Multi-Layer Active OAM for Service Function Chains in Networks
draft-wang-sfc-multi-layer-oam-10

Versions: 00 01 02 03 04 05 06 07 08 09 10                              
SFC WG                                                         G. Mirsky
Internet-Draft                                                 ZTE Corp.
Intended status: Standards Track                                 W. Meng
Expires: March 25, 2018                                  ZTE Corporation
                                                           B. Khasnabish
                                                            ZTE TX, Inc.
                                                                 C. Wang
                                                      September 21, 2017


     Multi-Layer Active OAM for Service Function Chains in Networks
                   draft-wang-sfc-multi-layer-oam-10

Abstract

   A multi-layer approach to the task of Operation, Administration and
   Maintenance (OAM) of Service Function Chains (SFCs) in networks is
   presented.  Based on the requirements towards active OAM for SFC, a
   multi-layer model is introduced.  A mechanism to detect and localize
   defects using the multi-layer model is also described.

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
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   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 March 25, 2018.

Copyright Notice

   Copyright (c) 2017 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
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect



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   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 . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     2.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Multi-layer Model of SFC OAM  . . . . . . . . . . . . . . . .   4
   4.  Requirements for Multi-layer Model of Active OAM  . . . . . .   4
   5.  Active OAM Identification in SFC NSH  . . . . . . . . . . . .   6
   6.  SFC OAM multi-layer model . . . . . . . . . . . . . . . . . .   6
   7.  Echo Request/Echo Reply for SFC in Networks . . . . . . . . .   7
     7.1.  SFC Echo Request Transmission . . . . . . . . . . . . . .   9
     7.2.  SFC Echo Request Reception  . . . . . . . . . . . . . . .   9
     7.3.  SFC Echo Reply Transmission . . . . . . . . . . . . . . .   9
     7.4.  Overlay Echo Reply Reception  . . . . . . . . . . . . . .  10
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
     9.1.  SFC Active OAM Protocol . . . . . . . . . . . . . . . . .  11
     9.2.  SFC Active OAM Message Type . . . . . . . . . . . . . . .  11
     9.3.  SFC Echo Request/Echo Reply Parameters  . . . . . . . . .  12
     9.4.  SFC Echo Request/Echo Reply Message Types . . . . . . . .  12
     9.5.  SFC Echo Reply Modes  . . . . . . . . . . . . . . . . . .  12
     9.6.  SFC TLV Type  . . . . . . . . . . . . . . . . . . . . . .  13
     9.7.  SFC OAM UDP Port  . . . . . . . . . . . . . . . . . . . .  14
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     10.2.  Informative References . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   [RFC7665] defines components necessary to implement Service Function
   Chain (SFC).  These include a classifier which performs
   classification of incoming packets.  A Service Function Forwarder
   (SFF) is responsible for forwarding traffic to one or more connected
   Service Functions (SFs) according to the information carried in the
   SFC encapsulation.  SFF also handles traffic coming back from the SF
   and transports the data packets to the next SFF.  And the SFF serves
   as termination element of the Service Function Path (SFP).  SF is
   responsible for specific treatment of received packets.

   Resulting from that SFC is constructed by a number of these
   components, there are different views from different levels of the



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   SFC.  One is the SFC, fully abstract entity, that defines an ordered
   set of SFs that must be applied to packets selected as a result of
   classification.  But SFC doesn't define exact mapping between SFFs
   and SFs.  Thus there exists another semi-abstract entity referred as
   SFP.  SFP is the instantiation of the SFC in the network and provides
   a level of indirection between the fully abstract SFC and a fully
   specified ordered list of SFFs and SFs identities that the packet
   will visit when it traverses the SFC.  The latter entity is being
   referred as Rendered Service Path (RSP).  The main difference between
   SFP and RSP is that in the former the authority to select the SFF/SF
   has been delegated to the network.

   This document proposes the multi-layer model of SFC active Operation,
   Administration and Maintenance (OAM), per [RFC7799] definition of
   active OAM, lists requirements to improve the troubleshooting
   efficiency and defines SFC Echo request and Echo reply that enables
   on-demand Continuity Check, Connectivity Verification among other
   operations over SFC in networks.

