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Versions: 00                                                            
anima                                                              Y. Li
Internet-Draft                                                   Y. Zhou
Intended status: Informational                                   L. Shen
Expires: April 22, 2022                              Huawei Technologies
                                                        October 19, 2021


         Requirement and a Reference Model of L2 ACP based ANI
                 draft-yizhou-anima-l2-acp-based-ani-00

Abstract

   This document discusses the scenarios, requirements and a reference
   model of ANI (Autonomic Networking Infrastructure) to be constructed
   in a layer 2 network using L2 Autonomic Control Plane (ACP) and the
   related functions.  It expands the applicability of ANI to L2 network
   and maintains the same infrastructure.

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
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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 April 22, 2022.

Copyright Notice

   Copyright (c) 2021 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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   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Scenarios requiring L2 ACP functions in ANI . . . . . . . . .   2
   3.  Requirements for L2 ACP and related functions in ANI  . . . .   4
   4.  Reference Model of L2 ACP based Autonomic Node  . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   [RFC8993] defines a generic set of functions of Autonomic Network
   Infrastructure (ANI).  It contains addressing and naming of autonomic
   nodes, discovery, negotiation and synchronization functions,
   distribution of information, reporting, feedback loops, and routing
   inside the Autonomic Control Plane (ACP) [RFC8994].  The Autonomic
   Service Agent (ASA) is the atomic entity of an autonomic function and
   is instantiated on autonomic nodes.  They use the services and data
   structures of the underlying ANI via the API exposed.  When ASAs
   communicate with each other, they should use the Generic Autonomic
   Signaling Protocol (GRASP) [RFC8990].  GRASP runs over a secure
   substrate that is isolated from regular data plane traffic which is
   known as Autonomic Control Plane (ACP).

   Though the design concept of ANI is generic, the methods for
   constructing an ACP and routing in ACP [RFC8994], discovery of
   adjacent system [RFC8990] and interaction of GRASP message are all at
   the network layer.  This document discusses the scenarios and
   requirements of a layer 2 (L2) ACP as an instance of a Generalized
   ACP to implement part of ANI functions in L2 network.  And it shows a
   reference model to construct such L2 ACP and the related functions.

2.  Scenarios requiring L2 ACP functions in ANI

   Current ACP implementation in ANI uses IPv6 link-local address based
   ACP tunnel, RPL as routing protocol in ACP and GRASP DULL to discover
   the adjacent node.  It is appropriate when the managed network is a
   large campus, a multi-site network or a carrier network.  However
   there are some cases which require L2 ACP functions in ANI.  The L2
   ACP is used in such cases that the managed network is a reletively



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   small layer 2 network where the network nodes have no L3 physical
   interfaces and the network manager would like to use and verify the
   L2 topology and reachability first for some management purpose.

              +-------+
           +--|core   |--+
           |  +-------+  |                  core switch
           |             |
           |             |
           |             |
           |             |
       +-------+     +-------+
       | agg 1 |---- | agg 2 |              L2 aggregation switch
       +-------+    /+-------+
        |  \       /  |     \
        |   \     /   |      \
        |    \   /    |       \
        |     \ /     |        \
        |      \      |         \
    +-------+ / \ +-------+   +-------+
    | acc 1 |/   \| acc 2 |   | acc 3 |     L2 access switch
    +-------+     +-------+   +-------+
                      |            |
                      |            |
                      |            |
                      |            |
                  +-------+    +-------+
                  | AP 1  |    | AP 2  |    wifi access point
                  +-------+    +-------+


                        Figure 1: L2 Campus Network

   In SOHO or SMB case, the network is not large and the network nodes
   have less resource.  They are pure layer 2 nodes or nodes to be
   enrolled as layer 2 first to form the initial simple topology for
   cabling verification.  In this case, autonomic network management
   with the layer 2 network nodes is required.  Figure 1 shows a typical
   example of layer 2 network.

   For small branch, the number of hosts is usually less than 200, and
   the number of WiFi AP and access switches are both less than 10.  Two
   layers of core and access switch topology is the most common
   structure.  For a small campus, the number of hosts is usually less
   than 2000.  Three layer structure, core, aggregation and access
   switch topology with some redundancy, might be used.  The number of
   access switches and WiFi APs are in the order of dozens.  The total




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   number of network nodes, including switches and APs, is usually less
   than 200.

   It is sometimes required to firstly form a local area network
   disconnected from the Internet.  A laptop or mobile phone connected
   to a specific node, usually the top level gateway as the core switch
   shown in Figure 1, can be used by the network manager to visualize
   and verify the topology.

3.  Requirements for L2 ACP and related functions in ANI

   The generic basic functions of ANI are required for L2 network to be
   compliant with the high level autonomic network and node structure.

   The assumptions and requirements include,

   1.  IP addresses of the node and its interface may not be available
       upfront.

   2.  L2 ACP construction can be based on L2 available information and/
       or mechanisms, such as MAC address, VLAN or physical port
       information.  It should not rely on the IP addresses of the
       interface.

