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rfc:rfc8330

Internet Engineering Task Force (IETF) H. Long Request for Comments: 8330 M. Ye Category: Standards Track Huawei Technologies Co., Ltd. ISSN: 2070-1721 G. Mirsky

                                                                   ZTE
                                                       A. D'Alessandro
                                                 Telecom Italia S.p.A.
                                                               H. Shah
                                                                 Ciena
                                                         February 2018
   OSPF Traffic Engineering (OSPF-TE) Link Availability Extension
             for Links with Variable Discrete Bandwidth

Abstract

 A network may contain links with variable discrete bandwidth, e.g.,
 microwave and copper.  The bandwidth of such links may change
 discretely in response to a changing external environment.  The word
 "availability" is typically used to describe such links during
 network planning.  This document defines a new type of Generalized
 Switching Capability-Specific Information (SCSI) TLV to extend the
 Generalized Multiprotocol Label Switching (GMPLS) Open Shortest Path
 First (OSPF) routing protocol.  The extension can be used for route
 computation in a network that contains links with variable discrete
 bandwidth.  Note that this document only covers the mechanisms by
 which the availability information is distributed.  The mechanisms by
 which availability information of a link is determined and the use of
 the distributed information for route computation are outside the
 scope of this document.  It is intended that technology-specific
 documents will reference this document to describe specific uses.

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 has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8330.

Long, et al. Standards Track [Page 1] RFC 8330 Availability Extension to OSPF-TE February 2018

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.

Table of Contents

 1. Introduction ....................................................3
    1.1. Conventions Used in This Document ..........................3
 2. Abbreviations ...................................................4
 3. Overview ........................................................4
 4. TE Metric Extension to OSPF-TE ..................................5
    4.1. Availability SCSI-TLV ......................................5
    4.2. Processing Procedures ......................................6
 5. Security Considerations .........................................6
 6. IANA Considerations .............................................7
 7. References ......................................................7
    7.1. Normative References .......................................7
    7.2. Informative References .....................................8
 Acknowledgments ...................................................10
 Authors' Addresses ................................................10

Long, et al. Standards Track [Page 2] RFC 8330 Availability Extension to OSPF-TE February 2018

1. Introduction

 Some data-plane technologies, e.g., microwave and copper, allow
 seamless changes of maximum physical bandwidth through a set of known
 discrete values.  The parameter "availability", as described in
 [G.827], [F.1703], and [P.530], is often used to describe the link
 capacity.  The availability is a time scale, representing a
 proportion of the operating time that the requested bandwidth is
 ensured.  To set up a Label Switched Path (LSP) across these links,
 availability information is required by the nodes to verify the
 bandwidth before making a bandwidth reservation.  Assigning different
 availability classes over such links provides for more efficient
 planning of link capacity to support different types of services.
 The link availability information will be determined by the operator
 and is statically configured.  It will usually be determined from the
 availability requirements of the services expected to be carried on
 the LSP.  For example, voice service usually needs "five nines"
 availability, while non-real-time services may adequately perform at
 four or three nines availability.  For the route computation, both
 the availability information and the bandwidth resource information
 are needed.  Since different service types may need different
 availability guarantees, multiple <availability, bandwidth> pairs may
 be required to be associated with a link.
 In this document, a new type of Generalized SCSI-TLV, the
 Availability SCSI-TLV, is defined.  It is intended that technology-
 specific documents will reference this document to describe specific
 uses.  The signaling extension to support links with variable
 discrete bandwidth is defined in [RSVP-TE-Availability].

1.1. Conventions Used in This Document

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
 capitals, as shown here.

Long, et al. Standards Track [Page 3] RFC 8330 Availability Extension to OSPF-TE February 2018

2. Abbreviations

 The following abbreviations are used in this document:
 GMPLS     Generalized Multiprotocol Label Switching
 ISCD      Interface Switching Capability Descriptor
 LSA       Link State Advertisement
 LSP       Label Switched Path
 OSPF      Open Shortest Path First
 SCSI      Switching Capability-Specific Information
 SPF       Shortest Path First
 TE        Traffic Engineering
 TLV       Type-Length-Value

3. Overview

 A node that has link(s) with variable discrete bandwidth attached
 should include an <availability, bandwidth> information list in its
 OSPF-TE LSA messages.  The list provides the mapping between the link
 nominal bandwidth and its availability level.  This information is
 used for path calculation by the node(s).  The setup of an LSP
 requires this information to be flooded in the network and used by
 the nodes or the PCE for the path computation.  In this document, a
 new type of Generalized SCSI-TLV, the Availability SCSI-TLV, is
 defined.  The computed path can then be provisioned via the signaling
 protocol [RSVP-TE-Availability].
 Note: The mechanisms described in this document only distribute
 availability information.  The methods for measuring the information
 or using the information for route computation are outside the scope
 of this document.

