draft-ietf-anima-grasp-08.txt   draft-ietf-anima-grasp-09.txt 
Network Working Group C. Bormann Network Working Group C. Bormann
Internet-Draft Universitaet Bremen TZI Internet-Draft Universitaet Bremen TZI
Intended status: Standards Track B. Carpenter, Ed. Intended status: Standards Track B. Carpenter, Ed.
Expires: May 3, 2017 Univ. of Auckland Expires: June 18, 2017 Univ. of Auckland
B. Liu, Ed. B. Liu, Ed.
Huawei Technologies Co., Ltd Huawei Technologies Co., Ltd
October 30, 2016 December 15, 2016
A Generic Autonomic Signaling Protocol (GRASP) A Generic Autonomic Signaling Protocol (GRASP)
draft-ietf-anima-grasp-08 draft-ietf-anima-grasp-09
Abstract Abstract
This document establishes requirements for a signaling protocol that This document establishes requirements for a signaling protocol that
enables autonomic devices and autonomic service agents to dynamically enables autonomic devices and autonomic service agents to dynamically
discover peers, to synchronize state with them, and to negotiate discover peers, to synchronize state with them, and to negotiate
parameter settings mutually with them. The document then defines a parameter settings mutually with them. The document then defines a
general protocol for discovery, synchronization and negotiation, general protocol for discovery, synchronization and negotiation,
while the technical objectives for specific scenarios are to be while the technical objectives for specific scenarios are to be
described in separate documents. An Appendix briefly discusses described in separate documents. An Appendix briefly discusses
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 3, 2017. This Internet-Draft will expire on June 18, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Negotiation . . . . . . . . . . . . . . . . . . . . . . . . . 4 Negotiation . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Requirements for Discovery . . . . . . . . . . . . . . . 5 2.1. Requirements for Discovery . . . . . . . . . . . . . . . 5
2.2. Requirements for Synchronization and Negotiation 2.2. Requirements for Synchronization and Negotiation
Capability . . . . . . . . . . . . . . . . . . . . . . . 6 Capability . . . . . . . . . . . . . . . . . . . . . . . 6
2.3. Specific Technical Requirements . . . . . . . . . . . . . 9 2.3. Specific Technical Requirements . . . . . . . . . . . . . 9
3. GRASP Protocol Overview . . . . . . . . . . . . . . . . . . . 10 3. GRASP Protocol Overview . . . . . . . . . . . . . . . . . . . 10
3.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 10 3.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 10
3.2. High Level Deployment Model . . . . . . . . . . . . . . . 12 3.2. High Level Deployment Model . . . . . . . . . . . . . . . 12
3.3. High Level Design Choices . . . . . . . . . . . . . . . . 13 3.3. High Level Design Choices . . . . . . . . . . . . . . . . 13
3.4. Quick Operating Overview . . . . . . . . . . . . . . . . 16 3.4. Quick Operating Overview . . . . . . . . . . . . . . . . 16
3.5. GRASP Protocol Basic Properties and Mechanisms . . . . . 17 3.5. GRASP Protocol Basic Properties and Mechanisms . . . . . 16
3.5.1. Required External Security Mechanism . . . . . . . . 17 3.5.1. Required External Security Mechanism . . . . . . . . 16
3.5.2. Limited Security Instances . . . . . . . . . . . . . 17 3.5.2. Constrained Instances . . . . . . . . . . . . . . . . 17
3.5.3. Transport Layer Usage . . . . . . . . . . . . . . . . 19 3.5.3. Transport Layer Usage . . . . . . . . . . . . . . . . 19
3.5.4. Discovery Mechanism and Procedures . . . . . . . . . 20 3.5.4. Discovery Mechanism and Procedures . . . . . . . . . 20
3.5.5. Negotiation Procedures . . . . . . . . . . . . . . . 23 3.5.5. Negotiation Procedures . . . . . . . . . . . . . . . 23
3.5.6. Synchronization and Flooding Procedure . . . . . . . 25 3.5.6. Synchronization and Flooding Procedure . . . . . . . 25
3.6. GRASP Constants . . . . . . . . . . . . . . . . . . . . . 27 3.6. GRASP Constants . . . . . . . . . . . . . . . . . . . . . 27
3.7. Session Identifier (Session ID) . . . . . . . . . . . . . 27 3.7. Session Identifier (Session ID) . . . . . . . . . . . . . 27
3.8. GRASP Messages . . . . . . . . . . . . . . . . . . . . . 28 3.8. GRASP Messages . . . . . . . . . . . . . . . . . . . . . 28
3.8.1. Message Overview . . . . . . . . . . . . . . . . . . 28 3.8.1. Message Overview . . . . . . . . . . . . . . . . . . 28
3.8.2. GRASP Message Format . . . . . . . . . . . . . . . . 28 3.8.2. GRASP Message Format . . . . . . . . . . . . . . . . 29
3.8.3. Message Size . . . . . . . . . . . . . . . . . . . . 29 3.8.3. Message Size . . . . . . . . . . . . . . . . . . . . 29
3.8.4. Discovery Message . . . . . . . . . . . . . . . . . . 29 3.8.4. Discovery Message . . . . . . . . . . . . . . . . . . 30
3.8.5. Discovery Response Message . . . . . . . . . . . . . 31 3.8.5. Discovery Response Message . . . . . . . . . . . . . 31
3.8.6. Request Messages . . . . . . . . . . . . . . . . . . 31 3.8.6. Request Messages . . . . . . . . . . . . . . . . . . 32
3.8.7. Negotiation Message . . . . . . . . . . . . . . . . . 32 3.8.7. Negotiation Message . . . . . . . . . . . . . . . . . 33
3.8.8. Negotiation End Message . . . . . . . . . . . . . . . 33 3.8.8. Negotiation End Message . . . . . . . . . . . . . . . 33
3.8.9. Confirm Waiting Message . . . . . . . . . . . . . 33 3.8.9. Confirm Waiting Message . . . . . . . . . . . . . 33
3.8.10. Synchronization Message . . . . . . . . . . . . . . . 33 3.8.10. Synchronization Message . . . . . . . . . . . . . . . 34
3.8.11. Flood Synchronization Message . . . . . . . . . . . . 34 3.8.11. Flood Synchronization Message . . . . . . . . . . . . 34
3.8.12. Invalid Message . . . . . . . . . . . . . . . . . . . 35 3.8.12. Invalid Message . . . . . . . . . . . . . . . . . . . 35
3.8.13. No Operation Message . . . . . . . . . . . . . . . . 35 3.8.13. No Operation Message . . . . . . . . . . . . . . . . 35
3.9. GRASP Options . . . . . . . . . . . . . . . . . . . . . . 35 3.9. GRASP Options . . . . . . . . . . . . . . . . . . . . . . 36
3.9.1. Format of GRASP Options . . . . . . . . . . . . . . . 35 3.9.1. Format of GRASP Options . . . . . . . . . . . . . . . 36
3.9.2. Divert Option . . . . . . . . . . . . . . . . . . . . 36 3.9.2. Divert Option . . . . . . . . . . . . . . . . . . . . 36
3.9.3. Accept Option . . . . . . . . . . . . . . . . . . . . 36 3.9.3. Accept Option . . . . . . . . . . . . . . . . . . . . 36
3.9.4. Decline Option . . . . . . . . . . . . . . . . . . . 36 3.9.4. Decline Option . . . . . . . . . . . . . . . . . . . 37
3.9.5. Locator Options . . . . . . . . . . . . . . . . . . . 37 3.9.5. Locator Options . . . . . . . . . . . . . . . . . . . 37
3.10. Objective Options . . . . . . . . . . . . . . . . . . . . 39 3.10. Objective Options . . . . . . . . . . . . . . . . . . . . 39
3.10.1. Format of Objective Options . . . . . . . . . . . . 39 3.10.1. Format of Objective Options . . . . . . . . . . . . 39
3.10.2. Objective flags . . . . . . . . . . . . . . . . . . 40 3.10.2. Objective flags . . . . . . . . . . . . . . . . . . 40
3.10.3. General Considerations for Objective Options . . . . 40 3.10.3. General Considerations for Objective Options . . . . 41
3.10.4. Organizing of Objective Options . . . . . . . . . . 41 3.10.4. Organizing of Objective Options . . . . . . . . . . 41
3.10.5. Experimental and Example Objective Options . . . . . 42 3.10.5. Experimental and Example Objective Options . . . . . 43
4. Implementation Status [RFC Editor: please remove] . . . . . . 42 4. Implementation Status [RFC Editor: please remove] . . . . . . 43
4.1. BUPT C++ Implementation . . . . . . . . . . . . . . . . . 42 4.1. BUPT C++ Implementation . . . . . . . . . . . . . . . . . 43
4.2. Python Implementation . . . . . . . . . . . . . . . . . . 43 4.2. Python Implementation . . . . . . . . . . . . . . . . . . 44
5. Security Considerations . . . . . . . . . . . . . . . . . . . 44 5. Security Considerations . . . . . . . . . . . . . . . . . . . 45
6. CDDL Specification of GRASP . . . . . . . . . . . . . . . . . 46 6. CDDL Specification of GRASP . . . . . . . . . . . . . . . . . 47
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 48 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 49
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 50 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 51
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 50 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 51
9.1. Normative References . . . . . . . . . . . . . . . . . . 50 9.1. Normative References . . . . . . . . . . . . . . . . . . 51
9.2. Informative References . . . . . . . . . . . . . . . . . 51 9.2. Informative References . . . . . . . . . . . . . . . . . 52
Appendix A. Open Issues [RFC Editor: Please remove if empty] . . 54 Appendix A. Open Issues [RFC Editor: Please remove if empty] . . 55
Appendix B. Closed Issues [RFC Editor: Please remove] . . . . . 54 Appendix B. Closed Issues [RFC Editor: Please remove] . . . . . 55
Appendix C. Change log [RFC Editor: Please remove] . . . . . . . 62 Appendix C. Change log [RFC Editor: Please remove] . . . . . . . 63
Appendix D. Example Message Formats . . . . . . . . . . . . . . 67 Appendix D. Example Message Formats . . . . . . . . . . . . . . 69
D.1. Discovery Example . . . . . . . . . . . . . . . . . . . . 68 D.1. Discovery Example . . . . . . . . . . . . . . . . . . . . 69
D.2. Flood Example . . . . . . . . . . . . . . . . . . . . . . 68 D.2. Flood Example . . . . . . . . . . . . . . . . . . . . . . 70
D.3. Synchronization Example . . . . . . . . . . . . . . . . . 68 D.3. Synchronization Example . . . . . . . . . . . . . . . . . 70
D.4. Simple Negotiation Example . . . . . . . . . . . . . . . 69 D.4. Simple Negotiation Example . . . . . . . . . . . . . . . 70
D.5. Complete Negotiation Example . . . . . . . . . . . . . . 69 D.5. Complete Negotiation Example . . . . . . . . . . . . . . 71
Appendix E. Capability Analysis of Current Protocols . . . . . . 70 Appendix E. Capability Analysis of Current Protocols . . . . . . 72
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 75
1. Introduction 1. Introduction
The success of the Internet has made IP-based networks bigger and The success of the Internet has made IP-based networks bigger and
more complicated. Large-scale ISP and enterprise networks have more complicated. Large-scale ISP and enterprise networks have
become more and more problematic for human based management. Also, become more and more problematic for human based management. Also,
operational costs are growing quickly. Consequently, there are operational costs are growing quickly. Consequently, there are
increased requirements for autonomic behavior in the networks. increased requirements for autonomic behavior in the networks.
General aspects of autonomic networks are discussed in [RFC7575] and General aspects of autonomic networks are discussed in [RFC7575] and
[RFC7576]. [RFC7576].
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trust has been established for a device, all ASAs within the trust has been established for a device, all ASAs within the
device inherit the device's credentials and are also trusted. device inherit the device's credentials and are also trusted.
o Depending on the type of network involved, discovery of other o Depending on the type of network involved, discovery of other
central functions might be needed, such as the Network Operations central functions might be needed, such as the Network Operations
Center (NOC) [I-D.ietf-anima-stable-connectivity]. The protocol Center (NOC) [I-D.ietf-anima-stable-connectivity]. The protocol
must be capable of supporting such discovery during must be capable of supporting such discovery during
initialisation, as well as discovery during ongoing operation. initialisation, as well as discovery during ongoing operation.
