with a unique GUID called RequestID that maps to a peering request for later reference. This GUID format should be standardized across all requests. This GUID should be provided by the receiver once it receives the request and must be embedded in all communication. If there is no RequestID present then that should be interpreted as a new request and the process starts again. An email address is needed for communication if the API fails or is not implemented properly (can be obtained through PeeringDB). For a programmatic specification of the API, please see the public Github (). This initial draft fully specifies the Public Peering endpoints. Private Peering and Maintenance are under discussion, and the authors invite collaboration and discussion from interested parties.

DATA TYPES Please see specification () for OpenAPI format. Peering Location Contains string field listing the desired peering location in format pdb:ix:$IX_ID, and an enum specifying peering type (public or private). Session Status Status of BGP Session, both as connection status and approval status (Established, Pending, Approved, Rejected, Down, Unestablished, etc) Session Array Array of potential BGP sessions, with request UUID. Request UUID is optional for client, and required for server. Return URL is optional, and indicates the client's Peering API endpoint. The client's return URL is used by the server to request additional sessions. Client may provide initial UUID for client-side tracking, but the server UUID will be the final definitive ID. RequestID will not change across the request. BGP Session A structure that describes a BGP session and contains the following elements:

• local_asn (ASN of requestor)
• local_ip (IP of requestor, v4 or v6)
• peer_asn (server ASN)
• peer_ip (server-side IP)
• peer_type (public or private)
• md5 (optional, as defined above)
• location (Peering Location, as defined above)
• status (Session Status, as defined above)
• session_id (of individual session and generated by the server)

Error API Errors, for field validation errors in requests, and request-level errors. The above is sourced largely from the linked OpenAPI specification.

Endpoints (As defined in ). On each call, there should be rate limits, allowed senders, and other optional restrictions.

Public Peering over an Internet Exchange (IX)

• /sessions: ADD/RETRIEVE sessions visible to the calling PEER
  • Batch create new session resources
    • Establish new BGP sessions between peers, at the desired exchange.
    • Below is based on OpenAPI specification: .
    • POST /sessions
      • Request body: Session Array
      • Responses:
        • 200 OK:
          • Contents: Session Array (all sessions in request accepted for configuration). Should not all the sessions be accepted, the response also contains a list of sessions and the respective errors.
        • 400:
          • Error
        • 403:
          • Unauthorized to perform the operation
  • List all session resources. The response is paginated.
    • Given a request ID, query for the status of that request.
    • Given an ASN without request ID, query for status of all connections between client and server.
    • Below is based on OpenAPI specification: .
    • GET /sessions
      • Request parameters:
        • asn (requesting client's asn)
        • request_id (optional, UUID of request)
        • max_results (integer to indicate an upper bound for a given response page)
        • next_token (opaque and optional string received on a previous response page and which allows the server to produce the next page of results. Its absence indicates to the server that the first page is expected)
      • Response:
        • 200: OK
          • Contents: Session Array of sessions in request_id, if provided. Else, all existing and in-progress sessions between client ASN and server.
            • next_token (opaque and optional string the server expects to be passed back on the request for the next page. Its absence indicates to the client that no more pages are available)
        • 400:
          • Error (example: request_id is invalid)
        • 403:
          • Unauthorized to perform the operation
• /sessions/{session_id}: Operate on individual sessions
  • Retrieve an existing session resource
    • Below is based on OpenAPI specification: .
    • GET /sessions/{session_id}
      • Request parameters:
        • session_id returned by the server on creation or through the session list operation.
      • Responses:
        • 200 OK:
          • Contents: Session structure with current attributes
        • 400:
          • Error (example: session_id is invalid)
        • 403:
          • Unauthorized to perform the operation
        • 404:
          • The session referred by the specified session_id does not exist or is not visible to the caller
  • Delete a session.
    • Given a session ID, delete it which effectively triggers an depeering from the initiator.
    • Below is based on OpenAPI specification: .
    • DELETE /sessions/{session_id}
      • Request parameters:
        • session_id returned by the server on creation or through the session list operation.
      • Response:
        • 204: OK
          • Contents: empty response as the session is processed and hard deleted
        • 400:
          • Error (example: session_id is invalid)
        • 403:
          • Unauthorized to perform the operation
        • 404:
          • The session referred by the specified session_id does not exist or is not visible to the caller

UTILITY API CALLS Endpoints which provide useful information for potential interconnections.

