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 April 13, 2016                                      July 6,                                October 16, 2015

     OSPF Routing Extension for Links with Variable Discrete Bandwidth
            draft-ietf-ccamp-ospf-availability-extension-02.txt
            draft-ietf-ccamp-ospf-availability-extension-03.txt

Abstract

   A packet switching network MAY contain links with variable discrete bandwidth, e.g.,
   copper, radio, etc. The bandwidth of such links MAY 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 optional ISCD
   Availability sub-TLV in OSPF routing protocol. This extension can be
   used for route computation in a Packet Switched Network (PSN) network that contains links with discretely
   variable discrete 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
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

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

   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, April 13, 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
   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 ................................................ 3
   2. Overview .................................................... 4 3
   3. Extension to OSPF Routing Protocol........................... 4
      3.1. Interface Switching Capacity Descriptor................. 4
      3.2. ISCD Availability sub-TLV............................... 5 4
      3.3. Signaling Process....................................... 6 5
   4. Security Considerations...................................... 7 5
   5. IANA Considerations ......................................... 7 5
   6. References .................................................. 7 5
      6.1. Normative References.................................... 7 5
      6.2. Informative References.................................. 8 6
   7. Acknowledgments ............................................. 8 6

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

   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 technologies, e.g., microwave, and copper,
   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. The availability is a time scale that the requested
   bandwidth is ensured. 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 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 may adequately perform at four or three
   nines availability. Since different service types may need different
   availabilities guarantees, multiple <availability, bandwidth> pairs
   may be required when signaling. The signaling extension for links
   with discrete bandwidth is defined in [ASTE].

   For the route computation, the availability information SHOULD 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 optional Availability sub-TLV.

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

2. Overview

   A node which has link(s) with variable bandwidth attached SHOULD 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 a label switching path (LSP), a PE node MAY 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:

       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 Section 1.4 of Availability sub-TLV for this
         ISCD sub-TLV. [RFC 4203].

3.2. ISCD Availability sub-TLV

   The Switching Capability field MAY be PSC-1/LSC. 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:

       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.

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

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

    [ASTE]    H., Long, M., Ye, Mirsky, G., Alessandro, A., Shah, H.,
             "Ethernet Traffic Parameters with Availability
             Information", Work in Progress, June, 2015

6.2. Informative References

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

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", RFC 2119, March 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]

   [MCOS]    Minei, I., Gan, D., Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions X. Li, "Extensions
             for Differentiated Services-aware Traffic Engineered
             LSPs", Work in Support of Generalized Multi-Protocol Label Switching
             (GMPLS)", RFC 4203, October 2005. Progress, June 2006.

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

   [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

   The authors would like to thank Lou Berger for his comments on the
   document.

   Authors' Addresses

   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