Extensions to OSPF for Temporal LSP
draft-chen-ospf-tts-02

Versions: 00 01 02                                                      
Internet Engineering Task Force                                  H. Chen
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                                  M. Toy
Expires: January 21, 2018                                        Verizon
                                                                  V. Liu
                                                            China Mobile
                                                                  L. Liu
                                                                 Fijitsu
                                                           July 20, 2017


                  Extensions to OSPF for Temporal LSP
                       draft-chen-ospf-tts-02.txt

Abstract

   This document specifies extensions to OSPF for distributing Traffic
   Engineering (TE) information on a link in a sequence of time
   intervals.

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   to this document.  Code Components extracted from this document must



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   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.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Conventions Used in This Document  . . . . . . . . . . . . . .  3
   4.  Representation of TE Information . . . . . . . . . . . . . . .  4
     4.1.  TE Information in Absolute Time  . . . . . . . . . . . . .  4
     4.2.  TE Information in Relative Time  . . . . . . . . . . . . .  5
   5.  Extensions to OSPF . . . . . . . . . . . . . . . . . . . . . .  6
     5.1.  TE LSA . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     5.2.  TTS Link TLV . . . . . . . . . . . . . . . . . . . . . . .  7
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 10
   8.  Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . . 10
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 10
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11




























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1.  Introduction

   Once an existing multiprotocol label switching (MPLS) traffic
   engineering (TE) label switched path (LSP) is set up, it is assumed
   to carry traffic forever until it is down.  When an MPLS TE LSP
   tunnel is up, it is assumed that the LSP consumes its reserved
   network resources forever even though the LSP may only use network
   resources during some period of time.  As a result, the network
   resources are not used efficiently.  Moreover, a tunnel service can
   not be reserved or booked in advance for a period of time.

   This document specifies extensions to OSPF for supporting the setup
   of an MPLS TE LSP in a period of time called a time interval or a
   sequence of time intervals.  It is assumed that the LSP carries
   traffic during this time interval or each of these time intervals.
   Thus the network resources are efficiently used.  More importantly,
   some new services can be provided.  For example, a consumer can book
   a tunnel service in advance for a time interval or a sequence of time
   intervals.  Tunnel services may be scheduled.


2.  Terminology

   A Time Interval: a time period from time Ta to time Tb.

   LSP: Label Switched Path.  An LSP is a P2P (point-to-point) LSP or a
   P2MP (point-to-multipoiint) LSP.

   LSP in a time interval: LSP that carries traffic in the time
   interval.

   LSP in a sequence of time intervals: LSP that carries traffic in each
   of the time intervals.

   Temporal LSP: LSP in a time interval or LSP in a sequence of time
   intervals.

   TEDB: Traffic Engineering Database.

   This document uses terminologies defined in RFC2328 and RFC3630.


3.  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.




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4.  Representation of TE Information

   The existing Open Shortest Path First (OSPF) Traffic Engineering (TE)
   distributes an unreserved bandwidth Bi at each of eight priority
   levels for a link at one point of time, for example, at the current
   time.

     Bandwidth
       ^
       |
     Bi|______________________________________________________
       |
       |
      -+------------------------------------------------------> Time
       |


   This means that the link has bandwidth Bi at a priority level from
   now to forever until there is a change to it.  This TE information on
   the link is stored in TEDB.

   Thus, a temporal LSP (i.e., an LSP in a time interval) cannot be set
   up using the information in the TEDB and the bandwidth cannot be
   reserved in advance for the LSP in the time interval.

   To support temporal LSPs, we should extend OSPF to distribute TE
   information on a link in a series of time intervals.

4.1.  TE Information in Absolute Time

   Suppose that the amount of the unreserved bandwidth at a priority
   level on a link is Bj in a time interval from time Tj to Tk (k =
   j+1), where j = 0, 1, 2, ....  The unreserved bandwidth on the link
   can be represented as

       [T0, B0], [T1, B1], [T2, B2], [T3, B3], ....


   This is an absolute time representation of bandwidths on a link.
   Time Tj (j = 0, 1, 2, ...)  MUST be a synchronized time among all
   network nodes.










