Peering API

1.1. 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¶

4.1. Example Peering Request Negotiation

Diagram of the Peering Request Process¶

+-------------------+                    +-------------------+
|     Step 1        |                    |     Step 2        |
|    Network 1      |------------------->|    Network 1      |
|  Identifies need  |                    |   Checks details  |
+-------------------+                    +-------------------+
                                                 |
                                                 v
+-------------------+                    +-------------------+
|      Step 4       |                    |      Step 3       |
|    Network 1      |<-------------------|    Network 1      |
|  gets approval    |                    |     Public or     |
|      token        |                    | Private Peering   |
+-------------------+                    +-------------------+
        |
        v
+-------------------+                    +-------------------+
|      Step 5       |                    |      Step 6       |
|  Network 1 finds  |------------------->|    Network 1      |
| common locations  |                    |  request peering  |
+-------------------+                    +-------------------+
                                                  |
                                                  v
+-------------------+                   +--------------------+
|      Step 8       |                   |       Step 7       |
|     Network 2     |<------------------|     Network 2      |
| accepts or reject |                   |      verifies      |
|    sessions       |                   |     credentials    |
+-------------------+                   +--------------------+
       /     \
      /       \
     /         \
(yes)           (no)
      \          |
       \         +-------------------------------|
        \                                        |
         \                                       |
          v                                      |
+---------------+          +----------------+    |
|    Step 9     |          |    Step 10     |    |
| Sessions are  |          | Network 1 or 2 |    |
|  provisioned  |--------->| checks session |    |
|     status    |          | until it is up |    |
+---------------+          +----------------+    |
                                   |             |
                      +------------+             |
                      |                          |
                      v                          |
            +-------------+                      |
            |   Step 11   |                      |
            |   Request   |<---------------------+
            |  Terminate  |
            +-------------+







Step 1 [Human]: Network 1 identifies that it would be useful to peer with Network 2 to interchange traffic more optimally


Step 2 [Human]: Network 1 checks technical and other peering details about Network 2 to check if peering is possible


Step 3 [Human]: Network 1 decides in type (Public or PNI) of peering and facility


Step 4 [API]: Network 1 gets approval/token that is authorized to ‘speak’ on behalf of Network 1’s ASN.


Step 5 [API]: Network 1 checks PeeringDB for common places between Network 1 and Network 2.
API: GET /locations


Step 6 [API]: Network 1 request peering with Network 2
API:      POST /add_sessions


Step 7 [API]: Network 2 verifies Network 1 credentials, check requirements for peering


Step 8 [API]: Network 2 accepts or rejects session(s)
API Server gives yes/no for request


Step 9 [API]: If yes, sessions are provisioned, Networks 1 or Network 2 can check status
API: /sessions Get session status


Step 10 [API]: API keeps polling until sessions are up


Step 11 [API]: Process Terminate

4.2. Example API Flow

The diagram below outlines the proposed API flow.¶

OIDC Authentication

+-----------+                 +-------+                    +-----------+
| Initiator |                 | Peer  |                    | PeeringDB |
+-----------+                 +-------+                    +-----------+
      |                           |                              |
      | OIDC Authentication       |                              |
      |--------------------------------------------------------->|
      |                           |                              |
      |                                        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.) |
      |<-----------------------------------------------------------|

4.3. AUTH

First, the initiating OAuth2 Client is also the Resource Owner (RO) so it can follow the OAuth2 client credentials grant Section 4.4 of [RFC6749]. 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.¶

4.4. 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.¶

4.5. 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.¶

4.6. SERVER CONFIGURATION

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

4.7. 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).¶

4.8. 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.¶

5.1. DATA TYPES

Please see specification ([autopeer]) 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.¶

5.2. Endpoints

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

9.1. Threats

Each of the following threats assume a scenario where an arbitrary actor is capable of reaching the peering API instance of a given operator, the client and the operator follow their own endpoint security and maintenance practices, and the trust anchors in use are already established following guidelines outside of the scope of this document.¶

• T1: A malicious actor with physical access to the IX fabric and peering API of the receiver can use ASN or IP address information to impersonate a different IX member to discover, create, update or delete peering information which leads to loss of authenticity, confidentiality, and authorization of the spoofed IX member.¶

• T2: A malicious actor with physical access to the IX fabric can expose a peering API for an IX member different of its own to accept requests on behalf of such third party and supplant it, leading to a loss of authenticity, integrity, non-repudiability, and confidentiality between IX members.¶

• T3: A malicious actor without physical access to the IX fabric but with access the the peering API can use any ASN to impersonate any autonomous system and overload the receiver's peering API internal validations leading to a denial of service.¶