2.  Conventions

2.1.  Requirements Language

   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.

2.2.  Terminology

   Unless explicitly specified in this document, active OAM in SFC and
   SFC OAM are being used interchangeably.

   e2e: End-to-End

   FM: Fault Management

   NSH: Network Service Header

   OAM: Operations, Administration, and Maintenance

   RDI: Remote Defect Indication

   RSP: Rendered Service Path

   SF: Service Function




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   SFC: Service Function Chain

   SFF: Service Function Forwarder

   SFP: Service Function Path

3.  Multi-layer Model of SFC OAM

   As described in [I-D.ietf-sfc-oam-framework], multiple layers come
   into play to realize the SFC, including the Service layer, the
   underlying Network layer, as well as the Link layer, which are
   depicted in Figure 1:

   o  The Service layer consists of classifiers and/or service
      functions/SFs.

   o  Network and Transport layers leverage various overlay network
      technologies interconnecting SFs to establish SFP.

   o  The Link layer is technology specific and reflects the technology
      used in the underlay network.


                      +---+  +---+   +---+  +---+     +---+
                      |SF1|  |SF2|   |SF3|  |SF4|     |SF5|
                      +---+  +---+   +---+  +---+     +---+
                         \    /          \  /           |
      +----------+       +----+         +----+        +----+
      |Classifier|-------|SFF1|---------|SFF2|--------|SFF3|
      +----------+       +----+         +----+        +----+
          0---------------------------------------------0  Service layer
          0----------------0--------------0-------------0  Network layer
          0-------------0------0-------0------0---------0  Link layer


                    Figure 1: SFC OAM Multi-Layer model

4.  Requirements for Multi-layer Model of Active OAM

   To perform the OAM task of fault management (FM) in an SFC, that
   includes failure detection, defect characterization and localization,
   this document defines the multi-layer model of OAM, presented in
   Section 3, and set of requirements towards active OAM mechanisms to
   be used on an SFC.

   In example presented in Figure 1 the service SFP1 may be realized
   through two RSPs, RSP1(SF1--SF3--SF5) and RSP2(SF2--SF4--SF6).  To
   perform end-to-end (e2e) FM SFC OAM:



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      REQ#1: Packets of active OAM in SFC SHOULD be fate sharing with
      data traffic, i.e. in-band with the monitored traffic, i.e. follow
      exactly the same RSP, in forward direction, i.e. from ingress
      toward egress end point(s) of the OAM test.

      REQ#2: SFC OAM MUST support pro-active monitoring of any element
      in the SFC availability.

   The egress, SFF3 in example in Figure 1, is the entity that detects
   the failure of the SFC.  It must be able to signal the new defect
   state to the ingress, i.e. SFF1.  Hence the following requirement:

      REQ#3: SFC OAM MUST support Remote Defect Indication (RDI)
      notification by egress to the ingress, i.e. source of continuity
      checking.

      REQ#4: SFC OAM MUST support connectivity verification.  Definition
      of mis-connectivity defect entry and exit criteria are outside the
      scope of this document.

   Once the SFF1 detects the defect objective of OAM switches from
   failure detection to defect characterization and localization.

      REQ#5: SFC OAM MUST support fault localization of Loss of
      Continuity check in the SFC.

      REQ#6: SFC OAM MUST support tracing an SFP in order to realize the
      RSP.

   It is practical, as presented in Figure 1, that several SFs share the
   same SFF.  In such case SFP1 may be realized over two RSPs,
   RSP1(SF1--SF3--SF5) and RSP2(SF2--SF4--SF6).

      REQ#7: SFC OAM MUST have the ability to discover and exercise all
      available RSPs in the transport network.

   In process of localizing the SFC failure separating SFC OAM layers is
   very attractive and efficient approach.  To achieve that continuity
   among SFFs that are part of the same SFP should be verified.  Once
   SFFs reachability along the particular SFP has been confirmed task of
   defect localization may focus on SF reachability verification.
   Because reachability of SFFs has already been verified, SFF local to
   the SF may be used as source.

      REQ#8: SFC OAM MUST be able to trigger on-demand FM with responses
      being directed towards initiator of such proxy request.





