Network Working Group                                              H. Li
Internet-Draft                                                     Q. Wu
Intended status: Standards Track                                O. Huang
Expires: March 26, 2015                                           Huawei
                                                            M. Boucadair
                                                            C. Jacquenet
                                                          France Telecom
                                                             W. Haeffner
                                                                Vodafone
                                                      September 22, 2014


       Service Function Chaining (SFC) Control Plane Achitecture
                     draft-ww-sfc-control-plane-03

Abstract

   This document defines the control plane architecture which include
   control plane components and interface between control plane
   component and data plane component.  This document further describes
   how Service Functions Chains are structured and how Service Function
   Chaining path is provisioned and setup.

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 http://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 March 26, 2015.

Copyright Notice

   Copyright (c) 2014 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
   (http://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.  Data plane basic assumption . . . . . . . . . . . . . . . . .   3
   4.  SFC Control Plane: An Overview  . . . . . . . . . . . . . . .   4
     4.1.  SFC Control plane . . . . . . . . . . . . . . . . . . . .   7
     4.2.  F interface . . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  C1 interface  . . . . . . . . . . . . . . . . . . . . . .   7
     4.4.  C2 interface  . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Signaling procedure . . . . . . . . . . . . . . . . . . . . .   8
     5.1.  Service Topology Building . . . . . . . . . . . . . . . .   8
     5.2.  Service Function Chain Structuring  . . . . . . . . . . .   9
     5.3.  Service Function Path Determining . . . . . . . . . . . .   9
     5.4.  Service Function Chaining Path Setup and Policy Table
           configuration . . . . . . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Appendix A.  SFC Control Plane Components Deployment
                Consideration in Mobile Backbone (MBB) Environment .  11
   Appendix B.  SFC Control Plane Components Deployment
                Consideration in Fixed Backbone (FBB) Environment  .  13
   Appendix C.  SFC Control Plane Components Deployment
                Consideration in Data Center(DC) Environment . . . .  14
   Appendix D.  SFC Control Plane Components Deployment
                Consideration in Data Center (DC) Environment  . . .  16
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  17

1.  Introduction

   The dynamic enforcement of a service-derived, adequate forwarding
   policy for packets entering a network that supports advanced Service
   Functions (SFs) has become a key challenge for operators and service
   providers.

   Service Function Chaining (SFC) typically observe, alter or even
   terminate and re-establish session flows between user equipment and
   application platforms (Web, Video, VoIP etc.) by invoking, in a given



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   order, a set of Service Functions [I.D-ietf-sfc-problem-statement].
   Service functions involved in a given SFC may include load-balancing,
   firewalling, intrusion prevention, etc.

   A given SFC-enabled domain may involve several instances of the same
   Service Function.  Service function instances can be automatically
   added to or removed from a given SFC.  SFs can be co-located or
   embedded in distinct physical nodes, or virtualized.

   This document describes SFC control plane architecture and discusses
   how the Service Function Chains are structured and how Service
   Function Chaining path is provisioned and setup.

2.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC2119 [RFC2119].

3.  Data plane basic assumption

   This document defines the control plane architecture while the data
   plane architecture is defined in [I.D-ietf-sfc-architecture].

   The SFC data plane characteristics considered as basic assumptions by
   the SFC control architecture are summarized below:

   o  Traffic that enters a SFC-enabled domain is classified according
      to the rules the SFC Control Plane provides to the Classifier.
      After classification, the traffic is forwarded into the SFC-
      enabled domain passing a set of Service Functions as defined in
      the corresponding SFC instructions.  SFC-specific forwarding
      information is used by Service Forwarder Entity (i.e., a node
      which include service forwarder function (SFF)) to make traffic
      forwarding decisions and pass the traffic to the next Service
      Function instance within the chain, through the Service Function
      Path derived from Control Plane Information and instantiated from
      the Classifier.

   o  The Service Forwarder Entity forwards packets according to the
      entries maintained in the SFC Policy rule base.  A Service
      Forwarder Entity can be a virtualized or physical L2/L3 network
      device that serves Service Functions within a given chain.  A
      Service Forwarder Entity may serve one or more Service Functions
      (Fig. 1).






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   o  When a Service Forwarder Entity needs to forward a packet to an
      SFC-unware legacy node, the packet is likely to be forwarded by a
      SFC proxy to SFC-unaware legacy node.

