Internet DRAFT - draft-dhillon-ccamp-super-channel-ospfte-ext

draft-dhillon-ccamp-super-channel-ospfte-ext



Network Working Group                                  Iftekhar Hussain
                                                              Rajan Rao
                                                             Marco Sosa
                                                               Infinera
                                                        Abinder Dhillon
Internet Draft                                                  Fujitsu
Intended status: Standard Track                        October 16, 2013
Expires: Apr 16, 2014



              OSPFTE extension to support GMPLS for Flex Grid
            draft-dhillon-ccamp-super-channel-ospfte-ext-06.txt


Abstract

   This document specifies the extension to TELINK LSA of OSPF routing
   protocol [RFC4203] [3] in support of GMPLS [1] for flex-grid
   networks [2].



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
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   This Internet-Draft will expire on Apr 16, 2014.






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Copyright Notice

   Copyright (c) 2012 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
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   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
   2. Terminology....................................................3
   3. Interface Switching Capability Descriptor......................3
      3.1. Switch Capability Specific Information ....................5
      3.2. BW sub TLV: Bit Map format................................5
         3.2.1. Meaning of sub TLV fields............................5
      3.3. BW sub TLV: List and Rage format..........................7
         3.3.1. Meaning of sub TLV fields............................7
      3.4. BW advertisement procedure................................8
   4. Examples.......................................................8
      4.1. Example: BW advertisement without any service present.....8
      4.2. Example: How to use advertized Bandwidth..................9
   5. Security Considerations.......................................10
   6. IANA Considerations...........................................10
   7. References....................................................10
      7.1. Normative References.....................................10
      7.2. Informative References...................................10
   8. Acknowledgments...............................................11

      1. Introduction

   To enable scaling of existing transport systems to ultra-high data
   rates of 1 Tbps and beyond, next generation systems providing super-
   channel[2] switching capability are currently being developed. To
   allow efficient allocation of optical spectral bandwidth for such
   high bit rate systems, International Telecommunication Union
   Telecommunication Standardization Sector (ITU-T) is extending the


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   G.694.1 grid standard (termed ''Fixed-Grid'') to include flexible grid
   (termed ''Flex-Grid'') support [10].

   This document defines OSPF-TE extensions in support of flex-grid
   networks.

   Figure-1 shows a network capable of switching in Flexible-Grid[10].
   The physical media/Fiber is modeled as a TE-Link to advertise
   spectrum (bandwidth) availability. This information is used during
   Flex-grid LSP[10] creation (also called super-channel LSPs[2]). This
   draft defines extensions to ISCD in support of Flexible-Grid.


           +-------+               +-------+               +-------+
           | SC    |               |  SC   |               |  SC   |
           |Switch |.---Link ---> |Switch |<- Link----- ->|Switch |
           |   A   |               |   B   |               |   C   |
           +-------+               +-------+               +-------+

                   |<-- TE-Link -->|       |<-- TE-Link -->|

                             Figure 1: TE-Links

      2. Terminology

   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].



      3. Interface Switching Capability Descriptor

The Interface Switching Capability Descriptor describes switching
capability of an interface [RFC 4203].  This document defines a new
Switching Capability value for Flex Grid [FLEX-GRID] as follows:

   Value                       Type
   -----                       ----
   102 (TBA by IANA)    Super-Channel-Switch-Capable (SCSC)

   Switching Capability and Encoding values MUST be used as follows:

        Switching Capability = SCSC


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        Encoding Type = Lambda [as defined in RFC3471]


    The Interface Switching Capability Descriptor is a sub-TLV (of type
    15) of the Link TLV.  The length is the length of value field in
    Octets. The format of the value field is as 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Switching Cap |   Encoding    |           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 Capability-specific information              |
   |                  (variable)                                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 2: ISCD & SCSI


Max LSP Bandwidth will be based on Max Slot Width field in BW-sub-TLV
(Ref to section 3.1 for details on BW sub-TLV) and the modulation
format used.





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3.1.  Switch Capability Specific Information

The technology specific part of the ISCD can include a variable number
of sub-TLVs. We propose to encode Slice Information in Bandwidth sub-
TLVs under SCSI field. The format of BW sub-TLVs is as shown below.

[Editor's note: To provide options similar to Label set field defined
in [9], we have included 2 variants to advertise slice level
information. These are bit-format and list/range format].


3.2. BW sub TLV: Bit Map format

The figure below shows format of Type=1 sub-TLV for encoding slice
information in bit-map format. This sub-TLV must be repeated for each
priority that is supported on the Te-link.