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5.  Active OAM Identification in SFC NSH

   The multi-layer model OAM that confirms to the above listed
   requirements enables active OAM protocols that are capable to perform
   efficient defect localization on an SFC.  [I-D.ietf-sfc-nsh] does not
   provide definition for identification of an SFC active OAM packet.
   This document defines that active OAM packet on SFC MUST have OAM bit
   set and MUST have the value on the Next Protocol field set to OAM
   (TBA1) according to Section 9.1.

   It is very unlikely that a single protocol will address all the
   requirements listed in Section 4.  Protocols may be identified by
   destination UDP port number if IP/UDP encapsulation used.  But extra
   IP/UDP headers, especially in case of IPv6, add noticeable overhead.
   This document defines Active OAM Header Figure 2 to demultiplex
   active OAM protocols on an SFC.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | V | Msg Type  |     Flags     |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~              SFC Active OAM Control Packet                    ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 2: SFC Active OAM Header

      V - two bits long field indicates the current version of the SFC
      active OAM header.  The current value is 0.

      Msg Type - six bits long field identifies OAM protocol, e.g.  Echo
      Request/Reply or BFD.

      Flags - eight bits long field carries bit flags that define
      optional capability and thus processing of the SFC active OAM
      control packet, e.g. optional timestamping.

      Length - two octets long field that is length of the SFC active
      OAM control packet in octets.

6.  SFC OAM multi-layer model

   Figure 3 presents a use case of applying the proposed SFC OAM multi-
   layer model.  In this scenario operator needs to discover SFFs and
   SFs of the same SFC.  The Layer 1 includes the SFFs that are part of
   the SFP.  The Layer 2 - the SFs along the RSP.  When trying to do SFC
   OAM, classifier or service nodes select and confirm which SFC OAM
   layering they plan to do, then encapsulate the layering information



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   in the SFC OAM packets, and send the SFC OAM packets along the
   service function paths to the destination.  When receiving the SFC
   OAM packets, service nodes analyze the layering information and then
   decide whether sending these packets to next SFFs directly without
   being processed by SFs for Layer 1 process or sending to SFs for
   Layer 2 process.


          +---+ +---+  +----+ +----+  +-----+ +-----+  +------+ +------+
          |SF1|.|SFn|  |SF1'|.|SFn'|  |SF1''|.|SFn''|  |SF1'''|.|SFn'''|
          +---+ +---+  +----+ +----+  +-----+ +-----+  +------+ +------+
              \   /        \   /  |      \     /           \    /   |
  +------+   +----+       +----+  |      +-----+           +-----+  |
  |Class.|---|SFF1|  ...  |SFFn|  |      |SFF1'|   ...     |SFFn'|  |
  +------+   +----+       +----+  |      +-----+           +-----+  |
                             |    |                            |    |
                             |    |                            |    |
                             |----|------Layer 1---------------|    |
                                  |                                 |
                                  |-------------Layer 2-------------|



                  Figure 3: SFC OAM multi-layering model

7.  Echo Request/Echo Reply for SFC in Networks

   Echo Request/Reply is well-known active OAM mechanism that is
   extensively used to detect inconsistencies between states in control
   plane and data plane, localize defects in the data plane.  The format
   of the Echo request/Echo reply control packet is to support ping and
   traceroute functionality in SFC in networks Figure 4 resembles the
   format of MPLS LSP Ping [RFC8029] with some exceptions.


















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        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         Version Number        |         Global Flags          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Message Type  |   Reply mode  |  Return Code  | Return S.code |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                        Sender's Handle                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         Sequence Number                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                              TLVs                             ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 4: SFC Echo Request/Reply format

   The interpretation of the fields is as following:

      The Version reflects the current version.  The version number is
      to be incremented whenever a change is made that affects the
      ability of an implementation to correctly parse or process control
      packet.

      The Global Flags is a bit vector field

      The Message Type filed reflects the type of the packet.  Value
      TBA3 identifies echo request and TBA4 - echo reply

      The Reply Mode defines the type of the return path requested by
      the sender of the echo request.

      Return Codes and Subcodes can be used to inform the sender about
      result of processing its request.