4.  SFC Control Plane: An Overview

   For the purpose of defining the SFC control plane architecture, the
   SFC control plane is broken up into five distinct components:

   Chain Selection Policy Control

      Chain Selection Policy Control component maintains SFC-related
      information models (chain structures, classification rules)
      derived from business or operational models.


   Chain Management Policy Control

      This component is responsible for:

      *  Structuring a SFC chain, based upon various inputs that include
         Service Function information as collected through the
         management interface (e.g., the outcomes of a negotiation
         between a customer and a service provider, as documented in
         [RFC7297], business guidelines, etc.).

      *  Adjusting a chain based on the external policy context or any
         path change computed by Service Overlay Topology management
         component.


   Service Overlay Topology management

      This is an optional component that is not needed particularly when
      SFC forwarding is fully distributed.  This component is
      responsible for:

      *  Creating the service topology which consist of Service
         Function-related information and network topology information.

      *  Helping Chain Mapping and forwarding Control Component
         determine forwarding path in case the said forwarding path is
         traffic engineered.


   Service Function (SF) Management





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      This component allows for the dynamic discovery of locations of
      Service Functions and is used to help the SFC control plane to
      gather Service Function-related information from various Service
      Functions available within a SFC-enabled domain.


   SFC Mapping and Forwarding Control

      This is a component that helps the SFC Control plane to
      dynamically:

      *  Map SFCs to the specific Service Function path.

      *  Populate forwarding rules on the data plane.





































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                  +-------------------------------------------------+
                  |                     SFC  Control Plane          |
                  | +---------------+  +---------------+            |
          +-------| |Chain Management  |Service Overlay|            |
          |       | |Policy Control |  |Topo Management|            |
          |       | +---------------+  +---------------+            |
          |       | +---------------+ +---------------+             |
          +---------|Chain Selection| | Chain Mapping | +----------+|
          |       | | Policy Control| | and Forwarding| |External SF|
          |         +---------------+ |    Control    | |Management||
          |       |                   +---------------+ +----------+|
          C1      +------^-----------^-------------^----------------+
   +---------------------|F----------|-------------|-------------+
   |      |            +----+        |             |             |
   |      |            | SF |        |C2           |C2           |
   |                   +----+        |             |             |
   | +----V--- --+       |           |             |             |
   | |   SFC     |     +----+      +-|--+        +----+          |
   | |Classifier |---->|SFF |----->|SFF |------->|SFF |          |
   | |   Node    |<----|    |<-----|    |<-------|    |          |
   | +-----------+     +----+      +----+        +----+          |
   |                     |           |              |            |
   |                     |C2      -------           |            |
   |                     |       |       |     +-----------+ F   |
   |                     V     +----+ +----+   | SFC Proxy |-->  |
   |                           | SF | |SF  |   +-----------+     |
   |                           +----+ +----+                     |
   |                             |F     |F                       |
   |  SFC Data Plane Components  V      V                        |
   |                                                             |
   +-------------------------------------------------------------+


                   Figure 1: SFC Control Plane Overview

   There are three interfaces connected to the SFC control plane.

      C1 Interface: the interface between the SFC control plane and the
      SFC Classifiers.  Classification rules are installed on the SFC
      Classifier Node(s) via this interface.In addition, this Interface
      may be used by the control plane to instantiate of traffic-
      engineered paths that will be used to forward traffic according to
      SFC information.

      C2 Interface: the interface between the SFC control plane and the
      Service Forwarder Function.  SFC-based forwarding entries on
      Service Function nodes are provided by the SFC Control plane via
      this interface.



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      F Interface: This interface is used by Service Function to
      feedback service or application level information of a data flow
      to the SFC control plane.

4.1.  SFC Control plane

   The SFC control plane is in charge of Service Function chain creation
   and maintenance, service chain path instantiation (in case of the
   traffic-engineered SFCs), mapping between SFC and Service Function
   path, SFC Policy Table creation and configuration, including the
   sequence of Service Functions in a Service Function chain, Service
   Function information, SFC paths information.

   The SFC control plane may be fed with Service Function chain
   information from the Management application.  A SFC service template
   information may look like:

      {{MBR>1Mbps, RAT='UMTS', protocol='HTTP', QOS='Gold'},goto'sfc1'}

   The SFC Control plane also creates classification rules and installs
   them on the classifier nodes.  The SFC control plane also assigns SFC
   identification and installs SFC Policy Tables in the Service
   forwarder function.

4.2.  F interface

   Service Functions, e.g., deep packet inspection (DPI) or firewall may
   need to output some processing results of packets to the control
   system.  This information can be used by the SFC control plane to
   update the SFC classification and SFC forwarding entries.

