[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits] [IPR]

Versions: 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 RFC 7579

Network Working Group                                      G. Bernstein
Internet Draft                                        Grotto Networking
Intended status: Standards Track                                 Y. Lee
Expires: April 2011                                               D. Li
                                                                 Huawei
                                                             W. Imajuku
                                                                    NTT


                                                       October 13, 2010

     General Network Element Constraint Encoding for GMPLS Controlled
                                 Networks


             draft-ietf-ccamp-general-constraint-encode-03.txt


Status of this Memo

   This Internet-Draft is submitted to IETF 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 March 13, 2007.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.






Bernstein and Lee       Expires April 13, 2011                 [Page 1]


Internet-Draft  General Network Element Constraint Encoding October 2010


   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.

Abstract

   Generalized Multiprotocol Label Switching can be used to control a
   wide variety of technologies. In some of these technologies network
   elements and links may impose additional routing constraints such as
   asymmetric switch connectivity, non-local label assignment, and label
   range limitations on links.

   This document provides efficient, protocol-agnostic encodings for
   general information elements representing connectivity and label
   constraints as well as label availability. It is intended that
   protocol-specific documents will reference this memo to describe how
   information is carried for specific uses.



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].

Table of Contents


   1. Introduction...................................................3
      1.1. Node Switching Asymmetry Constraints......................4
      1.2. Non-Local Label Assignment Constraints....................4
   2. Extension Encoding Usage Recommendations.......................5
      2.1. Extension Node TLV........................................6
      2.2. Extension Link TLV........................................6
      2.3. Extension Dynamic Link TLV................................6
   3. Encoding.......................................................6
      3.1. Link Set Field............................................6
      3.2. Label Set Field...........................................8
         3.2.1. Inclusive/Exclusive Label Lists......................9



Bernstein and Lee       Expires April 13, 2011                 [Page 2]


Internet-Draft  General Network Element Constraint Encoding October 2010


         3.2.2. Inclusive/Exclusive Label Ranges....................10
         3.2.3. Bitmap Label Set....................................10
      3.3. Available Labels Sub-TLV.................................11
      3.4. Shared Backup Labels Sub-TLV.............................12
      3.5. Connectivity Matrix Sub-TLV..............................12
      3.6. Port Label Restriction sub-TLV...........................13
         3.6.1. SIMPLE_LABEL........................................14
         3.6.2. CHANNEL_COUNT.......................................15
         3.6.3. LABEL_RANGE1........................................15
         3.6.4. SIMPLE_LABEL & CHANNEL_COUNT........................16
         3.6.5. Link Label Exclusivity..............................16
   4. Security Considerations.......................................16
   5. IANA Considerations...........................................17
   6. Acknowledgments...............................................17
   APPENDIX A: Encoding Examples....................................18
      A.1. Link Set Field...........................................18
      A.2. Label Set Field..........................................18
      A.3. Connectivity Matrix Sub-TLV..............................19
      A.4. Connectivity Matrix with Bi-directional Symmetry.........22
   7. References....................................................25
      7.1. Normative References.....................................25
      7.2. Informative References...................................25
   8. Contributors..................................................26
   Authors' Addresses...............................................27
   Intellectual Property Statement..................................28
   Disclaimer of Validity...........................................28

1. Introduction

   Some data plane technologies that wish to make use of a GMPLS control
   plane contain additional constraints on switching capability and
   label assignment. In addition, some of these technologies must
   perform non-local label assignment based on the nature of the
   technology, e.g., wavelength continuity constraint in WSON [WSON-
   Frame]. Such constraints can lead to the requirement for link by link
   label availability in path computation and label assignment.

   This document provides efficient encodings of information needed by
   the routing and label assignment process in technologies such as WSON
   and are potentially applicable to a wider range of technologies. Such
   encodings can be used to extend GMPLS signaling and routing
   protocols. In addition these encodings could be used by other
   mechanisms to convey this same information to a path computation
   element (PCE).





Bernstein and Lee       Expires April 13, 2011                 [Page 3]


Internet-Draft  General Network Element Constraint Encoding October 2010


1.1. Node Switching Asymmetry Constraints

   For some network elements the ability of a signal or packet on a
   particular ingress port to reach a particular egress port may be
   limited. In addition, in some network elements the connectivity
   between some ingress ports and egress ports may be fixed, e.g., a
   simple multiplexer. To take into account such constraints during path
   computation we model this aspect of a network element via a
   connectivity matrix.

