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DetNet Working Group                                            Y. Jiang
Internet-Draft                                                   N. Finn
Intended status: Standards Track                     Huawei Technologies
Expires: December 19, 2019                                       J. Ryoo
                                                                    ETRI
                                                                B. Varga
                                                                Ericsson
                                                                 L. Geng
                                                            China Mobile
                                                           June 17, 2019


        Deterministic Networking Application in Ring Topologies
                       draft-jiang-detnet-ring-04

Abstract

   Deterministic Networking (DetNet) provides a capability to carry data
   flows for real-time applications with extremely low data loss rates
   and bounded latency.  This document describes how DetNet can be used
   in ring topologies to support Point-to-Point (P2P) and Point-to-
   Multipoint (P2MP) real-time services.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on December 19, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  Abbreviations . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  P2P DetNet Ring . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  DetNet applications on a single ring for P2P traffic  . .   4
     4.2.  Implementation implications of a DetNet ring for P2P
           traffic . . . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  P2MP DetNet Ring  . . . . . . . . . . . . . . . . . . . . . .   5
     5.1.  DetNet applications on a single ring for P2MP traffic . .   5
     5.2.  Section LSPs as underlay (service sub-layer replication)    6
     5.3.  P2MP LSP tunnels as underlay (forwarding sub-layer
           replication)  . . . . . . . . . . . . . . . . . . . . . .   7
   6.  DetNet Ring Interconnections  . . . . . . . . . . . . . . . .   8
     6.1.  Single node interconnection . . . . . . . . . . . . . . .   8
     6.2.  Dual node interconnection . . . . . . . . . . . . . . . .   9
       6.2.1.  Dual node interconnection for P2P traffic . . . . . .   9
       6.2.2.  Dual node interconnection for P2MP traffic using
               section LSP . . . . . . . . . . . . . . . . . . . . .  10
       6.2.3.  Dual node interconnection for P2MP traffic using P2MP
               LSP . . . . . . . . . . . . . . . . . . . . . . . . .  11
   7.  Resource Reservation  . . . . . . . . . . . . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   The overall architecture for Deterministic Networking (DetNet), which
   provides a capability to carry specified unicast or multicast data
   flows for real-time applications with extremely low data loss rates
   and bounded latency, is specified in [I-D.ietf-detnet-architecture],
   and the generic data plane framework, which is common to any DetNet
   data plane implementations, is provided at
   [I-D.ietf-detnet-data-plane-framework].  In addition to the DetNet
   architecture documents, RFC 8578 [RFC8578] outlines several DetNet
   use cases where multicast capability is needed.  If a multicast



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   service replicates all of its packets from the source (as a
   traditional Virtual Private LAN Service (VPLS) does), the
   requirements of deterministic delay and high availability for all
   these replicated packets will pose a great challenge to the DetNet
   network.

   Ring topologies have been very popular and widely deployed in network
   arrangements for various transport networks, such as Synchronous
   Digital Hierarchy, Synchronous Optical Network, Optical Transport
   Network, and Ethernet.  For Multi-Protocol Label Switching -
   Transport Profile (MPLS-TP), the applicability of the MPLS-TP linear
   protection [RFC6378][RFC7271] for ring topologies and the ring-
   specific protection mechanism are specified in RFC 6974 [RFC6974] and
   RFC 8227 [RFC8227], respectively.  All these works, except Ethernet
   ring protection, typically use swapping or steering as the protection
   mechanism.  As ring topologies are widely deployed for transport
   networks, it is also necessary for the DetNet to support ring
   topologies.

