IGP extension for PCEP transport capability support in the PCE discovery
draft-wu-pce-discovery-priority-allocation-01

Abstract

[RFC5088][RFC5089] define a method to advertise path computation capabilities using IGP flooding. OSPF and ISIS are extended to support such capabilities advertisement. However [RFC5088][RFC5089]don’t provide a method to advertise PCEP over TLS support capability.

This document proposes new capability flag bit for PCE-CAP-FLAGS sub-TLV that can be announced as attribute in the IGP advertisement (defined in [RFC5088 ][RFC5089]) to distribute transport 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 working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on April 24, 2014.

Copyright Notice

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://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
2. Conventions used in this document
3. IGP extension for PCEP transport capability support
3.1. Use of PCEP transport capability support for PCE discovery
4. Security Considerations
5. IANA Considerations
6. References
6.1. Normative References
6.2. Informative References
Author's Address

1. Introduction

As described in [RFC5440], PCEP communication privacy is one importance issue, especially in an inter-AS context, where PCEP communication end-points do not reside in the same AS, as an attacker that intercepts a 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. In order for a PCC to begin a connection with a PCE server using TLS, PCC should know whether PCE server Support TLS as transport.

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].

3. IGP extension for PCEP transport capability support

The PCE-CAP-FLAGS sub-TLV is defined in section 4.5 of [RFC5088][RFC5089] and 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 over TLS support in the present document.

   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

In the PCE-CAP-FLAGS sub-TLV defined in [RFC5088][RFC5089], nine capability flags defined in [RFC4657] and two capability flags defined [RFC5557][RFC6006]are included and follows the following format: The PCE-CAP-FLAGS sub-TLV has the following format:

     Bit         Capability Description
     xx         TCP MD5 support
     xx         TCP AO Support
     xx         PCEP over TLS support
     xx         PCEP over TLS support and TCP AO support

and the processing rule of these flag bits are defined in [RFC5088][RFC5089]. In this document, we define one new capability flag bit that indicate TCP MD5 support, TCP AO support, PCEP over TLS support and PCEP over TLS and TCP AO support respectively as follows:

3.1. Use of PCEP transport capability support for PCE discovery

TCP MD5, TCP AO, PCEP over TLS support and PCEP over TLS and TCP AO support flag bits are advertised using IGP flooding. If the PCE server supports only TCP MD5 as transport, IGP advertisement Should not include PCEP over TLS support flag bit or TCP AO support flag bit. If the PCE server supports both TCP MD5 and TCP AO, IGP advertisment Should include both TCP AO support flag bit and TCP MD5 support flag bit in the PCE-CAP-FLAGS sub-TLV. If the PCE server only supports TLS over TCP as transport, IGP advertisement MUST include PCEP over TLS support flag bit in the PCE-CAP-FLAGS sub-TLV.

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 before retrieving PCE location information from IGP message. if not, the client should discard PCEPD TLV with TCP AO support flag bit clear. If the client is looking for connecting with PCE server using TLS, the client MUST check if PCEP over TLS support flag bit in the PCE-CAP-FLAGS sub-TLV is set before retrieving PCE location information from IGP message. If not, then the client should discard PCED TLV with PCEP over TLS support flag bit clear.

4. Security Considerations

This document raises no new security issues beyond those described in [RFC5088][RFC5089].

5. IANA Considerations

IANA is requested to allocate a new bit in "PCE Capability Flags" registry for PCEP over TLS support capability.

6. References

6.1. 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.

6.2. Informative References

[RFC5440]	Le Roux, JL., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009.
[RFC5246]	Dierks, T., "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5440, August 2008.

Author's Address

Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China EMail: sunseawq@huawei.com