Network Working Group C. Aguado
Internet-Draft Amazon
Intended status: Informational M. Griswold
Expires: 8 May 2025 FullCtl
J. Ramseyer
Meta
A. Servin
Google
T. Strickx
Cloudflare
4 November 2024
Peering API
draft-ramseyer-grow-peering-api-06
Abstract
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
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://bgp.github.io/draft-ietf-peering-api/draft-peering-api-
ramseyer-protocol.html. Status information for this document may be
found at https://datatracker.ietf.org/doc/draft-ramseyer-grow-
peering-api/.
Source for this draft and an issue tracker can be found at
https://github.com/bgp/draft-ietf-peering-api.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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 https://datatracker.ietf.org/drafts/current/.
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This Internet-Draft will expire on 8 May 2025.
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Copyright (c) 2024 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
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Business Justification . . . . . . . . . . . . . . . . . 3
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 3
3. Audience . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Example Peering Request Negotiation . . . . . . . . . . . 4
4.2. Example API Flow . . . . . . . . . . . . . . . . . . . . 6
4.3. AUTH . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.4. REQUEST . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.5. CLIENT CONFIGURATION . . . . . . . . . . . . . . . . . . 9
4.6. SERVER CONFIGURATION . . . . . . . . . . . . . . . . . . 10
4.7. MONITORING . . . . . . . . . . . . . . . . . . . . . . . 10
4.8. COMPLETION . . . . . . . . . . . . . . . . . . . . . . . 11
5. API Endpoints and Specifications . . . . . . . . . . . . . . 11
5.1. DATA TYPES . . . . . . . . . . . . . . . . . . . . . . . 11
5.2. Endpoints . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2.1. Public Peering over an Internet Exchange (IX) . . . . 13
5.2.2. UTILITY API CALLS . . . . . . . . . . . . . . . . . . 17
5.2.3. Private Peering (DRAFT) . . . . . . . . . . . . . . . 18
6. Public Peering Session Negotiation . . . . . . . . . . . . . 19
7. Private Peering . . . . . . . . . . . . . . . . . . . . . . . 19
8. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 19
9. Security Considerations . . . . . . . . . . . . . . . . . . . 20
9.1. Threats . . . . . . . . . . . . . . . . . . . . . . . . . 20
9.1.1. Mitigations . . . . . . . . . . . . . . . . . . . . . 21
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9.2. Authorization controls . . . . . . . . . . . . . . . . . 21
9.3. Proof of holdership . . . . . . . . . . . . . . . . . . . 22
9.4. Request integrity and proof of possession . . . . . . . . 24
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 24
11.1. Normative References . . . . . . . . . . . . . . . . . . 24
11.2. Informative References . . . . . . . . . . . . . . . . . 26
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. 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 ([RFC4271]). 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.
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
2. Conventions and Terminology
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
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* Established: session is already defined as per BGP-4 specification
Section 8.2.2 of [RFC4271]
3. 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.
4. Protocol
The Peering API follows the Representational State Transfer ([rest])
architecture where sessions, locations, and maintenance events are
the resources the API represents and is modeled after the OpenAPI
standard [openapi]. Using the token bearer model ([RFC6750]), 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.
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 |
+-------------------+ +-------------------+
|
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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
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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 |
|<---------------------------------------------------------|
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| | |
| 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.) |
|<-----------------------------------------------------------|
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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 the following
information, where local always refers to the receiver and peer
always refers to the initiator:
- Structure:
1. Local ASN
2. Local IP
3. Peer ASN
4. Peer IP
5. Local BGP Role according to [RFC9234]
6. Peer BGP Role according to [RFC9234]
7. Local insert ASN (optional to support route servers)
8. Peer insert ASN (optional to support route servers)
9. Local monitoring session (optional to support monitoring
systems)
10. Peer monitoring session (optional to support monitoring
systems)
11. Peer Type (public or private)
12. Session Secret (optional with encoding agreed outside of
this specification)
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13. 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. The client SHOULD pull and use
additional information on the new peering from public sources as
required to ensure routing security, e.g., AS-SETs to configure
appropriate filters. For every session that the server rejected, the
client removes that session from the list to be configured.
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4.6. SERVER CONFIGURATION
The server configures all sessions that are in its list of approved
peering sessions from its reply to the client. The server SHOULD
pull and use additional information on the new peering from public
sources to ensure routing security, e.g., AS-SETs to configure
appropriate filters.