• /locations: LIST POTENTIAL PEERING LOCATIONS
  • List potential peering locations, both public and private. The response is paginated.
    • Below is based on OpenAPI specification: .
    • GET /locations
      • Request parameters:
        • asn (Server ASN, with which to list potential connections)
        • location_type (Optional: Peering Location)
        • max_results (integer to indicate an upper bound for a given response page)
        • next_token (opaque and optional string received on a previous response page and which allows the server to produce the next page of results. Its absence indicates to the server that the first page is expected)
      • Response:
        • 200: OK
          • Contents: List of Peering Locations.
            • next_token (opaque and optional string the server expects to be passed back on the request for the next page. Its absence indicates to the client that no more pages are available)
        • 400:
          • Error
        • 403:
          • Unauthorized to perform the operation

Private Peering (DRAFT)

• ADD/AUGMENT PNI
• Parameters:
  • Peer ASN
  • Facility
  • email address (contact)
  • Action type: add/augment
  • LAG struct:
    • IPv4
    • IPv6
    • Circuit ID
  • Who provides LOA? (and where to provide it).
• Response:
  • 200:
    • LAG struct, with server data populated
    • LOA or way to receive it
    • Request ID
  • 40x: rejections
• REMOVE PNI
  • As ADD/AUGMENT in parameters. Responses will include a requestID and status.

Public Peering Session Negotiation As part of public peering configuration, this draft must consider how the client and server should handshake at which sessions to configure peering. At first, a client will request sessions A, B, and C. The server may choose to accept all sessions A, B, and C. At this point, configuration proceeds as normal. However, the server may choose to reject session B. At that point, the server will reply back with A and C marked as "Accepted," and B as "Rejected." The server will then configure A and C, and wait for the client to configure A and C. If the client configured B as well, it will not come up. This draft encourages peers to set up garbage collection for unconfigured or down peering sessions, to remove stale configuration and maintain good router hygiene. Related to rejection, if the server would like to configure additional sessions with the client, the server may either reject all the session that do not meet the criteria caused by such absence in the client's request or approve the client's request and issue a separate request to the client's server requesting those additional peering sessions D and E. The server will configure D and E on their side, and D and E will become part of the sessions requested in the UUID. The client may choose whether or not to accept those additional sessions. If they do, the client should configure D and E as well. If they do not, the client will not configure D and E, and the server should garbage-collect those pending sessions. As part of the IETF discussion, the authors would like to discuss how to coordinate which side unfilters first. Perhaps this information could be conveyed over a preferences vector.

Private Peering Through future discussion with the IETF, the specification for private peering will be solidified. Of interest for discussion includes Letter of Authorization (LOA) negotiation, and how to coordinate unfiltering and configuration checks.

Maintenance This draft does not want to invent a new ticketing system. However, there is an opportunity in this API to provide maintenance notifications to peering partners. If there is interest, this draft would extend to propose a maintenance endpoint, where the server could broadcast upcoming and current maintenance windows. A maintenance message would follow a format like:

• Title: string
• Start Date: date maintenance start(s/ed): UTC
• End Date: date maintenance ends: UTC
• Area: string or enum
• Details: freeform string

The "Area" field could be a freeform string, or could be a parseable ENUM, like (BGP, PublicPeering, PrivatePeering, Configuration, Caching, DNS, etc). Past maintenances will not be advertised.

Possible Extensions The authors acknowledge that route-server configuration may also be of interest for this proposed API, and look forward to future discussions in this area.

IANA Considerations This document has no IANA actions.