D8. The discovery process must not generate excessive traffic and D8. The discovery process must not generate excessive traffic and
must take account of sleeping nodes in the case of a constrained-node must take account of sleeping nodes.
network [RFC7228].
D9. There must be a mechanism for handling stale discovery results. D9. There must be a mechanism for handling stale discovery results.
2.2. Requirements for Synchronization and Negotiation Capability 2.2. Requirements for Synchronization and Negotiation Capability
As background, consider the example of routing protocols, the closest As background, consider the example of routing protocols, the closest
approximation to autonomic networking already in widespread use. approximation to autonomic networking already in widespread use.
Routing protocols use a largely autonomic model based on distributed Routing protocols use a largely autonomic model based on distributed
devices that communicate repeatedly with each other. The focus is devices that communicate repeatedly with each other. The focus is
reachability, so current routing protocols mainly consider simple reachability, so current routing protocols mainly consider simple
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SN6. Human intervention in large networks is often replaced by use SN6. Human intervention in large networks is often replaced by use
of a top-down network management system (NMS). It therefore follows of a top-down network management system (NMS). It therefore follows
that the protocol, as part of the Autonomic Networking that the protocol, as part of the Autonomic Networking
Infrastructure, should be capable of running in any device that would Infrastructure, should be capable of running in any device that would
otherwise be managed by an NMS, and that it can co-exist with an NMS, otherwise be managed by an NMS, and that it can co-exist with an NMS,
and with protocols such as SNMP and NETCONF. and with protocols such as SNMP and NETCONF.
SN7. Some features are expected to be implemented by individual SN7. Some features are expected to be implemented by individual
ASAs, but the protocol must be general enough to allow them: ASAs, but the protocol must be general enough to allow them:
o Dependencies and conflicts: In order to decide a configuration on o Dependencies and conflicts: In order to decide upon a
a given device, the device may need information from neighbors. configuration for a given device, the device may need information
This can be established through the negotiation procedure, or from neighbors. This can be established through the negotiation
through synchronization if that is sufficient. However, a given procedure, or through synchronization if that is sufficient.
item in a neighbor may depend on other information from its own However, a given item in a neighbor may depend on other
neighbors, which may need another negotiation or synchronization information from its own neighbors, which may need another
procedure to obtain or decide. Therefore, there are potential negotiation or synchronization procedure to obtain or decide.
dependencies and conflicts among negotiation or synchronization Therefore, there are potential dependencies and conflicts among
procedures. Resolving dependencies and conflicts is a matter for negotiation or synchronization procedures. Resolving dependencies
the individual ASAs involved. To allow this, there need to be and conflicts is a matter for the individual ASAs involved. To
clear boundaries and convergence mechanisms for negotiations. allow this, there need to be clear boundaries and convergence
Also some mechanisms are needed to avoid loop dependencies. In mechanisms for negotiations. Also some mechanisms are needed to
such a case, the protocol's role is limited to bilateral signaling avoid loop dependencies. In such a case, the protocol's role is
between ASAs. limited to bilateral signaling between ASAs.
o Recovery from faults and identification of faulty devices should o Recovery from faults and identification of faulty devices should
be as automatic as possible. The protocol's role is limited to be as automatic as possible. The protocol's role is limited to
the ability to handle discovery, synchronization and negotiation discovery, synchronization and negotiation. These processes can
at any time, in case an ASA detects an anomaly such as a occur at any time, and an ASA may need to repeat any of these
negotiation counterpart failing. steps when the ASA detects an anomaly such as a negotiation
counterpart failing.
o Since the goal is to minimize human intervention, it is necessary o Since the goal is to minimize human intervention, it is necessary
that the network can in effect "think ahead" before changing its that the network can in effect "think ahead" before changing its
parameters. One aspect of this is an ASA that relies on a parameters. One aspect of this is an ASA that relies on a
knowledge base to predict network behavior. This is out of scope knowledge base to predict network behavior. This is out of scope
for the signaling protocol. However, another aspect is for the signaling protocol. However, another aspect is
forecasting the effect of a change by a "dry run" negotiation forecasting the effect of a change by a "dry run" negotiation
before actually installing the change. This will be an before actually installing the change. This will be an
application of the protocol rather than a feature of the protocol application of the protocol rather than a feature of the protocol
itself. itself.
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is a special case of negotiation in which information is sent but is a special case of negotiation in which information is sent but
the ASAs do not request their peers to change parameter settings. the ASAs do not request their peers to change parameter settings.
All other definitions apply to both negotiation and All other definitions apply to both negotiation and
synchronization. synchronization.
o Technical Objective (usually abbreviated as Objective): A o Technical Objective (usually abbreviated as Objective): A
technical objective is a configurable parameter or set of technical objective is a configurable parameter or set of
parameters of some kind, which occurs in three contexts: parameters of some kind, which occurs in three contexts:
Discovery, Negotiation and Synchronization. In the protocol, an Discovery, Negotiation and Synchronization. In the protocol, an
objective is represented by an identifier and if relevant a value. objective is represented by an identifier and, if relevant, a
Normally, a given objective will not occur in negotiation and value. Normally, a given objective will not occur in negotiation
synchronization contexts simultaneously. and synchronization contexts simultaneously.
* One ASA may support multiple independent objectives. * One ASA may support multiple independent objectives.
* The parameter described by a given objective is naturally based * The parameter described by a given objective is naturally based
on a specific service or function or action. It may in on a specific service or function or action. It may in
principle be anything that can be set to a specific logical, principle be anything that can be set to a specific logical,
numerical or string value, or a more complex data structure, by numerical or string value, or a more complex data structure, by
a network node. That node is generally expected to contain an a network node. That node is generally expected to contain an
ASA which may itself manage subsidiary non-autonomic nodes. ASA which may itself manage subsidiary non-autonomic nodes.
* Discovery Objective: if a node needs to synchronize or * Discovery Objective: an objective in the process of discovery.
negotiate a specific objective but does not know a peer that Its value may be undefined.
supports this objective, it starts a discovery process. The
objective is called a Discovery Objective during this process.
* Synchronization Objective: an objective whose specific * Synchronization Objective: an objective whose specific
technical content needs to be synchronized among two or more technical content needs to be synchronized among two or more
ASAs. ASAs.
* Negotiation Objective: an objective whose specific technical * Negotiation Objective: an objective whose specific technical
content needs to be decided in coordination with another ASA. content needs to be decided in coordination with another ASA.
A detailed discussion of objectives, including their format, is
found in Section 3.10.
o Discovery Initiator: an ASA that spontaneously starts discovery by o Discovery Initiator: an ASA that spontaneously starts discovery by
sending a discovery message referring to a specific discovery sending a discovery message referring to a specific discovery
objective. objective.
o Discovery Responder: a peer that either contains an ASA supporting o Discovery Responder: a peer that either contains an ASA supporting
the discovery objective indicated by the discovery initiator, or the discovery objective indicated by the discovery initiator, or
caches the locator(s) of the ASA(s) supporting the objective. The caches the locator(s) of the ASA(s) supporting the objective. It
locator(s) are indicated in a Discovery Response, which is sends a Discovery Response, as described later.
normally sent by the protocol kernel, as described later.
o Synchronization Initiator: an ASA that spontaneously starts o Synchronization Initiator: an ASA that spontaneously starts
synchronization by sending a request message referring to a synchronization by sending a request message referring to a
specific synchronization objective. specific synchronization objective.
o Synchronization Responder: a peer ASA which responds with the o Synchronization Responder: a peer ASA which responds with the
value of a synchronization objective. value of a synchronization objective.
o Negotiation Initiator: an ASA that spontaneously starts o Negotiation Initiator: an ASA that spontaneously starts
negotiation by sending a request message referring to a specific negotiation by sending a request message referring to a specific
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device, these three components might be fully integrated. A more device, these three components might be fully integrated. A more
common model is expected to be a multi-purpose device capable of common model is expected to be a multi-purpose device capable of
containing several ASAs. In this case it is expected that the ACP, containing several ASAs. In this case it is expected that the ACP,
GRASP and the ASAs will be implemented as separate processes, which GRASP and the ASAs will be implemented as separate processes, which
are probably multi-threaded to support asynchronous and simultaneous are probably multi-threaded to support asynchronous and simultaneous
operations. It is expected that GRASP will access the ACP by using a operations. It is expected that GRASP will access the ACP by using a
typical socket interface. A well defined Application Programming typical socket interface. A well defined Application Programming
Interface (API) will be needed between GRASP and the ASAs. In some Interface (API) will be needed between GRASP and the ASAs. In some
implementations, ASAs would run in user space with a GRASP library implementations, ASAs would run in user space with a GRASP library
providing the API, and this library would in turn communicate via providing the API, and this library would in turn communicate via
system calls with core GRASP functions running in kernel mode. For system calls with core GRASP functions. For further details of
further details of possible deployment models, see possible deployment models, see [I-D.ietf-anima-reference-model].
[I-D.ietf-anima-reference-model].
A GRASP instance must be aware of its network interfaces, and of its A GRASP instance must be aware of its network interfaces, and of its
own global-scope and link-local addresses. In the presence of the own global-scope and link-local addresses. In the presence of the
ACP, such information will be available from the adjacency table ACP, such information will be available from the adjacency table
discussed in [I-D.ietf-anima-reference-model]. In other cases, GRASP discussed in [I-D.ietf-anima-reference-model]. In other cases, GRASP
must determine such information for itself. Details depend on the must determine such information for itself. Details depend on the
operating system. operating system.
Because GRASP needs to work whatever happens, especially during Because GRASP needs to work whatever happens, especially during
bootstrapping and during fault conditions, it is essential that every bootstrapping and during fault conditions, it is essential that every
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An autonomic node will normally run a single instance of GRASP, used An autonomic node will normally run a single instance of GRASP, used
by multiple ASAs. However, scenarios where multiple instances of by multiple ASAs. However, scenarios where multiple instances of
GRASP run in a single node, perhaps with different security GRASP run in a single node, perhaps with different security
properties, are not excluded. In this case, each instance MUST properties, are not excluded. In this case, each instance MUST
listen independently for GRASP link-local multicasts in order for listen independently for GRASP link-local multicasts in order for
discovery and flooding to work correctly. discovery and flooding to work correctly.
3.3. High Level Design Choices 3.3. High Level Design Choices
This section describes a behavior model and design considerations for This section describes a behavior model and design choices for GRASP,
GRASP, supporting discovery, synchronization and negotiation, to act supporting discovery, synchronization and negotiation, to act as a
as a platform for different technical objectives. platform for different technical objectives.
o A generic platform o A generic platform
The protocol is designed as a generic platform, which is The protocol is designed as a generic platform, which is
independent from the synchronization or negotiation contents. It independent from the synchronization or negotiation contents. It
takes care of the general intercommunication between counterparts. takes care of the general intercommunication between counterparts.
The technical contents will vary according to the various The technical contents will vary according to the various
technical objectives and the different pairs of counterparts. technical objectives and the different pairs of counterparts.
o The protocol is expected to form part of an Autonomic Networking o The protocol is expected to form part of an Autonomic Networking
Infrastructure [I-D.ietf-anima-reference-model]. It will provide Infrastructure [I-D.ietf-anima-reference-model]. It will provide
services to ASAs via a suitable application programming interface services to ASAs via a suitable application programming interface
(API), which will reflect the protocol elements but will not (API), which will reflect the protocol elements but will not
necessarily be in one-to-one correspondence to them. This API is necessarily be in one-to-one correspondence to them. This API is
out of scope for the present document. out of scope for the present document.
o It is normally expected that a single main instance of GRASP will o It is normally expected that a single main instance of GRASP will
exist in an autonomic node, and that the protocol engine and each exist in an autonomic node, and that the protocol engine and each
ASA will run as independent asynchronous processes. However, ASA will run as independent asynchronous processes. However,
separate GRASP instances may exist for security reasons separate GRASP instances may exist for security-related reasons
(Section 3.5.2). (Section 3.5.2).
o Security infrastructure and trust relationship o Security infrastructure and trust relationship
Because this negotiation protocol may directly cause changes to Because this negotiation protocol may directly cause changes to
device configurations and bring significant impacts to a running device configurations and bring significant impacts to a running
network, this protocol is assumed to run within an existing secure network, this protocol is required to run within an existing
environment with strong authentication. As a design choice, the secure environment with strong authentication. As a design
protocol itself is not provided with built-in security choice, the protocol itself is not provided with built-in security
functionality. functionality.
