RFC 9916

RFC 9916: Updates to the Usage of TLS for PCEP 💖

Okay bestie, this is RFC 9916 🎀 It's an IETF Standards Track document from July 2026, and it updates RFC 8253 ✨ It doesn't obsolete anything. The authors are D. Dhody of Huawei 💅, S. Turner of sn3rd 🦋, and R. Housley of Vigil Security 🌸 The ISSN is 2070-1721 🫶

The title is "Updates to the Usage of TLS to Provide a Secure Transport for the Path Computation Element Communication Protocol (PCEP)" 🧚

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Abstract

Okay so, Section 3.4 of RFC 8253 sets the TLS connection establishment restrictions for PCEPS 🔐 PCEPS is just the way we use TLS to give PCEP a secure transport 😭 This document adds more restrictions for two things: what PCEPS implementations do when they support more than one TLS version, and how they use TLS 1.3's early data 💀

Status of This Memo

This is an Internet Standards Track document 🌈

This document is a product of the Internet Engineering Task Force (IETF) ✨ It represents the consensus of the IETF community. It got public review and was approved for publication by the Internet Engineering Steering Group (IESG) 👑 If you want more on Internet Standards, check out Section 2 of RFC 7841 💜

Info about the current status of this doc, any errata, and how to give feedback is at https://www.rfc-editor.org/info/rfc9916 🍓

Copyright Notice

Copyright (c) 2026 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 (https://trustee.ietf.org/license-info) as they're in effect on the publication date. Please read these carefully, because they explain your rights and restrictions for this document 🙈 Code Components pulled out of this document must include Revised BSD License text, as described in Section 4.e of the Trust Legal Provisions, and they come without warranty as described in the Revised BSD License 🫶

Table of Contents

1.  Introduction
2.  Conventions
3.  TLS Connection Establishment Restrictions
4.  Security Considerations
5.  IANA Considerations
6.  References
  6.1.  Normative References
  6.2.  Informative References
Acknowledgments
Authors' Addresses

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1. Introduction ✨

Okay, Section 3.4 of [RFC8253] is where the TLS connection establishment restrictions for PCEPS live 🦋 PCEPS is TLS used as a secure transport for the Path Computation Element Communication Protocol (PCEP) [RFC5440] 🧚 This document adds restrictions for two things. The first is what PCEPS implementations do when they support more than one TLS version, like TLS 1.2 [RFC5246] and TLS 1.3 [RFC9846] 🌸 The second is limiting TLS 1.3's early data, which is also called 0-RTT data 🔥 Everything else in [RFC8253] stays exactly the same, including connection initiation, message framing, connection closure, certificate validation, peer identity, and failure handling 💅

2. Conventions

Here's the key word part 💖 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are interpreted as described in BCP 14 [RFC2119] [RFC8174], but only when they appear in all capitals, just like shown here ✨ Lowercase versions are just regular words, bestie 🙈

3. TLS Connection Establishment Restrictions

Step 1 in Section 3.4 of [RFC8253] already has restrictions on PCEPS TLS connection establishment 🎀 This document adds these:

• Implementations that support multiple versions of the TLS protocol MUST prefer to negotiate the latest version of the TLS protocol. See Section 4.2.1 of [RFC9846] 👑
• PCEPS implementations that support TLS 1.3 or later MUST NOT use early data 💀

NOTE: Okay, so early data (aka 0-RTT data) is a TLS 1.3 mechanism from [RFC9846] that lets a client send data ("early data") in the very first flight of messages to a server 🦋 TLS 1.3 can totally run without early data, as per Appendix F.5 of [RFC9846] 🌈 Honestly, TLS 1.3 only allows early data when the client and server share a Pre-Shared Key (PSK), either got externally or from an earlier handshake 🧚 The client uses that PSK to authenticate the server and to encrypt the early data 💜

NOTE: As noted in Section 2.3 of [RFC9846], early data has weaker security properties than the TLS-protected data that comes after it 😭 Early data isn't forward secret, and there's no protection against replaying early data between connections 💀 Appendix E.5 of [RFC9846] says applications shouldn't... sorry, it requires applications to not use early data without a profile that defines how it's used 🙈

4. Security Considerations

The security considerations for PCEP [RFC5440] [RFC8231] [RFC8253] [RFC8281] [RFC8283], TLS 1.2 [RFC5246], TLS 1.3 [RFC9846], and the TLS/DTLS recommendations [RFC9325] apply here too 🔥 Please take these seriously, because TLS mistakes can quietly break a whole network's trust 😭🔐

5. IANA Considerations

This document has no IANA actions 🍓

6. References

6.1. Normative References

[RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
           Requirement Levels", BCP 14, RFC 2119,
           DOI 10.17487/RFC2119, March 1997,
           <https://www.rfc-editor.org/info/rfc2119>.

[RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
           (TLS) Protocol Version 1.2", RFC 5246,
           DOI 10.17487/RFC5246, August 2008,
           <https://www.rfc-editor.org/info/rfc5246>.

[RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
           Element (PCE) Communication Protocol (PCEP)", RFC 5440,
           DOI 10.17487/RFC5440, March 2009,
           <https://www.rfc-editor.org/info/rfc5440>.

[RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
           2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
           May 2017, <https://www.rfc-editor.org/info/rfc8174>.

[RFC8253]  Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
           "PCEPS: Usage of TLS to Provide a Secure Transport for the
           Path Computation Element Communication Protocol (PCEP)",
           RFC 8253, DOI 10.17487/RFC8253, October 2017,
           <https://www.rfc-editor.org/info/rfc8253>.

[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, <https://www.rfc-editor.org/info/rfc9325>.

[RFC9846]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
           Version 1.3", RFC 9846, DOI 10.17487/RFC9846, July 2026,
           <https://www.rfc-editor.org/info/rfc9846>.

6.2. Informative References

[RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
           Computation Element Communication Protocol (PCEP)
           Extensions for Stateful PCE", RFC 8231,
           DOI 10.17487/RFC8231, September 2017,
           <https://www.rfc-editor.org/info/rfc8231>.

[RFC8281]  Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
           Computation Element Communication Protocol (PCEP)
           Extensions for PCE-Initiated LSP Setup in a Stateful PCE
           Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
           <https://www.rfc-editor.org/info/rfc8281>.

[RFC8283]  Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An
           Architecture for Use of PCE and the PCE Communication
           Protocol (PCEP) in a Network with Central Control",
           RFC 8283, DOI 10.17487/RFC8283, December 2017,
           <https://www.rfc-editor.org/info/rfc8283>.

Acknowledgments

Huge thanks to Adrian Farrel, Stephane Litkowski, Cheng Li, and Andrew Stone for reviewing this 🫶🌸

Authors' Addresses

• Dhruv Dhody, Huawei, Email: dhruv.ietf@gmail.com 💜
• Sean Turner, sn3rd, Email: sean@sn3rd.com 🦋
• Russ Housley, Vigil Security, LLC, 516 Dranesville Road, Herndon, VA 20170, United States of America, Email: housley@vigilsec.com 🧚