PCE working group D. Lopez
Internet-Draft Telefonica I+D
Intended status: Standards Track Q. Wu
Expires: February 24, 2019 D. Dhody
Z. Wang
Huawei
D. King
Old Dog Consulting
August 23, 2018
IGP extension for PCEP security capability support in the PCE discovery
draft-wu-lsr-pce-discovery-security-support-00
Abstract
When a Path Computation Element (PCE) is a Label Switching Router
(LSR) participating in the Interior Gateway Protocol (IGP), or even a
server participating in IGP, its presence and path computation
capabilities can be advertised using IGP flooding. The IGP
extensions for PCE discovery (RFC 5088 and RFC 5089) define a method
to advertise path computation capabilities using IGP flooding for
OSPF and IS-IS respectively. However these specifications lack a
method to advertise PCEP security (e.g., Transport Layer
Security(TLS),TCP Authentication Option (TCP-AO)) support capability.
This document proposes new capability flag bits for PCE-CAP-FLAGS
sub-TLV that can be announced as attribute in the IGP advertisement
to distribute PCEP security support information.
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
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 24, 2019.
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Copyright Notice
Copyright (c) 2018 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) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
1. Introduction
As described in [RFC5440], PCEP communication privacy is one
importance issue, as an attacker that intercepts a Path Computation
Element (PCE) message could obtain sensitive information related to
computed paths and resources.
Among the possible solutions mentioned in these documents, Transport
Layer Security (TLS) [RFC5246] provides support for peer
authentication, and message encryption and integrity while TCP
Authentication Option (TCP-AO) [RFC5925] and Cryptographic Algorithms
for TCP-AO [RFC5926] offer significantly improved security for
applications using TCP. As specified in section 4 of [RFC8253], in
order for a Path Computation Client(PCC) to begin a connection with a
PCE server using TLS or TCP-AO, PCC SHOULD know whether PCE server
supports TLS or TCP-AO as a secure transport.
[RFC5088] and [RFC5089] define a method to advertise path computation
capabilities using IGP flooding for OSPF and IS-IS respectively.
However [RFC5088] and [RFC5089] lacks a method to advertise PCEP
security (e.g., TLS) support capability.
This document proposes new capability flag bits for PCE-CAP-FLAGS
sub-TLV that can be announced as attributes in the IGP advertisement
(defined in [RFC5088] and [RFC5089]) to distribute PCEP security
support information.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [RFC2119].
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3. IGP extension for PCEP security capability support
The PCE-CAP-FLAGS sub-TLV is defined in section 4.5 of [RFC5088] and
[RFC5089] as an optional sub-TLV used to advertise PCE capabilities.
In this section, we extend the PCE-CAP-FLAGS sub-TLV to include the
capability and indications that are described for PCEP security
(e.g., TLS) support in the current document.
In the PCE-CAP-FLAGS sub-TLV defined in [RFC5088] and [RFC5089], nine
capability flags defined in [RFC5088] (as per [RFC4657]) and two
capability flags defined [RFC5557], [RFC6006] are included and
follows the following format:
o TYPE: 5
o LENGTH: Multiple of 4
o VALUE: This contains an array of units of 32 bit flags with
the most significant bit as 0. Each bit represents one PCE
capability.
and the processing rule of these flag bits are defined in [RFC5088]
and [RFC5089]. In this document, we define two new capability flag
bits that indicate TCP Authentication Option (TCP-AO) support, PCEP
over TLS support respectively as follows:
Bit Capability Description
xx TCP AO Support
xx PCEP over TLS support
3.1. Use of PCEP security capability support for PCE discovery
TCP-AO, PCEP over TLS support flag bits are advertised using IGP
flooding.
o PCE supports TCP-AO: IGP advertisement SHOULD include TCP-AO
support flag bit.
o PCE supports TLS: IGP advertisement SHOULD include PCEP over TLS
support flag bit.
If PCE supports multiple security mechanisms, it SHOULD include all
corresponding flag bits in IGP advertisement.