   This document demonstrates how the DetNet can be used in a ring
   topology.  Specifically, DetNet ring supports for Point-to-Point
   (P2P) and Point-to-Multipoint (P2MP, for multicast services) are
   discussed in details.  This document assumes that the Multi-Protocol
   Label Switching (MPLS) encapsulation for DetNet is supported as
   specified in [I-D.ietf-detnet-mpls] and all nodes in a ring network
   can support the MPLS functionalities.  It should be noted that it is
   more convenient for the DetNet to support a ring topology with the
   intrinsic duplication and elimination mechanism, as there is no need
   of swapping or steering operations (consequently, its Operations,
   Administration and Maintenance (OAM) can also be simplified) for
   service protection.

2.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Abbreviations










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   This document uses the following abbreviations:

   DetNet  Deterministic Networking
   LSP     Label Switched Path
   MPLS    Multi-Protocol Label Switching
   MPLS-TP Multi-Protocol Label Switching - Transport Profile
   P2MP    Point-to-Multipoint
   P2P     Point-to-Point
   PEF     Packet Elimination Function
   POF     Packet Ordering Function
   PRF     Packet Replication Function
   PW      Pseudowire

4.  P2P DetNet Ring

   This section describes how the DetNet can deliver P2P traffic over a
   single ring.

4.1.  DetNet applications on a single ring for P2P traffic

   Figure 1 shows an example of the DetNet ring for P2P real time
   traffic.  Nodes A and C are DetNet aware devices, and P2P DetNet
   traffic is transported from node A to node C.

                        +---+#############+---+
                        | B |-------------| C | +-- DetNet
                        +---+             +---+     egress
                        #/                    *\
                       #/                      *\
                      #/                        *\
                    +---+                     +---+
          DetNet--+ | A |                     | D |
          ingress   +---+                     +---+
                       \*                      */
                        \*                    */
                         \*                  */
                        +---+*************+---+
                        | F |-------------| E |
                        +---+             +---+

                         ----- Physical Links
                         ##### Clockwise_
                         ***** Counter Clockwise

                   Figure 1: DetNet Ring for P2P traffic

   A clockwise and a counter clockwise Label Switched Paths (LSPs) are
   configured from node A to node C using the DetNet forwarding labels



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   (F-Labels) are configured from node A to node C.  The DetNet service
   sub-layer functions are provided at nodes A and C utilizing the
   DetNet service label(s) (S-Label) and DetNet control word (d-CW) as
   described in [I-D.ietf-detnet-mpls].  The P2P traffic is replicated
   by a Packet Replication Function (PRF) in node A, encapsulated with
   the d-CW and specific S-Label and F-Label(s), and transported on both
   LSP paths towards node C.  Upon reception of the traffic, node C
   terminates the LSP and is aware of the DetNet traffic by inspection
   of the S-Label carried in each packet.  A Packet Elimination Function
   (PEF) in node C guarantees that only one copy of the DetNet service
   exits on egress with the help of the DetNet sequence number.  A
   Packet Ordering Function (POF) can further reorder packets in node C
   before transport of these packets to the destination.

4.2.  Implementation implications of a DetNet ring for P2P traffic

   In a DetNet ring for P2P traffic, one path may be far longer than the
   other path.  The buffer for reordering at the egress needs to be
   large enough to accommodate for the sequence number difference
   between these two paths.

5.  P2MP DetNet Ring

5.1.  DetNet applications on a single ring for P2MP traffic

   Figure 2 shows an example of the DetNet ring for P2MP real time
   traffic.  Nodes A, B, C, E and F are DetNet aware devices, and P2MP
   DetNet traffic is transported from head-end node A to multiple tail-
   end nodes C, E and F.

   Two approaches are described in Section 5.2 and Section 5.3 for P2MP
   traffic.



