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     Bandwidth
       ^
       |                                    B3
       |          B1                        ___________
       |          __________
       |B0                                             B4
       |__________          B2                         _________
       |                    ________________
       |
      -+-------------------------------------------------------> Time
       |T0        T1        T2              T3         T4


   If an LSP is deleted or down at time T and uses bandwidth B, then for
   every time interval/period (after time T) during which bandwidth B is
   reserved for the LSP on a link attached to a network node, the
   network node adds B to the link for that interval/period.

   If an LSP is set up at time T and uses bandwidth B, then for every
   time interval/period (after time T) during which bandwidth B is
   reserved for the LSP on a link attached to a network node, the
   network node subtracts bandwidth B from the link for that interval/
   period.

   If there are significant changes to the bandwidths on a link attached
   to a network node, the network node distributes the bandwidths on the
   link to other network nodes.  That is that a updated [T0, B0], [T1,
   B1], [T2, B2], [T3, B3], etc., are distributed to other network nodes
   in the network.  Each of the other network nodes can construct or
   determine the bandwidth for a series of time intervals/periods on a
   link after receiving the information.

4.2.  TE Information in Relative Time

   Alternatively, a relative time representation of bandwidths on a link
   can be used.  For example, the amount of the unreserved bandwidth at
   a priority level on a link is Bj during a series of time intervals/
   periods can be expressed as

       [P0, B0], [P1, B1], [P2, B2], [P3, B3], ..., where
       Pj = Tk - Tj, k = (j+1) and j = 0, 1, 2, 3, ....


   In this representation, every time Tj (j = 0, 1, 2, ...) can be a
   local time.  A timer may expire after every unit of time (e.g., every
   second) and trigger --P0, which decrements P0.  When P0 = 0, P1
   becomes P0, P2 becomes p1, and so on.




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   If there are significant changes to the bandwidths on a link attached
   to a node, the node distributes the bandwidths on the link to other
   nodes.  That is that a updated [P0, B0], [P1, B1], [P2, B2], [P3,
   B3], ..., are distributed to other network nodes in the network.  On
   each of the other network nodes, a timer may expire for every unit of
   time (e.g., every second) and trigger --P0, which decrements P0.
   When P0 = 0, P1 becomes P0, P2 becomes p1, and so on.

   An advantage of using relative time representation is that the times
   or clocks on all the network nodes can be different.


5.  Extensions to OSPF

   This section describes the extensions to OSPF for supporting the
   setup of temporal LSPs.

5.1.  TE LSA

   An opaque LSA of type 10 is originated by a network node to
   distribute TE information such as the bandwidth of a link that is
   attached to the network node.

     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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |            LS age             |     Options   |  LS Type=10   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       1       |                 Opaque ID                     |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Advertising Router                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     LS sequence number                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         LS checksum           |             length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     ~                             TLVs                              ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   The opaque LSA comprises a link-state (LS) age field, an options
   field, an LS type field, an opaque identifier (ID) field, an
   advertising router field, an LS sequence number field, an LS checksum
   field, a length field, and one or more TLVs.

   The LS age field indicates the time since the LSA was originated in
   seconds.  The options field indicates the optional capabilities



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   supported by the described portion of the routing domain.  The LS
   type field indicates the type of the LSA.  The opaque ID field is a
   number used to maintain multiple opaque LSAs.  The advertising router
   field indicates the Router ID of the router that originated the LSA.
   The LS sequence number field is used to detect old or duplicate LSAs.
   Successive instances of an LSA are given successive LS sequence
   numbers.  The LS checksum field indicates the Fletcher checksum of
   the complete contents of the LSA, including the LSA header but
   excluding the LS age field.  The length field indicates the length of
   the LSA in bytes.

5.2.  TTS Link TLV

   In addition to existing router address TLV and link TLV, TLVs fields
   may comprise a new temporal tunnel service (TTS) link TLV.

      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 (5)           |      Length (variable)        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |          Reserved (0)         |        Segment-Number         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          sub TLVs                             |
     ~                                                               ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   The TTS link TLV comprises a type field, a length field, a reserved
   field, a segment-number field, and a sub TLVs field.

   The type field may comprise a value assigned by the Internet Assigned
   Number Authority (IANA) to indicate that the TLV is a TTS link TLV.
   For example, the type field may comprise a value of 5.  The length
   field may indicate the length of the values in the TTS link TLV in
   bytes.