   3.  Adjacent node discovery should be carried as L2 frame.  When
       GRASP DULL is used, it should function without network layer
       multicast.

   4.  It is desired to reuse GRASP messages as much as possible.  GRASP
       messages should be able to be carried by L2 transport substrate.

   5.  L2 ACP module should provide API to the upper layer to allow ASA
       to invoke L2 based functions.

   6.  Physical connectivity and topology information should be able to
       be collected via L2 ACP for verification.

   7.  Routing in L2 ACP should support L2 loop-free logical topology
       creation.

   8.  Minimal manual configuration is required.  However, L2 ACP can
       assume some management VLAN ID is pre-configured and with a
       password or encryption key if necessary for security concern.

   9.  Re-use of the existing well-known multicast MAC addresses is
       desired.





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4.  Reference Model of L2 ACP based Autonomic Node

   Figure 2 shows a reference model when L2 ACP and the related function
   is present in ANI.

        +-------+                            +-------+
        | ASA 1 |                            | ASA 2 |
        +-------+                            +-------+
            ^                                    ^
            |                                    |
          -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
                        API Invoke (L2/L3)
          -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
            |                                    |
            |                                    |
     ---------------------------------------------------------------
            | Autonomic Networking Infrastructure|
            v                                    v
      +----------------------------------------------------------+
      | Basic ANI functions                                      |
      |   - Data strcutures                                      |
      |   - Discovery, negotiation and synchronization functions |
      |   - Information and Intent Distribution                  |
      |   - ...                                                  |
      +----------------------------------------------------------+
      +---------+ +----------------------------------------------+
      |         | |L2 ACP                                        |
      |         | |- Neighbour Discovery with L2 GRASP DULL      |
      | L3 ACP  | |- Addressing and reachability                 |
      |         | |- Topology collection and loop-free creation  |
      |         | |- GRASP with L2 extension in L2 ACP           |
      +---------+ +----------------------------------------------+
     ---------------------------------------------------------------
                           OS Functions
     ---------------------------------------------------------------


              Figure 2: Model of an Autonomic Node with L2ACP

   The conceptual API should allow the ASAs to communicate with other
   ASAs by invoking a set of L2 transport based functions in the
   underlying ANI.  The semantics of data models expressed by the
   invoked L2 APIs are expected to be consistent as much as possible
   with the L3 API with the similar functions.

   Generally L2 ACP provides the similar functions as L3 ACP without
   requiring the L3 address and reachability as the transport substrate.




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   The DULL instance of GRASP is used to discover neighbours.  It uses
   the IPv6 link-local multicast address.  In layer 2 network, L2 GRASP
   DULL is expected to be sent without the requiring L3 addresses.  One
   of the possible way is to extend L2 control plane protocol to carry
   GRASP information.  Link Layer Discovery Protocol (LLDP) defined by
   IEEE 802.1 can be a candidate of such a protocol as it is able to
   discover L2 neighbour nodes and the related L2 information such as
   the physical port information and VLAN IDs.

   RPL is suggested as a routing protocol used in L3 ACP [RFC8994].
   Routing is mostly used for L3 network.  RPL is not directly
   applicable to run in L2 ACP.  Therefore similar functions of topology
   collection and loop-free topology creation is required for L2 ACP.
   L2 ACP should have its own addressing and L2 reachability scheme to
   securely reach L2 autonomic node.

5.  Security Considerations

   [Editor's notes: It is not completed.  Further discussions are
   needed.]

   The network leverages the L2 ACP and the related functions are
   usually small to medium size network in a single or very closed
   physical locations.  Therefore physical security to prevent access by
   unauthorized persons can be used to protect against interlopers and
   eavesdroppers.

6.  IANA Considerations

   No IANA action is required for this document so far.  More
   consideration will be required for future normative specification of
   extensions of GRASP, LLDP and/or other protocols.

7.  References

7.1.  Normative References

   [RFC8990]  Bormann, C., Carpenter, B., Ed., and B. Liu, Ed., "GeneRic
              Autonomic Signaling Protocol (GRASP)", RFC 8990,
              DOI 10.17487/RFC8990, May 2021,
              <https://www.rfc-editor.org/info/rfc8990>.

   [RFC8993]  Behringer, M., Ed., Carpenter, B., Eckert, T., Ciavaglia,
              L., and J. Nobre, "A Reference Model for Autonomic
              Networking", RFC 8993, DOI 10.17487/RFC8993, May 2021,
              <https://www.rfc-editor.org/info/rfc8993>.





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7.2.  Informative References

   [RFC8994]  Eckert, T., Ed., Behringer, M., Ed., and S. Bjarnason, "An
              Autonomic Control Plane (ACP)", RFC 8994,
              DOI 10.17487/RFC8994, May 2021,
              <https://www.rfc-editor.org/info/rfc8994>.

Acknowledgements

   TBD

Authors' Addresses

   Yizhou Li
   Huawei Technologies

   Email: liyizhou@huawei.com


   Yujing Zhou
   Huawei Technologies

   Email: zhouyujing3@huawei.com


   Li Shen
   Huawei Technologies

   Email: kevin.shenli@huawei.com






















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