If the client is looking for connecting with PCE server with TCP-AO
support, the client MUST check if TCP-AO support flag bit in the PCE-
CAP-FLAGS sub-TLV is set. If not, the client SHOULD NOT consider
this PCE. If the client is looking for connecting with PCE server
using TLS, the client MUST check if PCEP over TLS support flag bit in
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the PCE-CAP-FLAGS sub-TLV is set. If not, the client SHOULD NOT
consider this PCE.
4. Backward Compatibility Consideration
An LSR that does not support the new IGP PCE capability bits
specified in this document silently ignores those bits.
IGP extensions defined in this document do not introduce any new
interoperability issues.
5. Management Considerations
A configuration option may be provided for advertising and
withdrawing PCE security capability via IGP.
6. Security Considerations
This document raises no new security issues beyond those described in
[RFC5088] and [RFC5089].
7. IANA Considerations
IANA is requested to allocate a new bit in "PCE Security Capability
Flags" registry for PCEP Security support capability.
Bit Meaning Reference
xx TCP-AO Support [This.I.D]
xx PCEP over TLS support [This.I.D]
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC5088] Le Roux, JL., "OSPF Protocol Extensions for Path
Computation Element (PCE) Discovery", RFC 5088, January
2008.
[RFC5089] Le Roux, JL., "IS-IS Protocol Extensions for Path
Computation Element (PCE) Discovery", RFC 5089, January
2008.
[RFC5925] Touch , J., "The TCP Authentication Option", RFC 5925,
June 2010.
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[RFC5926] Gregory Lebovitz, G., "Cryptographic Algorithms for the
TCP Authentication Option (TCP-AO)", RFC 5926, June 2010.
[RFC8253] R. Lopez, D., "PCEPS: Usage of TLS to Provide a Secure
Transport for the Path Computation Element Communication
Protocol (PCEP)", RFC 8253, October 2017.
8.2. Informative References
[RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE)
Communication Protocol Generic Requirements", RFC 4657,
September 2006.
[RFC5246] Dierks, T., "The Transport Layer Security (TLS) Protocol
Version 1.2", RFC 5246, August 2008.
[RFC5440] Le Roux, JL., "Path Computation Element (PCE)
Communication Protocol (PCEP)", RFC 5440, March 2009.
[RFC5557] Lee, Y., Le Roux, JL., King, D., and E. Oki, "Path
Computation Element Communication Protocol (PCEP)
Requirements and Protocol Extensions in Support of Global
Concurrent Optimization", RFC 5557, July 2009.
[RFC6006] Zhao, Q., King, D., Verhaeghe, F., Takeda, T., Ali, Z.,
and J. Meuric, "Extensions to the Path Computation Element
Communication Protocol (PCEP) for Point-to-Multipoint
Traffic Engineering Label Switched Paths", RFC 6006,
September 2010.
Appendix A. Appendix A: No MD5 Capability Support
To be compliant with Section 10.2 of RFC5440, this document doesn't
consider to add capability for TCP-MD5. Therefore by default, PCEP
Speaker in communication supports capability for TCP-MD5 (See section
10.2,[RFC5440]). A method to advertise TCP-MD5 Capability support
using IGP flooding is not required. If the client is looking for
connecting with PCE server with other Security capability support
(e.g., TLS support) than TCP-MD5, the client MUST check if flag bit
in the PCE- CAP-FLAGS sub-TLV for specific capability is set (See
section 3.1).
Authors' Addresses
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Diego R. Lopez
Telefonica I+D
Spain
Email: diego.r.lopez@telefonica.com
Qin Wu
Huawei Technologies
12 Mozhou East Road, Jiangning District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560037
India
Email: dhruv.ietf@gmail.com
Michael Wang
Huawei
12 Mozhou East Road, Jiangning District
Nanjing, Jiangsu 210012
China
Email: wangzitao@huawei.com
Daniel King
Old Dog Consulting
UK
Email: daniel@olddog.co.uk
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