Network Working Group B. Carpenter
Internet-Draft Univ. of Auckland
Intended status: Informational B. Liu, Ed.
Expires: September 1, 2019 Huawei Technologies
February 28, 2019
Scenarios and Requirements for Layer 2 Autonomic Control Planes
draft-carpenter-anima-l2acp-scenarios-00
Abstract
This document discusses scenarios and requirements for Autonomic
Control Planes (ACPs) constructed and secured at Layer 2. These
would be alternatives to an ACP constructed and secured at the
network layer. A secure ACP is required as the substrate for the
Generic Autonomic Signaling Protocol (GRASP) used by Autonomic
Service Agents.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 1, 2019.
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
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
Carpenter & Liu Expires September 1, 2019 [Page 1]
Internet-Draft L2 ACP Scenarios February 2019
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Network Scenarios Suitable for a Layer 2 ACP . . . . . . . . 2
3. Requirements for a Layer 2 Technology . . . . . . . . . . . . 3
4. Multiple Segments . . . . . . . . . . . . . . . . . . . . . . 4
5. Implementation Status [RFC Editor: please remove] . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 5
Appendix A. Change log [RFC Editor: Please remove] . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
As defined in [I-D.ietf-anima-reference-model], the Autonomic Service
Agent (ASA) is the atomic entity of an autonomic function, and it is
instantiated on autonomic nodes. When ASAs communicate with each
other, they should use the Generic Autonomic Signaling Protocol
(GRASP) [I-D.ietf-anima-grasp]. It is essential that such
communication is strongly secured to avoid malicious interference
with the Autonomic Infrastructure (ANI).
For this reason, GRASP must run over a secure substrate that is
isolated from regular data plane traffic. This substrate is known as
the Autonomic Control Plane (ACP). A method for constructing an ACP
at the network layer is described in
[I-D.ietf-anima-autonomic-control-plane]. The present document
discusses scenarios and requirements for constructing an ACP at layer
2.
2. Network Scenarios Suitable for a Layer 2 ACP
The ANI design is aimed at managed networks, as explained in the
reference model [I-D.ietf-anima-reference-model]. For a wide area
network (such as a large campus, a multi-site enterprise network, or
a carrier network considered as a whole) it is appropriate to
construct the ACP using network layer techniques and network layer
security. and that is the model described in
[I-D.ietf-anima-autonomic-control-plane], However, in at least two
cases an ACP covering a smaller geographical area may be appropriate:
Carpenter & Liu Expires September 1, 2019 [Page 2]
Internet-Draft L2 ACP Scenarios February 2019
1. A small enterprise that is completely within one building or
several adjacent buildings, but is large enough to require
autonomic network management.
2. An enterprise that prefers in any case to segment its network
into smaller units for management purposes.
In either case, we assume that the L2 ACP may extend into the Network
Operations Centre (NOC) so that it can be interfaced to traditional
tools for Operations, Administration and Maintenance, as described in
[RFC8368]. In the terminology of that document, an L2 ACP is an
instance of a Generalized ACP.
3. Requirements for a Layer 2 Technology
1. The technology must support transmission of IPv6 packets
according to [RFC8200]. Since GRASP can run on a single network
segment using link-local addresses, there is not required to be
an IPv6 router or DHCPv6 server.
2. The technology must support multicast. If the switches are not
completely transparent to layer 2 multicast, they must support
Multicast Listener Discovery Version 2 (MLDv2) for IPv6
[RFC3810].
3. The technology should have a minimum MTU of 1500 bytes.
4. The technology must support isolation of a given set of nodes
(the "ACP VLAN").
5. The technology must support secure authorization for access to
the ACP VLAN. If the VLAN technology in use does not support
password protection, a VLAN access control list could be used.
6. The technology should support both the normal dataplane VLAN and
the ACP VLAN on the same physical sockets. (Possibly the
dataplane may be the native VLAN, i.e. frames with no VLAN tag.)
7. The technology should support line speed encryption of the ACP
VLAN.
8. The technology should support wired/wireless bridging if
relevant.