   The segment-number indicates a segment of the TTS link TLV.  The
   information on a link may be too big to fit into one TTS link TLV.
   In this case, the information may be split into a few of segments,
   each of which is put into a TTS link TLV and identified by a segment
   number.

   The sub TLV field comprises a link type sub-TLV and a link ID sub-
   TLV.  It may further comprise a local address sub-TLV, a remote
   address sub-TLV, a TE metric sub-TLV, a maximum bandwidth sub-TLV, a
   maximum reservable bandwidth sub-TLV, an unreserved bandwidth sub-
   TLV, an administrator group sub-TLV, a relative TTS unreserved



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   bandwidth sub-TLV, an absolute TTS unreserved bandwidth sub-TLV, and
   any other suitable sub-TLVs.

   The format of an absolute TTS unreserved bandwidth sub-TLV is shown
   below.

      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 (21)          |      Length (36+36*n)         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                              T0                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             B0[8]                             |
     ~                                                               ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                              T1                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             B1[8]                             |
     ~                                                               ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     ~                                                               ~
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                              Tn                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             Bn[8]                             |
     ~                                                               ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   It comprises a type field, a length field, absolute time fields, and
   unreserved bandwidth fields.

   The type field may comprise a value assigned by the IANA to indicate
   that the sub-TLV is an absolute TTS unreserved bandwidth sub-TLV.
   For example, the type field may comprise a value of 21.

   The length field may indicate the length of the values in the
   absolute TTS unreserved bandwidth sub-TLV in bytes.

   The absolute time fields and the unreserved bandwidth fields may be
   in pairs such as

       [ T0, B0[8] ], [ T1, B1[8] ], ..., [ Tn, Bn[8] ],





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   where T0, T1, ..., Tn are the times synchronized among all the nodes
   and Bj[8] (j=0, 1,..., n) are the amount of unreserved bandwidth at
   eight priority levels in the time interval/period from Tj to Tk
   (k=j+1).

   The format of a relative TTS unreserved bandwidth sub-TLV is
   illustrated as follows.

      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 (22)          |      Length (36+36*n)         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                              P0                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             B0[8]                             |
     ~                                                               ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                              P1                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             B1[8]                             |
     ~                                                               ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     ~                                                               ~
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                              Pn                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             Bn[8]                             |
     ~                                                               ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   It comprises a type field, a length field, relative time fields, and
   unreserved bandwidth fields.

   The type field may comprise a value assigned by the IANA to indicate
   that the sub-TLV is a relative TTS unreserved bandwidth sub-TLV.  For
   example, the type field may comprise a value of 22.

   The length field may indicate the length of the values in the
   relative TTS unreserved bandwidth sub-TLV in bytes.

   The relative time fields and the unreserved bandwidth fields may be
   in pairs such as

      [ P0, B0[8] ], [ P1, B1[8] ], ... , [ Pn, Bn[8] ],



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   where Pj (j=0, 1,..., n) is the time period during which the
   unreserved bandwidth is Bj[8], containing the amount of unreserved
   bandwidth at eight priority levels.


6.  Security Considerations

   The mechanism described in this document does not raise any new
   security issues for the OSPF protocols.


7.  IANA Considerations

   This section specifies requests for IANA allocation.


8.  Acknowledgement

   The author would like to thank people for their valuable comments on
   this draft.


9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
              RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328, DOI 10.17487/
              RFC2328, April 1998,
              <http://www.rfc-editor.org/info/rfc2328>.

   [RFC5250]  Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The
              OSPF Opaque LSA Option", RFC 5250, DOI 10.17487/RFC5250,
              July 2008, <http://www.rfc-editor.org/info/rfc5250>.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              DOI 10.17487/RFC3630, September 2003,
              <http://www.rfc-editor.org/info/rfc3630>.

9.2.  Informative References

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



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              Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
              <http://www.rfc-editor.org/info/rfc3209>.


Authors' Addresses

   Huaimo Chen
   Huawei Technologies
   Boston, MA
   US

   Email: huaimo.chen@huawei.com


   Mehmet Toy
   Verizon
   USA

   Email: mehmet.toy@verizon.com


   Vic Liu
   China Mobile
   No.32 Xuanwumen West Street, Xicheng District
   Beijing,   100053
   China

   Email: liu.cmri@gmail.com


   Lei Liu
   Fijitsu
   USA

   Email: lliu@us.fujitsu.com
















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