9.2. Authorization controls

The peering API instance receives HTTP requests from a client application from a peering initiator. Those requests can be authorized using the authorization model based on OAuth 2.0 ([RFC6749]) with the OpenID Connect [oidc] core attribute set. The choice of OpenID Connect is to use a standardized and widely adopted authorization exchange format based on JSON Web Tokens ([RFC7519]) which allows interoperation with existing web-based application flows. JWT tokens also supply sufficient claims to implement receiver-side authorization decisions by third parties when used as bearer access tokens ([RFC9068]). The peering API instance (a resource server in OAuth2 terms) should follow the bearer token usage ([RFC6750]) which describes the format and validation of an access token obtained from the Oauth 2.0 Authorization Server. The resource server should follow the best practices for JWT access validation ([RFC8725]) and in particular verify that the access token is constrained to the resource server via the audience claim. Upon successful access token validation, the resource server should decide whether to proceed with the request based on the presence of expected and matching claims in the access token or reject it altogether. The core identity and authorization claims present in the access token may be augmented with specific claims vended by the Authorization Service. This document proposes to use PeeringDB's access token claims as a baseline to use for authorization, however the specific matching of those claims to an authorization business decision is specific to each operator and outside of this specification. Resource servers may also use the claims in the access token to present the callers' identity to the application and for auditing purposes.¶

9.3. Proof of holdership

The peering API defined in this document uses ASNs as primary identifiers to identify each party on a peering session besides other resources such as IP addresses. ASNs are explicitly expected in some API payloads but are also implicitly expected when making authorization business decisions such as listing resources that belong to an operator. Given that ASNs are Internet Number Resources assigned by RIRs and that the OAuth2 Authorization Server in use may not be operated by any of those RIRs, as it is the case of PeeringDB or any other commercial OAuth2 service, JWT claims that contain an ASN need be proved to be legitimately used by the initiator. This document proposes to attest ASN resource holdership using a mechanism based on RPKI ([RFC6480]) and in particular with the use of RPKI Signed Checklists (RSCs) ([RFC9323]).¶

JWT access tokens can be of two kinds, identifier-based tokens or self-contained tokens (Section 1.4 of [RFC6749]). Resource servers must validate them for every request. AS operators can hint other operators to validate whether a caller holds ownership of the ASN their request represent by issuing a signed checklist that is specific to the different validation methods as described below.¶

For Identifier-based access tokens, if the Authorization Server supports metadata, ASN holders must create a signed checklist that contains the well-known Authorization Server Metadata URI and a digest of the JSON document contained (Section 3 of [RFC8414]). If the authorization server does not support metadata, the signed checklist contains the token introspection URI and its digest.¶

Self-contained access tokens are cryptographically signed by the token issuer using a JSON Web Signature (JWS) ([RFC7515]). The cryptographic keys used for signature validation is exposed as a JSON Web Key (JWK) ([RFC7517]). ASN holders must create a signed checklist for the "jwks_uri" field of the Authorization Server Metadata URI and a digest of the JSON document contained (Section 3.2 of [RFC8414]).¶

Resource servers must validate the JWT access token in the following manner:¶

• If the access token is identifier-based, the resource server must resolve what introspection endpoint to use for the given access token, that is, either resolved through the Authorization Server Metadata URI (Section 3 of [RFC8414]) or pre-configured upon registration in the absence of metadata support.¶

  • The resource server must verify the metadata URI and its content with a signed checklist issued by the ASN contained in the access token claims.¶

  • If the Authorization Server does not support metadata, the resource server must validate the introspection endpoint URI matches exactly the URI contained in a signed checklist issued by the ASN contained in the access token claims.¶

  • Upon successful signed checklist validation, resource servers must use the introspection endpoint for regular access token validation process ([RFC7662]).¶

• If the access token is self-contained, the resource server must follow the regular validation process for signed access tokens (Section 5.2 of [RFC7515]).¶

  • After discovering the valid public keys used to sign the token, the resource server must validate that the JWKS URI where the public keys have been discovered, and the content of such JSON document referred by it, match the signed checklist issued by the ASN contained in the access token claims.¶

• Resource servers must reject the request if any of these validations fail.¶

9.4. Request integrity and proof of possession

The API described in this document follows REST ([rest]) principles over an HTTP channel to model the transfer of requests and responses between peers. Implementations of this API should use the best common practices for the API transport ([RFC9325]) such as TLS. However, even in the presence of a TLS channel with OAuth2 bearer tokens alone, neither the client application nor the API can guarantee the end-to-end integrity of the message request or the authenticity of its content. One mechanism to add cryptographic integrity and authenticity validation can be the use a mutual authentication scheme to negotiate the parameters of the TLS channel. This requires the use of a web PKI ([RFC5280]) to carry claims for use in authorization controls, to bind such PKI to ASNs for proof of holdership, and the use of client certificates on the application.¶

Instead, this document proposes to address the message integrity property by cryptographically signing the parameters of the request with a key pair that creates a HTTP message signature to be included in the request ([RFC9421]). The client application controls the lifecycle of this key pair. The authenticity property of the messages signed with such key pair is addressed by binding the public key of the pair to the JWT access token in one of its claims of the access token using a mechanism that demonstrates proof of possession of the private key [RFC9449]. With these two mechanisms, the resource server should authenticate, authorize, and validate the integrity of the request using a JWT access token that can rightfully claim to represent a given ASN.¶