   The connectivity matrix (ConnectivityMatrix) represents either the
   potential connectivity matrix for asymmetric switches or fixed
   connectivity for an asymmetric device such as a multiplexer. Note
   that this matrix does not represent any particular internal blocking
   behavior but indicates which ingress ports and labels (e.g.,
   wavelengths) could possibly be connected to a particular output port.
   Representing internal state dependent blocking for a node is beyond
   the scope of this document and due to it's highly implementation
   dependent nature would most likely not be subject to standardization
   in the future. The connectivity matrix is a conceptual M by N matrix
   representing the potential switched or fixed connectivity, where M
   represents the number of ingress ports and N the number of egress
   ports.

   ConnectivityMatrix(i, j) ::= <MatrixID> <ConnType> <Matrix>

   Where

   <MatrixID> is a unique identifier for the matrix.

   <ConnType> can be either 0 or 1 depending upon whether the
   connectivity is either fixed or potentially switched.

   <Matrix> represents the fixed or switched connectivity in that
   Matrix(i, j) = 0 or 1 depending on whether ingress port i can connect
   to egress port j for one or more labels.



1.2. Non-Local Label Assignment Constraints

   If the nature of the equipment involved in a network results in a
   requirement for non-local label assignment we can have constraints
   based on limits imposed by the ports themselves and those that are
   implied by the current label usage. Note that constraints such as
   these only become important when label assignment has a non-local



Bernstein and Lee       Expires April 13, 2011                 [Page 4]


Internet-Draft  General Network Element Constraint Encoding October 2010


   character. For example in MPLS an LSR may have a limited range of
   labels available for use on an egress port and a set of labels
   already in use on that port and hence unavailable for use. This
   information, however, does not need to be shared unless there is some
   limitation on the LSR's label swapping ability. For example if a TDM
   node lacks the ability to perform time-slot interchange or a WSON
   lacks the ability to perform wavelength conversion then the label
   assignment process is not local to a single node and it may be
   advantageous to share the label assignment constraint information for
   use in path computation.

   Port label restrictions (PortLabelRestriction) model the label
   restrictions that the network element (node) and link may impose on a
   port. These restrictions tell us what labels may or may not be used
   on a link and are intended to be relatively static. More dynamic
   information is contained in the information on available labels. Port
   label restrictions are specified relative to the port in general or
   to a specific connectivity matrix for increased modeling flexibility.
   Reference [Switch] gives an example where both switch and fixed
   connectivity matrices are used and both types of constraints occur on
   the same port.

   <PortLabelRestriction> ::= [<GeneralPortRestrictions>...]
   [<MatrixSpecificRestrictions>...]

   <GeneralPortRestrictions> ::= <RestrictionType>
   [<RestrictionParameters>]

   <MatrixSpecificRestriction> ::= <MatrixID> <RestrictionType>
   [<RestrictionParameters>]

   Where

   MatrixID is the ID of the corresponding connectivity matrix

   The RestrictionType parameter is used to specify general port
   restrictions and matrix specific restrictions.

2. Extension Encoding Usage Recommendations

   In this section we give recommendations of typical usage of the sub-
   TLVs and composite TLVs.







Bernstein and Lee       Expires April 13, 2011                 [Page 5]


Internet-Draft  General Network Element Constraint Encoding October 2010


2.1. Extension Node TLV

   The Extension Node TLV could consist of the following list of sub-
   TLVs:

   <Node_Info> ::= <Node_ID>[Other GMPLS sub-TLVs]
   [<ConnectivityMatrix>...]

2.2. Extension Link TLV

   The new link related sub-TLVs could be incorporated into a composite
   link TLV as follows:

   <LinkInfo> ::=  <LinkID> [Other GMPLS sub-TLVs]
   [<PortLabelRestriction>...][<AvailableLabels>] [<SharedBackupLabels>]

2.3. Extension Dynamic Link TLV

   If the protocol supports the separation of dynamic information from
   relatively static information then the available wavelength and
   shared backup status can be separated from the general link TLV into
   a TLV for dynamic link information.

