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I2RS                                                              D. Liu
Internet-Draft                                              China Mobile
Intended status: Informational                             B. Khasnabish
Expires: January 16, 2014                                            ZTE
                                                                 H. Deng
                                                            China Mobile
                                                           July 15, 2013


                    Architecture Discussion of I2RS
                     draft-liu-i2rs-architecture-02

Abstract

   This document discusses the high level architecture of I2RS.  This
   document also provides brief descriptions on the use of
   virtualization and its impact on constructing chained and grouped
   services.  We plan to include further details on virtualization,
   service chaining, and grouping in a future version of this draft.

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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   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 January 16, 2014.

Copyright Notice

   Copyright (c) 2013 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must



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   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.  Architecture of I2RS  . . . . . . . . . . . . . . . . . . . .   4
   4.  I2RS Application/Agent  . . . . . . . . . . . . . . . . . . .   5
   5.  I2RS Interfaces . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  Network/Service Control . . . . . . . . . . . . . . . . . . .   6
   7.  Management Considerations . . . . . . . . . . . . . . . . . .   7
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   8
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   8
     11.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   This document discusses the high level architecture of I2RS.  As
   illustrated in figure 1, the I2RS architecture is composed by three
   types of building blocks.  The first type of the building block is
   the user of I2RS interface.  The users could be network controllers,
   network management functions, other user applications etc.  The user
   application uses the I2RS interface interacts with the routing
   system.  The second type of the building block is management
   functions.  This include configuration management function and
   security management function.  The configuration management function
   is used to configure the I2RS interface.  The security function is
   used to enforce the security polices of the I2RS interface.  The
   third type of the building block is routing function.  This build
   block includes routing information base, IP forwarding table etc.
   The routing information base could be accessed by the I2RS users
   using the I2RS interface.  Besides, the routing control and the
   forwarding function could also be separated.  The interface between
   the routing control and forwarding function could be open flow,
   ForCES etc.










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     +------------------+  +------------------+  +-----------------+
     |Network Controller|  |Network Management|  | User Application|..
     +------------------+  +------------------+  +-----------------+
                 |               | |                     |
                 \---------------| |--------------------/
                                 | | I2RS Interface
     +----------------------+    | |     +------------------+
     |Configuration Function|----| |-----|Security Function |
     +----------------------+    | |     +------------------+
                                 | |
                                 | |                 Routing Function
     +---------------------------| |--------------------------------+
     |                           | |                                |
     |   +------------+          | |             +-----------+      |
     |   |OSPF process|          | |             |BGP process| ...  |
     |   +------------+          | |             +-----------+      |
     |          |            +--------+                |            |
     |          |            | Agent  |                |            |
     |          |            +--------+                |            |
     |          |     +----------|-------------+       |            |
     |          +-----|Routing Information Base|-------+            |
     |                +------------------------+                    |
     |                           |                                  |
     +---------------------------|----------------------------------+
                                 |
      {OF, ForCES, .. Protocol}  |               Forwarding Function
     +---------------------------|----------------------------------+
     |                           |                                  |
     |                           |                                  |
     |                   +--------------------+                     |
     |                   | IP Forwarding Table|                     |
     |                   +--------------------+                     |
     |                                                              |
     +--------------------------------------------------------------+


                      Figure 1: architecture of I2RS

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 RFC-2119 [RFC2119].

   In this document, these words will appear with that interpretation
   only when in ALL CAPS.  Lower case uses of these words are not to be
   interpreted as carrying RFC-2119 significance.




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   A list of acronyms and abbreviations used in this document are
   presented below.

   o  ForCES: Forwarding and Control Element separation
   o  I2RS: Interface to Routing System
   o  NF: Network Function
   o  NSC: Network Service Chaining
   o  NSG: Network Service Grouping
   o  OF: Open Flow
   o  RIB: Routing Information Base
   o  SF: Service Function
   o  TIB: Topology Information Base
   o  VF: Virtualized Function
   o  VNF: Virtualized Network Function
   o  VSF: Virtualized Service Function

3.  Architecture of I2RS

   This section discusses the function of the building block of the I2RS
   architecture.  These functional building blocks could be either
   physical or virtual or hybrid, i.e., a combination of physical and
   virtual blocks.

   i. I2RS application

   The I2RS applications communicate with the I2RS agent using the I2RS
   interface.  The I2RS agent locates in the router that implement the
   I2RS interface.  The I2RS agent communicates with the routing system.
   The interface between the I2RS agent and the routing system could be
   implementation specific.  The I2RS application can read the routing
   information from the routing information base, it can also inject
   polices, routing information etc into the routing information base.
   The I2RS interface could be RESTful API or websocket etc.  There
   should be an authentication mechanism in the I2RS architecture that
   only allow the authorized application communicate with the I2RS
   agent.

   ii.  Configuration function

   The I2RS interface could be configured by the configuration function.
   The I2RS user application could customize the I2RS interface function
   and set the I2RS interface parameters by the configuration function.
   The network administrator can also use this configuration function to
   control the I2RS interface parameters.  For example, the network
   administrator may need to control a certain scope of the routing
   information could be accessed by a specific I2RS application.  The
   network administrator can use the configuration function to implement
   those settings.



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   Virtualization of the configuration function through appropriate
   management and/or visor function would help achieve (a) efficient
   management of configuration resources, and (b) desired chaining/
   grouping of the resources for dynamically balancing/distributing
   operational loads.

   iii.  Security function

   Security function is an important building block of the I2RS
   architecture.  It will ensure only authorized application can use the
   I2RS interface and communicate with the routing system.  There could
   be different level of authorization.  For example, the security
   function can allow some application only read from the routing system
   while other application can both read and inject polices into the
   routing system.

