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Versions: (draft-long-ccamp-ospf-availability-extension) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 RFC 8330

Network Working Group                                     H. Long, M.Ye
Internet Draft                             Huawei Technologies Co., Ltd
Intended status: Standards Track                              G. Mirsky
                                                               Ericsson
                                                         A.D'Alessandro
                                                   Telecom Italia S.p.A
                                                                H. Shah
                                                                  Ciena
Expires: January 2016                                      July 6, 2015


     OSPF Routing Extension for Links with Variable Discrete Bandwidth
            draft-ietf-ccamp-ospf-availability-extension-02.txt


Abstract

   A packet switching network MAY contain links with variable discrete
   bandwidth, e.g., copper, radio, etc. The bandwidth of such links MAY
   change discretely in reaction to changing external environment.
   Availability is typically used for describing such links during
   network planning. This document introduces an OPTIONAL ISCD
   Availability sub-TLV in OSPF routing protocol. This extension can be
   used for route computation in a Packet Switched Network (PSN) that
   contains links with discretely variable bandwidth.



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), its areas, and its working groups.  Note that
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   reference material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt





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   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

   This Internet-Draft will expire on January 6, 2016.

Copyright Notice

   Copyright (c) 2015 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
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   warranty as described in the Simplified BSD License.

Table of Contents

   1. Introduction ................................................ 3
   2. Overview .................................................... 4
   3. Extension to OSPF Routing Protocol........................... 4
      3.1. Interface Switching Capacity Descriptor................. 4
      3.2. ISCD Availability sub-TLV............................... 5
      3.3. Signaling Process....................................... 6
   4. Security Considerations...................................... 7
   5. IANA Considerations ......................................... 7
   6. References .................................................. 7
      6.1. Normative References.................................... 7
      6.2. Informative References.................................. 8
   7. Acknowledgments ............................................. 8

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 RFC-2119 [RFC2119].

   The following acronyms are used in this draft:

   OSPF    Open Shortest Path First

   PSN     Packet Switched Network



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   SNR     Signal-to-noise Ratio

   LSP     Label Switched Path

   ISCD    Interface Switching Capacity Descriptor

   PE      Provider Edge

   LSA     Link State Advertisement

1. Introduction

   Some data communication technologies allow seamless change of
   maximum physical bandwidth through a set of known discrete values.
   For example, in mobile backhaul network, microwave links are very
   popular for providing connection of last hops. In case of heavy rain,
   to maintain the link connectivity, the microwave link MAY lower the
   modulation level since demodulating the lower modulation level needs
   lower signal-to-noise ratio (SNR). This is called adaptive
   modulation technology [EN 302 217]. However, a lower modulation
   level also means lower link bandwidth. When link bandwidth is
   reduced because of modulation down-shifting, high-priority traffic
   can be maintained, while lower-priority traffic is dropped.
   Similarly, the copper links MAY change their effective link
   bandwidth due to external interference.

   The parameter availability [G.827, F.1703, P.530] is often used to
   describe the link capacity during network planning. Assigning
   different availability classes to different types of service over
   such kind of links provides more efficient planning of link capacity.
   To set up an LSP across these links, availability information is
   required for the nodes to verify bandwidth satisfaction and make
   bandwidth reservation. The availability information SHOULD be
   inherited 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, the availability information SHOULD be
   provided along with bandwidth resource information. In this document,
   an extension on Interface Switching Capacity Descriptor (ISCD)
   [RFC4202] for availability information is defined to support in
   routing signaling. The extension reuses the reserved field in the
   ISCD and also introduces an OPTIONAL Availability sub-TLV.

   If there is a hop that cannot support the Availability sub-TLV, the
   Availability sub-TLV SHOULD be ignored.


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2. Overview

   A node which has link(s) with variable bandwidth attached SHOULD
   contain a <bandwidth, availability> information list in its OSPF TE
   LSA messages. The list provides the information that how much
   bandwidth a link can support for a specified availability. This
   information is used for path calculation by the PE node(s).

   To setup an label switching path (LSP), a PE node MAY collect link
   information which is spread in OSPF TE LSA messages by network nodes
   to get know about the network topology, calculate out an LSP route
   based on the network topology and send the calculated LSP route to
   signaling to initiate a PATH/RESV message for setting up the LSP.

   Availability information is required to carry in the signaling
   message to better utilize the link bandwidth. The signaling
   extension for availability can be found in [ASTE].

3. Extension to OSPF Routing Protocol

3.1. Interface Switching Capacity Descriptor

   The Interface Switching Capacity Descriptor (ISCD) sub-TLV [RFC 4203]
   has the following format:
























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       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               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Switching Cap |   Encoding    |      AI       |   Reserved    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 0              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 1              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 2              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 3              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 4              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 5              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 6              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 7              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Switching Capacity-specific Information      |
      |                         (variable)                            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      A new AI field is defined in this document.