   <DynamicLinkInfo> ::=  <LinkID> <AvailableLabels>
   [<SharedBackupLabels>]

3. Encoding

   A type-length-value (TLV) encoding of the general connectivity and
   label restrictions and availability extensions is given in this
   section. This encoding is designed to be suitable for use in the
   GMPLS routing protocols OSPF [RFC4203] and IS-IS [RFC5307] and in the
   PCE protocol PCEP [PCEP]. Note that the information distributed in
   [RFC4203] and [RFC5307] is arranged via the nesting of sub-TLVs
   within TLVs and this document makes use of such constructs. First,
   however we define two general purpose fields that will be used
   repeatedly in the subsequent TLVs.



3.1. Link Set Field

   We will frequently need to describe properties of groups of links. To
   do so efficiently we can make use of a link set concept similar to
   the label set concept of [RFC3471]. This Link Set Field is used in




Bernstein and Lee       Expires April 13, 2011                 [Page 6]


Internet-Draft  General Network Element Constraint Encoding October 2010


   the <ConnectivityMatrix> sub-TLV, which is defined in Section 3.5.
   The information carried in a Link Set is defined by:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Action     |Dir|  Format   |         Length                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Link Identifier 1                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                               :                               :
      :                               :                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Link Identifier N                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     Action: 8 bits

         0 - Inclusive List

   Indicates that one or more link identifiers are included in the Link
   Set. Each identifies a separate link that is part of the set.

         1 - Inclusive Range

   Indicates that the Link Set defines a range of links.  It contains
   two link identifiers. The first identifier indicates the start of the
   range (inclusive). The second identifier indicates the end of the
   range (inclusive). All links with numeric values between the bounds
   are considered to be part of the set. A value of zero in either
   position indicates that there is no bound on the corresponding
   portion of the range. Note that the Action field can be set to
   0x02(Inclusive Range) only when unnumbered link identifier is used.

     Dir: Directionality of the Link Set (2 bits)

        0 -- bidirectional
         1 -- ingress

         2 -- egress

   For example in optical networks we think in terms of unidirectional
   as well as bidirectional links. For example, label restrictions or
   connectivity may be different for an ingress port, than for its



Bernstein and Lee       Expires April 13, 2011                 [Page 7]


Internet-Draft  General Network Element Constraint Encoding October 2010


   "companion" egress port if one exists. Note that "interfaces" such as
   those discussed in the Interfaces MIB [RFC2863] are assumed to be
   bidirectional. This also applies to the links advertised in various
   link state routing protocols.

     Format: The format of the link identifier (6 bits)

         0 -- Link Local Identifier

   Indicates that the links in the Link Set are identified by link local
   identifiers. All link local identifiers are supplied in the context
   of the advertising node.

         1 -- Local Interface IPv4 Address

        2 -- Local Interface IPv6 Address

   Indicates that the links in the Link Set are identified by Local
   Interface IP Address. All Local Interface IP Address are supplied in
   the context of the advertising node.

         Others TBD.

   Note that all link identifiers in the same list must be of the same
   type.

     Length: 16 bits

   This field indicates the total length in bytes of the Link Set field.

     Link Identifier: length is dependent on the link format

   The link identifier represents the port which is being described
   either for connectivity or label restrictions. This can be the link
   local identifier of [RFC4202], GMPLS routing, [RFC4203] GMPLS OSPF
   routing, and [RFC5307] IS-IS GMPLS routing. The use of the link local
   identifier format can result in more compact encodings when the
   assignments are done in a reasonable fashion.

3.2. Label Set Field

   Label Set Field is used within the <AvailableLabels> sub-TLV or the
   <SharedBackupLabels> sub-TLV, which is defined in Section 3.3.  and
   3.4. , respectively.





Bernstein and Lee       Expires April 13, 2011                 [Page 8]


Internet-Draft  General Network Element Constraint Encoding October 2010


   The general format for a label set is given below. This format uses
   the Action concept from [RFC3471] with an additional Action to define
   a "bit map" type of label set. The second 32 bit field is a base
   label used as a starting point in many of the specific formats.

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Action|    Num Labels         |          Length               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Base Label                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Additional fields as necessary per action                 |
     |



   Action:

         0 - Inclusive List

         1 - Exclusive List

         2 - Inclusive Range

         3 - Exclusive Range

         4 - Bitmap Set

   Num Labels is only meaningful for Action value of 4 (Bitmap Set). It
   indicates the number of labels represented by the bit map. See more
   detail in section 3.2.3.

   Length is the length in bytes of the entire field.