   Virtualization of the security function would help move the service
   closer to the utilization point based on the desired requirements
   without moving the physical device (or installing new purpose-built
   devices).

   iv.  Routing function

   The routing function is composed of routing information base (RIB),
   IP forwarding table and the routing processes.  The I2RS application
   could communicate with the routing information base using the I2RS
   interface.  The agent function locates in the router could
   communicate with the routing information base and the I2RS
   application.  It receives the I2RS application's request and convert
   it to the implementation specific command to get/set the routing
   information base.  By this way, the I2RS application can read or
   inject routing information into the routing information base.  The
   routing processes can also inject routing information into the
   routing information base.  There should be a protection mechanism to
   prevent any race condition of the routing information base be
   modified by different entities simultaneously.  The Routing function
   can be virtualized.

   iv.  Forwarding function

   The forwarding function facilitates forwarding of flows/packets.  It
   can operate using simple Table or sophisticated dynamic matrix for
   intelligent processing of flows.  The forwarding function can be
   virtualized.

4.  I2RS Application/Agent





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   This section discusses the I2RS application and agent function in the
   architecture.  There are many applications can use the I2RS
   interfaces.  For example, network management application can use I2RS
   interface to get the network topology information.  I2RS agent
   locates in the routing function and communicates with the I2RS
   application.  The I2RS agent locates in the router, it can
   communicate with the I2RS application using the I2RS interface.  The
   I2RS agent convert the I2RS application's command into implementation
   specific functions to get/set the routing information base.

5.  I2RS Interfaces

   This section discusses the I2RS interfaces in the architecture.  The
   I2RS interface is the interface between the I2RS application and the
   I2RS agent.  The requirement of the I2RS interface includes the
   following aspects: (1) The I2RS interface should support multiplexing
   function that allows multiple I2RS applications communicate with one
   I2RS agent and one I2RS application communicates with multiple I2RS
   agents.  (2) The I2RS interface should support authentication/
   authorization mechanism that allow only the authorized I2RS
   application access specific routing information.  The I2RS interface
   should support encryption and data integrity protection mechanism.
   (3) The I2RS interface should support data protection mechanism to
   prevent the race condition.  (4) The I2RS interface should provide
   scalability and extensibility.

6.  Network/Service Control

   This section discusses the network and service control in the
   architecture.  Network control may include control of both virtual
   and physical network entities.  The services may include chaining of
   network services (NSCs) and grouping network services (NSGs).





                                                                      ^
                    ._._._._._._._._._._._._._._      |
                    |                        ---|----------------
                 -------      -------        |Control/Managemnt |
              <- |VNF-1|   <- |VNF-n|._._._._|   of VNFs        |-->
                 |     |  ... |     |        |                  |
                 -------      -------        --------------------
                    |.............|
                          |
                          |
                  /----------------\



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                 | Virtualization/  |
                 |   Abstraction    |
                  \----------------/
                          |
                          |
                  ...................
                  :   Network       :
                  :   Function (NF) :
                  :.................:


                Figure 2: Network Function Service Chaining

                                                                      ^
                    ._._._._._._._._._._._._._._      |
                    |                        ---|----------------
                 -------      -------        |Control/Managemnt |
              <- |VSF-1|   <- |VSF-n|._._._._|   of VSFs        |-->
                 |     |  ... |     |        |                  |
                 -------      -------        --------------------
                    |.............|
                          |
                          |
                  /----------------\
                 | Virtualization/  |
                 |   Abstraction    |
                  \----------------/
                          |
                          |
                  ...................
                  :   Service       :
                  :   Function (SF) :
                  :.................:


                Figure 3: Service Function Service Chaining

7.  Management Considerations

   This section discusses the management consideration of the
   architecture.  In addition to managing the configurations of the
   virtual and physical network entities, this may include managing
   service-specific meta-data and configurations of the hosts that
   provide network-based value-added services like policy, compliance,
   load-balancing, and so on.

8.  Security Considerations




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   Security function is very important for the I2RS architecture.  It
   should provide authentication mechanism and data protection mechanism
   to protect critical routing information.

9.  IANA Considerations

   To be determined later.

10.  Acknowledgments

   .

11.  References

11.1.  Normative References

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

11.2.  Informative References

   [DMTF-DSP0243]
              , "DMTF DSP0243, Open Virtualization Format Specification
              2.0", December 2012.

   [DMTF-DSP0263]
              , "DMTF DSP0263, Cloud Infrastructure Management Interface
              (CIMI) Model and REST Interface over HTTP 1.0", September
              2012.

   [DMTF-DSP2029]
              , "DMTF DSP2029, Cloud Management for Communications
              Service Providers 1.0", January 2012.

   [DMTF-DSP2034]
              , "DMTF DSP2034, Network Services Management Use Cases,
              1.0a", March 2013.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.









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Authors' Addresses

   Dapeng Liu
   China Mobile
   Unit2, 28 Xuanwumenxi Ave,Xuanwu District
   Beijing 100053
   China

   Email: liudapeng@chinamobile.com


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

   Phone: +001-781-752-8003
   Email: vumip1@gmail.com, bhumip.khasnabish@zteusa.com


   Hui Deng
   China Mobile
   Unit2, 28 Xuanwumenxi Ave,Xuanwu District
   Beijing 100053
   China

   Email: denghui@chinamobile.com























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