   The F Interface is used to collect such kind of feedback information
   from the Service Functions or the SF nodes.

4.3.  C1 interface

   This interface is used to install SFC classification rules in Service
   Classifier nodes.  These rules are created by the SFC control Plane.
   They may be updated by information provided by the Service Function
   nodes (in case a change of the network topology has occurred, for
   example).

   SFC Classifier Node binds incoming traffic to SFCs according to these
   classification rules.







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4.4.  C2 interface

   Service forwarder entity make traffic forwarding decisions according
   to the entries maintained in their SFC Policy Table.  Such Table is
   populated by the SFC control plane through the C2 interface.

   Each Service Function has a unique Service Function identifier to
   identify itself in the SFC forwarding plane.  The Service Function
   locator is typically referred to as a network address.  In case the
   Service Function instance is directly connected to a Service
   forwarder entity, the forwarding entry may also include the port
   through which the Service Function instance can be reached.

   Some proxy function may also use the C2 interface to retrieve the
   mapping between a Service Function Identifier and a Service Function
   locator from the SFC control plane.

5.  Signaling procedure

5.1.  Service Topology Building

   When a Service Function is instantiated into the network it is
   necessary to select the locator of the specific instances of Service
   Functions that will be used, and to construct the service overlay
   using Service Function's network locator.  The service overlay is
   built on top of the underlying network.  The resulting service
   overlay is meant to facilitate SFC-enabled domain operation, as it
   may provide a better, up-to-date, network-wise overview of the
   Service Functions status and usage.

   A service specific overlay utilized by SFC then results in the
   creation of the service topology.  Service topology information
   consists of network topology information collected from the
   underlying network and Service Function-related information (such as
   Service Function administration information and Service Function
   capability information) that may be collected from the management
   interface.  For example, Network topology information can be
   collected from the network using an IGP or BGP-LS [I.D-draft-idr-ls-
   distribution].

   Service Function-related information includes Service Function
   Identifier, Service Function Locator, Service Function administration
   information (e.g., available memory, CPU utilization, available
   storage capacity, etc.) or Service Function capability information
   (e.g., supported ACL numbers, virtual context number).  This
   information can be retrieved by various means (e.g., registration
   mechanism that provides binding between Service Function Identifier




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   and Service Function Locator(s) and allows for the dynamic discovery
   of locations of Service Functions).

   Network topology is not required for dynamically structuring service
   chains, but it may be helpful during service troubleshooting and
   diagnostics.

   The creation of the service topology is not conditioned by the
   creation of the network topology: what is required is the mapping
   between Service Function-related information and existing network
   topology information.  Additional Service Functions or Service
   Function instances, for redundancy or load distribution purposes, can
   be added to or removed from the service topology as required.  Means
   to dynamically discover the location of available Service Function
   instances may be supported.

5.2.  Service Function Chain Structuring

   The chain management component of the SFC control plane is
   responsible for the dynamic structuring of Service Function chains
   (i.e., define an ordered list of Service Function identifiers) that
   can be supported, as a function of the services that can be
   delivered, among other information that may include subscriber-
   specific information.  For example, a Service Function chain can be
   structured as follows:

   service-chain 100 {
             10 url-filter
             20 web-cache
             30 web-optimizer
             40 firewall
   }

   In this Service Function chain, each Service Function needs to be
   assigned with a unique Service Function identifier and can be located
   using Service Function locators.  A Service Function chain should be
   assigned an SFC Index.  A Service Function identifier does not
   necessarily hint the service offered by that Service Function; its
   purpose is to uniquely identify a Service Function among those
   present in a SFC-enabled domain.

5.3.  Service Function Path Determining

   The Chain Mapping and forwarding Control Component of the SFC control
   plane is a component that is responsible for Service Function path
   determination based on Service Overlay Topology information
   maintained in the Service Overlay Topology management component.
   However, not all SFC deployments may require Service Function path



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   determination (e.g., SFC forwarding is fully distributed ).  Service
   Function path determination is referred to determine an ordered list
   of locators of each Service Function that belongs to a Service
   Function chain.

   The Service Function path determining may be static or pre-determined
   using specific Service Function instances, or dynamic - choosing
   explicit Service Function instances at the time of delivering traffic
   to the Service Function.

