Internet DRAFT - draft-carpenter-anima-ani-objectives
draft-carpenter-anima-ani-objectives
Network Working Group B. Carpenter
Internet-Draft Univ. of Auckland
Intended status: Informational B. Liu
Expires: January 17, 2018 Huawei Technologies Co., Ltd
July 16, 2017
Technical Objective Formats for the Autonomic Network Infrastructure
draft-carpenter-anima-ani-objectives-03
Abstract
This document defines the formats of several technical objectives for
the Generic Autonomic Signaling Protocol (GRASP) used by components
of the Autonomic Networking Infrastructure outlined in the ANIMA
reference model.
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 January 17, 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
(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
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.
Carpenter & Liu Expires January 17, 2018 [Page 1]
Internet-Draft ANI GRASP Objectives July 2017
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Objectives for Secure Bootstrap . . . . . . . . . . . . . . . 3
2.1. Additional value for GRASP message syntax . . . . . . . . 3
2.2. Discovered Sychronization Objective for the Join
Registrar . . . . . . . . . . . . . . . . . . . . . . . . 3
2.3. Flooded Objective for Join Proxy . . . . . . . . . . . . 5
3. Objective for Autonomic Control Plane . . . . . . . . . . . . 6
4. Objective for Stable Connectivity of Network OAM . . . . . . 7
5. Flood Frequency . . . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Change log [RFC Editor: Please remove] . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
This document defines several technical objectives for use with for
the Generic Autonomic Signaling Protocol (GRASP)
[I-D.ietf-anima-grasp]. They are intended for use by corresponding
Autonomic Service Agents (ASAs) that support infrastructure
components of the Autonomic Network Infrastructure (ANI) outlined in
the ANIMA reference model [I-D.ietf-anima-reference-model].
Note: This draft is posted to allow systematic discussion of the
various objectives in a consistent way. It is possible that rather
than this being published as an RFC, the various objective
definitions will be incorporated directly in the relevant
specifications.
The reference model identifies several infrastructure components that
will fit together with GRASP to form the ANI:
Secure Bootstrap.
Autonomic Control Plane (ACP).
Stable Connectivity of Network OAM.
The following sections define GRASP objectives for each of these
cases. They are described in an informal object notation and
formally using CBOR data definition language (CDDL)
Carpenter & Liu Expires January 17, 2018 [Page 2]
Internet-Draft ANI GRASP Objectives July 2017
[I-D.greevenbosch-appsawg-cbor-cddl]. Undefined CDDL terms are
defined in [I-D.ietf-anima-grasp].
2. Objectives for Secure Bootstrap
Three ANI components are involved in the Bootstrapping Remote Secure
Key Infrastructures (BRSKI) process described in
[I-D.ietf-anima-bootstrapping-keyinfra]: the Join Registrar, the Join
Proxy, and the Pledge (a node joining the domain). In the present
document we only consider interactions between autonomic nodes
involved in BRSKI; non-autonomic nodes are expected to use different
methods not involving GRASP.
Note that since secure bootstrap takes place, by definition, on an
incompletely secure network, the use of any protocol needs to be kept
as simple and limited as possible. Between the proxy and the pledge,
therefore, only one GRASP message type is used - flooding - to avoid
giving away any unnecessary information. The proxy and pledge have a
link-local connection between them. Mutual discovery and bootstrap
can happen without any prior provisioning of helper information by an
external mechanism. Instead, link-local multicast with GRASP is
used. This will minimize exposure to eavesdroppers and malicious
nodes. On the other hand, there may be multiple physical hops
between the proxy and the registrar. Therefore, two different GRASP
objectives are required: one that is used over an existing secure
network (typically the ACP) between the registrar and the proxy, and
another that is used over an insecure link-local hop between the
proxy and the pledge. Furher security aspects are discussed in
[I-D.ietf-anima-bootstrapping-keyinfra] and [I-D.ietf-anima-grasp].
2.1. Additional value for GRASP message syntax
This document extends the syntax of the GRASP protocol
[I-D.ietf-anima-grasp] by adding an additional value for the
"transport-proto" element:
transport-proto /= IPPROTO_IPV6
IPPROTO_IPV6 = 41
This value indicates IP-in-IP encapsulation.
