





Network Working Group                                   K. Kompella, Ed.
Request for Comments: 4203                               Y. Rekhter, Ed.
Updates: 3630                                           Juniper Networks
Category: Standards Track                                   October 2005


                     OSPF Extensions in Support of
           Generalized Multi-Protocol Label Switching (GMPLS)

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document specifies encoding of extensions to the OSPF routing
   protocol in support of Generalized Multi-Protocol Label Switching
   (GMPLS).

1.  Introduction

   This document specifies extensions to the OSPF routing protocol
   [OSPF] in support of carrying link state information for Generalized
   Multi-Protocol Label Switching (GMPLS).  The set of required
   enhancements to OSPF are outlined in [GMPLS-ROUTING].

   In this section, we define the enhancements to the Traffic
   Engineering (TE) properties of GMPLS TE links that can be announced
   in OSPF TE LSAs.  The TE LSA, which is an opaque LSA with area
   flooding scope [OSPF-TE], has only one top-level Type/Length/Value
   (TLV) triplet and has one or more nested sub-TLVs for extensibility.
   The top-level TLV can take one of two values (1) Router Address or
   (2) Link.  In this document, we enhance the sub-TLVs for the Link TLV
   in support of GMPLS.  Specifically, we add the following sub-TLVs to
   the Link TLV:








Kompella & Rekhter          Standards Track                     [Page 1]

RFC 4203                OSPF Extensions in MPLS             October 2005


   Sub-TLV Type      Length    Name
             11           8    Link Local/Remote Identifiers
             14           4    Link Protection Type
             15    variable    Interface Switching Capability Descriptor
             16    variable    Shared Risk Link Group

   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 BCP 14, RFC 2119
   [RFC2119].

1.1.  Link Local/Remote Identifiers

   Link Local/Remote Identifiers is a sub-TLV of the Link TLV.  The type
   of this sub-TLV is 11, and length is eight octets.  The value field
   of this sub-TLV contains four octets of Link Local Identifier
   followed by four octets of Link Remote Identifier (see Section
   "Support for unnumbered links" of [GMPLS-ROUTING]).  If the Link
   Remote Identifier is unknown, it is set to 0.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Link Local Identifier                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Link Remote Identifier                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   A node can communicate its Link Local Identifier to its neighbor
   using a link local Opaque LSA, as described in Section "Exchanging
   Link Local TE Information".

1.2.  Link Protection Type

   The Link Protection Type is a sub-TLV of the Link TLV.  The type of
   this sub-TLV is 14, and length is four octets.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Protection Cap |                    Reserved                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The first octet is a bit vector describing the protection
   capabilities of the link (see Section "Link Protection Type" of
   [GMPLS-ROUTING]).  They are:

      0x01  Extra Traffic



Kompella & Rekhter          Standards Track                     [Page 2]

RFC 4203                OSPF Extensions in MPLS             October 2005


      0x02  Unprotected

      0x04  Shared

      0x08  Dedicated 1:1

      0x10  Dedicated 1+1

      0x20  Enhanced

      0x40  Reserved

      0x80  Reserved

   The remaining three octets SHOULD be set to zero by the sender, and
   SHOULD be ignored by the receiver.

   The Link Protection Type sub-TLV may occur at most once within the
   Link TLV.

1.3.  Shared Risk Link Group (SRLG)

   The SRLG is a sub-TLV (of type 16) of the Link TLV.  The length is
   the length of the list in octets.  The value is an unordered list of
   32 bit numbers that are the SRLGs that the link belongs to.  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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Shared Risk Link Group Value                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        ............                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Shared Risk Link Group Value                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   This sub-TLV carries the Shared Risk Link Group information (see
   Section "Shared Risk Link Group Information" of [GMPLS-ROUTING]).

   The SRLG sub-TLV may occur at most once within the Link TLV.

1.4.  Interface Switching Capability Descriptor

   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:




Kompella & Rekhter          Standards Track                     [Page 3]

RFC 4203                OSPF Extensions in MPLS             October 2005


    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)                                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Switching Capability (Switching Cap) field contains one of the
   following values:

      1     Packet-Switch Capable-1 (PSC-1)
      2     Packet-Switch Capable-2 (PSC-2)
      3     Packet-Switch Capable-3 (PSC-3)
      4     Packet-Switch Capable-4 (PSC-4)
      51    Layer-2 Switch Capable  (L2SC)
      100   Time-Division-Multiplex Capable (TDM)
      150   Lambda-Switch Capable   (LSC)
      200   Fiber-Switch Capable    (FSC)

   The Encoding field contains one of the values specified in Section
   3.1.1 of [GMPLS-SIG].

   Maximum LSP Bandwidth is encoded as a list of eight 4 octet fields in
   the IEEE floating point format [IEEE], with priority 0 first and
   priority 7 last.  The units are bytes (not bits!) per second.

   The content of the Switching Capability specific information field
   depends on the value of the Switching Capability field.