References Normative References n.d. n.d. n.d. The OAuth 2.0 authorization framework enables a third-party application to obtain limited access to an HTTP service, either on behalf of a resource owner by orchestrating an approval interaction between the resource owner and the HTTP service, or by allowing the third-party application to obtain access on its own behalf. This specification replaces and obsoletes the OAuth 1.0 protocol described in RFC 5849. [STANDARDS-TRACK] JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is used as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure, enabling the claims to be digitally signed or integrity protected with a Message Authentication Code (MAC) and/or encrypted. This specification defines a profile for issuing OAuth 2.0 access tokens in JSON Web Token (JWT) format. Authorization servers and resource servers from different vendors can leverage this profile to issue and consume access tokens in an interoperable manner. JSON Web Tokens, also known as JWTs, are URL-safe JSON-based security tokens that contain a set of claims that can be signed and/or encrypted. JWTs are being widely used and deployed as a simple security token format in numerous protocols and applications, both in the area of digital identity and in other application areas. This Best Current Practices document updates RFC 7519 to provide actionable guidance leading to secure implementation and deployment of JWTs. This specification describes how to use bearer tokens in HTTP requests to access OAuth 2.0 protected resources. Any party in possession of a bearer token (a "bearer") can use it to get access to the associated resources (without demonstrating possession of a cryptographic key). To prevent misuse, bearer tokens need to be protected from disclosure in storage and in transport. [STANDARDS-TRACK] Informative References This document discusses the Border Gateway Protocol (BGP), which is an inter-Autonomous System routing protocol. The primary function of a BGP speaking system is to exchange network reachability information with other BGP systems. This network reachability information includes information on the list of Autonomous Systems (ASes) that reachability information traverses. This information is sufficient for constructing a graph of AS connectivity for this reachability from which routing loops may be pruned, and, at the AS level, some policy decisions may be enforced. BGP-4 provides a set of mechanisms for supporting Classless Inter-Domain Routing (CIDR). These mechanisms include support for advertising a set of destinations as an IP prefix, and eliminating the concept of network "class" within BGP. BGP-4 also introduces mechanisms that allow aggregation of routes, including aggregation of AS paths. This document obsoletes RFC 1771. [STANDARDS-TRACK] This document describes an architecture for an infrastructure to support improved security of Internet routing. The foundation of this architecture is a Resource Public Key Infrastructure (RPKI) that represents the allocation hierarchy of IP address space and Autonomous System (AS) numbers; and a distributed repository system for storing and disseminating the data objects that comprise the RPKI, as well as other signed objects necessary for improved routing security. As an initial application of this architecture, the document describes how a legitimate holder of IP address space can explicitly and verifiably authorize one or more ASes to originate routes to that address space. Such verifiable authorizations could be used, for example, to more securely construct BGP route filters. This document is not an Internet Standards Track specification; it is published for informational purposes. This document defines a Cryptographic Message Syntax (CMS) protected content type for use with the Resource Public Key Infrastructure (RPKI) to carry a general-purpose listing of checksums (a 'checklist'). The objective is to allow for the creation of an attestation, termed an "RPKI Signed Checklist (RSC)", which contains one or more checksums of arbitrary digital objects (files) that are signed with a specific set of Internet Number Resources. When validated, an RSC confirms that the respective Internet resource holder produced the RSC. This document specifies how to augment the Routing Policy Specification Language inetnum: class to refer specifically to geofeed data comma-separated values (CSV) files and describes an optional scheme that uses the Routing Public Key Infrastructure to authenticate the geofeed data CSV files. This document updates the specification of the WHOIS protocol, thereby obsoleting RFC 954. The update is intended to remove the material from RFC 954 that does not have to do with the on-the-wire protocol, and is no longer applicable in today's Internet. This document does not attempt to change or update the protocol per se, or document other uses of the protocol that have come into existence since the publication of RFC 954. [STANDARDS-TRACK]

Acknowledgments The authors would like to thank their collaborators, who implemented API versions and provided valuable feedback on the design.

• Ben Blaustein (Meta)
• Jakub Heichman (Meta)
• Stefan Prattner (20c)
• Ben Ryall (Meta)
• Erica Salvaneschi (Cloudflare)
• Job Snijders (Fastly)
• David Tuber (Cloudflare)
• Aaron Rose (Amazon)
• Prithvi Nath Manikonda (Amazon)