      The Sender's Handle is filled in by the sender, and returned
      unchanged by the receiver in the echo reply.

      The Sequence Number is assigned by the sender and can be (for
      example) used to detect missed replies.

      TLVs (Type-Length-Value tuples) have the two octets long Type
      field, two octets long Length field that is length of the Value
      field in octets.








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7.1.  SFC Echo Request Transmission

   SFC echo request control packet MUST use the appropriate
   encapsulation of the monitored SFP.  If Network Service Header (NSH)
   is used, echo request MUST set O bit, as defined in
   [I-D.ietf-sfc-nsh].  SFC NSH MUST be immediately followed by the SFC
   Active OAM Header defined in Section 5.  Message Type field in the
   SFC Active OAM Header MUST be set to SFC Echo Request/Echo Reply
   value (TBA2) per Section 9.2.

   Value of the Reply Mode field MAY be set to:

   o  Do Not Reply (TBA5) if one-way monitoring is desired.  If echo
      request is used to measure synthetic packet loss, the receiver may
      report loss measurement results to a remote node.

   o  Reply via an IPv4/IPv6 UDP Packet (TBA6) value likely will be the
      most used.

   o  Reply via Application Level Control Channel (TBA7) value if the
      SFP may have bi-directional paths.

   o  Reply via Specified Path (TBA7) value in order to enforce use of
      the particular return path specified in the included TLV to verify
      bi-directional continuity and also increase robustness of the
      monitoring by selecting more stable path.

7.2.  SFC Echo Request Reception

7.3.  SFC Echo Reply Transmission

   The Reply Mode field directs whether and how the echo reply message
   should be sent.  The sender of the echo request MAY use TLVs to
   request that corresponding echo reply be sent using the specified
   path.  Value TBA3 is referred as "Do not reply" mode and suppresses
   transmission of echo reply packet.  Default value (TBA6) for the
   Reply mode field requests the responder to send the echo reply packet
   out-of-band as IPv4 or IPv6 UDP packet.

   Responder to the SFC echo request sends the echo reply over IP
   network if the Reply mode is Reply via an IPv4/IPv6 UDP Packet.
   Because SFC NSH does not identify the ingress of the SFP the echo
   request MUST include this information that to be used as IP
   destination address for IP/UDP encapsulation of the SFC echo reply.
   Sender of the SFC echo request MUST include SFC Source TLV Figure 5.






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    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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |   SFC OAM Source ID Type    |           Length              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                           Value                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                         Figure 5: SFC Source TLV

   where

      SFC OAM Source Id Type is two octets in length and has the value
      of TBA9 Section 9.6.

      Length is two octets long field and the values is equal to the
      length of the Value field.

      Value field contains IP address of the sender of the SFC OAM
      control message, IPv4 or IPv6.

   The UDP destination port for SFC Echo Reply TBA10 will be allocated
   by IANA Section 9.7.

7.4.  Overlay Echo Reply Reception

8.  Security Considerations

   Overlay Echo Request/Reply operates withing the domain of the overlay
   network and thus inherits any security considerations that apply to
   the use of that overlay technology and, consequently, underlay data
   plane.  Also, the security needs for SFC echo request/reply are
   similar to those of ICMP ping [RFC0792], [RFC4443] and MPLS LSP ping
   [RFC8029].

   There are at least three approaches of attacking a node in the
   overlay network using the mechanisms defined in the document.  One is
   a Denial-of-Service attack, by sending SFC ping to overload an
   element of the SFC.  The second may use spoofing, hijacking,
   replying, or otherwise tampering with SFC echo requests and/or
   replies to misrepresent, alter operator's view of the state of the
   SFC.  The third is an unauthorized source using an SFC echo request/
   reply to obtain information about the SFC and/or its elements, e.g.
   SFF or SF.






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   To mitigate potential Denial-of-Service attacks, it is RECOMMENDED
   that implementations throttle the SFC ping traffic going to the
   control plane.

   Reply and spoofing attacks involving faking or replying SFC echo
   reply messages would have to match the Sender's Handle and Sequence
   Number of an outstanding SFC echo request message which is highly
   unlikely.  Thus the non-matching reply would be discarded.