On the other hand, a limited negotiation model might be deployed On the other hand, a limited negotiation model might be deployed
based on a limited trust relationship. For example, between two based on a limited trust relationship such as that between two
administrative domains, ASAs might also exchange limited administrative domains. ASAs might then exchange limited
information and negotiate some particular configurations based on information and negotiate some particular configurations.
a limited conventional or contractual trust relationship.
o Discovery, synchronization and negotiation are designed together. o Discovery, synchronization and negotiation are designed together.
The discovery method and the synchronization and negotiation The discovery method and the synchronization and negotiation
methods are designed in the same way and can be combined when this methods are designed in the same way and can be combined when this
is useful. These processes can also be performed independently is useful, allowing a rapid mode of operation described in
when appropriate. Section 3.5.4. These processes can also be performed
independently when appropriate.
* GRASP discovery is always available for efficient discovery of * Thus, for some objectives, especially those concerned with
GRASP peers and allows a rapid mode of operation described in application layer services, another discovery mechanism such as
Section 3.5.4. For some objectives, especially those concerned the future DNS Service Discovery [RFC7558] MAY be used. The
with application layer services, another discovery mechanism choice is left to the designers of individual ASAs.
such as the future DNS Service Discovery [RFC7558] or Service
Location Protocol [RFC2608] MAY be used. The choice is left to
the designers of individual ASAs.
o A uniform pattern for technical contents o A uniform pattern for technical objectives
The synchronization and negotiation contents are defined according The synchronization and negotiation objectives are defined
to a uniform pattern. They could be carried either in simple according to a uniform pattern. The values that they contain
binary format or in payloads described by a flexible language. could be carried either in a simple binary format or in a complex
The basic protocol design uses the Concise Binary Object object format. The basic protocol design uses the Concise Binary
Representation (CBOR) [RFC7049]. The format is extensible for Object Representation (CBOR) [RFC7049], which is readily
unknown future requirements. extensible for unknown future requirements.
o A flexible model for synchronization o A flexible model for synchronization
GRASP supports bilateral synchronization, which could be used to GRASP supports bilateral synchronization, which could be used to
perform synchronization among a small number of nodes. It also perform synchronization among a small number of nodes. It also
supports an unsolicited flooding mode when large groups of nodes, supports an unsolicited flooding mode when large groups of nodes,
possibly including all autonomic nodes, need data for the same possibly including all autonomic nodes, need data for the same
technical objective. technical objective.
* There may be some network parameters for which a more * There may be some network parameters for which a more
traditional flooding mechanism such as DNCP [RFC7787] is traditional flooding mechanism such as DNCP [RFC7787] is
considered more appropriate. GRASP can coexist with DNCP. considered more appropriate. GRASP can coexist with DNCP.
o A simple initiator/responder model for negotiation o A simple initiator/responder model for negotiation
Multi-party negotiations are too complicated to be modeled and Multi-party negotiations are very complicated to model and cannot
there might be too many dependencies among the parties to converge readily be guaranteed to converge. GRASP uses a simple bilateral
efficiently. A simple initiator/responder model is more feasible model and can support multi-party negotiations by indirect steps.
and can complete multi-party negotiations by indirect steps.
o Organizing of synchronization or negotiation content o Organizing of synchronization or negotiation content
Naturally, the technical content will be organized according to
the relevant function or service. The content from different The technical content transmitted by GRASP will be organized
functions or services is kept independent from each other. They according to the relevant function or service. The objectives for
are not combined into a single option or single session because different functions or services are kept separate, because they
these contents may be negotiated or synchronized with different may be negotiated or synchronized with different counterparts or
counterparts or may be different in response time. Thus a normal have different response times. Thus a normal arrangement would be
arrangement would be a single ASA managing a small set of closely a single ASA managing a small set of closely related objectives,
related objectives, with a version of that ASA in each relevant with a version of that ASA in each relevant autonomic node.
autonomic node. Further discussion of this aspect is out of scope Further discussion of this aspect is out of scope for the current
for the current document. document.
o Requests and responses in negotiation procedures o Requests and responses in negotiation procedures
The initiator can negotiate with its relevant negotiation The initiator can negotiate a specific negotiation objective with
counterpart ASAs, which may be different according to the specific relevant counterpart ASAs. It can request relevant information
negotiation objective. It can request relevant information from from a counterpart so that it can coordinate its local
the negotiation counterpart so that it can decide its local configuration. It can request the counterpart to make a matching
configuration to give the most coordinated performance. It can configuration. It can request simulation or forecast results by
request the negotiation counterpart to make a matching
configuration in order to set up a successful communication with
it. It can request certain simulation or forecast results by
sending some dry run conditions. sending some dry run conditions.
Beyond the traditional yes/no answer, the responder can reply with Beyond the traditional yes/no answer, the responder can reply with
a suggested alternative value for the objective concerned. This a suggested alternative value for the objective concerned. This
would start a bi-directional negotiation ending in a compromise would start a bi-directional negotiation ending in a compromise
between the two ASAs. between the two ASAs.
o Convergence of negotiation procedures o Convergence of negotiation procedures
To enable convergence, when a responder makes a suggestion of a To enable convergence, when a responder suggests a new value or
changed condition in a negative reply, it should be as close as condition in a negotiation step reply, it should be as close as
possible to the original request or previous suggestion. The possible to the original request or previous suggestion. The
suggested value of the third or later negotiation steps should be suggested value of later negotiation steps should be chosen
chosen between the suggested values from the last two negotiation between the suggested values from the previous two steps. GRASP
steps. In any case there must be a mechanism to guarantee provides mechanisms to guarantee convergence (or failure) in a
convergence (or failure) in a small number of steps, such as a small number of steps, i.e. a timeout and a maximum number of
timeout or maximum number of iterations. iterations.
* End of negotiation
A limited number of rounds, for example three, or a timeout, is
needed on each ASA for each negotiation objective. It may be
an implementation choice, a pre-configurable parameter, or
network Intent. These choices might vary between different
types of ASA. Therefore, the definition of each negotiation
objective MUST clearly specify this, so that the negotiation
can always be terminated properly.
* Failed negotiation
There must be a well-defined procedure for concluding that a
negotiation cannot succeed, and if so deciding what happens
next (deadlock resolution, tie-breaking, or revert to best-
effort service). Again, this MUST be specified for individual
negotiation objectives, as an implementation choice, a pre-
configurable parameter, or network Intent.
o Extensibility o Extensibility
GRASP does not have a version number. In most cases new semantics GRASP does not have a version number. In most cases new semantics
will be added by defining new synchronization or negotiation will be added by defining new synchronization or negotiation
objectives. However, the protocol could be extended by adding new objectives. However, the protocol could be extended by adding new
message types and options in future. message types and options in future.
3.4. Quick Operating Overview 3.4. Quick Operating Overview
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turn. Two other functions support negotiating steps (M_WAIT, turn. Two other functions support negotiating steps (M_WAIT,
M_END). M_END).
o A synchronization mechanism (M_REQ_SYN), by which an ASA can o A synchronization mechanism (M_REQ_SYN), by which an ASA can
request the current value of an objective from a counterpart ASA. request the current value of an objective from a counterpart ASA.
With this, there is a corresponding response function (M_SYNCH) With this, there is a corresponding response function (M_SYNCH)
for an ASA that wishes to respond to synchronization requests. for an ASA that wishes to respond to synchronization requests.
o A flood mechanism (M_FLOOD), by which an ASA can cause the current o A flood mechanism (M_FLOOD), by which an ASA can cause the current
value of an objective to be flooded throughout the AN so that any value of an objective to be flooded throughout the AN so that any
ASA can receive it. ASA can receive it. One application of this is to act as an
announcement, avoiding the need for discovery of a widely
applicable objective.
Some example messages and simple message flows are provided in
Appendix D.
3.5. GRASP Protocol Basic Properties and Mechanisms 3.5. GRASP Protocol Basic Properties and Mechanisms
3.5.1. Required External Security Mechanism 3.5.1. Required External Security Mechanism
The protocol SHOULD run within a secure Autonomic Control Plane (ACP) The protocol SHOULD always run within a secure Autonomic Control
[I-D.ietf-anima-autonomic-control-plane]. The ACP is assumed to Plane (ACP) [I-D.ietf-anima-autonomic-control-plane]. The ACP is
carry all messages securely, including link-local multicast if assumed to carry all messages securely, including link-local
possible. A GRASP implementation MUST verify whether the ACP is multicast if possible. A GRASP implementation MUST verify whether
operational. the ACP is operational.
If there is no ACP, the protocol MUST use another form of strong If there is no ACP, the protocol MUST use another form of strong
authentication and SHOULD use a form of strong encryption. TLS authentication and SHOULD use a form of strong encryption. See
[RFC5246] is RECOMMENDED for this purpose, based on a local Public Section 3.5.2.1 for further discussion.
Key Infrastructure (PKI) [RFC5280] managed within the autonomic
network itself. The details of such a PKI and how its boundary is
established are out of scope for this document. DTLS [RFC6347] MAY
be used but since GRASP operations usually involve several messages
this is not expected to be advantageous.
The ACP, or in its absence the local PKI, sets the boundary within The ACP, or in its absence another security mechanism, sets the
which nodes are trusted as GRASP peers. A GRASP implementation MUST boundary within which nodes are trusted as GRASP peers. A GRASP
refuse to execute GRASP synchronization and negotiation functions if implementation MUST refuse to execute GRASP synchronization and
there is neither an operational ACP nor an operational TLS or DTLS negotiation functions if there is neither an operational ACP nor
environment. another secure environment.
Link-local multicast is used for discovery messages. Responses to Link-local multicast is used for discovery messages. Responses to
discovery messages MUST be secured, with one exception mentioned in discovery messages MUST be secured, with one exception mentioned in
the next section. the next section.
3.5.2. Limited Security Instances 3.5.2. Constrained Instances
This section describes three cases where additional instances of This section describes some examples of cases where additional
GRASP are appropriate. instances of GRASP subject to certain constraints are appropriate.
1) As mentioned in Section 3.3, some GRASP operations might be 3.5.2.1. No ACP
performed across an administrative domain boundary by mutual
agreement. Such operations MUST be confined to a separate instance
of GRASP with its own copy of all GRASP data structures. Messages
MUST be authenticated and SHOULD be encrypted. TLS is RECOMMENDED
for this purpose.
2) During initialisation, before a node has joined the applicable As mentioned in Section 3.3, some GRASP operations might be performed
trust infrastructure, [I-D.ietf-anima-bootstrapping-keyinfra], it is across an administrative domain boundary by mutual agreement, without
impossible to secure messages. Thus, the security bootstrap process the benefit of an ACP. Such operations MUST be confined to a
needs to use insecure GRASP discovery, response and flood messages. separate instance of GRASP with its own copy of all GRASP data
Such usage MUST be limited to link-local operations and MUST be structures. Messages MUST be authenticated and SHOULD be encrypted.
confined to a separate insecure instance of GRASP with its own copy TLS [RFC5246] and DTLS [RFC6347] based on a Public Key Infrastructure
of all GRASP data structures. This instance is nicknamed DULL - (PKI) [RFC5280] are RECOMMENDED for this purpose. Further details
Discovery Unsolicited Link Local. are out of scope for this document.
3.5.2.2. Discovery Unsolicited Link-Local
Some services may need to use insecure GRASP discovery, response and
flood messages without being able to use pre-existing security
associations. Such operations being intrinsically insecure, they
need to be confined to link-local use to minimise the risk of
malicious actions. Possible examples include discovery of candidate
ACP neighbors [I-D.ietf-anima-autonomic-control-plane], discovery of
bootstrap proxies [I-D.ietf-anima-bootstrapping-keyinfra] or perhaps
initialisation services in networks using GRASP without being fully
autonomic (e.g., no ACP). Such usage MUST be limited to link-local
operations and MUST be confined to a separate insecure instance of
GRASP with its own copy of all GRASP data structures. This instance
is nicknamed DULL - Discovery Unsolicited Link-Local.