    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=1            |              Length           |
   +---------------------------------------------------------------+
   |Slice Spacing | Pri |                    Reserved              |
   +---------------------------------------------------------------+
   |               N-Start         |          Num of Slices        |
   +---------------------------------------------------------------+
   |         Min Slot Width        |       Max Slot Width          |
   +---------------------------------------------------------------+
   |                                                               |
   |                   Bit-Map showing Available Slices           |
   |                     (up to 48 bytes)                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 3: Type=1 BW sub TLV in Bit-Map format

3.2.1. Meaning of sub TLV fields

  o Slice Spacing: 8-bit field (S.S) which can take one of the values
     as shown in table below.
       o For e.g., the 12.5GHz spacing is specified by setting this
          field to value 4.




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                          +----------+---------+
                          |S.S. (GHz)|  Value  |
                          +----------+---------+
                          | Reserved |    0    |
                          +----------+---------+
                          |    100   |    1    |
                          +----------+---------+
                          |    50    |    2    |
                          +----------+---------+
                          |    25    |    3    |
                          +----------+---------+
                          |    12.5  |    4    |
                          +----------+---------+
                          |Future use|  5 - 15 |
                          +----------+---------+

                    Table 1: Slice Spacing Values

  o Priority:  3-bit field
       o 3-bit field to identify one of the 8 priorities for which
          Slice information (BW) is advertised.
  o N-Start: 16-bit field
       o Is a two's complement integer to specify start of the grid
       o Use center freq formula to determine start of spectrum
  o Number of slices: 16-bit field
       o Total number of slices advertised for the link. This includes
          (available plus consumed).
  o Minimum  Slot Width: 16-bit field
       o This is a positive integer value
       o This field is similar to Min LSP BW field. The value in this
          field is used to determine the smallest frequency slot width
          that the advertising node can allocate for an LSP.   This is
          defined by the following equation:
          Smallest Frequency slot width = Slice Spacing * integer value
          in 'Minimum Slot Width' field
  o Maximum  Slot Width: 16-bit field
       o This is a positive integer value
       o This field is used to determine the Maximum contiguous
          frequency slot width that the advertising node can allocate
          for an LSP.   This is defined by the following equation:
          Largest Contiguous Frequency slot width = Slice Spacing *
          integer value in 'Maximum Slot Width' field
  o Available slices encoded as bit-map
       o Each bit represents availability of one slice of width
          identified by S.S field
       o Zero: Available ; One: occupied
       o Padding MUST be used to align with 32 bit boundary.



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3.3. BW sub TLV: List and Rage format

The figure below shows format of Type=2 sub-TLV for encoding slice
information in list/range format. This sub-TLV must be repeated for
each priority that is supported on the Te-Link.

    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=2            |              Length           |
   +---------------------------------------------------------------+
   |Slice Spacing | Pri |  Res     |         Num of Entries        |
   +---------------------------------------------------------------+
   |         Min Slot Width        |       Max Slot Width          |
   +---------------------------------------------------------------+
   |             N-Start-1         |          N-end-1              |
   +---------------------------------------------------------------+
   |             N-Start-2         |          N-end-2              |
   +---------------------------------------------------------------+
   |                      More Entries                             |
   +---------------------------------------------------------------+
   |             N-Start-n         |          N-end-n              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 4: Type=2 BW sub TLV in List/Range format


3.3.1. Meaning of sub TLV fields

  o The meaning of above fields is same as in Type=1 BW-sub-TLV. For
     details refer to section 3.2.1.
       o Slice Spacing,
       o Priority,
       o Maximum Slot Width &
       o Minimum Slot Width
  o Number of Entries: 16-bit field
       o Is a positive integer value.
       o Total number of N-start & N-End rows advertised for the link.
  o N-Start-x: 16-bit field
       o Is a two's complement integer value (+ve, -ve or zero) to
          specify start of the grid.


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       o Use center freq formula to determine start of spectrum

  o N-end-x: 16-bit field
       o Is a two's complement integer value (+ve, -ve or zero)to
          specify end of the list/range.
       o Use center freq formula to determine end of spectrum



3.4. BW advertisement procedure

   This section describes bandwidth advertisement for Te-Links capable
   SCSC.

  o Optical nodes capable of Super Channel Switching advertise slices
     of certain width available based on the frequency spectrum
     supported by the node (e.g. C band, extended C-band). For example,
     node(s) supporting extended C-band will advertise 384 slices.
  o The BW advertisement involves an ISCD containing
       o Slice information in bit-map format (Type=1 BW-sub-TLV) where
          each bit corresponds to a single slice of width as identified
          by S.S field.   OR
       o Slice information in list/range format (Type=2 BW-sub-TLV)
          where each 32-bit entry represents an individual slice or
          list or range.
  o The slice position/numbering in Type=1 sub-TLV is identified based
     on N-start field.  The N-start field is derived based on ITU
     center frequency formula.
  o The advertising node MUST also set Number of Slices field.
  o Minimum & Maximum slot width fields are included to allow for any
     restrictions on the link for carrying super channel LSPs.
  o The BW advertisement is priority based and up to 8 priority levels
     are allowed.
  o The node capable of supporting one or more priorities MUST set the
     priority field and include BW-sub TLV for each of the priority
     supported.