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 (where local refers to the server and peer refers to the
client):
- Session ID
- Local ASN
- Local IP
- Peer ASN
- Peer IP
- Local BGP Role ([RFC9234])
- Peer BGP Role ([RFC9234])
- Local insert ASN (optional, as defined above)
- Peer insert ASN (optional, as defined above)
- Local monitoring session (optional, as defined above)
- Peer monitoring session (optional, as defined above)
- Peer Type
- Session secret (optional, as defined above)
- Location
- Status
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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. 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 [RFC9092] which could provide endpoint
integration to WHOIS ([RFC3912]). 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 ([autopeer]).
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.
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
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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)
* local_bgp_role (BGP role according to [RFC9234])
* peer_bgp_role (BGP role according to [RFC9234])
* local_insert_asn (optional, to support route servers, defaults to
true)
* peer_insert_asn (optional, to support route servers, defaults to
true)
* local_monitoring_session (optional, to support monitoring systems,
defaults to false)
* peer_monitoring_session (optional, to support monitoring systems,
defaults to false)
* peer_type (public or private)
* session_secret (optional, as defined above)
* location (Peering Location, as defined above)
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* status (Session Status, as defined above)
* session_id (of individual session and generated by the server)
As not all elements are reflected in the [autopeer] OpenAPI
definition to date, we define the missing fields here to be reflected
in [autopeer] in the future.
* local_bgp_role and peer_bgp_role: these field describe the BGP
roles of the local and peer side of the session according to
[RFC9234] represented by an integer. The roles for both sides
MUST be set in a way that does not violate role correctness as
defined in Section 4.2 of [RFC9234].
* local_insert_asn and peer_insert_asn: these fields define whether
the local or peer side will insert their ASN into the AS path
attribute of forwarded BGP routes. They are mostly relevant to
route servers. The fields are boolean and optional. If not
provided, they default to true.
* local_monitoring_session and peer_monitoring_session: these fields
define whether the local or peer side of the session will forward
routes to other ASes or not. As the role of monitoring systems is
not defined in [RFC9234], we add this role via a boolean, optional
flag. If not provided, they default to false.
local_monitoring_session and peer_monitoring_sessions MUST NOT be
true at the same time for the same session to avoid a role
mismatch.
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.
5.2.1. Public Peering over an Internet Exchange (IX)
* /sessions: ADD/RETRIEVE sessions visible to the calling PEER
- Batch create new session resources
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o Establish new BGP sessions between peers, at the desired
exchange.
o Below is based on OpenAPI specification: [autopeer].
o 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
* 422:
- Please contact us, human intervention required
- List all session resources. The response is paginated.
o Given a request ID, query for the status of that request.
o Given an ASN without request ID, query for status of all
connections between client and server.
o Below is based on OpenAPI specification: [autopeer].
o GET /sessions
+ Request parameters:
* asn (requesting client's asn)
* request_id (optional, UUID of request)
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* 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.
o 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
o Below is based on OpenAPI specification: [autopeer].
o 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
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* 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.
o Given a session ID, delete it which effectively triggers an
depeering from the initiator.
o Below is based on OpenAPI specification: [autopeer].
o 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
* 422:
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- Please contact us, human intervention required
5.2.2. 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.
o Below is based on OpenAPI specification: [autopeer].
o 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.
o 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:
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- Unauthorized to perform the operation
5.2.3. Private Peering (DRAFT)
* ADD/AUGMENT PNI
* Parameters:
- Peer ASN
- Facility
- email address (contact)
- Action type: add/augment
- LAG struct:
o IPv4
o IPv6
o Circuit ID
- Who provides LOA? (and where to provide it).
* Response:
- 200:
o LAG struct, with server data populated
o LOA or way to receive it
o Request ID
- 40x: rejections
* REMOVE PNI
- As ADD/AUGMENT in parameters. Responses will include a
requestID and status.
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6. 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.
7. 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.
8. 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:
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* 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.
9. Security Considerations
This document describes a mechanism to standardize the discovery,
creation and maintenance of peering relationships across autonomous
systems (AS) using an out-of-band application programming interface
(API). With it, AS operators take a step to operationalize their
peering policy with new and existing peers in ways that improve or
completely replace manual business validations, ultimately leading to
the automation of the interconnection. However, this improvement can
only be fully materialized when operators are certain that such API
follows the operational trust and threat models they are comfortable
with, some of which are documented in BGP operations and security
best practices ([RFC7454]). To that extent, this document assumes
the peering API will be deployed following a strategy of defense in-
depth and proposes the following common baseline threat model below.