The detailed rules for the DULL instance of GRASP are as follows: The detailed rules for the DULL instance of GRASP are as follows:
o An initiator MUST only send Discovery or Flood Synchronization o An initiator MUST only send Discovery or Flood Synchronization
link-local multicast messages with a loop count of 1. A responder link-local multicast messages with a loop count of 1. A responder
MAY send a Discovery Response message. Other GRASP message types SHOULD NOT send a Discovery Response message unless it cannot be
MUST NOT be sent. avoided. Other GRASP message types MUST NOT be sent.
o A responder MUST silently discard any message whose loop count is o A responder MUST silently discard any message whose loop count is
not 1. not 1.
o A responder MUST silently discard any message referring to a GRASP o A responder MUST silently discard any message referring to a GRASP
Objective that is not directly part of the bootstrap creation Objective that is not directly part of a service that requires
process. this insecure mode.
o A responder MUST NOT relay any multicast messages. o A responder MUST NOT relay any multicast messages.
o A Discovery Response MUST indicate a link-local address. o A Discovery Response MUST indicate a link-local address.
o A Discovery Response MUST NOT include a Divert option. o A Discovery Response MUST NOT include a Divert option.
o A node MUST silently discard any message whose source address is o A node MUST silently discard any message whose source address is
not link-local. not link-local.
3) During ACP formation [I-D.ietf-anima-autonomic-control-plane], a GRASP traffic SHOULD be minimized by using only Flood Synchronization
separate instance of GRASP is used, with unicast messages secured by to announce objectives and their associated locators, rather than by
TLS, and with its own copy of all GRASP data structures. This using Discovery and Response. Further details are out of scope for
instance is nicknamed SONN - Secure Only Neighbor Negotiation. this document
3.5.2.3. Secure Only Neighbor Negotiation
Some services might use insecure on-link operations as in DULL, but
also use unicast synchronization or negotiation operations protected
by TLS. A separate instance of GRASP is used, with its own copy of
all GRASP data structures. This instance is nicknamed SONN - Secure
Only Neighbor Negotiation.
The detailed rules for the SONN instance of GRASP are as follows: The detailed rules for the SONN instance of GRASP are as follows:
o Any type of GRASP message MAY be sent. o Any type of GRASP message MAY be sent.
o An initiator MUST send any Discovery or Flood Synchronization o An initiator MUST send any Discovery or Flood Synchronization
link-local multicast messages with a loop count of 1. link-local multicast messages with a loop count of 1.
o A responder MUST silently discard any Discovery or Flood o A responder MUST silently discard any Discovery or Flood
Synchronization message whose loop count is not 1. Synchronization message whose loop count is not 1.
o A responder MUST silently discard any message referring to a GRASP o A responder MUST silently discard any message referring to a GRASP
Objective that is not directly part of the ACP creation process. Objective that is not directly part of the service concerned.
o A responder MUST NOT relay any multicast messages. o A responder MUST NOT relay any multicast messages.
o A Discovery Response MUST indicate a link-local address. o A Discovery Response MUST indicate a link-local address.
o A Discovery Response MUST NOT include a Divert option. o A Discovery Response MUST NOT include a Divert option.
o A node MUST silently discard any message whose source address is o A node MUST silently discard any message whose source address is
not link-local. not link-local.
Further details, including TLS and PKI usage, are out of scope for
this document.
3.5.3. Transport Layer Usage 3.5.3. Transport Layer Usage
GRASP discovery and flooding messages are designed for use over link- GRASP discovery and flooding messages are designed for use over link-
local multicast UDP. They MUST NOT be fragmented, and therefore MUST local multicast UDP. They MUST NOT be fragmented, and therefore MUST
NOT exceed the link MTU size. Nothing in principle prevents them NOT exceed the link MTU size. Nothing in principle prevents them
from working over some other method of sending packets to all on-link from working over some other method of sending packets to all on-link
neighbors, but this is out of scope for the present specification. neighbors, but this is out of scope for the present specification.
All other GRASP messages are unicast and could in principle run over All other GRASP messages are unicast and could in principle run over
any transport protocol. An implementation MUST support use of TCP. any transport protocol. An implementation MUST support use of TCP.
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Nevertheless, when running within a secure ACP on reliable Nevertheless, when running within a secure ACP on reliable
infrastructure, UDP MAY be used for unicast messages not exceeding infrastructure, UDP MAY be used for unicast messages not exceeding
the minimum IPv6 path MTU; however, TCP MUST be used for longer the minimum IPv6 path MTU; however, TCP MUST be used for longer
messages. In other words, IPv6 fragmentation is avoided. If a node messages. In other words, IPv6 fragmentation is avoided. If a node
receives a UDP message but the reply is too long, it MUST open a TCP receives a UDP message but the reply is too long, it MUST open a TCP
connection to the peer for the reply. Note that when the network is connection to the peer for the reply. Note that when the network is
under heavy load or in a fault condition, UDP might become under heavy load or in a fault condition, UDP might become
unreliable. Since this is when autonomic functions are most unreliable. Since this is when autonomic functions are most
necessary, automatic fallback to TCP MUST be implemented. The necessary, automatic fallback to TCP MUST be implemented. The
simplest implementation is therefore to use only TCP. In particular, simplest implementation is therefore to use only TCP.
to guarantee interoperability during bootstrap and startup, using TCP
for discovery responses is strongly advised.
When running without an ACP, TLS MUST be supported and used by For considerations when running without an ACP, see Section 3.5.2.1.
default, except for link-local multicast messages. DTLS MAY be
supported as an alternative but the details are out of scope for this
document. Transport protocols other than TCP and UDP are also out of
scope for this document.
For link-local multicast, the GRASP protocol listens to the well- For link-local multicast, the GRASP protocol listens to the well-
known GRASP Listen Port (Section 3.6). For unicast transport known GRASP Listen Port (Section 3.6). For unicast transport
sessions used for discovery responses, synchronization and sessions used for discovery responses, synchronization and
negotiation, the ASA concerned normally listens on its own negotiation, the ASA concerned normally listens on its own
dynamically assigned ports, which are communicated to its peers dynamically assigned ports, which are communicated to its peers
during discovery. However, a minimal implementation MAY use the during discovery. However, a minimal implementation MAY use the
GRASP Listen Port for this purpose. GRASP Listen Port for this purpose.
3.5.4. Discovery Mechanism and Procedures 3.5.4. Discovery Mechanism and Procedures
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3.5.4.1. Separated discovery and negotiation mechanisms 3.5.4.1. Separated discovery and negotiation mechanisms
Although discovery and negotiation or synchronization are defined Although discovery and negotiation or synchronization are defined
together in GRASP, they are separate mechanisms. The discovery together in GRASP, they are separate mechanisms. The discovery
process could run independently from the negotiation or process could run independently from the negotiation or
synchronization process. Upon receiving a Discovery (Section 3.8.4) synchronization process. Upon receiving a Discovery (Section 3.8.4)
message, the recipient node should return a response message in which message, the recipient node should return a response message in which
it either indicates itself as a discovery responder or diverts the it either indicates itself as a discovery responder or diverts the
initiator towards another more suitable ASA. initiator towards another more suitable ASA.
The discovery action will normally be followed by a negotiation or The discovery action (M_DISCOVERY) will normally be followed by a
synchronization action. The discovery results could be utilized by negotiation (M_REQ_NEG) or synchronization (M_REQ_SYN) action. The
the negotiation protocol to decide which ASA the initiator will discovery results could be utilized by the negotiation protocol to
negotiate with. decide which ASA the initiator will negotiate with.
The initiator of a discovery action for a given objective need not be The initiator of a discovery action for a given objective need not be
capable of responding to that objective as a Negotiation Counterpart, capable of responding to that objective as a Negotiation Counterpart,
as a Synchronization Responder or as source for flooding. For as a Synchronization Responder or as source for flooding. For
example, an ASA might perform discovery even if it only wishes to act example, an ASA might perform discovery even if it only wishes to act
a Synchronization Initiator or Negotiation Initiator. Such an ASA a Synchronization Initiator or Negotiation Initiator. Such an ASA
does not itself need to respond to discovery messages. does not itself need to respond to discovery messages.
It is also entirely possible to use GRASP discovery without any It is also entirely possible to use GRASP discovery without any
subsequent negotiation or synchronization action. In this case, the subsequent negotiation or synchronization action. In this case, the
discovered objective is simply used as a name during the discovery discovered objective is simply used as a name during the discovery
process and any subsequent operations between the peers are outside process and any subsequent operations between the peers are outside
the scope of GRASP. the scope of GRASP.
3.5.4.2. Discovery Overview 3.5.4.2. Discovery Overview
A complete discovery process will start with a multicast on the local A complete discovery process will start with a multicast (of
link. On-link neighbors supporting the discovery objective will M_DISCOVERY) on the local link. On-link neighbors supporting the
respond directly. A neighbor with multiple interfaces will respond discovery objective will respond directly (with M_RESPONSE). A
with a cached discovery response if any. If not, it will relay the neighbor with multiple interfaces will respond with a cached
discovery response if any. However, it SHOULD NOT respond with a
cached response on an interface if it learnt that information from
the same interface. If it has no cached response, it will relay the
discovery on its other interfaces, for example reaching a higher- discovery on its other interfaces, for example reaching a higher-
level gateway in a hierarchical network. If a node receiving the level gateway in a hierarchical network. If a node receiving the
relayed discovery supports the discovery objective, it will respond relayed discovery supports the discovery objective, it will respond
to the relayed discovery. If it has a cached response, it will to the relayed discovery. If it has a cached response, it will
respond with that. If not, it will repeat the discovery process, respond with that. If not, it will repeat the discovery process,
which thereby becomes recursive. The loop count and timeout will which thereby becomes recursive. The loop count and timeout will
ensure that the process ends. ensure that the process ends.
Exceptionally, a Discovery message MAY be sent unicast to a peer Exceptionally, a Discovery message MAY be sent unicast (via UDP or
node, which will then proceed exactly as if the message had been TCP) to a peer node, which will then proceed exactly as if the
multicast. However, this mode does not guarantee successful message had been multicast, except that when TCP is used, the
discovery in the general case. response will be on the same socket as the query. However, this mode
does not guarantee successful discovery in the general case.
3.5.4.3. Discovery Procedures 3.5.4.3. Discovery Procedures
Discovery starts as an on-link operation. The Divert option can tell Discovery starts as an on-link operation. The Divert option can tell
the discovery initiator to contact an off-link ASA for that discovery the discovery initiator to contact an off-link ASA for that discovery
objective. Every Discovery message is sent by a discovery initiator objective. Every Discovery message is sent by a discovery initiator
via UDP to the ALL_GRASP_NEIGHBOR link-local multicast address via UDP to the ALL_GRASP_NEIGHBOR link-local multicast address
(Section 3.6). Every network device that supports GRASP always (Section 3.6). Every network device that supports GRASP always
listens to a well-known UDP port to capture the discovery messages. listens to a well-known UDP port to capture the discovery messages.
Because this port is unique in a device, this is a function of the Because this port is unique in a device, this is a function of the
GRASP kernel and not of an individual ASA. As a result, each ASA GRASP core and not of an individual ASA. As a result, each ASA will
will need to register the objectives that it supports with the GRASP need to register the objectives that it supports with the GRASP core.
kernel.
If an ASA in a neighbor device supports the requested discovery If an ASA in a neighbor device supports the requested discovery
objective, the device SHOULD respond to the link-local multicast with objective, the device SHOULD respond to the link-local multicast with
a unicast Discovery Response message (Section 3.8.5) with locator a unicast Discovery Response message (Section 3.8.5) with locator
option(s), unless it is temporarily unavailable. Otherwise, if the option(s), unless it is temporarily unavailable. Otherwise, if the
neighbor has cached information about an ASA that supports the neighbor has cached information about an ASA that supports the
requested discovery objective (usually because it discovered the same requested discovery objective (usually because it discovered the same
objective before), it SHOULD respond with a Discovery Response objective before), it SHOULD respond with a Discovery Response
message with a Divert option pointing to the appropriate Discovery message with a Divert option pointing to the appropriate Discovery
Responder. Responder.
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and MUST NOT perform discovery relaying. and MUST NOT perform discovery relaying.
If a relaying instance receives a Discovery message on a given If a relaying instance receives a Discovery message on a given
interface for a specific objective that it does not support and for interface for a specific objective that it does not support and for
which it has not previously cached a Discovery Responder, it MUST which it has not previously cached a Discovery Responder, it MUST
relay the query by re-issuing a Discovery message as a link-local relay the query by re-issuing a Discovery message as a link-local
multicast on its other interfaces. multicast on its other interfaces.