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                        +---+#############+---+
                        | B |-------------| C | +-- DetNet
                        +---+*************+---+     egress
                        #/                    *\#
                       #/                      *\#
                      #/                        *\#
                    +---+                     +---+
          DetNet--+ | A |                     | D |
          ingress   +---+                     +---+
                       \*                      */#
                        \*                    */#
                         \*                  */#
                        +---+*************+---+
              DetNet--+ | F |-------------| E |+-- DetNet
              egress    +---+#############+---+    egress

                         ----- Physical Links
                         ##### Clockwise traffic
                         ***** Counter Clockwise traffic

                  Figure 2: DetNet Ring for P2MP traffic

5.2.  Section LSPs as underlay (service sub-layer replication)

   If section LSPs are used as an underlay for DetNet services, a
   bidirectional section LSP tunnel is set up between each pair of
   neighboring nodes in the ring (e.g., node A and node B, ..., node F
   and node A).  In this case, the DetNet sub-layer replicates the
   DetNet packets from one tail-end to another neighboring tail-end.

   The DetNet head-end (i.e., node A) in the ring needs to support
   DetNet replication function.  Upon reception on node A, the DetNet
   traffic is replicated with a d-CW, encapsulated with a S-Label and a
   section LSP label per DetNet member flow, and transported on both
   section LSPs (i.e., A-B and A-F).

   All intermediate nodes (non tail-ends) on the ring MUST transparently
   forward the DetNet packet, which contains a d-CW and S-Label, to the
   next hop on the ring.

   All DetNet tail-ends except the penultimate node (egress nodes such
   as nodes C and E in the clockwise, and nodes F, E and C in the
   counter clockwise) on the ring MUST support both DetNet PRF and PEF
   functions, and MAY further support a DetNet POF function.  For the
   example of Figure 2, upon reception of the clockwise traffic, node C
   terminates the section LSP and recognizes the DetNet flow by
   inspection of the S-label in the packet.  Firstly, node C needs to
   forward the DetNet packet to the next hop on the ring in the



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   clockwise direction.  Secondly, the DetNet packet is also directed to
   a DetNet PEF associated with the DetNet flow, only one copy is
   egressed from the ring by inspection of the sequence number in the
   d-CW.  Furthermore, if the DetNet POF function is enabled, the
   packets in the DetNet flow are reordered before exit to DetNet
   egress.

   If multiple endpoints are attached to a tail-end node, a multicast
   module can be used to forward the traffic to all these endpoints.

   To avoid a loop of DetNet service, the penultimate node in the ring
   (such as node B on the counter clock-wise LSP) MUST terminate the
   DetNet flow.  For example, upon reception of the clockwise DetNet
   traffic, node F terminates the DetNet traffic by inspection of the
   S-Label in the packet.  As an alternative, the last DetNet tail-end
   (such as node C on the counter clock-wise LSP) MAY terminate the
   DetNet flow, so that the bandwidth from this node to the penultimate
   node can be saved.

5.3.  P2MP LSP tunnels as underlay (forwarding sub-layer replication)

   If P2MP LSPs are used as an underlay for the DetNet service, a P2MP
   unidirectional LSP tunnel in clockwise is set up from head-end
   (ingress node A) to all the tail-ends (egress nodes C, E and F) for
   the ring, and another P2MP unidirectional LSP tunnel in counter
   clockwise is set up from head-end (ingress node A) to all the tail-
   ends (egress nodes F, E and C) for the ring.  Thus, a PRF in LSP
   layer replicates the DetNet packets from one tail-end to another
   neighboring tail-end.

   The DetNet head-end (i.e., node A) in the ring needs to support the
   DetNet PRF function.  Upon reception on node A, the DetNet traffic is
   replicated with a d-CW, encapsulated with a S-Label per DetNet member
   flow, and transported on both P2MP LSP tunnels in the ring.

   All DetNet tail-ends (egress nodes such as nodes C, E and F in
   Figure 2) on the ring need to support the DetNet PEF function.  For
   example, upon reception of the traffic, node C pops the P2MP LSP
   label and is aware of the DetNet traffic by inspection of the S-Label
   label in the label stack.  Two DetNet member flows are identified
   with their S-Labels and directed to the same PEF so that only one
   copy of the DetNet service is selected by inspection of the DetNet
   sequence number in the d-CW.  Furthermore, if DetNet POF function is
   enabled, the packets in the DetNet flow are reordered before exit to
   DetNet egress.