      4. Examples

4.1. Example: BW advertisement without any service present

   Figure 5 shows an example of BW sub-TLV for a te-link which has no
   service established over it yet. Attributes of BW sub-TLV in the te-
   link are:




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      o N-start=-142 for extended C-band (2's complement should be
        included in this field)
      o Total number of slices available on the link = 384 (based on
        Slice spacing = 12.5GHz)
      o Min SW field shows min consumption of 4 Slices per LSP
        ( =50GHz)
      o Max SW field shows up to 400GHz BW allowed per LSP (32x12.5GHz)
      o 48 bytes showing that all 384 slices are available.



    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=1            |              Length           |
   +---------------------------------------------------------------+
   |S.S = 4(12.5) | Pri |                    Reserved              |
   +---------------------------------------------------------------+
   |               N-Start=-142    |          Num of Slices=384    |
   +---------------------------------------------------------------+
   |         Min Slot Width=4      |       Max Slot Width=32       |
   +---------------------------------------------------------------+
   |                                                               |
   |                 Bit-Map showing info for 384 slice           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

           Figure 5: Type=1 BW sub-TLV without any service present


4.2. Example: How to use advertise Bandwidth

  Assume user wants to setup Super Channel LSP over a single Flex-Grid
  link with BW requirement = 200GHz and transponder fully tunable.

  o The path computing node performs the following:
       o Determine the number of slices required for the LSP (200/S.S =
          16)
       o Look for contiguous spectrum availability on each link from BW
          advertisement (both dir)
       o Look for 16 contiguous bits in the BW advertisement TLV
       o If available select the link for LSP creation.
       o Signal for LSP creation.  Once LSP is created, update BW
          available via new advertisement using the same Bandwidth sub-
          TLV.



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      5. Security Considerations

   <Add any security considerations>

      6. IANA Considerations

   IANA needs to assign a new Grid field value to represent ITU-T Flex-
   Grid.

      7. References

7.1. Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

7.2. Informative References

   [1]   Berger, L., Ed., "Generalized Multi-Protocol Label Switching
         (GMPLS) Signaling Functional Description", RFC 3471, January
         2003

   [2]   Iftekhar H, Abinder , Zhong , Marco , ''Generalized Label for
         Super-Channel Assignment on Flexible Grid'', draft-hussain-
         ccamp-super-channel-label-04.txt, July 2011.

   [3]   K. Kompella, Y., " OSPF Extensions in Support of
         Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203,
         Oct 2005

   [4]   Lee, Y., Ed., "Framework for GMPLS and Path Computation
         Element (PCE) Control of Wavelength Switched Optical Networks
         (WSONs)", RFC 6163, April 2011

   [5]   M. Jinno et. al., ''Spectrum-Efficient and Scalable Elastic
         Optical Path Network: Architecture, Benefits and Enabling
         Technologies'', IEEE Comm. Mag., Nov. 2009, pp. 66-73.

   [6]   S. Chandrasekhar and X. Liu, ''Terabit Super-Channels for High
         Spectral Efficiency Transmission '',in Proc. ECOC 2010, paper
         Tu.3.C.5, Torino (Italy), September 2010.

   [7]   ITU-T Recommendation G.694.1, "Spectral grids for WDM
         applications: DWDM frequency grid", June 2002



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   [8]   Oscar G, et al., ''Framework and Requirements for GMPLS based
         control of Flexi-grid DWDM networks'', draft-ietf-ccamp-flexi-
         grid-fwk-00, work in progress.

   [9]   G. Bernstein, Y. Lee, D. Li, W. Imajuku, " General Network
         Element Constraint Encoding for GMPLS Controlled Networks",
         work in progress: draft-ietf-ccamp-general-constraint-encode-
         05, May 2011

   [10]  [FLEX-GRID] "ITU-T Recommendation G.694.1, Spectral grids for
         WDM applications: DWDM frequency grid", November 2012.

      8. Acknowledgments

The authors would like to thank Khuzema Pithewan, Ashok Kunjidhapatham
& Mohit Misra for their valuable comments.

































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Authors' Addresses

   Abinder Dhillon
   Fujitsu
   Richardson, TX
   Email: Abinder.Dhillon@us.fujitsu.com


   Iftekhar Hussain
   Infinera
   140 Caspian Ct., Sunnyvale, CA 94089
   Email: ihussain@infinera.com


   Rajan Rao
   Infinera
   140 Caspian Ct., Sunnyvale, CA 94089
   Email: rrao@infinera.com

   Marco Sosa
   Infinera
   140 Caspian Ct., Sunnyvale, CA 94089
   Email: msosa@infinera.com


Contributor's Addresses


   Biao Lu
   Email: blu@infinera.com

   Subhendu Chattopadhyay
   Email: schattopadhyay@infinera.com

   Harpreet Uppal
   Email: harpreet.uppal@infinera.com
   Infinera
   140 Caspian Ct., Sunnyvale, CA 94089











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