IGP extension for PCEP security capability support in the PCE discovery
draft-wu-pce-discovery-pceps-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. [RFC5088] and [RFC5089] define a method to advertise path computation capabilities using IGP flooding for OSPF and ISIS respectively. However [RFC5088] and [RFC5089] lacks a method to advertise PCEP security (e.g., Transport Layer Security(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] and [RFC5089]) 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 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 August 14, 2014.

Copyright Notice

Copyright (c) 2014 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 (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.

Table of Contents

• 1. Introduction
• 2. Conventions used in this document
• 3. IGP extension for PCEP security capability support
• 3.1. Use of PCEP transport capability support for PCE discovery
• 4. Backward Compatibility Consideration
• 5. Management Considerations
• 6. Security Considerations
• 7. IANA Considerations
• 8. References
• 8.1. Normative References
• 8.2. Informative References
• Authors' Addresses

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. In order for a Path Computation Client(PCC) to begin a connection with a PCE server using TLS, PCC SHOULD know whether PCE server supports TLS as a secure transport.

[RFC5088] and [RFC5089] define a method to advertise path computation capabilities using IGP flooding for OSPF and ISIS respectively. However [RFC5088] and [RFC5089] lacks a method to advertise PCEP security (ex. 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] 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].

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 (ex. 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] and [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

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

3.1. Use of PCEP transport capability support for PCE discovery

TCP MD5, TCP-AO, PCEP over TLS support flag bits are advertised using IGP flooding. If the PCE server supports only TCP MD5, IGP advertisement SHOULD include TCP MD5 support flag bit. If the PCE server supports both TCP MD5 and TCP-AO, IGP advertisement SHOULD only include TCP-AO support flag bit in the PCE-CAP-FLAGS sub-TLV. If the PCE server supports both TCP MD5 and PCEP over TLS, IGP advertisement SHOULD include both TCP MD5 support flag bit and PCEP over TLS support flag bit in the PCE-CAP-FLAGS sub-TLV. If the PCE server supports both TCP-AO and PCEP over TLS, IGP advertisement SHOULD include both TCP-AO support flag bit and PCEP over TLS flag bit in the PCE-CAP-FLAGS sub-TLV. If the PCE server only supports TLS over TCP , 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. 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 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 MD5 support         [This.I.D] 
     xx            TCP-AO Support          [This.I.D] 
     xx            PCEP over TLS support   [This.I.D] 

8. References

8.1. Normative References

8.2. Informative References

Authors' Addresses