The relayed discovery message MUST have the same Session ID as the The relayed discovery message MUST have the same Session ID as the
incoming discovery message and MUST be tagged with the IP address of incoming discovery message and MUST be tagged with the IP address of
its original initiator (see Section 3.8.4). Since the relay device its original initiator (see Section 3.8.4). Note that this initiator
is unaware of the timeout set by the original initiator it SHOULD set address is only used to allow for disambiguation of the Session ID
a timeout at least equal to GRASP_DEF_TIMEOUT milliseconds. and is never used to address Response packets.
Since the relay device is unaware of the timeout set by the original
initiator it SHOULD set a timeout at least equal to GRASP_DEF_TIMEOUT
milliseconds.
The relaying instance MUST decrement the loop count within the The relaying instance MUST decrement the loop count within the
objective, and MUST NOT relay the Discovery message if the result is objective, and MUST NOT relay the Discovery message if the result is
zero. Also, it MUST limit the total rate at which it relays zero. Also, it MUST limit the total rate at which it relays
discovery messages to a reasonable value, in order to mitigate discovery messages to a reasonable value, in order to mitigate
possible denial of service attacks. It MUST cache the Session ID possible denial of service attacks. It MUST cache the Session ID
value and initiator address of each relayed Discovery message until value and initiator address of each relayed Discovery message until
any Discovery Responses have arrived or the discovery process has any Discovery Responses have arrived or the discovery process has
timed out. To prevent loops, it MUST NOT relay a Discovery message timed out. To prevent loops, it MUST NOT relay a Discovery message
which carries a given cached Session ID and initiator address more which carries a given cached Session ID and initiator address more
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distinction between dry run and an actual configuration change, will distinction between dry run and an actual configuration change, will
be defined separately for each type of negotiation objective. be defined separately for each type of negotiation objective.
If no reply message of any kind is received within a reasonable If no reply message of any kind is received within a reasonable
timeout (default GRASP_DEF_TIMEOUT milliseconds, Section 3.6), the timeout (default GRASP_DEF_TIMEOUT milliseconds, Section 3.6), the
negotiation request MAY be repeated, with a newly generated Session negotiation request MAY be repeated, with a newly generated Session
ID (Section 3.7). An exponential backoff SHOULD be used for ID (Section 3.7). An exponential backoff SHOULD be used for
subsequent repetitions. subsequent repetitions.
If the counterpart can immediately apply the requested configuration, If the counterpart can immediately apply the requested configuration,
it will give an immediate positive (accept) answer. This will end it will give an immediate positive (O_ACCEPT) answer (using M_END).
the negotiation phase immediately. Otherwise, it will negotiate. It This will end the negotiation phase immediately. Otherwise, it will
will reply with a proposed alternative configuration that it can negotiate (using M_NEGOTIATE). It will reply with a proposed
apply (typically, a configuration that uses fewer resources than alternative configuration that it can apply (typically, a
requested by the negotiation initiator). This will start a bi- configuration that uses fewer resources than requested by the
directional negotiation to reach a compromise between the two ASAs. negotiation initiator). This will start a bi-directional negotiation
(using M_NEGOTIATE) to reach a compromise between the two ASAs.
The negotiation procedure is ended when one of the negotiation peers The negotiation procedure is ended when one of the negotiation peers
sends a Negotiation Ending message, which contains an accept or sends a Negotiation Ending (M_END) message, which contains an accept
decline option and does not need a response from the negotiation (O_ACCEPT) or decline (O_DECLINE) option and does not need a response
peer. Negotiation may also end in failure (equivalent to a decline) from the negotiation peer. Negotiation may also end in failure
if a timeout is exceeded or a loop count is exceeded. (equivalent to a decline) if a timeout is exceeded or a loop count is
exceeded.
A negotiation procedure concerns one objective and one counterpart. A negotiation procedure concerns one objective and one counterpart.
Both the initiator and the counterpart may take part in simultaneous Both the initiator and the counterpart may take part in simultaneous
negotiations with various other ASAs, or in simultaneous negotiations negotiations with various other ASAs, or in simultaneous negotiations
about different objectives. Thus, GRASP is expected to be used in a about different objectives. Thus, GRASP is expected to be used in a
multi-threaded mode. Certain negotiation objectives may have multi-threaded mode. Certain negotiation objectives may have
restrictions on multi-threading, for example to avoid over-allocating restrictions on multi-threading, for example to avoid over-allocating
resources. resources.
Some configuration actions, for example wavelength switching in Some configuration actions, for example wavelength switching in
optical networks, might take considerable time to execute. The ASA optical networks, might take considerable time to execute. The ASA
concerned needs to allow for this by design, but GRASP does allow for concerned needs to allow for this by design, but GRASP does allow for
a peer to insert latency in a negotiation process if necessary a peer to insert latency in a negotiation process if necessary
(Section 3.8.9). (Section 3.8.9, M_WAIT).
3.5.5.1. Rapid Mode (Discovery/Negotiation Linkage) 3.5.5.1. Rapid Mode (Discovery/Negotiation Linkage)
A Discovery message MAY include a Negotiation Objective option. In A Discovery message MAY include a Negotiation Objective option. In
this case the Discovery message also acts as a Request Negotiation this case it is as if the initiator sent the sequence M_DISCOVERY,
message to indicate to the Discovery Responder that it could directly immediately followed by M_REQ_NEG. This has implications for the
reply to the Discovery Initiator with a Negotiation message for rapid construction of the GRASP core, as it must carefully pass the
processing, if it could act as the corresponding negotiation contents of the Negotiation Objective option to the ASA so that it
counterpart. However, the indication is only advisory not may evaluate the objective directly. When a Negotiation Objective
prescriptive. option is present the ASA replies with an M_NEGOTIATE message (or
M_END with O_ACCEPT if it is immediately satisfied with the
proposal), rather than with an M_RESPONSE. However, if the recipient
node does not support rapid mode, discovery will continue normally.
It is possible that a Discovery Response will arrive from a responder It is possible that a Discovery Response will arrive from a responder
that does not support rapid mode, before such a Negotiation message that does not support rapid mode, before such a Negotiation message
arrives. In this case, rapid mode will not occur. arrives. In this case, rapid mode will not occur.
This rapid mode could reduce the interactions between nodes so that a This rapid mode could reduce the interactions between nodes so that a
higher efficiency could be achieved. However, a network in which higher efficiency could be achieved. However, a network in which
some nodes support rapid mode and others do not will have complex some nodes support rapid mode and others do not will have complex
timing-dependent behaviors. Therefore, the rapid negotiation timing-dependent behaviors. Therefore, the rapid negotiation
function SHOULD be configured off by default and MAY be configured on function SHOULD be configured off by default and MAY be configured on
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concerns only one synchronization objective. For large groups of concerns only one synchronization objective. For large groups of
nodes requiring the same data, synchronization flooding is available. nodes requiring the same data, synchronization flooding is available.
For this, a flooding initiator MAY send an unsolicited Flood For this, a flooding initiator MAY send an unsolicited Flood
Synchronization message containing one or more Synchronization Synchronization message containing one or more Synchronization
Objective option(s), if and only if the specification of those Objective option(s), if and only if the specification of those
objectives permits it. This is sent as a multicast message to the objectives permits it. This is sent as a multicast message to the
ALL_GRASP_NEIGHBOR multicast address (Section 3.6). ALL_GRASP_NEIGHBOR multicast address (Section 3.6).
Every network device that supports GRASP always listens to a well- Every network device that supports GRASP always listens to a well-
known UDP port to capture flooding messages. Because this port is known UDP port to capture flooding messages. Because this port is
unique in a device, this is a function of the GRASP kernel. unique in a device, this is a function of the GRASP core.
To ensure that flooding does not result in a loop, the originator of To ensure that flooding does not result in a loop, the originator of
the Flood Synchronization message MUST set the loop count in the the Flood Synchronization message MUST set the loop count in the
objectives to a suitable value (the default is GRASP_DEF_LOOPCT). objectives to a suitable value (the default is GRASP_DEF_LOOPCT).
Also, a suitable mechanism is needed to avoid excessive multicast Also, a suitable mechanism is needed to avoid excessive multicast
traffic. This mechanism MUST be defined as part of the specification traffic. This mechanism MUST be defined as part of the specification
of the synchronization objective(s) concerned. It might be a simple of the synchronization objective(s) concerned. It might be a simple
rate limit or a more complex mechanism such as the Trickle algorithm rate limit or a more complex mechanism such as the Trickle algorithm
[RFC6206]. [RFC6206].
A GRASP device with multiple link-layer interfaces (typically a A GRASP device with multiple link-layer interfaces (typically a
router) MUST support synchronization flooding on all interfaces. If router) MUST support synchronization flooding on all interfaces. If
it receives a multicast Flood Synchronization message on a given it receives a multicast Flood Synchronization message on a given
interface, it MUST relay it by re-issuing a Flood Synchronization interface, it MUST relay it by re-issuing a Flood Synchronization
message on its other interfaces. The relayed message MUST have the message on its other interfaces. The relayed message MUST have the
same Session ID as the incoming message and MUST be tagged with the same Session ID as the incoming message and MUST be tagged with the
IP address of its original initiator. IP address of its original initiator.
Link-layer Flooding is supported by GRASP by setting the loop count
to 1, and sending with a link-local source address. Floods with
link-local source addresses and a loop count other than 1 are
invalid, and such messages MUST be discarded.
The relaying device MUST decrement the loop count within the first The relaying device MUST decrement the loop count within the first
objective, and MUST NOT relay the Flood Synchronization message if objective, and MUST NOT relay the Flood Synchronization message if
the result is zero. Also, it MUST limit the total rate at which it the result is zero. Also, it MUST limit the total rate at which it
relays Flood Synchronization messages to a reasonable value, in order relays Flood Synchronization messages to a reasonable value, in order
to mitigate possible denial of service attacks. It MUST cache the to mitigate possible denial of service attacks. It MUST cache the
Session ID value and initiator address of each relayed Flood Session ID value and initiator address of each relayed Flood
Synchronization message for a finite time not less than twice Synchronization message for a finite time not less than twice
GRASP_DEF_TIMEOUT milliseconds. To prevent loops, it MUST NOT relay GRASP_DEF_TIMEOUT milliseconds. To prevent loops, it MUST NOT relay
a Flood Synchronization message which carries a given cached Session a Flood Synchronization message which carries a given cached Session
ID and initiator address more than once. These precautions avoid ID and initiator address more than once. These precautions avoid
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the recipient ASA. the recipient ASA.
3.5.6.2. Rapid Mode (Discovery/Synchronization Linkage) 3.5.6.2. Rapid Mode (Discovery/Synchronization Linkage)
A Discovery message MAY include a Synchronization Objective option. A Discovery message MAY include a Synchronization Objective option.
In this case the Discovery message also acts as a Request In this case the Discovery message also acts as a Request
Synchronization message to indicate to the Discovery Responder that Synchronization message to indicate to the Discovery Responder that
it could directly reply to the Discovery Initiator with a it could directly reply to the Discovery Initiator with a
Synchronization message Section 3.8.10 with synchronization data for Synchronization message Section 3.8.10 with synchronization data for
rapid processing, if the discovery target supports the corresponding rapid processing, if the discovery target supports the corresponding
synchronization objective. However, the indication is only advisory synchronization objective. The design implications are similar to
not prescriptive. those discussed in Section 3.5.5.1.
It is possible that a Discovery Response will arrive from a responder It is possible that a Discovery Response will arrive from a responder
that does not support rapid mode, before such a Synchronization that does not support rapid mode, before such a Synchronization
message arrives. In this case, rapid mode will not occur. message arrives. In this case, rapid mode will not occur.
This rapid mode could reduce the interactions between nodes so that a This rapid mode could reduce the interactions between nodes so that a
higher efficiency could be achieved. However, a network in which higher efficiency could be achieved. However, a network in which
some nodes support rapid mode and others do not will have complex some nodes support rapid mode and others do not will have complex
timing-dependent behaviors. Therefore, the rapid synchronization timing-dependent behaviors. Therefore, the rapid synchronization
function SHOULD be configured off by default and MAY be configured on function SHOULD be configured off by default and MAY be configured on
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in Section 6. in Section 6.