      AI: ISCD Availability sub-TLV index, 8 bits

         This new field is the index of Availability sub-TLV for this
         ISCD sub-TLV.

3.2. ISCD Availability sub-TLV

   The Switching Capability field MAY be PSC-1/LSC. The Switching
   Capability specific information field MAY include one or more ISCD
   Availability sub-TLV(s). The ISCD Availability sub-TLV has the
   following format:








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       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          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      Index    |                     Reserved                  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   Availability level                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   LSP Bandwidth at Availability level n       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Type: 0x01, 16 bits;

      Length: 16 bits;

      Index: 8 bits

           This field is the index of this Availability sub-TLV,
           referred by the AI field of the ISCD sub-TLV.

       Availability level: 32 bits

           This field is a 32-bit IEEE floating point number which
           describes the decimal value of availability guarantee of the
           switching capacity in the ISCD object which has the AI value
           equal to Index of this sub-TLV. The value MUST be less than
           1.

       LSP Bandwidth at Availability level n: 32 bits

           This field is a 32-bit IEEE floating point number which
           describes the LSP Bandwidth at a certain Availability level
           which was described in the Availability field.

3.3. Signaling Process

   A node which has link(s) with variable bandwidth attached SHOULD
   contain one or more ISCD Availability sub-TLVs in its OSPF TE LSA
   messages. Each ISCD Availability sub-TLV provides the information
   about how much bandwidth a link can support for a specified
   availability. This information SHOULD be used for path calculation
   by the PE node(s).

   A node that doesn't support ISCD Availability sub-TLV SHOULD ignore
   ISCD Availability sub-TLV.




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4. Security Considerations

   This document does not introduce new security considerations to the
   existing OSPF protocol.

5. IANA Considerations

   This document introduces an Availability sub-TLV of the ISCD sub-TLV
   of the TE Link TLV in the TE Opaque LSA for OSPF v2. This document
   proposes a suggested value for the Availability sub-TLV; it is
   recommended that the suggested value be granted by IANA. Initial
   values are as follows:

   Type    Length            Format                   Description

   ---     ----              ------------------       -----------

   0        -                Reserved                 Reserved value

   0x01      8               see Section 3.2          Availability

6. References

6.1. Normative References

   [RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
             Services", RFC 2210, September 1997.

   [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
             V.,and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
             Tunnels", RFC 3209, December 2001.

   [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
             (GMPLS) Signaling Resource ReserVation Protocol-Traffic
             Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

   [RFC4202] Kompella, K. and Rekhter, Y. (Editors), "Routing
             Extensions in Support of Generalized Multi-Protocol Label
             Switching (GMPLS)", RFC 4202, October 2005.

   [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
             in Support of Generalized Multi-Protocol Label Switching
             (GMPLS)", RFC 4203, October 2005.

   [G.827]  ITU-T Recommendation, "Availability performance parameters
             and objectives for end-to-end international constant bit-
             rate digital paths", September, 2003.


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   [F.1703]  ITU-R Recommendation, "Availability objectives for real
             digital fixed wireless links used in 27 500 km
             hypothetical reference paths and connections", January,
             2005.

   [P.530]   ITU-R Recommendation," Propagation data and prediction
             methods required for the design of terrestrial line-of-
             sight systems", February, 2012

   [EN 302 217] ETSI standard, "Fixed Radio Systems; Characteristics
             and requirements for point-to-point equipment and
             antennas", April, 2009

   [ASTE]    H., Long, M., Ye, Mirsky, G., Alessandro, A., Shah, H.,
             "RSVP-TE Signaling Extension for Links with Variable
             Discrete Bandwidth", Work in Progress, February, 2014

6.2. Informative References

   [MCOS]    Minei, I., Gan, D., Kompella, K., and X. Li, "Extensions
             for Differentiated Services-aware Traffic Engineered
             LSPs", Work in Progress, June 2006.

7. Acknowledgments





   Authors' Addresses


















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   Hao Long
   Huawei Technologies Co., Ltd.
   No.1899, Xiyuan Avenue, Hi-tech Western District
   Chengdu 611731, P.R.China

   Phone: +86-18615778750
   Email: longhao@huawei.com


   Min Ye
   Huawei Technologies Co., Ltd.
   No.1899, Xiyuan Avenue, Hi-tech Western District
   Chengdu 611731, P.R.China

   Email: amy.yemin@huawei.com

   Greg Mirsky
   Ericsson

   Email: gregory.mirsky@ericsson.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
   US

   Email: hshah@ciena.com















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