2.2. Discovered Sychronization Objective for the Join Registrar
The Join Proxy discovers a Join Registrar by using the
"AN_join_registrar" GRASP objective. It must only be used when GRASP
is running securely, typically because the Join Proxy is in a node
that has already joined the ACP. The value of the objective will
Carpenter & Liu Expires January 17, 2018 [Page 3]
Internet-Draft ANI GRASP Objectives July 2017
indicate the BRSKI methods supported by the registrar and the
corresponding locators for BRSKI traffic.
First, the pledge performs GRASP discovery. If multiple responses
occur, it chooses one by an implementation-defined method. Then the
pledge initiates GRASP synchronization to obtain the BRSKI methods
supported by the discovered registrar. Alternatively, if
implemented, GRASP rapid mode could be used to combine the two
operations.
An example of the objective is informally:
["AN_join_registrar", 5, 6, [["BRSKI-TCP", [O_IPv6_LOCATOR,
fd45:1345::6789, 6, 443]]]]
The formal CDDL definition is:
registrar-objective = ["AN_join_registrar", objective-flags,
loop-count, [*[method, locator-option]]]
objective-flags = ; as in the GRASP specification
loop-count = ; as in the GRASP specification
locator-option = ; as in the GRASP specification
method = "BRSKI-TCP" / "BRSKI-UDP" / "BRSKI-IPIP"
; name of the BRSKI method supported
The objective-flags field is set to indicate synchronization.
The loop-count is set to a suitable value to limit the scope of
discovery. A suggested default value is 6.
The Join Proxy, upon receiving this objective, will select one or
more of the methods for announcement to Pledges. It will store the
provided locator for each method for subsequent BRSKI operations.
Note that this locator is distinct from the locator for the Join
Registrar's ASA, which is used only for GRASP operations.
Thus, locators for "BRSKI-TCP", "BRSKI-UDP" and "BRSKI-IPIP" could
be:
[O_IPv6_LOCATOR, ipv6-address, IPPROTO_TCP, rport1]
[O_IPv6_LOCATOR, ipv6-address, IPPROTO_UDP, rport2]
[O_IPv6_LOCATOR, ipv6-address, IPPROTO_IPV6, null]
Carpenter & Liu Expires January 17, 2018 [Page 4]
Internet-Draft ANI GRASP Objectives July 2017
where 'ipv6-address' is the address of the registrar (typically an
ACP address), and 'rport1' and 'rport2' are the appropriate TCP and
UDP ports at the registrar.
2.3. Flooded Objective for Join Proxy
A Join Proxy announces itself to potential pledges by use of the
"AN_join_proxy" objective. This is a synchronization objective
intended only to be flooded on a single link using the GRASP Flood
Synchronization (M_FLOOD) message. In accordance with the design of
the Flood message, a locator consisting of a specific link-local IP
address, IP protocol number and port number will be distributed with
the flooded objective. An example of the objective is informally:
["AN_join_proxy", 5, 1, "BRSKI-TCP"]
The formal CDDL definition is:
proxy-objective = ["AN_join_proxy", objective-flags, loop-count,
method]
objective-flags = ; as in the GRASP specification
loop-count = 1 ; limit to link-local operation
method = "BRSKI-TCP" / "BRSKI-UDP"
The objective-flags field is set to indicate synchronization.
The loop-count is fixed at 1 since this is a link-local operation.
A Join Proxy that supports more than one method will flood multiple
versions of the "AN_join_proxy" objective. As specified for the
GRASP M_FLOOD message, a locator may be attached to each version.
The 'method' parameter indicates the specific BRSKI method available
at the given locator.
Thus, locators for "BRSKI-TCP" and "BRSKI-UDP" would be:
[O_IPv6_LOCATOR, ipv6-address, IPPROTO_TCP, pport1]
[O_IPv6_LOCATOR, ipv6-address, IPPROTO_UDP, pport2]
where 'ipv6-address' is the link-local address of the proxy and
'pport1' and 'pport2' are the appropriate TCP and UDP ports at the
proxy.