   3.2.1. Inclusive/Exclusive Label Lists

   In the case of the inclusive/exclusive lists the wavelength set
   format is given by:










Bernstein and Lee       Expires April 13, 2011                 [Page 9]


Internet-Draft  General Network Element Constraint Encoding October 2010


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 or 1 | Num Labels (not used) |          Length               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Base Label                            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     :                                                               :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Last  Label                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Where:

   Num Labels is not used in this particular format since the Length
   parameter is sufficient to determine the number of labels in the
   list.

   3.2.2. Inclusive/Exclusive Label Ranges

   In the case of inclusive/exclusive ranges the label set format is
   given by:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |2 or 3 | Num Labels(not used)  |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                    Start Label                                |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     End Label                                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



   Note that the start and end label must in some sense "compatible" in
   the technology being used.

   3.2.3. Bitmap Label Set

   In the case of Action = 4, the bitmap the label set format is given
   by:






Bernstein and Lee       Expires April 13, 2011                [Page 10]


Internet-Draft  General Network Element Constraint Encoding October 2010


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  4    |   Num Labels          |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Base Label                            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Bit Map Word #1 (Lowest numerical labels)                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     :                                                               :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Bit Map Word #N (Highest numerical labels)                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Where Num Labels in this case tells us the number of labels
   represented by the bit map. Each bit in the bit map represents a
   particular label with a value of 1/0 indicating whether the label is
   in the set or not. Bit position zero represents the lowest label and
   corresponds to the base label, while each succeeding bit position
   represents the next label logically above the previous.

   The size of the bit map is Num Label bits, but the bit map is padded
   out to a full multiple of 32 bits so that the TLV is a multiple of
   four bytes. Bits that do not represent labels (i.e., those in
   positions (Num Labels) and beyond SHOULD be set to zero and MUST be
   ignored.

3.3. Available Labels Sub-TLV

   To indicate the labels available for use on a link the Available
   Labels sub-TLV consists of a single variable length label set field
   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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                           Label Set Field                     |
     :                                                               :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Note that Label Set Field is defined in Section 3.2.






Bernstein and Lee       Expires April 13, 2011                [Page 11]


Internet-Draft  General Network Element Constraint Encoding October 2010


3.4. Shared Backup Labels Sub-TLV

   To indicate the labels available for shared backup use on a link the
   Shared Backup Labels sub-TLV consists of a single variable length
   label set field 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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Label Set Field                           |
     :                                                               :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




3.5. Connectivity Matrix Sub-TLV

   The Connectivity Matrix represents how ingress ports are connected to
   egress ports for network elements. The switch and fixed connectivity
   matrices can be compactly represented in terms of a minimal list of
   ingress and egress port set pairs that have mutual connectivity. As
   described in [Switch] such a minimal list representation leads
   naturally to a graph representation for path computation purposes
   that involves the fewest additional nodes and links.

   A TLV encoding of this list of link set pairs is:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Connectivity  |   MatrixID    |             Reserved          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Link Set A #1                         |
      :                               :                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Link Set B #1                         :
      :                               :                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Additional Link set pairs as needed     |
      :                     to specify connectivity                   :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Where




Bernstein and Lee       Expires April 13, 2011                [Page 12]


Internet-Draft  General Network Element Constraint Encoding October 2010


   Connectivity is the device type.

         0 -- the device is fixed

         1 -- the device is switched(e.g., ROADM/OXC)

   MatrixID represents the ID of the connectivity matrix and is an 8 bit
   integer. The value of 0xFF is reserved for use with port wavelength
   constraints and should not be used to identify a connectivity matrix.

   Link Set A #1 and Link Set B #1 together represent a pair of link
   sets. There are two permitted combinations for the link set field
   parameter "dir" for Link Set A and B pairs:

   o  Link Set A dir=ingress, Link Set B dir=egress

     The meaning of the pair of link sets A and B in this case is that
     any signal that ingresses a link in set A can be potentially
     switched out of an egress link in set B.

   o  Link Set A dir=bidirectional, Link Set B dir=bidirectional

      The meaning of the pair of link sets A and B in this case is that
      any signal that ingresses on the links in set A can potentially
      egress on a link in set B, and any ingress signal on the links in
      set B can potentially egress on a link in set A.

   See Appendix A for both types of encodings as applied to a ROADM
   example.


3.6. Port Label Restriction sub-TLV

   Port Label Restriction tells us what labels may or may not be used on
   a link.