   When there are multiple instances of a given Service Function that
   belongs to a given SFC, each of these instances is assigned a unique
   locator.  These multiple instances may actually be invoked within the
   context of a single chain, or within the context of multiple chains
   depending on how the said chains are structured.  The latter case may
   lead to multiple SFPs.  In some other cases, a Service Function path
   can pre-determined by SFC mapping and forwarding component for
   traffic engineering purposes by interacting with Service Overlay
   Topology management component.  However Service Function path doesn't
   need to be pre- determined.  The chain management component
   responsible for structuring the service chains cannot decide in
   advance the actual path that will be followed by packets.

   In addition, the SFC mapping and forwarding component also maintains
   the mapping between Service Function chains and Service Function
   paths.  When Service Function chain structuring is complete, the SFC
   control plane will use the SFC forwarding and mapping component to
   determine the locator of each specific Service Function instance in
   the chain and return a set of Service Function locators associated
   with a Service Function chain.

5.4.  Service Function Chaining Path Setup and Policy
      Table configuration

   Once a SFC is structured, traffic classification rules are derived
   and provided to the classifier nodes, along with other information
   maintained in Policy Tables.  The policy table is built based on SFC
   policy and service information(e.g.,subscriber being mapped into a
   service class related to a SFC) captured by using policy related
   components, when a Service Function path is determined.  The policy
   table will be populated at each participating node involved in the
   application of a Service Function chain and used by them to make
   their forwarding decisions on a typical hop-by-hop basis.








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6.  Security Considerations

   The SFC Control and the participating SFC functional elements must be
   mutually authenticated.  Means to protect against an attacker who
   would install/remove/modify classification rules must be supported.
   When means to dynamically discover the location of SF instances are
   in use, they should be designed to avoid illegitimate SFs to belong
   to the SFC-enabled domain.

7.  Acknowledgements

   The author would like to thank Shibi Huang for providing input and
   LAC Chidung for his review and comments that helped improve this
   document.

8.  References

8.1.  Normative References

   [I.D-ietf-sfc-architecture]
              Halpern, J. and C. Pignataro, "Service Function Chaining
              (SFC) Architecture", ID draft-ietf-sfc-architecture-01,
              September 2014.

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

8.2.  Informative References

   [I.D-ietf-sfc-problem-statement]
              Quinn, P., "Network Service Chaining Problem Statement",
              ID draft-ietf-sfc-problem-statement-10, August 2014.

   [I.D-wu-pce-traffic-steering-sfc]
              Wu, Q., Dhody, D., Boucadair, M., Boucadair, C., and J.
              Tantsura, "PCEP Extensions for traffic steering support in
              Service Function Chaining", ID draft-wu-pce-traffic-
              steering-sfc-05, September 2014.

Appendix A.  SFC Control Plane Components Deployment Consideration in
             Mobile Backbone (MBB) Environment










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+---------------------------------------------------------------+
| SFC Control Plane   +----------------------+                  |
|                     |  +------------+      |                  |
|                     |  |   SFC      |      |                  |
|       +----------------|Orchestrator-----------+              |
|       |             |  +------------+      |   |              |
|       |             | SFC Management System|   |              |
|       |             +----------------------+   |              |
|       |                                        |              |
|       |                                        |              |
|+------|-------------+                 +--------|------------+ |
||+-----|----+        |                 | +------|---------+  | |
|||SFC Policy|        |                 | | SFC Forwarding |  | |
|||  Control |        |           |-------|   Control      -----|----+
||+-----|----+        |           |     | +----------------+  | |    |
|| Enhancement in PCRF|           |     |   SFC  Controller   | |    |
|+------|-------------+           |     |                     | |    |
|       |                         |     +---------------------+ |    |
+-------|-------------------------|-----------------------------+    |
+-------|-------------------------|------------------------------------+
|+--------------------+     +---------------+      +---------------+ | |
||Enhancement in PCEF |     | Enhancement in|      | Enhancement in| | |
||      or TDF        |     | ToR switch or |      | ToR Switch or | | |
||+-----|-------+     |     |    Router     |      |    Router     | | |
|||    SFC      |     |     |+----|--+      |      |+-------+      | | |
||| Classifier  |-----------||       |------------- |       |      | | |
|||   Function  |     |     ||  SFF1 |      |      ||  SFF2 ---------+ |
||+-------------+     |     ||       |      |      ||       |      |   |
|+--------------------+     |+---|---+      |      |+---|---+      |   |
|                           +----|----------+      +----|----------+   |
|                          ------------            -----|------        |
|                          |          |            |          |        |
|                        +----+     +---+        +----+     +---+      |
|                        | SF1|     |SF2|        | SF3|     |SF4|      |
|                        +----+     +---+        +----+     +---+      |
|SFC Data Plane                                                        |
-----------------------------------------------------------------------+


                                SFC in MBB

   In MBB environment, Policy Control component and Chain Management
   Policy Control component defined in section 4 can be supported using
   Enhanced PCRF.  Service Overlay Topology management defined in
   section 4 can be supported using SFC Orchestrator.  SFC Mapping and
   Forwarding Control component defined in section 4 can be supported
   using SFC Controller.  Note that 3GPP is considering integrating




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   Chain Selection Policy Control component and Chain Management Policy
   Control component using PCRF.