Note that the BRSKI-IPIP method is never announced to the Pledges,
because it applies exclusively between the Proxy and the Join
Registrar, being used to encapsulate one of the other methods.
Carpenter & Liu Expires January 17, 2018 [Page 5]
Internet-Draft ANI GRASP Objectives July 2017
By this mechanism, a proxy may announce one or more connection
methods to all pledges, each with an associated link-local address,
protocol number and port number.
This objective is only to be used in a Discovery Unsolicited Link-
Local (DULL) instance of GRASP [I-D.ietf-anima-grasp].
3. Objective for Autonomic Control Plane
The Autonomic Control Plane (ACP)
[I-D.ietf-anima-autonomic-control-plane] constructs itself without
outside intervention. To achieve this, each node needs to identify
its link-local neighbors on all interfaces, and agree on a secure
connection method with each of them. As for the Join Proxy, a
flooding mechanism, in which each node announces itself and it
security methods to its neighbors, is used.
Thus each autonomic node runs an ASA that supports the corresponding
objective. This ASA runs permanently, as long as the node is capable
of being part of the ACP, in order to discover or detect new ACP
neighbors or to remove failed neighbors.
A node announces itself to potential ACP peers by use of the "AN_ACP"
objective. This is a synchronization objective intended to be
flooded on a single link using the GRASP Flood Synchronization
(M_FLOOD) message. In accordance with the design of the Flood
message, a locator consisting of a specific link-local IP address, IP
protocol number and port number will be distributed with the flooded
objective. An example of the objective is informally:
["AN_ACP", 5, 1, ["IKEv2","dTLS"]]
The formal CDDL definition is:
acp-objective = ["AN_ACP", objective-flags, loop-count, method]
objective-flags = ; as in the GRASP specification
loop-count = 1 ; limit to link-local operation
method = "IKEv2" / "dTLS" ; connection method supported
The objective-flags field is set to indicate synchronization.
The loop-count is fixed at 1 since this is a link-local operation.
A node that supports more than one method may flood multiple versions
of the "AN_ACP" objective, each accompanied by its own locator,
similar to "AN_join_proxy". The 'method' parameter indicates the
Carpenter & Liu Expires January 17, 2018 [Page 6]
Internet-Draft ANI GRASP Objectives July 2017
specific connection method available at the given locator. The
initial possible values are "IKEv2" and "dTLS".
This objective is only to be used in a Discovery Unsolicited Link-
Local (DULL) instance of GRASP [I-D.ietf-anima-grasp].
Note that a node serving both as an ACP node and BRSKI Join Proxy may
choose to distribute the "AN_ACP" objective and "AN_join_proxy"
objective in the same flood message, since GRASP allows multiple
objectives in one Flood message.
4. Objective for Stable Connectivity of Network OAM
For OAM purposes [I-D.ietf-anima-stable-connectivity], a special-
purpose ASA, which we will call the NOC ASA, mediates connectivity
between NOC systems performing OAM operations and autonomic nodes
that can be reached securely via the ACP. This requires a discovery
operation, which could be handled in two ways: the NOC ASA discovers
all nodes, or each node discovers the NOC ASA. The latter seems much
more practical since nodes might join or leave the network at any
time. However, the NOC might need to know something about each
target node, so the corresponding objective is defined as a
negotiation objective to allow for this: each node can pass data to
the NOC in an M_REQ_NEG message, and receive data from the NOC in an
M_NEGOTIATE message.
An example of the objective is informally:
["AN_NOC", 3, 6, [TBD]]
The formal CDDL definition is:
noc-objective = ["AN_NOC", objective-flags, loop-count, [TBD]]
objective-flags = ; as in the GRASP specification
TBD = any ; node information to be defined
The objective-flags field is set to indicate negotiation.
Dry run mode must not be used.
The loop-count is set to a suitable value to limit the scope of
discovery. A suggested default value is 6.
When a node joins the ACP, one of its initial actions must be to
perform GRASP discovery for "AN_NOC" and then to send a Request
Negotiate message to the NOC ASA supplying the value TBD. If
successfully received, the NOC ASA should reply with a Negotiate
Carpenter & Liu Expires January 17, 2018 [Page 7]
Internet-Draft ANI GRASP Objectives July 2017
message, providing a value TBD in return. This value will inform the
requesting node of various NOC parameters. The requesting node must
then send an End Negotiate message. From then on, any OAM
communication between NOC services and the node in question will
proceed over the ACP using the information TBD.