   The port label restriction of section 1.2.  can be encoded as a sub-
   TLV as follows. More than one of these sub-TLVs may be needed to
   fully specify a complex port constraint. When more than one of these
   sub-TLVs are present the resulting restriction is the intersection of
   the restrictions expressed in each sub-TLV. To indicate that a
   restriction applies to the port in general and not to a specific
   connectivity matrix use the reserved value of 0xFF for the MatrixID.






Bernstein and Lee       Expires April 13, 2011                [Page 13]


Internet-Draft  General Network Element Constraint Encoding October 2010


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   MatrixID    |  RestrictionType |      Reserved/Parameter    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Additional Restriction Parameters per RestrictionType    |
     :                                                               :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Where:

   MatrixID: either is the value in the corresponding Connectivity
   Matrix sub-TLV or takes the value OxFF to indicate the restriction
   applies to the port regardless of any Connectivity Matrix.

   RestrictionType can take the following values and meanings:

         0: SIMPLE_LABEL  (Simple label selective restriction)

         1: CHANNEL_COUNT (Channel count restriction)

         2: LABEL_RANGE1 (Label range device with a movable center label
         and width)

         3: SIMPLE_LABEL & CHANNEL_COUNT (Combination of SIMPLE_LABEL
         and CHANNEL_COUNT restriction. The accompanying label set and
         channel count indicate labels permitted on the port and the
         maximum number of channels that can be simultaneously used on
         the port)

         4: LINK_LABEL_EXCLUSIVITY (A label may be used at most once
         amongst a set of specified ports)

   3.6.1. SIMPLE_LABEL

   In the case of the SIMPLE_LABEL the GeneralPortRestrictions (or
   MatrixSpecificRestrictions) format is given by:











Bernstein and Lee       Expires April 13, 2011                [Page 14]


Internet-Draft  General Network Element Constraint Encoding October 2010


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | MatrixID      | RstType = 0   |             Reserved          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                        Label Set Field                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In this case the accompanying label set indicates the labels
   permitted on the port.


   3.6.2. CHANNEL_COUNT

   In the case of the CHANNEL_COUNT the format is given by:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | MatrixID      | RstType = 1   |        MaxNumChannels         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   In this case the accompanying MaxNumChannels indicates the maximum
   number of channels (labels) that can be simultaneously used on the
   port/matrix.


   3.6.3. LABEL_RANGE1

   In the case of the LABEL_RANGE1 the GeneralPortRestrictions (or
   MatrixSpecificRestrictions) format is given by:


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | MatrixID      | RstType = 2   |     MaxLabelRange             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                        Label Set Field                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   In this case the accompanying MaxLabelRange indicates the maximum
   range of the labels. The corresponding label set is used to indicate
   the overall label range. Specific center label information can be
   obtained from dynamic label in use information. It is assumed that



Bernstein and Lee       Expires April 13, 2011                [Page 15]


Internet-Draft  General Network Element Constraint Encoding October 2010


   both center label and range tuning can be done without causing faults
   to existing signals.


   3.6.4. SIMPLE_LABEL & CHANNEL_COUNT

   In the case of the SIMPLE_LABEL & CHANNEL_COUNT the format is given
   by:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | MatrixID      | RstType = 3   |        MaxNumChannels         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Label Set Field                     |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In this case the accompanying label set and MaxNumChannels indicate
   labels permitted on the port and the maximum number of labels that
   can be simultaneously used on the port.

   3.6.5. Link Label Exclusivity

   In the case of the SIMPLE_LABEL & CHANNEL_COUNT the format is given
   by:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | MatrixID      | RstType = 4   |        Reserved               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Set Field                            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In this case the accompanying port set indicate that a label may be
   used at most once among the ports in the link set field.



4. Security Considerations

   This document defines protocol-independent encodings for WSON
   information and does not introduce any security issues.




Bernstein and Lee       Expires April 13, 2011                [Page 16]


Internet-Draft  General Network Element Constraint Encoding October 2010


   However, other documents that make use of these encodings within
   protocol extensions need to consider the issues and risks associated
   with, inspection, interception, modification, or spoofing of any of
   this information. It is expected that any such documents will
   describe the necessary security measures to provide adequate
   protection.

5. IANA Considerations

   TBD. Once our approach is finalized we may need identifiers for the
   various TLVs and sub-TLVs.

6. Acknowledgments

   This document was prepared using 2-Word-v2.0.template.dot.


