   To protect against unauthorized sources trying to obtain information
   about the overlay and/or underlay an implementation MAY check that
   the source of the echo request is indeed part of the SFP.

9.  IANA Considerations

9.1.  SFC Active OAM Protocol

   IANA is requested to assign new type from the SFC Next Protocol
   registry as follows:

                +-------+----------------+---------------+
                | Value |  Description   | Reference     |
                +-------+----------------+---------------+
                | TBA1  | SFC Active OAM | This document |
                +-------+----------------+---------------+

                     Table 1: SFC Active OAM Protocol

9.2.  SFC Active OAM Message Type

   IANA is requested to create new registry called "SFC Active OAM
   Message Type".  All code points in the range 1 through 32767 in this
   registry shall be allocated according to the "IETF Review" procedure
   as specified in [RFC8126] .  Remaining code points are allocated
   according to the table Table 2:

         +---------------+-------------+-------------------------+
         | Value         | Description | Reference               |
         +---------------+-------------+-------------------------+
         | 0             |   Reserved  |                         |
         | 1 - 32767     |   Reserved  | IETF Consensus          |
         | 32768 - 65530 |   Reserved  | First Come First Served |
         | 65531 - 65534 |   Reserved  | Private Use             |
         | 65535         |   Reserved  |                         |
         +---------------+-------------+-------------------------+

                   Table 2: SFC Active OAM Message Type




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   IANA is requested to assign new type from the SFC Active OAM Message
   Type registry as follows:

          +-------+-----------------------------+---------------+
          | Value |         Description         | Reference     |
          +-------+-----------------------------+---------------+
          | TBA2  | SFC Echo Request/Echo Reply | This document |
          +-------+-----------------------------+---------------+

                 Table 3: SFC Echo Request/Echo Reply Type

9.3.  SFC Echo Request/Echo Reply Parameters

   IANA is requested to create new SFC Echo Request/Echo Reply
   Parameters registry.

9.4.  SFC Echo Request/Echo Reply Message Types

   IANA is requested to create in the SFC Echo Request/Echo Reply
   Parameters registry the new sub-registry Message Types.  All code
   points in the range 1 through 191 in this registry shall be allocated
   according to the "IETF Review" procedure as specified in [RFC8126]
   and assign values as follows:

        +------------+------------------+-------------------------+
        | Value      |   Description    | Reference               |
        +------------+------------------+-------------------------+
        | 0          |     Reserved     |                         |
        | TBA3       | SFC Echo Request | This document           |
        | TBA4       |  SFC Echo Reply  | This document           |
        | TBA4+1-191 |    Unassigned    | IETF Review             |
        | 192-251    |    Unassigned    | First Come First Served |
        | 252-254    |    Unassigned    | Private Use             |
        | 255        |     Reserved     |                         |
        +------------+------------------+-------------------------+

            Table 4: SFC Echo Request/Echo Reply Message Types

9.5.  SFC Echo Reply Modes

   IANA is requested to create in the SFC Echo Request/Echo Reply
   Parameters registry the new sub-registry Reply Modes All code points
   in the range 1 through 191 in this registry shall be allocated
   according to the "IETF Review" procedure as specified in [RFC8126]
   and assign values as follows:






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   +------------+---------------------------------+--------------------+
   | Value      |           Description           | Reference          |
   +------------+---------------------------------+--------------------+
   | 0          |             Reserved            |                    |
   | TBA5       |           Do Not Reply          | This document      |
   | TBA6       |    Reply via an IPv4/IPv6 UDP   | This document      |
   |            |              Packet             |                    |
   | TBA7       |   Reply via Application Level   | This document      |
   |            |         Control Channel         |                    |
   | TBA8       |     Reply via Specified Path    | This document      |
   | TBA8+1-191 |            Unassigned           | IETF Review        |
   | 192-251    |            Unassigned           | First Come First   |
   |            |                                 | Served             |
   | 252-254    |            Unassigned           | Private Use        |
   | 255        |             Reserved            |                    |
   +------------+---------------------------------+--------------------+

