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SPRING Working Group                                      Sanjoy Bardhan
Internet-Draft                                            Madhukar Anand
Intended Status: Informational                       Ramesh Subrahmaniam
                                                    Infinera Corporation
                                                           Jeff Tantsura
                                                              Individual
Expires: June 25, 2017                                 December 22, 2016


         OAM for Packet-Optical Integration in Segment Routing
                   draft-bardhan-spring-poi-sr-oam-01


Abstract

   This document describes a list of functional requirements for
   transport segment OAM in Segment Routing (SR) based networks.




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
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Copyright and License Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors. All rights reserved.




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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document. Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1  Terminology . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Detailed Requirement List  . . . . . . . . . . . . . . . . . .  4
   3  Security Considerations . . . . . . . . . . . . . . . . . . . .  7
   4  IANA Considerations . . . . . . . . . . . . . . . . . . . . . .  7
   5  References  . . . . . . . . . . . . . . . . . . . . . . . . . .  7
     5.1  Normative References  . . . . . . . . . . . . . . . . . . .  7
     5.2  Informative References  . . . . . . . . . . . . . . . . . .  7
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  7
   Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . . .  8



























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1  Introduction

   [I-D.filsfils-rtgwg-segment-routing] introduces and explains Segment
   Routing architecture that leverages source routing and tunneling
   standards which can be applied directly to MPLS dataplane with no
   changes on forwarding plane and on IPv6 dataplane with new Routing
   Extension Header. In addition [I-D. draft-anand-spring-poi-sr]
   introduces the concept of a Transport Segment at the edge of the
   packet and optical network that represents the optical path taken for
   a given flow.




                                 P5
     P1 _                      .-'-._                    ,'P4
         `._                .-'      `-.               ,'
            `.          _.-'            `-._         ,'
              `-.    .-'                    `-.    ,'
               P2`.-'--------------------------`-.- P3
                  |\                             /|
                  | \                           / |   Packet
            ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
                  |   \                       /   |
                  |    \                     /    |   Transport
                  |     \                   /     |
                  |      ................../      |
                  |    ,'O2              O3`.     |
                  |  ,'                      `.   |
                  |,'                          `. |
                O1\                              | O4
                   \                           ,'
                    \                        ,'
                     .......................-
                    O6                     O5

       Figure 1:  Representation of a packet-optical path




In Figure 1 above, the nodes represent a packet optical network.
P1,...,P5 are packet devices. Nodes P2 and P3 are connected via optical
network comprising of nodes O1,...,O6. Nodes P2 and P3 are POGs that
communicate with other packet devices and also with the devices in the
optical transport domain.





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This document is a place holder to identify and list the OAM
requirements for Segment Routing based network which can further be
extended to produce OAM tools for path liveliness and service validation
across the optical domain using Transport Segments. In the above figure,
these requirements would pertain to nodes P2 and P3.


1.1  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].

   SR: Segment Routing

   Initiator: Centralized OAM initiator

   POG: Packet Optical Gateway that interworks between a packet and
optical network


2.  Detailed Requirement List

This section list the OAM requirement for Transport Segments in a
Segment Routing based network.  The below listed requirements MUST be
supported within an optical dataplane.


REQ#1:  Transport Segment OAM SHOULD support Continuity Check
(liveliness of a path - BFD), Connectivity Verification (BFD, Ping),
Fault Verification - exercised on demand to validate the reported fault
(Ping).

REQ#2:   Transport Segment OAM MUST support both On-demand and
Continuous OAM functionality.

REQ#3:   Transport Segment OAM packet MUST follow exactly the same path
as the dataplane traffic.

REQ#4:   The Transport Segment  OAM packet MUST have the ability to
exercise any available paths as defined by the transport segment label.

REQ#5:   Transport Segment OAM SHOULD have the ability to allow the
Initiator to add the Remote Transport Label and control the return path
from egress responder. draft-ietf-mpls-bfd-directed has provided the
semantics of a return path which would suit this need.