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   If multiple endpoints are attached to a tail-end node, a multicast
   module can be used to forward the filtered DetNet traffic to all
   these endpoints

6.  DetNet Ring Interconnections

   Two DetNet rings can be connected via one or more interconnection
   nodes.  Figure 3 shows the ring interconnection scenarios with a
   single node and dual nodes.  In the interconnected rings, each ring
   operates in the same way as described in Section 4 and Section 5
   except the node or nodes that are used to interconnect two rings.

                                                   S    T
             B    C     S    T                     O----O
             O----O     O----O                    /      \
            /      \   /      \            B   I1/        \
           /        \ /        \           O----O  Ring R  O U
        A O  Ring L  O  Ring R  O U       /      \        /
           \        /I\        /         /        \      /
            \      /   \      /       A O  Ring L  O----O
             O----O     O----O           \        /I2   V
             F    E     W    V            \      /
                                           O----O
                                           F    E
                    (a)                          (b)

   Figure 3: DetNet ring interconnection with: (a) single node (node I),
                   and (b) dual nodes (nodes I1 and I2)

   In this section, we describe the behavior of interconnection nodes
   with the traffic going from Ring L to Ring R.  Symmetrical
   description is assumed for the traffic in the other direction (i.e.,
   from Ring R to Ring L).

6.1.  Single node interconnection

   In the case of the single node interconnection, as shown in
   Figure 3(a), both P2P and P2MP DetNet traffic that needs to be
   transported between Ring L and Ring R use a single interconnection
   node between two rings.  Thus, the interconnection node acts as a
   DetNet relay node, which provides both PRF and PEF functions.

   For P2P DetNet traffic going from Ring L to Ring R, interconnection
   node I receives the same DetNet flow traffic from both node C and
   node E (i.e., clockwise and counter-clockwise), a PEF in node I
   performs packet elimination, and a PRF in node I replicates the
   packet, node I then sends one copy to node S and another copy to node
   W.



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   For P2MP DetNet traffic going from Ring L to Ring R, interconnection
   node I performs the same packet elimination and replication functions
   as described above.  In addition, node I further transparently
   forwards the P2MP DetNet traffic on Ring L in the same direction if
   it is not the last tail-end node.

6.2.  Dual node interconnection

   In order to prevent a single point of failure, two interconnection
   nodes can be used as shown in Figure 3(b).  To provide high
   availability for DetNet services, dual node interconnection is
   recommended.  Two interconnection nodes act as DetNet relay nodes,
   each provides both packet replication and elimination functions.

6.2.1.  Dual node interconnection for P2P traffic

   For the P2P DetNet traffic that flows from Ring L to Ring R in
   Figure 3(b), the operations of interconnection nodes I1 and I2 are
   described below.

   When interconnection node I1 receives clockwise traffic from node B,
   it replicates the traffic and sends one copy to interconnection node
   I2 and the other copy to a PEF in interconnection node I1.

   When interconnection node I1 receives counter-clockwise traffic from
   interconnection node I2, it forwards the traffic to the PEF of
   interconnection node I1.

   At the PEF of interconnection node I1, duplicate elimination is
   performed for the clockwise traffic from node B and the counter-
   clockwise traffic from interconnection node I2, and only one copy is
   sent to the clockwise direction of Ring R (i.e., sent towards node
   S).  Furthermore, if DetNet POF function is enabled on
   interconnection node I1, the packets in the DetNet flow are reordered
   before being forwarded to Ring R.

   When interconnection node I2 receives counter-clockwise traffic from
   node E, it replicates the traffic and sends one copy to
   interconnection node I1 and the other copy to a PEF in
   interconnection node I2.

   When interconnection node I2 receives clockwise traffic from
   interconnection node I1, it forwards the traffic to the PEF of
   interconnection node I2.