Bernstein and Lee       Expires April 13, 2011                [Page 17]


Internet-Draft  General Network Element Constraint Encoding October 2010


APPENDIX A: Encoding Examples

   Here we give examples of the general encoding extensions applied to
   some simple ROADM network elements and links.

A.1. Link Set Field

   Suppose that we wish to describe a set of ingress ports that are have
   link local identifiers number 3 through 42. In the link set field we
   set the Action = 1 to denote an inclusive range; the Dir = 1 to
   denote ingress links; and, the Format = 0 to denote link local
   identifiers. In particular we have:

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=1     |0 1|0 0 0 0 0 0|             Length = 12       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #3                |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #42               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


A.2. Label Set Field

   Example:

   A 40 channel C-Band DWDM system with 100GHz spacing with lowest
   frequency 192.0THz (1561.4nm) and highest frequency 195.9THz
   (1530.3nm). These frequencies correspond to n = -11, and n = 28
   respectively. Now suppose the following channels are available:

   Frequency (THz)    n Value      bit map position
   --------------------------------------------------
      192.0             -11               0
      192.5              -6               5
      193.1               0              11
      193.9               8              19
      194.0               9              20
      195.2              21              32
      195.8              27              38

   With the Grid value set to indicate an ITU-T G.694.1 DWDM grid, C.S.
   set to indicate 100GHz this lambda bit map set would then be encoded
   as follows:





Bernstein and Lee       Expires April 13, 2011                [Page 18]


Internet-Draft  General Network Element Constraint Encoding October 2010


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  4    | Num Wavelengths = 40  |    Length = 16 bytes          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = -11 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |1 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |1 0 0 0 0 0 1 0|   Not used in 40 Channel system (all zeros)   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   To encode this same set as an inclusive list we would have:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  0    | Num Wavelengths = 40  |    Length = 20 bytes          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = -11 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = -6  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = -0  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = 8   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = 9   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = 21  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid |  C.S. |      Reserved   | n  for lowest frequency = 27  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




A.3. Connectivity Matrix Sub-TLV

   Example:

   Suppose we have a typical 2-degree 40 channel ROADM. In addition to
   its two line side ports it has 80 add and 80 drop ports. The picture
   below illustrates how a typical 2-degree ROADM system that works with
   bi-directional fiber pairs is a highly asymmetrical system composed
   of two unidirectional ROADM subsystems.



Bernstein and Lee       Expires April 13, 2011                [Page 19]


Internet-Draft  General Network Element Constraint Encoding October 2010




                         (Tributary) Ports #3-#42
                     Ingress added to    Egress dropped from
                     West Line Egress    East Line Ingress
                           vvvvv          ^^^^^
                          | |||.|       | |||.|
                    +-----| |||.|--------| |||.|------+
                    |    +----------------------+     |
                    |    |                      |     |
        Egress      |    | Unidirectional ROADM |     |    Ingress
   -----------------+    |                      |     +--------------
   <=====================|                      |===================<
   -----------------+    +----------------------+     +--------------
                    |                                 |
        Port #1     |                                 |   Port #2
   (West Line Side) |                                 |(East Line Side)
   -----------------+    +----------------------+     +--------------
   >=====================|                      |===================>
   -----------------+    | Unidirectional ROADM |     +--------------
        Ingress     |    |                      |     |    Egress
                    |    |              _       |     |
                    |    +----------------------+     |
                    +-----| |||.|--------| |||.|------+
                          | |||.|        | |||.|
                           vvvvv          ^^^^^
                     (Tributary) Ports #43-#82
                Egress dropped from    Ingress added to
                West Line ingress      East Line egress


   Referring to the figure we see that the ingress direction of ports
   #3-#42 (add ports) can only connect to the egress on port #1. While
   the ingress side of port #2 (line side) can only connect to the
   egress on ports #3-#42 (drop) and to the egress on port #1 (pass
   through). Similarly, the ingress direction of ports #43-#82 can only
   connect to the egress on port #2 (line). While the ingress direction
   of port #1 can only connect to the egress on ports #43-#82 (drop) or
   port #2 (pass through). We can now represent this potential
   connectivity matrix as follows. This representation uses only 30 32-
   bit words.