Appendix B.  SFC Control Plane Components Deployment Consideration in
             Fixed Backbone (FBB) Environment

+---------------------------------------------------------------+
| SFC Control Plane   +----------------------+                  |
|                     |  +------------+      |                  |
|                     |  |   SFC      |      |                  |
|       +----------------|Orchestrator-----------+              |
|       |             |  +------------+      |   |              |
|       |             | SFC Management System|   |              |
|       |             +----------------------+   |              |
|       |                                        |              |
|       |                                        |              |
|+------|-------------+                 +--------|------------+ |
||+-----|----+        |                 | +------|---------+  | |
|||SFC Policy|        |                 | | SFC Forwarding |  | |
|||  Control |        |          -|-------|   Control      -----|----+
||+-----|----+        |           |     | +----------------+  | |    |
|| Enhancement in RADIUS          |     |   SFC Controller    | |    |
|+------|-------------+           |     |                     | |    |
|       |                         |     +---------------------+ |    |
+---------------------------------------------------------------+    |
+----------------------------------------------------------------------+
|+--------------------+     +---------------+      +---------------+ | |
||Enhancement in BRAS |     | Enhancement in|      | Enhancement in| | |
||      or BNG        |     | ToR switch or |      | ToR Switch or | | |
||+-----|-------+     |     |    Router     |      |    Router     | | |
|||    SFC      |     |     |+----|--+      |      |+-------+      | | |
||| Classifier  |-----------||       |------------- |       |      | | |
|||   Function  |     |     ||  SFF1 |      |      ||  SFF2 ---------+ |
||+-------------+     |     ||       |      |      ||       |      |   |
|+--------------------+     |+---|---+      |      |+---|---+      |   |
|                           +----|----------+      +----|----------+   |
|                          ------------            -----|------        |
|                          |          |            |          |        |
|                        +----+     +---+        +----+     +---+      |
|                        | SF1|     |SF2|        | SF3|     |SF4|      |
|                        +----+     +---+        +----+     +---+      |
|SFC Data Plane                                                        |
-----------------------------------------------------------------------+


                                SFC in FBB





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   In FBB environment, Policy Control component and Chain Management
   Policy Control component defined in section 4 can be supported using
   Enhanced RADIUS.  Service Overlay Topology management defined in
   section 4 can be supported using SFC Orchestrator.  SFC Mapping and
   Forwarding Control component defined in section 4 can be supported
   using SFC Controller.  Note that BBF is considering integrating Chain
   Selection Policy Control component and Chain Management Policy
   Control component using RADIUS.

Appendix C.  SFC Control Plane Components Deployment Consideration in
             Data Center(DC) Environment








































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+---------------------------------------------------------------+
| SFC Control Plane   +----------------------+                  |
|                     |  +------------+      |                  |
|                     |  |   SFC      |      |                  |
|       +----------------|Orchestrator-----------+              |
|       |             |  +------------+      |   |              |
|       |             | SFC Management System|   |              |
|       |             +----------------------+   |              |
|       |                                        |              |
|       |                                        |              |
|       |Download Classifier            +--------|------------+ |
|       |  Rule directly                | +------|---------+  | |
|       |                               | | SFC Forwarding |  | |
|       |                        -|-------|   Control      -----|----+
|       |                         |     | +----------------+  | |    |
|       |                         |     |    SFC Controller   | |    |
|       |                         |     |                     | |    |
|       |                         |     +---------------------+ |    |
+-------|-------------------------------------------------------+    |
+-------|--------------------------------------------------------------+
|+------|-------------+     +---------------+      +---------------+ | |
|| Enhancement in DC  |     | Enhancement in|      | Enhancement in| | |
||      |  Gateway    |     | ToR switch or |      | ToR Switch or | | |
||+-----|-------+     |     |    Router     |      |    Router     | | |
|||    SFC      |     |     |+----|--+      |      |+-------+      | | |
||| Classifier  |-----------||       |------------- |       |      | | |
|||   Function  |     |     ||  SFF1 |      |      ||  SFF2 ---------+ |
||+-------------+     |     ||       |      |      ||       |      |   |
|+--------------------+     |+---|---+      |      |+---|---+      |   |
|                           +----|----------+      +----|----------+   |
|                          ------------            -----|------        |
|                          |          |            |          |        |
|                        +----+     +---+        +----+     +---+      |
|                        | SF1|     |SF2|        | SF3|     |SF4|      |
|                        +----+     +---+        +----+     +---+      |
|SFC Data Plane                                                        |
-----------------------------------------------------------------------+