   At the PEF of interconnection node I2, duplicate elimination is
   performed for the counter-clockwise traffic from node E and the
   clockwise traffic from interconnection node I1, and only one copy is



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   sent to the counter-clockwise direction of Ring R (i.e., sent towards
   node V).  Furthermore, if DetNet POF function is enabled on
   interconnection node I2, the packets in the DetNet flow are reordered
   before being forwarded to Ring R.

6.2.2.  Dual node interconnection for P2MP traffic using section LSP

   For the P2MP traffic that flows from Ring L to Ring R in Figure 3(b),
   each ring is configured and operated as described in Section 5.2
   except the interconnection nodes, whose operations are described
   below.

   When interconnection node I1 receives clockwise traffic from node B,
   its PRF replicates the traffic and sends one copy to interconnection
   node I2 and the other copy to interconnection node I1's PEF.

   When interconnection node I1 receives the counter-clockwise traffic
   from interconnection node I2, its PRF replicates the traffic and
   sends one copy to node B and the other copy to interconnection node
   I1's PEF unless interconnection node I1 is the penultimate node for
   the counter-clockwise traffic on Ring L.  In the case that
   interconnection node I1 is the penultimate node for the counter-
   clockwise traffic on Ring L, the counter-clockwise traffic from
   interconnection node I2 is only forwarded to interconnection node
   I1's PEF.

   At interconnection node I1's PEF, duplicate elimination is performed
   for the clockwise traffic from node B and the counter-clockwise
   traffic from interconnection node I2, and only one copy is sent to
   the clockwise direction of Ring R (i.e., sent towards node S).
   Furthermore, if DetNet POF function is enabled on node I1, the
   packets in the DetNet flow are reordered before being forwarded to
   Ring R.

   When interconnection node I2 receives the counter-clockwise traffic
   from node E, its PRF replicates the traffic and sends one copy to
   interconnection node I1 and the other copy to node I2's PEF.

   When interconnection node I2 receives the clockwise traffic from
   interconnection node I1, its PRF replicates the traffic and sends one
   copy to node E and the other copy to interconnection node I2's PEF
   unless interconnection node I2 is the penultimate node for the
   clockwise traffic on Ring L.  In the case that interconnection node
   I2 is the penultimate node for the clockwise traffic on Ring L, the
   clockwise traffic from interconnection node I1 is only forwarded to
   node I2's PEF.





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   At node I2's PEF, duplicate elimination is performed for the counter-
   clockwise traffic from node E and the clockwise traffic from
   interconnection node I1, and only one copy is sent to the counter-
   clockwise direction of Ring R (i.e., sent towards node V).
   Furthermore, if DetNet POF function is enabled on interconnection
   node I2, the packets in the DetNet flow are reordered before being
   forwarded to Ring R.

6.2.3.  Dual node interconnection for P2MP traffic using P2MP LSP

   If P2MP LSPs are used in the interconnected rings, two P2MP
   unidirectional LSP tunnels are used on each ring for the clockwise
   and counter-clockwise directions.

   When the P2MP traffic is forwarded from one ring to another ring, for
   example from Ring L to Ring R in Figure 3(b), each P2MP LSP in Ring L
   MUST include interconnection nodes I1 and I2 as its tail-ends.  For
   Ring R, one P2MP LSP is set up from interconnection node I1 to all
   the tail-ends in the clockwise direction on Ring R, and the other
   P2MP LSP is set up from interconnection node I2 to all the tail-ends
   in the counter-clockwise direction on Ring R.  Therefore, an
   interconnection node acts as a tail-end for one ring and a head-end
   for another ring in one direction, and performs the same operation of
   tail-end and head-end as specified in Section 5.3.

7.  Resource Reservation

   In order to guarantee that DetNet flows do not suffer from network
   congestion, the DetNet data plane considerations on resource
   reservation and allocation as described in
   [I-D.ietf-detnet-data-plane-framework] apply here.