3.8.3. Message Size 3.8.3. Message Size
GRASP nodes MUST be able to receive messages of at least GRASP nodes MUST be able to receive messages of at least
GRASP_DEF_MAX_SIZE bytes. GRASP nodes MUST NOT send messages longer GRASP_DEF_MAX_SIZE bytes. GRASP nodes MUST NOT send messages longer
than GRASP_DEF_MAX_SIZE bytes unless a longer size is explicitly than GRASP_DEF_MAX_SIZE bytes unless a longer size is explicitly
allowed for the objective concerned. For example, GRASP negotiation allowed for the objective concerned. For example, GRASP negotiation
itself could be used to agree on a longer message size. itself could be used to agree on a longer message size.
The message parser used by GRASP should be configured to know about
the GRASP_DEF_MAX_SIZE, or any larger negotiated message size, so
that it may defend against overly long messages.
3.8.4. Discovery Message 3.8.4. Discovery Message
In fragmentary CDDL, a Discovery message follows the pattern: In fragmentary CDDL, a Discovery message follows the pattern:
discovery-message = [M_DISCOVERY, session-id, initiator, objective] discovery-message = [M_DISCOVERY, session-id, initiator, objective]
A discovery initiator sends a Discovery message to initiate a A discovery initiator sends a Discovery message to initiate a
discovery process for a particular objective option. discovery process for a particular objective option.
The discovery initiator sends all Discovery messages via UDP to port The discovery initiator sends all Discovery messages via UDP to port
skipping to change at page 32, line 38 skipping to change at page 32, line 46
synchronization has failed if there is no response before the timer synchronization has failed if there is no response before the timer
expires. expires.
When an initiator sends a Request message, it MUST initialize the When an initiator sends a Request message, it MUST initialize the
loop count of the objective option with a value defined in the loop count of the objective option with a value defined in the
specification of the option or, if no such value is specified, with specification of the option or, if no such value is specified, with
GRASP_DEF_LOOPCT. GRASP_DEF_LOOPCT.
If a node receives a Request message for an objective for which no If a node receives a Request message for an objective for which no
ASA is currently listening, it MUST immediately close the relevant ASA is currently listening, it MUST immediately close the relevant
socket to indicate this to the initiator. socket to indicate this to the initiator. This is to avoid
unnecessary timeouts if, for example, an ASA exits prematurely but
the GRASP core is listening on its behalf.
To avoid the highly unlikely race condition in which two nodes To avoid the highly unlikely race condition in which two nodes
simultaneously request sessions with each other using the same simultaneously request sessions with each other using the same
Session ID (Section 3.7), when a node receives a Request message, it Session ID (Section 3.7), when a node receives a Request message, it
MUST verify that the received Session ID is not already locally MUST verify that the received Session ID is not already locally
active. In case of a clash, it MUST discard the Request message, in active. In case of a clash, it MUST discard the Request message, in
which case the initiator will detect a timeout. which case the initiator will detect a timeout.
3.8.7. Negotiation Message 3.8.7. Negotiation Message
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with the synchronization data, in the form of a GRASP Option for the with the synchronization data, in the form of a GRASP Option for the
specific synchronization objective present in the Request specific synchronization objective present in the Request
Synchronization. Synchronization.
3.8.11. Flood Synchronization Message 3.8.11. Flood Synchronization Message
In fragmentary CDDL, a Flood Synchronization message follows the In fragmentary CDDL, a Flood Synchronization message follows the
pattern: pattern:
flood-message = [M_FLOOD, session-id, initiator, ttl, flood-message = [M_FLOOD, session-id, initiator, ttl,
(locator-option / []), +objective] +[objective, (locator-option / [])]]
ttl = 0..4294967295 ; in milliseconds ttl = 0..4294967295 ; in milliseconds
A node MAY initiate flooding by sending an unsolicited Flood A node MAY initiate flooding by sending an unsolicited Flood
Synchronization Message with synchronization data. This MAY be sent Synchronization Message with synchronization data. This MAY be sent
to the link-local ALL_GRASP_NEIGHBOR multicast address, in accordance to the link-local ALL_GRASP_NEIGHBOR multicast address, in accordance
with the rules in Section 3.5.6. with the rules in Section 3.5.6.
The initiator address is provided as described for Discovery The initiator address is provided, as described for Discovery
messages. messages (Section 3.8.4), only to disambiguate the Session ID.
The message MUST contain a time-to-live (ttl) for the validity of The message MUST contain a time-to-live (ttl) for the validity of
the response, given as a positive integer value in milliseconds. the contents, given as a positive integer value in milliseconds.
There is no default; zero indicates an indefinite lifetime. There is no default; zero indicates an indefinite lifetime.
The message MAY contain a locator option indicating the ASA that
initiated the flooded data. In its absence, an empty option MUST
be included.
The synchronization data are in the form of GRASP Option(s) for The synchronization data are in the form of GRASP Option(s) for
specific synchronization objective(s). The loop count(s) MUST be specific synchronization objective(s). The loop count(s) MUST be
set to a suitable value to prevent flood loops (default value is set to a suitable value to prevent flood loops (default value is
GRASP_DEF_LOOPCT). GRASP_DEF_LOOPCT).
Each objective option MAY be followed by a locator option
associated with the flooded objective. In its absence, an empty
option MUST be included to indicate a null locator.
A node that receives a Flood Synchronization message MUST cache the A node that receives a Flood Synchronization message MUST cache the
received objectives for use by local ASAs. Each cached objective received objectives for use by local ASAs. Each cached objective
MUST be tagged with the locator option sent with it, or with a null MUST be tagged with the locator option sent with it, or with a null
tag if an empty locator option was sent. If a subsequent Flood tag if an empty locator option was sent. If a subsequent Flood
Synchronization message carrying the same objective arrives with the Synchronization message carrying the same objective arrives with the
same tag, the corresponding cached copy of the objective MUST be same tag, the corresponding cached copy of the objective MUST be
overwritten. If a subsequent Flood Synchronization message carrying overwritten. If a subsequent Flood Synchronization message carrying
the same objective arrives with a different tag, a new cached entry the same objective arrives with a different tag, a new cached entry
MUST be created. MUST be created.
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transport-proto = IPPROTO_TCP / IPPROTO_UDP transport-proto = IPPROTO_TCP / IPPROTO_UDP
IPPROTO_TCP = 6 IPPROTO_TCP = 6
IPPROTO_UDP = 17 IPPROTO_UDP = 17
port-number = 0..65535 port-number = 0..65535
The content of this option is a binary IPv6 address followed by the The content of this option is a binary IPv6 address followed by the
protocol number and port number to be used. protocol number and port number to be used.
Note 1: The IPv6 address MUST normally have global scope. Note 1: The IPv6 address MUST normally have global scope.
Exceptionally, during node bootstrap, a link-local address MAY be Exceptionally, during initialisation, a link-local address MAY be
used for specific objectives only. used for specific objectives only (Section 3.5.2). In this case the
corresponding Discovery Response message MUST be sent via the
interface to which the link-local address applies.
Note 2: A link-local IPv6 address MUST NOT be used when this option Note 2: A link-local IPv6 address MUST NOT be used when this option
is included in a Divert option. is included in a Divert option.
3.9.5.2. Locator IPv4 address option 3.9.5.2. Locator IPv4 address option
In fragmentary CDDL, the IPv4 address option follows the pattern: In fragmentary CDDL, the IPv4 address option follows the pattern:
ipv4-locator-option = [O_IPv4_LOCATOR, ipv4-address, ipv4-locator-option = [O_IPv4_LOCATOR, ipv4-address,
transport-proto, port-number] transport-proto, port-number]
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The 'any' field is to express the actual value of a negotiation or The 'any' field is to express the actual value of a negotiation or
synchronization objective. Its format is defined in the synchronization objective. Its format is defined in the
specification of the objective and may be a single value or a data specification of the objective and may be a single value or a data
structure of any kind. It is optional because it is optional in a structure of any kind. It is optional because it is optional in a
Discovery or Discovery Response message. Discovery or Discovery Response message.
3.10.2. Objective flags 3.10.2. Objective flags
An objective may be relevant for discovery only, for discovery and An objective may be relevant for discovery only, for discovery and
negotiation, or for discovery and synchronization. This is expressed negotiation, or for discovery and synchronization. This is expressed
in the objective by logical flags: in the objective by logical flag bits:
objective-flags = uint .bits objective-flag objective-flags = uint .bits objective-flag
objective-flag = &( objective-flag = &(
F_DISC: 0 ; valid for discovery only F_DISC: 0 ; valid for discovery
F_NEG: 1 ; valid for discovery and negotiation F_NEG: 1 ; valid for negotiation
F_SYNCH: 2 ; valid for discovery and synchronization F_SYNCH: 2 ; valid for synchronization
F_NEG_DRY: 3 ; negotiation is dry-run
) )
These bits are independent and may be combined appropriately, e.g.
(F_DISC and F_SYNCH) or (F_DISC and F_NEG) or (F_DISC and F_NEG and
F_NEG_DRY).
Note that for a given negotiation session, an objective must be
either used for negotiation, or for dry-run negotiation. Mixing the
two modes in a single negotiation is not possible.
3.10.3. General Considerations for Objective Options 3.10.3. General Considerations for Objective Options
As mentioned above, Objective Options MUST be assigned a unique name. As mentioned above, Objective Options MUST be assigned a unique name.
As long as privately defined Objective Options obey the rules above, As long as privately defined Objective Options obey the rules above,
this document does not restrict their choice of name, but the entity this document does not restrict their choice of name, but the entity
or person concerned SHOULD publish the names in use. or person concerned SHOULD publish the names in use.
All Objective Options MUST respect the CBOR patterns defined above as All Objective Options MUST respect the CBOR patterns defined above as
"objective" and MUST replace the "any" field with a valid CBOR data "objective" and MUST replace the "any" field with a valid CBOR data
definition for the relevant use case and application. definition for the relevant use case and application.
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in Section 3.3, it is acceptable for an ASA to use an alternative in Section 3.3, it is acceptable for an ASA to use an alternative
method of discovery. method of discovery.
Normally, a GRASP objective will refer to specific technical Normally, a GRASP objective will refer to specific technical
parameters as explained in Section 3.1. However, it is acceptable to parameters as explained in Section 3.1. However, it is acceptable to
define an abstract objective for the purpose of managing or define an abstract objective for the purpose of managing or
coordinating ASAs. It is also acceptable to define a special-purpose coordinating ASAs. It is also acceptable to define a special-purpose
objective for purposes such as trust bootstrapping or formation of objective for purposes such as trust bootstrapping or formation of
the ACP. the ACP.
To guarantee convergence, a limited number of rounds or a timeout is
needed for each negotiation objective. Therefore, the definition of
each negotiation objective SHOULD clearly specify this, for example a
default loop count and timeout, so that the negotiation can always be
terminated properly. If not, the GRASP defaults will apply.
There must be a well-defined procedure for concluding that a
negotiation cannot succeed, and if so deciding what happens next
(e.g., deadlock resolution, tie-breaking, or revert to best-effort
service). This MUST be specified for individual negotiation
objectives.
3.10.5. Experimental and Example Objective Options 3.10.5. Experimental and Example Objective Options
The names "EX0" through "EX9" have been reserved for experimental The names "EX0" through "EX9" have been reserved for experimental
options. Multiple names have been assigned because a single options. Multiple names have been assigned because a single
experiment may use multiple options simultaneously. These experiment may use multiple options simultaneously. These
experimental options are highly likely to have different meanings experimental options are highly likely to have different meanings
when used for different experiments. Therefore, they SHOULD NOT be when used for different experiments. Therefore, they SHOULD NOT be
used without an explicit human decision and SHOULD NOT be used in used without an explicit human decision and SHOULD NOT be used in
unmanaged networks such as home networks. unmanaged networks such as home networks.
These names are also RECOMMENDED for use in documentation examples. These names are also RECOMMENDED for use in documentation examples.
4. Implementation Status [RFC Editor: please remove] 4. Implementation Status [RFC Editor: please remove]
Two prototype implementations of GRASP have been made. Two prototype implementations of GRASP have been made.
4.1. BUPT C++ Implementation 4.1. BUPT C++ Implementation
o Name: BaseNegotiator.cpp, msg.cpp, Client.cpp, Server.cpp o Name: BaseNegotiator.cpp, msg.cpp, Client.cpp, Server.cpp
o Description: C++ implementation of GRASP kernel and API o Description: C++ implementation of GRASP core and API
o Maturity: Prototype code, interoperable between Ubuntu. o Maturity: Prototype code, interoperable between Ubuntu.
o Coverage: Corresponds to draft-carpenter-anima-gdn-protocol-03. o Coverage: Corresponds to draft-carpenter-anima-gdn-protocol-03.