Kompella & Rekhter          Standards Track                     [Page 4]

RFC 4203                OSPF Extensions in MPLS             October 2005


   When the Switching Capability field is PSC-1, PSC-2, PSC-3, or PSC-4,
   the Switching Capability specific information field includes Minimum
   LSP Bandwidth, Interface MTU, and padding.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Minimum LSP Bandwidth                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Interface MTU       |            Padding            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Minimum LSP Bandwidth is encoded in a 4 octets field in the IEEE
   floating point format.  The units are bytes (not bits!) per second.
   The Interface MTU is encoded as a 2 octets integer.  The padding is 2
   octets, and is used to make the Interface Switching Capability
   Descriptor sub-TLV 32-bits aligned.  It SHOULD be set to zero by the
   sender and SHOULD be ignored by the receiver.

   When the Switching Capability field is L2SC, there is no Switching
   Capability specific information field present.

   When the Switching Capability field is TDM, the Switching Capability
   specific information field includes Minimum LSP Bandwidth, an
   indication whether the interface supports Standard or Arbitrary
   SONET/SDH, and padding.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Minimum LSP Bandwidth                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Indication  |                 Padding                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Minimum LSP Bandwidth is encoded in a 4 octets field in the IEEE
   floating point format.  The units are bytes (not bits!) per second.
   The indication whether the interface supports Standard or Arbitrary
   SONET/SDH is encoded as 1 octet.  The value of this octet is 0 if the
   interface supports Standard SONET/SDH, and 1 if the interface
   supports Arbitrary SONET/SDH.  The padding is 3 octets, and is used
   to make the Interface Switching Capability Descriptor sub-TLV 32-bits
   aligned.  It SHOULD be set to zero by the sender and SHOULD be
   ignored by the receiver.

   When the Switching Capability field is LSC, there is no Switching
   Capability specific information field present.




Kompella & Rekhter          Standards Track                     [Page 5]

RFC 4203                OSPF Extensions in MPLS             October 2005


   To support interfaces that have more than one Interface Switching
   Capability Descriptor (see Section "Interface Switching Capability
   Descriptor" of [GMPLS-ROUTING]) the Interface Switching Capability
   Descriptor sub-TLV may occur more than once within the Link TLV.

2.  Implications on Graceful Restart

   The restarting node should follow the OSPF restart procedures
   [OSPF-RESTART], and the RSVP-TE restart procedures [GMPLS-RSVP].

   When a restarting node is going to originate its TE LSAs, the TE LSAs
   containing Link TLV should be originated with 0 unreserved bandwidth,
   Traffic Engineering metric set to 0xffffffff, and if the Link has LSC
   or FSC as its Switching Capability then also with 0 as Max LSP
   Bandwidth, until the node is able to determine the amount of
   unreserved resources taking into account the resources reserved by
   the already established LSPs that have been preserved across the
   restart.  Once the restarting node determines the amount of
   unreserved resources, taking into account the resources reserved by
   the already established LSPs that have been preserved across the
   restart, the node should advertise these resources in its TE LSAs.

   In addition in the case of a planned restart prior to restarting, the
   restarting node SHOULD originate the TE LSAs containing Link TLV with
   0 as unreserved bandwidth, and if the Link has LSC or FSC as its
   Switching Capability then also with 0 as Max LSP Bandwidth.  This
   would discourage new LSP establishment through the restarting router.

   Neighbors of the restarting node should continue advertise the actual
   unreserved bandwidth on the TE links from the neighbors to that node.

   Regular graceful restart should not be aborted if a TE LSA or TE
   topology changes.  TE graceful restart need not be aborted if a TE
   LSA or TE topology changes.

3.  Exchanging Link Local TE Information

   It is often useful for a node to communicate some Traffic Engineering
   information for a given interface to its neighbors on that interface.
   One example of this is a Link Local Identifier.  If nodes X and Y are
   connected by an unnumbered point-to-point interface I, then X's Link
   Local Identifier for I is Y's Link Remote Identifier for I.  X can
   communicate its Link Local Identifier for I by exchanging with Y a TE
   link local opaque LSA described below.  Note that this information
   need only be exchanged over interface I, hence the use of a link
   local Opaque LSA.





Kompella & Rekhter          Standards Track                     [Page 6]

RFC 4203                OSPF Extensions in MPLS             October 2005


   A TE Link Local LSA is an opaque LSA of type 9 (link-local flooding
   scope) with Opaque Type 1 (TE LSA) and Opaque ID of 0.

    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    |       9       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Opaque Type  |                   Opaque ID                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Advertising Router                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     LS sequence number                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         LS checksum           |             length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +-                            TLVs                             -+
   |                             ...                               |

   The format of the TLVs that make up the body of the TE Link Local LSA
   is the same as that of the TE TLVs: a 2-octet Type field followed by
   a 2-octet Length field which indicates the length of the Value field
   in octets.  The Top Level Type for the Link Local TLV is 4.  The
   Value field is zero-padded at the end to a four octet boundary.