8.  IANA Considerations

   There are no IANA actions required by this document

9.  Security Considerations

   This document describes the application of DetNet MPLS on ring
   topologies.  Thus, the security considerations described in
   [I-D.ietf-detnet-mpls] are also applied to this document.  If any new
   security considerations specific to ring topologies are identified,
   they will be added in a future version of this draft.








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10.  References

10.1.  Normative References

   [I-D.ietf-detnet-architecture]
              Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", draft-ietf-
              detnet-architecture-13 (work in progress), May 2019.

   [I-D.ietf-detnet-data-plane-framework]
              Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
              Bryant, S., and J. Korhonen, "DetNet Data Plane
              Framework", draft-ietf-detnet-data-plane-framework-00
              (work in progress), May 2019.

   [I-D.ietf-detnet-mpls]
              Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
              Bryant, S., and J. Korhonen, "DetNet Data Plane: MPLS",
              draft-ietf-detnet-mpls-00 (work in progress), May 2019.

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

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

10.2.  Informative References

   [RFC6378]  Weingarten, Y., Ed., Bryant, S., Osborne, E., Sprecher,
              N., and A. Fulignoli, Ed., "MPLS Transport Profile (MPLS-
              TP) Linear Protection", RFC 6378, DOI 10.17487/RFC6378,
              October 2011, <https://www.rfc-editor.org/info/rfc6378>.

   [RFC6974]  Weingarten, Y., Bryant, S., Ceccarelli, D., Caviglia, D.,
              Fondelli, F., Corsi, M., Wu, B., and X. Dai,
              "Applicability of MPLS Transport Profile for Ring
              Topologies", RFC 6974, DOI 10.17487/RFC6974, July 2013,
              <https://www.rfc-editor.org/info/rfc6974>.










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   [RFC7271]  Ryoo, J., Ed., Gray, E., Ed., van Helvoort, H.,
              D'Alessandro, A., Cheung, T., and E. Osborne, "MPLS
              Transport Profile (MPLS-TP) Linear Protection to Match the
              Operational Expectations of Synchronous Digital Hierarchy,
              Optical Transport Network, and Ethernet Transport Network
              Operators", RFC 7271, DOI 10.17487/RFC7271, June 2014,
              <https://www.rfc-editor.org/info/rfc7271>.

   [RFC8227]  Cheng, W., Wang, L., Li, H., van Helvoort, H., and J.
              Dong, "MPLS-TP Shared-Ring Protection (MSRP) Mechanism for
              Ring Topology", RFC 8227, DOI 10.17487/RFC8227, August
              2017, <https://www.rfc-editor.org/info/rfc8227>.

   [RFC8578]  Grossman, E., Ed., "Deterministic Networking Use Cases",
              RFC 8578, DOI 10.17487/RFC8578, May 2019,
              <https://www.rfc-editor.org/info/rfc8578>.

Authors' Addresses

   Yuanlong Jiang
   Huawei Technologies
   Bantian, Longgang district
   Shenzhen  518129
   China

   Phone: +86-18926415311
   Email: jiangyuanlong@huawei.com


   Norman Finn
   Huawei Technologies
   3755 Avocado Blvd
   California  91941
   USA

   Phone: +1 925 980 6430
   Email: norman.finn@mail01.huawei.com


   Jeong-dong Ryoo
   ETRI
   218 Gajeongno
   Yuseong-gu, Daejeon  34129
   South Korea

   Phone: +82-42-860-5384
   Email: ryoo@etri.re.kr




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Internet-Draft                 DetNet Ring                     June 2019


   Balazs Varga
   Ericsson
   Konyves Kalman krt. 11/B
   Budapest  1097
   Hungary

   Email: balazs.a.varga@ericsson.com


   Liang Geng
   China Mobile
   Beijing
   China

   Email: gengliang@chinamobile.com




































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