                           SFC in DC Environment

   In DC environment, Policy Control component and Chain Management
   Policy Control component, Service Overlay Topology management defined
   in section 4 can be supported using SFC Orchestrator.  SFC Mapping
   and Forwarding Control component defined in section 4 can be
   supported using SFC Controller.






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Appendix D.  SFC Control Plane Components Deployment Consideration in
             Data Center (DC) Environment

+---------------------------------------------------------------+
| SFC Control Plane                                             |
|                     +------------------------+                |
|                     |           stateful PCE |                |
|       +-------------|  +-------+  +-------+  |                |
|       |             |  |Policy |  | TE-DB |  |<-------|       |
|       |             |  +-------+  +-------+  |        |       |
|       |             +------------------------+        |       |
|       |                                ---------------|-----| |
|       |                            SFC Controller     |     | |
|       |                               | +----------------+  | |
|       |     +---------------------------|  Policy Control|  | |
|       |     |                         | +----------------+  | |
|       |     |                           +------ ------ --+  |
|       |     |                         | | SFC Forwarding |  | |
|       |     |                   +-------|   Control      -----|----+
|       |     |                   |     | +----------------+  | |    |
|       |     |                   |     +---------------------+ |    |
+-------|-----|-------------------------------------------------+    |
+-------|-----|--------------------------------------------------------+
|+------|-----|-------+     +---------------+      +---------------+ | |
|| Enhancement in DC  |     | Enhancement in|      | Enhancement in| | |
||      |  Gateway    |     | ToR switch or |      | ToR Switch or | | |
||+-----|-------+     |     |    Router     |      |    Router     | | |
|||    SFC      |     |     |+----|--+      |      |+-------+      | | |
||| Classifier  |-----------||       |------------- |       |      | | |
|||   Function  |     |     ||  SFF1 |      |      ||  SFF2 ---------+ |
||+-------------+     |     ||       |      |      ||       |      |   |
|+--------------------+     |+---|---+      |      |+---|---+      |   |
|                           +----|----------+      +----|----------+   |
|                          ------------            -----|------        |
|                          |          |            |          |        |
|                        +----+     +---+        +----+     +---+      |
|                        | SF1|     |SF2|        | SF3|     |SF4|      |
|                        +----+     +---+        +----+     +---+      |
|SFC Data Plane                                                        |
-----------------------------------------------------------------------+

                           SFC in DC Environment

   Alternatively, In DC environment, Policy Control component and Chain
   Management Policy Control component, Service Overlay Topology
   management defined in section 4 can be supported, SFC Mapping and
   Forwarding Control component defined in section 4 can be supported
   together using SFC Controller.  In addtion, SFC Controler operates a



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   stateful PCE and its instantiation mechanism to compute and
   instantiate Service Function Paths (SFP).

   The PCE maybe co-located with the SFC Control plane component or an
   external entity (e.g., [I.D-wu-pce-traffic-steering-sfc]).

Authors' Addresses

   Hongyu Li
   Huawei
   Huawei Industrial Base,Bantian,Longgang
   Shenzhen
   China

   Email: hongyu.li@huawei.com


   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: bill.wu@huawei.com


   Yong(Oliver) Huang
   Huawei
   Huawei Industrial Base,Bantian,Longgang
   Shenzhen
   China

   Email: oliver.huang@huawei.com


   Mohamed Boucadair
   France Telecom
   Rennes 35000
   France

   Email: mohamed.boucadair@orange.com










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   Christian Jacquenet
   France Telecom
   Rennes 35000
   France

   Email: christian.jacquenet@orange.com


   Walter Haeffner
   Vodafone D2 GmbH
   Ferdinand-Braun-Platz 1
   Duesseldorf  40549
   DE

   Email: walter.haeffner@vodafone.com




































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