Bernstein and Lee       Expires April 13, 2011                [Page 20]


Internet-Draft  General Network Element Constraint Encoding October 2010



       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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Conn = 1   |    MatrixID   |      Reserved                 |1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                          Note: adds to line
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=1     |0 1|0 0 0 0 0 0|          Length = 12          |2
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #3                |3
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #42               |4
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |1 0|0 0 0 0 0 0|          Length = 8           |5
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #1                |6
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Note: line to drops
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 1|0 0 0 0 0 0|          Length = 8           |7
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #2                |8
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=1     |1 0|0 0 0 0 0 0|          Length = 12          |9
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #3                |10
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #42               |11
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Note: line to line
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 1|0 0 0 0 0 0|          Length = 8           |12
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #2                |13
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |1 0|0 0 0 0 0 0|          Length = 8           |14
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #1                |15
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                Note: adds to line
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=1     |0 1|0 0 0 0 0 0|          Length = 12          |16
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #43               |17
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



Bernstein and Lee       Expires April 13, 2011                [Page 21]


Internet-Draft  General Network Element Constraint Encoding October 2010


     |                     Link Local Identifier = #82               |18
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |1 0|0 0 0 0 0 0|          Length = 8           |19
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #2                |20
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Note: line to drops
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 1|0 0 0 0 0 0||          Length = 8          |21
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #1                |22
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=1     |1 0|0 0 0 0 0 0|          Length = 12          |23
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #43               |24
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #82               |25
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Note: line to line
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 1|0 0 0 0 0 0|          Length = 8           |26
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #1                |27
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |1 0|0 0 0 0 0 0|          Length = 8           |28
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #2                |30
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


A.4. Connectivity Matrix with Bi-directional Symmetry

   If one has the ability to renumber the ports of the previous example
   as shown in the next figure then we can take advantage of the bi-
   directional symmetry and use bi-directional encoding of the
   connectivity matrix. Note that we set dir=bidirectional in the link
   set fields.












Bernstein and Lee       Expires April 13, 2011                [Page 22]


Internet-Draft  General Network Element Constraint Encoding October 2010


                                (Tributary)
                     Ports #3-42         Ports #43-82
                     West Line Egress    East Line Ingress
                           vvvvv          ^^^^^
                          | |||.|        | |||.|
                    +-----| |||.|--------| |||.|------+
                    |    +----------------------+     |
                    |    |                      |     |
        Egress      |    | Unidirectional ROADM |     |    Ingress
   -----------------+    |                      |     +--------------
   <=====================|                      |===================<
   -----------------+    +----------------------+     +--------------
                    |                                 |
        Port #1     |                                 |   Port #2
   (West Line Side) |                                 |(East Line Side)
   -----------------+    +----------------------+     +--------------
   >=====================|                      |===================>
   -----------------+    | Unidirectional ROADM |     +--------------
        Ingress     |    |                      |     |    Egress
                    |    |              _       |     |
                    |    +----------------------+     |
                    +-----| |||.|--------| |||.|------+
                          | |||.|        | |||.|
                           vvvvv          ^^^^^
                     Ports #3-#42         Ports #43-82
                Egress dropped from    Ingress added to
                West Line ingress      East Line egress






















Bernstein and Lee       Expires April 13, 2011                [Page 23]


Internet-Draft  General Network Element Constraint Encoding October 2010


       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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Conn = 1   |    MatrixID   |      Reserved                 |1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                          Add/Drops #3-42 to Line side #1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=1     |0 0|0 0 0 0 0 0|          Length = 12          |2
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #3                |3
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #42               |4
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 0|0 0 0 0 0 0|          Length = 8           |5
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #1                |6
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Note: line #2 to add/drops #43-82
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 0|0 0 0 0 0 0|          Length = 8           |7
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #2                |8
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=1     |0 0|0 0 0 0 0 0|          Length = 12          |9
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #43               |10
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #82               |11
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Note: line to line
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 0|0 0 0 0 0 0|          Length = 8           |12
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #1                |13
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Action=0     |0 0|0 0 0 0 0 0|          Length = 8           |14
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Link Local Identifier = #2                |15
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+










Bernstein and Lee       Expires April 13, 2011                [Page 24]


Internet-Draft  General Network Element Constraint Encoding October 2010




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.

   [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
             MIB", RFC 2863, June 2000.

   [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
             (GMPLS) Signaling Functional Description", RFC 3471,
             January 2003.

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

   [RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "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.



7.2. Informative References

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

   [G.694.2] ITU-T Recommendation G.694.2, Spectral grids for WDM
             applications: CWDM wavelength grid, December 2003.