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.
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* 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.
9.1.1. Mitigations
The following list of mitigations address different parts of the
threats identified above:
* M1: Authorization controls - A initiator using a client
application is authorized using the claims presented in the
request prior to any interaction with the peering API (addresses
T1, T2).
* M2: Proof of holdership - The initiator of a request through a
client can prove their holdership of an Internet Number Resource
(addresses T1, T3).
* M3: Request integrity and proof of possession - The peering API
can verify HTTP requests signed with a key that is
cryptographically bound to the authorized initiator (addresses T1,
T2).
The Peering API does not enforce any kind of peering policy on the
incoming requests. It is left to the peering API instance
implementation to enforce the AS-specific peering policy. This
document encourages each peer to consider the needs of their peering
policy and implement request validation as desired.
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
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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.
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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.
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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.
10. IANA Considerations
This document has no IANA actions.
11. References
11.1. Normative References
[autopeer] "Github repository with the API specification and
diagrams", n.d., .
[oidc] "OpenID.Core", n.d.,
.
[openapi] "OpenAPI-v3.1.0", n.d.,
.
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[rest] Fielding, R. T., "Architectural Styles and the Design of
Network-based Software Architectures", 2000,
.
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012,
.
[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
Framework: Bearer Token Usage", RFC 6750,
DOI 10.17487/RFC6750, October 2012,
.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, .
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
.
[RFC8414] Jones, M., Sakimura, N., and J. Bradley, "OAuth 2.0
Authorization Server Metadata", RFC 8414,
DOI 10.17487/RFC8414, June 2018,
.
[RFC8725] Sheffer, Y., Hardt, D., and M. Jones, "JSON Web Token Best
Current Practices", BCP 225, RFC 8725,
DOI 10.17487/RFC8725, February 2020,
.
[RFC9068] Bertocci, V., "JSON Web Token (JWT) Profile for OAuth 2.0
Access Tokens", RFC 9068, DOI 10.17487/RFC9068, October
2021, .
[RFC9323] Snijders, J., Harrison, T., and B. Maddison, "A Profile
for RPKI Signed Checklists (RSCs)", RFC 9323,
DOI 10.17487/RFC9323, November 2022,
.
[RFC9421] Backman, A., Ed., Richer, J., Ed., and M. Sporny, "HTTP
Message Signatures", RFC 9421, DOI 10.17487/RFC9421,
February 2024, .
[RFC9449] Fett, D., Campbell, B., Bradley, J., Lodderstedt, T.,
Jones, M., and D. Waite, "OAuth 2.0 Demonstrating Proof of
Possession (DPoP)", RFC 9449, DOI 10.17487/RFC9449,
September 2023, .
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11.2. Informative References
[RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912,
DOI 10.17487/RFC3912, September 2004,
.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
.
[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
February 2012, .
[RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations
and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454,
February 2015, .
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
.
[RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection",
RFC 7662, DOI 10.17487/RFC7662, October 2015,
.
[RFC9092] Bush, R., Candela, M., Kumari, W., and R. Housley,
"Finding and Using Geofeed Data", RFC 9092,
DOI 10.17487/RFC9092, July 2021,
.
[RFC9234] Azimov, A., Bogomazov, E., Bush, R., Patel, K., and K.
Sriram, "Route Leak Prevention and Detection Using Roles
in UPDATE and OPEN Messages", RFC 9234,
DOI 10.17487/RFC9234, May 2022,
.
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[RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, .
Appendix A. 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 Pratter (20C)
* Ben Ryall (Meta)
* Erica Salvaneschi (Cloudflare)
* Job Snijders (Fastly)
* David Tuber (Cloudflare)
* Aaron Rose (Amazon)
* Prithvi Nath Manikonda (Amazon)
* Matthias Wichtlhuber (DE-CIX)
Authors' Addresses
Carlos Aguado
Amazon
Email: crlsa@amazon.com
Matt Griswold
FullCtl
Email: grizz@20c.com
Jenny Ramseyer
Meta
Email: ramseyer@meta.com
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Arturo Servin
Google
Email: arturolev@google.com
Tom Strickx
Cloudflare
Email: tstrickx@cloudflare.com
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