Since it was implemented based on the old version draft, the most Since it was implemented based on the old version draft, the most
significant limitations comparing to current protocol design significant limitations comparing to current protocol design
include: include:
* Not support CBOR * Not support CBOR
skipping to change at page 43, line 27 skipping to change at page 44, line 17
o Experience: https://github.com/liubingpang/IETF-Anima-Signaling- o Experience: https://github.com/liubingpang/IETF-Anima-Signaling-
Protocol/blob/master/README.md Protocol/blob/master/README.md
o Contact: https://github.com/liubingpang/IETF-Anima-Signaling- o Contact: https://github.com/liubingpang/IETF-Anima-Signaling-
Protocol Protocol
4.2. Python Implementation 4.2. Python Implementation
o Name: graspy o Name: graspy
o Description: Python 3 implementation of GRASP kernel and API. o Description: Python 3 implementation of GRASP core and API.
o Maturity: Prototype code, interoperable between Windows 7 and o Maturity: Prototype code, interoperable between Windows 7 and
Linux. Linux.
o Coverage: Corresponds to draft-ietf-anima-grasp-08. Limitations o Coverage: Corresponds to draft-ietf-anima-grasp-08. Limitations
include: include:
* insecure: uses a dummy ACP module and does not implement TLS * insecure: uses a dummy ACP module and does not implement TLS
* only coded for IPv6, any IPv4 is accidental * only coded for IPv6, any IPv4 is accidental
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Generally speaking, no personal information is expected to be Generally speaking, no personal information is expected to be
involved in the signaling protocol, so there should be no direct involved in the signaling protocol, so there should be no direct
impact on personal privacy. Nevertheless, traffic flow paths, impact on personal privacy. Nevertheless, traffic flow paths,
VPNs, etc. could be negotiated, which could be of interest for VPNs, etc. could be negotiated, which could be of interest for
traffic analysis. Also, operators generally want to conceal traffic analysis. Also, operators generally want to conceal
details of their network topology and traffic density from details of their network topology and traffic density from
outsiders. Therefore, since insider attacks cannot be excluded in outsiders. Therefore, since insider attacks cannot be excluded in
a large network, the security mechanism for the protocol MUST a large network, the security mechanism for the protocol MUST
provide message confidentiality. This is why Section 3.5.1 provide message confidentiality. This is why Section 3.5.1
requires either an ACP or the use of TLS. requires either an ACP or an alternative security mechanism.
- Link-local multicast security - Link-local multicast security
GRASP has no reasonable alternative to using link-local multicast GRASP has no reasonable alternative to using link-local multicast
for Discovery or Flood Synchronization messages and these messages for Discovery or Flood Synchronization messages and these messages
are sent in clear and with no authentication. They are therefore are sent in clear and with no authentication. They are therefore
available to on-link eavesdroppers, and could be forged by on-link available to on-link eavesdroppers, and could be forged by on-link
attackers. In the case of Discovery, the Discovery Responses are attackers. In the case of Discovery, the Discovery Responses are
unicast and will therefore be protected (Section 3.5.1), and an unicast and will therefore be protected (Section 3.5.1), and an
untrusted forger will not be able to receive responses. In the untrusted forger will not be able to receive responses. In the
skipping to change at page 46, line 43 skipping to change at page 47, line 33
message /= response-message ;response to Discovery message /= response-message ;response to Discovery
response-message = [M_RESPONSE, session-id, initiator, ttl, response-message = [M_RESPONSE, session-id, initiator, ttl,
(+locator-option // divert-option), ?objective] (+locator-option // divert-option), ?objective]
message /= synch-message ;response to Synchronization request message /= synch-message ;response to Synchronization request
synch-message = [M_SYNCH, session-id, objective] synch-message = [M_SYNCH, session-id, objective]
message /= flood-message message /= flood-message
flood-message = [M_FLOOD, session-id, initiator, ttl, flood-message = [M_FLOOD, session-id, initiator, ttl,
(locator-option / []), +objective] +[objective, (locator-option / [])]]
message /= request-negotiation-message message /= request-negotiation-message
request-negotiation-message = [M_REQ_NEG, session-id, objective] request-negotiation-message = [M_REQ_NEG, session-id, objective]
message /= request-synchronization-message message /= request-synchronization-message
request-synchronization-message = [M_REQ_SYN, session-id, objective] request-synchronization-message = [M_REQ_SYN, session-id, objective]
message /= negotiation-message message /= negotiation-message
negotiation-message = [M_NEGOTIATE, session-id, objective] negotiation-message = [M_NEGOTIATE, session-id, objective]
message /= end-message message /= end-message
end-message = [M_END, session-id, accept-option / decline-option ] end-message = [M_END, session-id, accept-option / decline-option ]
message /= wait-message message /= wait-message
wait-message = [M_WAIT, session-id, waiting-time] wait-message = [M_WAIT, session-id, waiting-time]
message /= invalid-message message /= invalid-message
invalid-message = [M_INVALID, session-id, ?any] invalid-message = [M_INVALID, session-id, ?any]
noop-message = [M_NOOP] noop-message = [M_NOOP]
divert-option = [O_DIVERT, +locator-option] divert-option = [O_DIVERT, +locator-option]
accept-option = [O_ACCEPT] accept-option = [O_ACCEPT]
decline-option = [O_DECLINE, ?reason] decline-option = [O_DECLINE, ?reason]
reason = text ;optional error message reason = text ;optional error message
waiting-time = 0..4294967295 ; in milliseconds waiting-time = 0..4294967295 ; in milliseconds
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IPPROTO_UDP = 17 IPPROTO_UDP = 17
port-number = 0..65535 port-number = 0..65535
locator-option /= [O_URI_LOCATOR, text] locator-option /= [O_URI_LOCATOR, text]
initiator = ipv4-address / ipv6-address initiator = ipv4-address / ipv6-address
objective-flags = uint .bits objective-flag objective-flags = uint .bits objective-flag
objective-flag = &( objective-flag = &(
F_DISC: 0 ; valid for discovery only F_DISC: 0 ; valid for discovery
F_NEG: 1 ; valid for discovery and negotiation F_NEG: 1 ; valid for negotiation
F_SYNCH: 2) ; valid for discovery and synchronization F_SYNCH: 2 ; valid for synchronization
F_NEG_DRY: 3 ; negotiation is dry-run
)
objective = [objective-name, objective-flags, loop-count, ?any] objective = [objective-name, objective-flags, loop-count, ?any]
objective-name = text ;see specification for uniqueness rules objective-name = text ;see specification for uniqueness rules
loop-count = 0..255 loop-count = 0..255
; Constants for message types and option types ; Constants for message types and option types
M_NOOP = 0 M_NOOP = 0
M_DISCOVERY = 1 M_DISCOVERY = 1
M_RESPONSE = 2 M_RESPONSE = 2
M_REQ_NEG = 3 M_REQ_NEG = 3
M_REQ_SYN = 4 M_REQ_SYN = 4
M_NEGOTIATE = 5 M_NEGOTIATE = 5
M_END = 6 M_END = 6
M_WAIT = 7 M_WAIT = 7
M_SYNCH = 8 M_SYNCH = 8
M_FLOOD = 9 M_FLOOD = 9
skipping to change at page 50, line 9 skipping to change at page 51, line 9
EX5 EX5
EX6 EX6
EX7 EX7
EX8 EX8
EX9 EX9
8. Acknowledgements 8. Acknowledgements
A major contribution to the original version of this document was A major contribution to the original version of this document was
made by Sheng Jiang. Significant review inputs were received from made by Sheng Jiang. Significant review inputs were received from
Joel Halpern and Michael Richardson. Joel Halpern, Toerless Eckert and Michael Richardson.
Valuable comments were received from Michael Behringer, Jeferson Valuable comments were received from Michael Behringer, Jeferson
Campos Nobre, Laurent Ciavaglia, Zongpeng Du, Toerless Eckert, Yu Fu, Campos Nobre, Laurent Ciavaglia, Zongpeng Du, Yu Fu, Zhenbin Li,
Zhenbin Li, Dimitri Papadimitriou, Pierre Peloso, Reshad Rahman, Dimitri Papadimitriou, Pierre Peloso, Reshad Rahman, Markus Stenberg,
Markus Stenberg, Rene Struik, Dacheng Zhang, and other participants Rene Struik, Dacheng Zhang, and other participants in the NMRG
in the NMRG research group and the ANIMA working group. research group and the ANIMA working group.
9. References 9. References
9.1. Normative References 9.1. Normative References
[I-D.greevenbosch-appsawg-cbor-cddl] [I-D.greevenbosch-appsawg-cbor-cddl]
Vigano, C. and H. Birkholz, "CBOR data definition language Vigano, C. and H. Birkholz, "CBOR data definition language
(CDDL): a notational convention to express CBOR data (CDDL): a notational convention to express CBOR data
structures", draft-greevenbosch-appsawg-cbor-cddl-09 (work structures", draft-greevenbosch-appsawg-cbor-cddl-09 (work
in progress), September 2016. in progress), September 2016.
skipping to change at page 51, line 30 skipping to change at page 52, line 30
[I-D.chaparadza-intarea-igcp] [I-D.chaparadza-intarea-igcp]
Behringer, M., Chaparadza, R., Petre, R., Li, X., and H. Behringer, M., Chaparadza, R., Petre, R., Li, X., and H.
Mahkonen, "IP based Generic Control Protocol (IGCP)", Mahkonen, "IP based Generic Control Protocol (IGCP)",
draft-chaparadza-intarea-igcp-00 (work in progress), July draft-chaparadza-intarea-igcp-00 (work in progress), July
2011. 2011.
[I-D.ietf-anima-autonomic-control-plane] [I-D.ietf-anima-autonomic-control-plane]
Behringer, M., Eckert, T., and S. Bjarnason, "An Autonomic Behringer, M., Eckert, T., and S. Bjarnason, "An Autonomic
Control Plane", draft-ietf-anima-autonomic-control- Control Plane", draft-ietf-anima-autonomic-control-
plane-03 (work in progress), July 2016. plane-04 (work in progress), October 2016.
[I-D.ietf-anima-bootstrapping-keyinfra] [I-D.ietf-anima-bootstrapping-keyinfra]
Pritikin, M., Richardson, M., Behringer, M., and S. Pritikin, M., Richardson, M., Behringer, M., Bjarnason,
Bjarnason, "Bootstrapping Remote Secure Key S., and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping- Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping-
keyinfra-03 (work in progress), June 2016. keyinfra-04 (work in progress), October 2016.
[I-D.ietf-anima-reference-model] [I-D.ietf-anima-reference-model]
Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L., Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
Pierre, P., Liu, B., Nobre, J., and J. Strassner, "A Pierre, P., Liu, B., Nobre, J., and J. Strassner, "A
Reference Model for Autonomic Networking", draft-ietf- Reference Model for Autonomic Networking", draft-ietf-
anima-reference-model-02 (work in progress), July 2016. anima-reference-model-02 (work in progress), July 2016.
[I-D.ietf-anima-stable-connectivity] [I-D.ietf-anima-stable-connectivity]
Eckert, T. and M. Behringer, "Using Autonomic Control Eckert, T. and M. Behringer, "Using Autonomic Control
Plane for Stable Connectivity of Network OAM", draft-ietf- Plane for Stable Connectivity of Network OAM", draft-ietf-
skipping to change at page 54, line 10 skipping to change at page 55, line 10
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<http://www.rfc-editor.org/info/rfc6763>. <http://www.rfc-editor.org/info/rfc6763>.
[RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and [RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and
P. Selkirk, "Port Control Protocol (PCP)", RFC 6887, P. Selkirk, "Port Control Protocol (PCP)", RFC 6887,
DOI 10.17487/RFC6887, April 2013, DOI 10.17487/RFC6887, April 2013,
<http://www.rfc-editor.org/info/rfc6887>. <http://www.rfc-editor.org/info/rfc6887>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<http://www.rfc-editor.org/info/rfc7228>.
[RFC7558] Lynn, K., Cheshire, S., Blanchet, M., and D. Migault, [RFC7558] Lynn, K., Cheshire, S., Blanchet, M., and D. Migault,
"Requirements for Scalable DNS-Based Service Discovery "Requirements for Scalable DNS-Based Service Discovery
(DNS-SD) / Multicast DNS (mDNS) Extensions", RFC 7558, (DNS-SD) / Multicast DNS (mDNS) Extensions", RFC 7558,
DOI 10.17487/RFC7558, July 2015, DOI 10.17487/RFC7558, July 2015,
<http://www.rfc-editor.org/info/rfc7558>. <http://www.rfc-editor.org/info/rfc7558>.