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REQ#6:   Transport Segment OAM MUST have the ability to be initialized
from an ingress POG node to perform connectivity verification and
continuity check to any remote POG  within the same optical domain ID
based on the declared Transport Segment Label.

REQ#7:   In case of any failure with continuity check, Transport Segment
OAM Layer SHOULD support rapid Connectivity Fault notification to the
Packet Control plane of the POG to withdraw the Transport Segment Label
associated with the affected path and/or take a local protection action.

REQ#8:  Transport Segment OAM SHOULD also have the ability to be
initialized from a centralized controller.

REQ#9:  When Transport Segment OAM is initialized from centralized
controller, the node on receiving the alert MAY take a local protection
action and/or  pop an informational message.

REQ#10:  When Transport Segment OAM is initialized, it SHOULD support
node redundancy based on network configuration.  If primary Initiator
fails, secondary one MUST take over the responsibility without having
any impact on customer traffic.

REQ#11:  Transport Segment OAM MUST have the ability to measure
bidirectional packet loss, throughput measurement, delay variation, as
well as unidirectional and dyadic measurements.

REQ#12:  When a new path is instantiated, Transport Segment OAM SHOULD
allow path verification without noticeable delay. It may be desired to
check for liveliness of the optical path using Transport Segment OAM
before announcing the Transport Segment.

REQ#13:  The above listed requirements SHOULD be supported without any
scalability limitation imposed and SHOULD be extensible to accommodate
any new SR functionality.

REQ#14:  Transport Segment OAM SHOULD maintain per Transport label state
entry at the originating POG.

REQ#15:  When traffic engineering is initiated by centralized controller
device, and when Transport Segment OAM is performed by POGs, there MUST
be a mechanism to communicate the failure to a centralized controller
device.

REQ#16: When a local repair in the optical network takes place, the
characteristics of the path between the POGS may have changed. If there
is significant change in the path characteristics based on thresholds,
the ingress POG SHALL trigger a re-advertisement of the transport
segment label at the global level.



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REQ#17: The format of the Transport Segment OAM Ping packet SHALL follow
RFC 4379.

REQ#18: The format of the Transport Segment OAM BFD packet SHALL follow
RFC 5884.














































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3  Security Considerations

This document does not introduce any new security considerations.


4  IANA Considerations

TBD.


5  References

5.1  Normative References


              [I-D.ietf-spring-segment-routing]        Filsfils, C.,
              Previdi, S., Decraene, B., Litkowski, S.,        and r.
              rjs@rob.sh, "Segment Routing Architecture", draft-
              ietf-spring-segment-routing-04 (work in progress), July
                  2015.

              [I-D.ietf-mpls-bfd-directed]         Mirsky, G., Tantsura,
              J., Varlashkin, I., and M. Chen,         "Bidirectional
              Forwarding Detection (BFD) Directed Return         Path",
              draft-ietf-mpls-bfd-directed-02 (work in progress),
               March 2016.

              [I-D.draft-anand-spring-poi-sr-01]        Madhukar Anand,
              Sanjoy Bardhan, Ramesh Subrahmaniam, Tantsura, J.
              "Packet-Optical Integration in Segment Routing",  draft-
              anand-spring-poi-sr-01        (work in progress), July
              2016.


5.2  Informative References



Authors' Addresses



      Sanjoy Bardhan
      Infinera Corporation
      169 W Java Dr, Sunnyvale, CA 94089

      Email: sbardhan@infinera.com




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      Madhukar Anand
      Infinera Corporation
      169 W Java Dr, Sunnyvale, CA 94089

      Email: manand@infinera.com


      Ramesh Subrahmaniam
      Infinera Corporation
      169 W Java Dr, Sunnyvale, CA 94089

      Email: RSubrahmaniam@infinera.com

      Jeff Tantsura

      Email: jefftant.ietf@gmail.com



Acknowledgments

   The authors would like to thank Krish Verma for his comments and
   review of this document.




























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