   [RFC5307] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions
             in Support of Generalized Multi-Protocol Label Switching
             (GMPLS)", RFC 5307, October 2008.









Bernstein and Lee       Expires April 13, 2011                [Page 25]


Internet-Draft  General Network Element Constraint Encoding October 2010


   [Switch] G. Bernstein, Y. Lee, A. Gavler, J. Martensson, " Modeling
         WDM Wavelength Switching Systems for Use in GMPLS and Automated
         Path Computation", Journal of Optical Communications and
         Networking, vol. 1, June, 2009, pp. 187-195.

   [PCEP]    Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
             Element (PCE) communication Protocol (PCEP) - Version 1",
             RFC5440.





8. Contributors

   Diego Caviglia
   Ericsson
   Via A. Negrone 1/A 16153
   Genoa Italy

   Phone: +39 010 600 3736
   Email: diego.caviglia@(marconi.com, ericsson.com)

   Anders Gavler
   Acreo AB
   Electrum 236
   SE - 164 40 Kista Sweden

   Email: Anders.Gavler@acreo.se

   Jonas Martensson
   Acreo AB
   Electrum 236
   SE - 164 40 Kista, Sweden

   Email: Jonas.Martensson@acreo.se

   Itaru Nishioka
   NEC Corp.
   1753 Simonumabe, Nakahara-ku, Kawasaki, Kanagawa 211-8666
   Japan

   Phone: +81 44 396 3287
   Email: i-nishioka@cb.jp.nec.com





Bernstein and Lee       Expires April 13, 2011                [Page 26]


Internet-Draft  General Network Element Constraint Encoding October 2010



Authors' Addresses

   Greg M. Bernstein (ed.)
   Grotto Networking
   Fremont California, USA

   Phone: (510) 573-2237
   Email: gregb@grotto-networking.com


   Young Lee (ed.)
   Huawei Technologies
   1700 Alma Drive, Suite 100
   Plano, TX 75075
   USA

   Phone: (972) 509-5599 (x2240)
   Email: ylee@huawei.com


   Dan Li
   Huawei Technologies Co., Ltd.
   F3-5-B R&D Center, Huawei Base,
   Bantian, Longgang District
   Shenzhen 518129 P.R.China

   Phone: +86-755-28973237
   Email: danli@huawei.com

   Wataru Imajuku
   NTT Network Innovation Labs
   1-1 Hikari-no-oka, Yokosuka, Kanagawa
   Japan

   Phone: +81-(46) 859-4315
   Email: imajuku.wataru@lab.ntt.co.jp












Bernstein and Lee       Expires April 13, 2011                [Page 27]


Internet-Draft  General Network Element Constraint Encoding October 2010


   Jianrui Han
   Huawei Technologies Co., Ltd.
   F3-5-B R&D Center, Huawei Base,
   Bantian, Longgang District
   Shenzhen 518129 P.R.China

   Phone: +86-755-28972916
   Email: hanjianrui@huawei.com


Intellectual Property Statement

   The IETF Trust takes no position regarding the validity or scope of
   any Intellectual Property Rights or other rights that might be
   claimed to pertain to the implementation or use of the technology
   described in any IETF Document or the extent to which any license
   under such rights might or might not be available; nor does it
   represent that it has made any independent effort to identify any
   such rights.

   Copies of Intellectual Property disclosures made to the IETF
   Secretariat and any assurances of licenses to be made available, or
   the result of an attempt made to obtain a general license or
   permission for the use of such proprietary rights by implementers or
   users of this specification can be obtained from the IETF on-line IPR
   repository at http://www.ietf.org/ipr

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   any standard or specification contained in an IETF Document. Please
   address the information to the IETF at ietf-ipr@ietf.org.

Disclaimer of Validity

   All IETF Documents and the information contained therein are provided
   on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
   REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
   IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
   WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
   WARRANTY THAT THE USE OF THE INFORMATION THEREIN WILL NOT INFRINGE
   ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
   FOR A PARTICULAR PURPOSE.






Bernstein and Lee       Expires April 13, 2011                [Page 28]


Internet-Draft  General Network Element Constraint Encoding October 2010


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.













































Bernstein and Lee       Expires April 13, 2011                [Page 29]


Html markup produced by rfcmarkup 1.129d, available from https://tools.ietf.org/tools/rfcmarkup/