5. Flood Frequency
Any ASA that floods one of the above objectives should do so at a
carefully chosen frequency. Recipient nodes may be starting up,
reconnecting, or waking up from sleep, so floods need to be refreshed
periodically. On the other hand, excessive flooding will consume
bandwidth, CPU and battery capacity throughout the network, and might
even resemble a DoS attack. A general guideline is to flood an
objective once immediately after its value is initialised or changed,
and then repeat the flood at intervals of at least 30 seconds.
Additionally, the flooding interval should be slightly jittered to
avoid synchronicity with other floods. Finally, the value of a
flooded objective should change as rarely as possible (on a timescale
of at least minutes, not seconds).
6. Security Considerations
General security issues for GRASP are covered in
[I-D.ietf-anima-grasp]. The objectives "AN_join_proxy" and "AN_ACP"
must be implemented using a DULL instance of GRASP. Specific issues
not mentioned above are discussed in the referenced drafts for each
use case.
7. IANA Considerations
IANA is requested to add the following entries to the GRASP Objective
Names Table registry created by [I-D.ietf-anima-grasp]:
AN_join_registrar
AN_join_proxy
AN_ACP
AN_NOC
8. Acknowledgements
Valuable comments were made by Toerless Eckert, Max Pritikin, and
Michael Richardson.
Carpenter & Liu Expires January 17, 2018 [Page 8]
Internet-Draft ANI GRASP Objectives July 2017
9. References
9.1. Normative References
[I-D.greevenbosch-appsawg-cbor-cddl]
Birkholz, H., Vigano, C., and C. Bormann, "Concise data
definition language (CDDL): a notational convention to
express CBOR data structures", draft-greevenbosch-appsawg-
cbor-cddl-11 (work in progress), July 2017.
[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.
9.2. Informative References
[I-D.ietf-anima-autonomic-control-plane]
Behringer, M., Eckert, T., and S. Bjarnason, "An Autonomic
Control Plane", draft-ietf-anima-autonomic-control-
plane-07 (work in progress), July 2017.
[I-D.ietf-anima-bootstrapping-keyinfra]
Pritikin, M., Richardson, M., Behringer, M., Bjarnason,
S., and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping-
keyinfra-07 (work in progress), July 2017.
[I-D.ietf-anima-reference-model]
Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
Pierre, P., Liu, B., Nobre, J., and J. Strassner, "A
Reference Model for Autonomic Networking", draft-ietf-
anima-reference-model-04 (work in progress), July 2017.
[I-D.ietf-anima-stable-connectivity]
Eckert, T. and M. Behringer, "Using Autonomic Control
Plane for Stable Connectivity of Network OAM", draft-ietf-
anima-stable-connectivity-03 (work in progress), July
2017.
Appendix A. Change log [RFC Editor: Please remove]
draft-carpenter-anima-ani-objectives-03, 2017-07-16:
Align with latest BRSKI and ACP drafts and discussions, various
details corrected.
draft-carpenter-anima-ani-objectives-02, 2017-06-30:
Carpenter & Liu Expires January 17, 2018 [Page 9]
Internet-Draft ANI GRASP Objectives July 2017
Limited scope to initial ANI components
Updated details and removed alternatives
draft-carpenter-anima-ani-objectives-01, 2017-02-13:
Added prefix management case
Updated objectives for BRSKI
Editorial corrections
draft-carpenter-anima-ani-objectives-00, 2016-11-15:
Initial version
Authors' Addresses
Brian Carpenter
Department of Computer Science
University of Auckland
PB 92019
Auckland 1142
New Zealand
Email: brian.e.carpenter@gmail.com
Bing Liu
Huawei Technologies Co., Ltd
Q22, Huawei Campus
No.156 Beiqing Road
Hai-Dian District, Beijing 100095
P.R. China
Email: leo.liubing@huawei.com
Carpenter & Liu Expires January 17, 2018 [Page 10]