Long, et al. Standards Track [Page 4] RFC 8330 Availability Extension to OSPF-TE February 2018

4. TE Metric Extension to OSPF-TE

4.1. Availability SCSI-TLV

 The Generalized SCSI is defined in [RFC8258].  This document defines
 a new type of Generalized SCSI-TLV called the Availability SCSI-TLV.
 The Availability SCSI-TLV can be included one or more times.  It has
 the following format:
    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Type            |               Length          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Availability level                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   LSP Bandwidth at Availability level n       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Type: 0x000A, 16 bits
    Length: 2 octets (16 bits)
    Availability level: 32 bits
       This field is a binary32-format floating-point number as
       defined by [IEEE754-2008].  The bytes are transmitted in
       network order; that is, the byte containing the sign bit is
       transmitted first.  This field describes the decimal value of
       the availability guarantee of the Switching Capability in the
       Interface Switching Capability Descriptor object [RFC4202].
       The value MUST be less than 1.  The Availability level field is
       usually expressed as the value 0.99/0.999/0.9999/0.99999.
    LSP Bandwidth at Availability level n: 32 bits
       This field is a 32-bit IEEE floating-point number as defined by
       [IEEE754-2008].  The bytes are transmitted in network order;
       that is, the byte containing the sign bit is transmitted first.
       This field describes the LSP bandwidth for the availability
       level represented in the Availability level field.  The units
       are bytes per second.

Long, et al. Standards Track [Page 5] RFC 8330 Availability Extension to OSPF-TE February 2018

4.2. Processing Procedures

 The ISCD allows routing protocols such as OSPF to carry technology-
 specific information in the "Switching Capability-specific
 information" field; see [RFC4203].  A node advertising an interface
 with a Switching Capability that supports variable discrete bandwidth
 attached SHOULD contain one or more Availability SCSI-TLVs in its
 OSPF-TE LSA messages.  Each Availability SCSI-TLV provides
 information about how much bandwidth a link can support for a
 specified availability.  This information may be used for path
 calculation by the node(s).
 The Availability SCSI-TLV MUST NOT be sent in ISCDs with Switching
 Capability field values that have not been defined to support the
 Availability SCSI-TLV.  Non-supporting nodes would see such an
 ISCD/LSA as malformed.
 The absence of the Availability SCSI-TLV in an ISCD containing
 Switching Capability field values that have been defined to support
 the Availability SCSI-TLV SHALL be interpreted as representing the
 fixed-bandwidth link with the highest availability value.
 Only one Availability SCSI-TLV for the specific availability level
 SHOULD be sent.  If multiple TLVs are present, the Availability
 SCSI-TLV with the lowest bandwidth value SHALL be processed.  If an
 Availability SCSI-TLV with an invalid value (e.g., larger than 1) is
 received, the Availability SCSI-TLV will be ignored.

5. Security Considerations

 This document specifies the contents of Opaque LSAs in OSPFv2.
 Tampering with GMPLS-TE LSAs may have an effect on TE computations.
 [RFC3630] suggests such mechanisms as the mechanism described in
 [RFC2154] to protect the transmission of this information, and those
 or other mechanisms should be used to secure and/or authenticate the
 information carried in the Opaque LSAs.  An analysis of the security
 of OSPF is provided in [RFC6863] and applies to the OSPF extension
 defined in this document.  Any new mechanisms developed to protect
 the transmission of information carried in Opaque LSAs will also
 automatically protect the extension defined in this document.
 Please refer to [RFC5920] for details on security threats; defensive
 techniques; monitoring, detection, and reporting of security attacks;
 and requirements.

Long, et al. Standards Track [Page 6] RFC 8330 Availability Extension to OSPF-TE February 2018

6. IANA Considerations

 This document introduces a new type of Generalized SCSI-TLV
 (Availability) that is carried in the OSPF-TE LSA messages.
 Technology-specific documents will reference this document to
 describe the specific use of this Availability SCSI-TLV.
 IANA created a registry called the "Generalized SCSI (Switching
 Capability Specific Information) TLV Types" registry [RFC8258].  The
 registry has been updated to include the following Availability
 SCSI-TLV:
    Type     Description    Switching Type   Reference
    ------   ------------   --------------   ---------
    0x000A   Availability   5, 52            RFC 8330
 New switching types are required in order to use the Availability
 SCSI-TLV.  IANA has registered the following in the "Switching Types"
 registry:
   Value  Name                       Reference
   -----  -------------------------- ---------
       5  PSC with GSCSI support     RFC 8330
      52  L2SC with GSCSI support    RFC 8330