9. The technology should require minimal manual configuration of ACP
nodes. However, it is expected that the nodes will need to be
preconfigured before deployment with the VLAN ID, and a password
or encryption key if necessary. A solution which is both secure
Carpenter & Liu Expires September 1, 2019 [Page 3]
Internet-Draft L2 ACP Scenarios February 2019
and self-configuring at Layer 2 is out of scope for this
document.
A small ACP software module will be needed in each autonomic node,
whose job is to provide the GRASP core with the following information
about the L2 ACP:
1. A signal that the L2 ACP is available and secure.
2. The current global scope IPv6 address that GRASP should use as
its primary locator, preferably a ULA, if available. As
mentioned, if no such address is available, GRASP will simply
operate with link-local addresses.
3. A list of [interface_index, link_local_address] pairs for all
valid IPv6 interfaces attached to the L2 ACP. The interface
index is an integer for maximum portability between operating
systems.
4. Multiple Segments
This section is for further study.
The L2 ACP could in principle be extended across multiple segments or
even multiple sites by use of secure L2VPN technology.
5. Implementation Status [RFC Editor: please remove]
A simple ACP software module emulating that needed for a secure L2
ACP has been implemented, but it does not in fact verify security.
It may be found at
<https://github.com/becarpenter/graspy/blob/master/acp.py> and is
briefly documented in
<https://github.com/becarpenter/graspy/blob/master/graspy.pdf>.
6. Security Considerations
The assumption of this document is that any Layer 2 solution chosen
must have adequate security against interlopers and eavesdroppers.
It should be noted that (at least in a wired network) this also
requires adequate physical security to prevent access by unauthorized
persons, including physical intrusion detection.
The fact that an IPv6 router is not required in an L2 ACP excludes
many Layer 3 vulnerabilities by construction. No outside entity can
generate link-local IPv6 packets, and no outside entity can send
global scope packets to any autonomic node.
Carpenter & Liu Expires September 1, 2019 [Page 4]
Internet-Draft L2 ACP Scenarios February 2019
7. IANA Considerations
This document makes no request of the IANA.
8. Acknowledgements
Excellent suggestions were made by TBD and other participants in the
ANIMA WG.
9. References
9.1. Normative References
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004,
<https://www.rfc-editor.org/info/rfc3810>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
9.2. Informative References
[I-D.ietf-anima-autonomic-control-plane]
Eckert, T., Behringer, M., and S. Bjarnason, "An Autonomic
Control Plane (ACP)", draft-ietf-anima-autonomic-control-
plane-18 (work in progress), August 2018.
[I-D.ietf-anima-grasp]
Bormann, C., Carpenter, B., and B. Liu, "A Generic
Autonomic Signaling Protocol (GRASP)", draft-ietf-anima-
grasp-15 (work in progress), July 2017.
[I-D.ietf-anima-reference-model]
Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
and J. Nobre, "A Reference Model for Autonomic
Networking", draft-ietf-anima-reference-model-10 (work in
progress), November 2018.
[RFC8368] Eckert, T., Ed. and M. Behringer, "Using an Autonomic
Control Plane for Stable Connectivity of Network
Operations, Administration, and Maintenance (OAM)",
RFC 8368, DOI 10.17487/RFC8368, May 2018,
<https://www.rfc-editor.org/info/rfc8368>.
Carpenter & Liu Expires September 1, 2019 [Page 5]
Internet-Draft L2 ACP Scenarios February 2019
Appendix A. Change log [RFC Editor: Please remove]
draft-carpenter-anima-l2acp-scenarios-00, 2019-02-28:
Initial version
Authors' Addresses
Brian Carpenter
The University of Auckland
School of Computer Science
University of Auckland
PB 92019
Auckland 1142
New Zealand
Email: brian.e.carpenter@gmail.com
Bing Liu (editor)
Huawei Technologies
Q14, Huawei Campus
No.156 Beiqing Road
Hai-Dian District, Beijing 100095
P.R. China
Email: leo.liubing@huawei.com
Carpenter & Liu Expires September 1, 2019 [Page 6]