   The only TLV defined here is the Link Local Identifier TLV, with Type
   1, Length 4 and Value the 32 bit Link Local Identifier for the link
   over which the TE Link Local LSA is exchanged.

4.  Contributors

   Ayan Banerjee
   Calient Networks
   5853 Rue Ferrari
   San Jose, CA 95138

   Phone: +1.408.972.3645
   EMail: abanerjee@calient.net

   John Drake
   Calient Networks
   5853 Rue Ferrari
   San Jose, CA 95138

   Phone: +1.408.972.3720
   EMail: jdrake@calient.net




Kompella & Rekhter          Standards Track                     [Page 7]

RFC 4203                OSPF Extensions in MPLS             October 2005


   Greg Bernstein
   Ciena Corporation
   10480 Ridgeview Court
   Cupertino, CA 94014

   Phone: +1.408.366.4713
   EMail: greg@ciena.com

   Don Fedyk
   Nortel Networks Corp.
   600 Technology Park Drive
   Billerica, MA 01821

   Phone: +1.978.288.4506
   EMail: dwfedyk@nortelnetworks.com

   Eric Mannie
   Independent Consultant

   EMail: eric_mannie@hotmail.com

   Debanjan Saha
   Tellium Optical Systems
   2 Crescent Place
   P.O. Box 901
   Ocean Port, NJ 07757

   Phone: +1.732.923.4264
   EMail: dsaha@tellium.com

   Vishal Sharma
   Metanoia, Inc.
   335 Elan Village Lane, Unit 203
   San Jose, CA 95134-2539

   Phone: +1.408.943.1794
   EMail: v.sharma@ieee.org

5.  Acknowledgements

   The authors would like to thank Suresh Katukam, Jonathan Lang,
   Quaizar Vohra, and Alex Zinin for their comments on the document.









Kompella & Rekhter          Standards Track                     [Page 8]

RFC 4203                OSPF Extensions in MPLS             October 2005


6.  Security Considerations

   This document specifies the contents of Opaque LSAs in OSPFv2.  As
   Opaque LSAs are not used for SPF computation or normal routing, the
   extensions specified here have no direct effect on IP routing.
   Tampering with GMPLS TE LSAs may have an effect on the underlying
   transport (optical and/or SONET-SDH) network.  [OSPF-TE] suggests
   mechanisms such as [OSPF-SIG] to protect the transmission of this
   information, and those or other mechanisms should be used to secure
   and/or authenticate the information carried in the Opaque LSAs.

7.  IANA Considerations

   The memo introduces four new sub-TLVs of the TE Link TLV in the TE
   Opaque LSA for OSPF v2; [OSPF-TE] says that the sub-TLVs of the TE
   Link TLV in the range 10-32767 must be assigned by Expert Review, and
   must be registered with IANA.

   The memo has four suggested values for the four sub-TLVs of the TE
   Link TLV; it is strongly recommended that the suggested values be
   granted, as there are interoperable implementations using these
   values.

   Finally, a new Top Level Type for OSPF TE LSAs for the Link Local TLV
   has been allocated from the Standards Action space.

8.  References

8.1.  Normative References

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

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

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

   [IEEE]          IEEE, "IEEE Standard for Binary Floating-Point
                   Arithmetic", Standard 754-1985, 1985 (ISBN 1-5593-
                   7653-8).





Kompella & Rekhter          Standards Track                     [Page 9]

RFC 4203                OSPF Extensions in MPLS             October 2005


   [OSPF]          Moy, J., "OSPF Version 2", STD 54, RFC 2328, April
                   1998.

   [OSPF-RESTART]  Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful
                   OSPF Restart", RFC 3623, November 2003.

   [OSPF-SIG]      Murphy, S., Badger, M., and B. Wellington, "OSPF with
                   Digital Signatures", RFC 2154, June 1997.

   [OSPF-TE]       Katz, D., Kompella, K., and Yeung, D., "Traffic
                   Engineering (TE) Extensions to OSPF Version 2", RFC
                   3630, September 2003.

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

Authors' Addresses

   Kireeti Kompella
   Juniper Networks, Inc.
   1194 N. Mathilda Ave
   Sunnyvale, CA 94089

   EMail: kireeti@juniper.net


   Yakov Rekhter
   Juniper Networks, Inc.
   1194 N. Mathilda Ave
   Sunnyvale, CA 94089

   EMail: yakov@juniper.net



















Kompella & Rekhter          Standards Track                    [Page 10]

RFC 4203                OSPF Extensions in MPLS             October 2005


Full Copyright Statement

   Copyright (C) The Internet Society (2005).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY 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 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Intellectual Property

   The IETF 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
   this 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.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR 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
   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org.

Acknowledgement

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







Kompella & Rekhter          Standards Track                    [Page 11]