7. References

7.1. Normative References

 [IEEE754-2008]
            IEEE, "IEEE Standard for Floating-Point Arithmetic",
            IEEE 754-2008, DOI 10.1109/IEEESTD.2008.4610935.
 [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>.
 [RFC4202]  Kompella, K., Ed., and Y. Rekhter, Ed., "Routing
            Extensions in Support of Generalized Multi-Protocol Label
            Switching (GMPLS)", RFC 4202, DOI 10.17487/RFC4202,
            October 2005, <https://www.rfc-editor.org/info/rfc4202>.
 [RFC4203]  Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
            in Support of Generalized Multi-Protocol Label Switching
            (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
            <https://www.rfc-editor.org/info/rfc4203>.

Long, et al. Standards Track [Page 7] RFC 8330 Availability Extension to OSPF-TE February 2018

 [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>.
 [RFC8258]  Ceccarelli, D. and L. Berger, "Generalized SCSI: A Generic
            Structure for Interface Switching Capability Descriptor
            (ISCD) Switching Capability Specific Information (SCSI)",
            RFC 8258, DOI 10.17487/RFC8258, October 2017,
            <https://www.rfc-editor.org/info/rfc8258>.

7.2. Informative References

 [F.1703]   International Telecommunication Union, "Availability
            objectives for real digital fixed wireless links used in
            27 500 km hypothetical reference paths and connections",
            ITU-R Recommendation F.1703-0, January 2005,
            <https://www.itu.int/rec/R-REC-F.1703-0-200501-I/en>.
 [G.827]    International Telecommunication Union, "Availability
            performance parameters and objectives for end-to-end
            international constant bit-rate digital paths", ITU-T
            Recommendation G.827, September 2003,
            <https://www.itu.int/rec/T-REC-G.827/en>.
 [P.530]    International Telecommunication Union, "Propagation data
            and prediction methods required for the design of
            terrestrial line-of-sight systems", ITU-R
            Recommendation P.530-17, December 2017,
            <https://www.itu.int/rec/R-REC-P.530/en>.
 [RFC2154]  Murphy, S., Badger, M., and B. Wellington, "OSPF with
            Digital Signatures", RFC 2154, DOI 10.17487/RFC2154,
            June 1997, <https://www.rfc-editor.org/info/rfc2154>.
 [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
            (TE) Extensions to OSPF Version 2", RFC 3630,
            DOI 10.17487/RFC3630, September 2003,
            <https://www.rfc-editor.org/info/rfc3630>.
 [RFC5920]  Fang, L., Ed., "Security Framework for MPLS and GMPLS
            Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
            <https://www.rfc-editor.org/info/rfc5920>.

Long, et al. Standards Track [Page 8] RFC 8330 Availability Extension to OSPF-TE February 2018

 [RFC6863]  Hartman, S. and D. Zhang, "Analysis of OSPF Security
            According to the Keying and Authentication for Routing
            Protocols (KARP) Design Guide", RFC 6863,
            DOI 10.17487/RFC6863, March 2013,
            <https://www.rfc-editor.org/info/rfc6863>.
 [RSVP-TE-Availability]
            Long, H., Ye, M., Mirsky, G., D'Alessandro, A., and H.
            Shah, "Ethernet Traffic Parameters with Availability
            Information", Work in Progress, draft-ietf-ccamp-rsvp-te-
            bandwidth-availability-08, January 2018.

Long, et al. Standards Track [Page 9] RFC 8330 Availability Extension to OSPF-TE February 2018

Acknowledgments

 The authors would like to thank Acee Lindem, Daniele Ceccarelli, and
 Lou Berger for their comments on the document.

Authors' Addresses

 Hao Long
 Huawei Technologies Co., Ltd.
 No. 1899, Xiyuan Avenue, Hi-tech Western District
 Chengdu  611731
 China
 Phone: +86-18615778750
 Email: longhao@huawei.com
 Min Ye
 Huawei Technologies Co., Ltd.
 No. 1899, Xiyuan Avenue, Hi-tech Western District
 Chengdu  611731
 China
 Email: amy.yemin@huawei.com
 Greg Mirsky
 ZTE
 Email: gregimirsky@gmail.com
 Alessandro D'Alessandro
 Telecom Italia S.p.A.
 Email: alessandro.dalessandro@telecomitalia.it
 Himanshu Shah
 Ciena Corp.
 3939 North First Street
 San Jose, CA  95134
 United States of America
 Email: hshah@ciena.com

Long, et al. Standards Track [Page 10]

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