                       Table 5: SFC Echo Reply Modes

9.6.  SFC TLV Type

   IANA is requested to create SFC OAM TLV Type registry.  All code
   points in the range 1 through 32759 in this registry shall be
   allocated according to the "IETF Review" procedure as specified in
   [RFC8126].  Code points in the range 32760 through 65279 in this
   registry shall be allocated according to the "First Come First
   Served" procedure as specified in [RFC8126].  Remaining code points
   are allocated according to the Table 6:

        +---------------+--------------+-------------------------+
        | Value         | Description  | Reference               |
        +---------------+--------------+-------------------------+
        | 0             |   Reserved   | This document           |
        | 1- 32759      |  Unassigned  | IETF Review             |
        | 32760 - 65279 |  Unassigned  | First Come First Served |
        | 65280 - 65519 | Experimental | This document           |
        | 65520 - 65534 | Private Use  | This document           |
        | 65535         |   Reserved   | This document           |
        +---------------+--------------+-------------------------+

                      Table 6: SFC TLV Type Registry

   This document defines the following new value in SFC OAM TLV Type
   registry:







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               +-------+-------------------+---------------+
               | Value |    Description    | Reference     |
               +-------+-------------------+---------------+
               | TBA9  | Source IP Address | This document |
               +-------+-------------------+---------------+

                  Table 7: SFC OAM Source IP Address Type

9.7.  SFC OAM UDP Port

   IANA is requested to allocate UDP port number according to

   +---------+--------+------------+---------+--------------+----------+
   | Service | Port   | Transport  | Descrip | Semantics    | Referenc |
   | Name    | Number | Protocol   | tion    | Definition   | e        |
   +---------+--------+------------+---------+--------------+----------+
   | SFC OAM | TBA10  | UDP        | SFC OAM | Section 7.3  | This     |
   |         |        |            |         |              | document |
   +---------+--------+------------+---------+--------------+----------+

                           Table 8: SFC OAM Port

10.  References

10.1.  Normative References

   [I-D.ietf-sfc-nsh]
              Quinn, P., Elzur, U., and C. Pignataro, "Network Service
              Header (NSH)", draft-ietf-sfc-nsh-21 (work in progress),
              September 2017.

   [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

   [I-D.ietf-sfc-oam-framework]
              Aldrin, S., Pignataro, C., Kumar, N., Akiya, N., Krishnan,
              R., and A. Ghanwani, "Service Function Chaining (SFC)
              Operation, Administration and Maintenance (OAM)
              Framework", draft-ietf-sfc-oam-framework-03 (work in
              progress), September 2017.



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   [RFC0792]  Postel, J., "Internet Control Message Protocol", STD 5,
              RFC 792, DOI 10.17487/RFC0792, September 1981,
              <https://www.rfc-editor.org/info/rfc792>.

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
              Control Message Protocol (ICMPv6) for the Internet
              Protocol Version 6 (IPv6) Specification", STD 89,
              RFC 4443, DOI 10.17487/RFC4443, March 2006,
              <https://www.rfc-editor.org/info/rfc4443>.

   [RFC7665]  Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
              Chaining (SFC) Architecture", RFC 7665,
              DOI 10.17487/RFC7665, October 2015,
              <https://www.rfc-editor.org/info/rfc7665>.

   [RFC7799]  Morton, A., "Active and Passive Metrics and Methods (with
              Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
              May 2016, <https://www.rfc-editor.org/info/rfc7799>.

   [RFC8029]  Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
              Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
              Switched (MPLS) Data-Plane Failures", RFC 8029,
              DOI 10.17487/RFC8029, March 2017,
              <https://www.rfc-editor.org/info/rfc8029>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

Authors' Addresses

   Greg Mirsky
   ZTE Corp.

   Email: gregimirsky@gmail.com


   Wei Meng
   ZTE Corporation
   No.50 Software Avenue, Yuhuatai District
   Nanjing
   China

   Email: meng.wei2@zte.com.cn,vally.meng@gmail.com






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   Bhumip Khasnabish
   ZTE TX, Inc.
   55 Madison Avenue, Suite 160
   Morristown, New Jersey  07960
   USA

   Email: bhumip.khasnabish@ztetx.com


   Cui Wang

   Email: lindawangjoy@gmail.com







































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