[RFC7575] Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A., [RFC7575] Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
Networking: Definitions and Design Goals", RFC 7575, Networking: Definitions and Design Goals", RFC 7575,
DOI 10.17487/RFC7575, June 2015, DOI 10.17487/RFC7575, June 2015,
skipping to change at page 54, line 42 skipping to change at page 55, line 37
[RFC7787] Stenberg, M. and S. Barth, "Distributed Node Consensus [RFC7787] Stenberg, M. and S. Barth, "Distributed Node Consensus
Protocol", RFC 7787, DOI 10.17487/RFC7787, April 2016, Protocol", RFC 7787, DOI 10.17487/RFC7787, April 2016,
<http://www.rfc-editor.org/info/rfc7787>. <http://www.rfc-editor.org/info/rfc7787>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking [RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <http://www.rfc-editor.org/info/rfc7788>. 2016, <http://www.rfc-editor.org/info/rfc7788>.
Appendix A. Open Issues [RFC Editor: Please remove if empty] Appendix A. Open Issues [RFC Editor: Please remove if empty]
o 59. Placeholder. o 63. Placeholder
Appendix B. Closed Issues [RFC Editor: Please remove] Appendix B. Closed Issues [RFC Editor: Please remove]
o 1. UDP vs TCP: For now, this specification suggests UDP and TCP o 1. UDP vs TCP: For now, this specification suggests UDP and TCP
as message transport mechanisms. This is not clarified yet. UDP as message transport mechanisms. This is not clarified yet. UDP
is good for short conversations, is necessary for multicast is good for short conversations, is necessary for multicast
discovery, and generally fits the discovery and divert scenarios discovery, and generally fits the discovery and divert scenarios
well. However, it will cause problems with large messages. TCP well. However, it will cause problems with large messages. TCP
is good for stable and long sessions, with a little bit of time is good for stable and long sessions, with a little bit of time
consumption during the session establishment stage. If messages consumption during the session establishment stage. If messages
skipping to change at page 62, line 30 skipping to change at page 63, line 23
RESOLVED: Done. RESOLVED: Done.
o 57. Add M_INVALID message? o 57. Add M_INVALID message?
RESOLVED: Done. RESOLVED: Done.
o 58. Maximum message size? o 58. Maximum message size?
RESOLVED by specifying default maximum message size (2048 bytes). RESOLVED by specifying default maximum message size (2048 bytes).
o 59. Add F_NEG_DRY flag to specify a "dry run" objective?.
RESOLVED: Done.
o 60. Change M_FLOOD syntax to associate a locator with each
objective?
RESOLVED: Done.
o 61. Is the SONN constrained instance really needed?
RESOLVED: Retained but only as an option.
o 62. Is it helpful to tag descriptive text with message names
(M_DISCOVER etc.)?
RESOLVED: Yes, done in various parts of the text.
Appendix C. Change log [RFC Editor: Please remove] Appendix C. Change log [RFC Editor: Please remove]
draft-ietf-anima-grasp-09, 2016-12-15:
Protocol change: Add F_NEG_DRY flag to specify a "dry run" objective.
Protocol change: Change M_FLOOD syntax to associate a locator with
each objective.
Concentrated mentions of TLS in one section, with all details out of
scope.
Clarified text around constrained instances of GRASP.
Strengthened text restricting LL addresses in locator options.
Clarified description of rapid mode processsing.
Specified that cached discovery results should not be returned on the
same interface where they were learned.
Shortened text in "High Level Design Choices"
Dropped the word 'kernel' to avoid confusion with o/s kernel mode.
Editorial improvements and clarifications.
draft-ietf-anima-grasp-08, 2016-10-30: draft-ietf-anima-grasp-08, 2016-10-30:
Protocol change: Added M_INVALID message. Protocol change: Added M_INVALID message.
Protocol change: Increased Session ID space to 32 bits. Protocol change: Increased Session ID space to 32 bits.
Enhanced rules to avoid Session ID clashes. Enhanced rules to avoid Session ID clashes.
Corrected and completed description of timeouts for Request messages. Corrected and completed description of timeouts for Request messages.
skipping to change at page 64, line 19 skipping to change at page 66, line 6
draft-ietf-anima-grasp-05, 2016-05-13: draft-ietf-anima-grasp-05, 2016-05-13:
Noted in requirement T1 that it should be possible to implement ASAs Noted in requirement T1 that it should be possible to implement ASAs
independently as user space programs. independently as user space programs.
Protocol change: Added protocol number and port to discovery Protocol change: Added protocol number and port to discovery
response. Updated protocol description, CDDL and IANA considerations response. Updated protocol description, CDDL and IANA considerations
accordingly. accordingly.
Clarified that discovery and flood multicasts are handled by the Clarified that discovery and flood multicasts are handled by the
GRASP kernel, not directly by ASAs. GRASP core, not directly by ASAs.
Clarified that a node may discover an objective without supporting it Clarified that a node may discover an objective without supporting it
for synchronization or negotiation. for synchronization or negotiation.
Added Implementation Status section. Added Implementation Status section.
Added reference to SCSP. Added reference to SCSP.
Editorial fixes. Editorial fixes.
skipping to change at page 67, line 50 skipping to change at page 69, line 37
Appendix D. Example Message Formats Appendix D. Example Message Formats
For readers unfamiliar with CBOR, this appendix shows a number of For readers unfamiliar with CBOR, this appendix shows a number of
example GRASP messages conforming to the CDDL syntax given in example GRASP messages conforming to the CDDL syntax given in
Section 6. Each message is shown three times in the following Section 6. Each message is shown three times in the following
formats: formats:
1. CBOR diagnostic notation. 1. CBOR diagnostic notation.
2. Similar, but showing the names of the constants. 2. Similar, but showing the names of the constants. (Details of the
flag bit encoding are omitted.)
3. Hexadecimal version of the CBOR wire format. 3. Hexadecimal version of the CBOR wire format.
Long lines are split for display purposes only. Long lines are split for display purposes only.
D.1. Discovery Example D.1. Discovery Example
The initiator multicasts a discovery message: The initiator (2001:db8:f000:baaa:28cc:dc4c:9703:6781) multicasts a
discovery message looking for objective EX1:
[1, 13948744, h'20010db8f000baaa28ccdc4c97036781', ["EX1", 2, 2, 0]] [1, 13948744, h'20010db8f000baaa28ccdc4c97036781', ["EX1", 5, 2, 0]]
[M_DISCOVERY, 13948744, h'20010db8f000baaa28ccdc4c97036781', [M_DISCOVERY, 13948744, h'20010db8f000baaa28ccdc4c97036781',
["EX1", F_SYNCH, 2, 0]] ["EX1", F_SYNCH_bits, 2, 0]]
h'84011a00d4d7485020010db8f000baaa28ccdc4c970367818463455831020200' h'84011a00d4d7485020010db8f000baaa28ccdc4c970367818463455831050200'
A peer responds with a locator: A peer (2001:0db8:f000:baaa:f000:baaa:f000:baaa) responds with a
locator:
[2, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000, [2, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000,
[103, h'20010db8f000baaaf000baaaf000baaa', 6, 49443]] [103, h'20010db8f000baaaf000baaaf000baaa', 6, 49443]]
[M_RESPONSE, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000, [M_RESPONSE, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000,
[O_IPv6_LOCATOR, h'20010db8f000baaaf000baaaf000baaa', [O_IPv6_LOCATOR, h'20010db8f000baaaf000baaaf000baaa',
IPPROTO_TCP, 49443]] IPPROTO_TCP, 49443]]
h'85021a00d4d7485020010db8f000baaa28ccdc4c9703678119ea6084186750 h'85021a00d4d7485020010db8f000baaa28ccdc4c9703678119ea6084186750
20010db8f000baaaf000baaaf000baaa0619c123' 20010db8f000baaaf000baaaf000baaa0619c123'
D.2. Flood Example D.2. Flood Example
The initiator multicasts a flood message. There is no response: The initiator multicasts a flood message. The single objective has a
null locator. There is no response:
[9, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000, [], [9, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000,
["EX1", 2, 2, ["Example 1 value=", 100]]] [["EX1", 5, 2, ["Example 1 value=", 100]],[] ] ]
[M_FLOOD, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000, [], [M_FLOOD, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000,
["EX1", F_SYNCH, 2, ["Example 1 value=", 100]]] [["EX1", F_SYNCH_bits, 2, ["Example 1 value=", 100]],[] ] ]
h'86091a00357b4e5020010db8f000baaa28ccdc4c9703678119271080846345 h'86091a00357b4e5020010db8f000baaa28ccdc4c97036781192710
5831020282704578616d706c6520312076616c75653d1864' 828463455831050282704578616d706c6520312076616c75653d186480'
D.3. Synchronization Example D.3. Synchronization Example
The initiator unicasts a request: Following successful discovery of objective EX2, the initiator
unicasts a request:
[4, 4038926, ["EX2", 2, 5, 0]] [4, 4038926, ["EX2", 5, 5, 0]]
[M_REQ_SYN, 4038926, ["EX2", F_SYNCH, 5, 0]] [M_REQ_SYN, 4038926, ["EX2", F_SYNCH_bits, 5, 0]]
h'83041a003da10e8463455832020500' h'83041a003da10e8463455832050500'
The peer responds with a value: The peer responds with a value:
[8, 4038926, ["EX2", 2, 5, ["Example 2 value=", 200]]] [8, 4038926, ["EX2", 5, 5, ["Example 2 value=", 200]]]
[M_SYNCH, 4038926, ["EX2", F_SYNCH, 5, ["Example 2 value=", 200]]] [M_SYNCH, 4038926, ["EX2", F_SYNCH_bits, 5, ["Example 2 value=", 200]]]
h'83081a003da10e8463455832020582704578616d706c6520322076616c75653d18c8' h'83081a003da10e8463455832050582704578616d706c6520322076616c75653d18c8'
D.4. Simple Negotiation Example D.4. Simple Negotiation Example
The initiator unicasts a request: Following successful discovery of objective EX3, the initiator
unicasts a request:
[3, 802813, ["EX3", 1, 6, ["NZD", 47]]] [3, 802813, ["EX3", 3, 6, ["NZD", 47]]]
[M_REQ_NEG, 802813, ["EX3", 1, 6, ["NZD", 47]]] [M_REQ_NEG, 802813, ["EX3", F_NEG_bits, 6, ["NZD", 47]]]
h'83031a000c3ffd8463455833010682634e5a44182f' h'83031a000c3ffd8463455833030682634e5a44182f'
The peer responds with immediate acceptance. Note that no objective The peer responds with immediate acceptance. Note that no objective
is needed, because the initiator's request was accepted without is needed, because the initiator's request was accepted without
change: change:
[6, 802813, [101]] [6, 802813, [101]]
[M_END , 802813, [O_ACCEPT]] [M_END , 802813, [O_ACCEPT]]
h'83061a000c3ffd811865' h'83061a000c3ffd811865'
D.5. Complete Negotiation Example D.5. Complete Negotiation Example
The initiator unicasts a request: Again the initiator unicasts a request:
[3, 13767778, ["EX3", 1, 6, ["NZD", 410]]] [3, 13767778, ["EX3", 3, 6, ["NZD", 410]]]
[M_REQ_NEG, 13767778, ["EX3", F_NEG, 6, ["NZD", 410]]] [M_REQ_NEG, 13767778, ["EX3", F_NEG_bits, 6, ["NZD", 410]]]
h'83031a00d214628463455833010682634e5a4419019a' h'83031a00d214628463455833030682634e5a4419019a'
The responder starts to negotiate (making an offer): The responder starts to negotiate (making an offer):
[5, 13767778, ["EX3", 1, 6, ["NZD", 80]]] [5, 13767778, ["EX3", 3, 6, ["NZD", 80]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG, 6, ["NZD", 80]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 6, ["NZD", 80]]]
h'83051a00d214628463455833010682634e5a441850' h'83051a00d214628463455833030682634e5a441850'
The initiator continues to negotiate (reducing its request): The initiator continues to negotiate (reducing its request, and note
that the loop count is decremented):
[5, 13767778, ["EX3", 1, 5, ["NZD", 307]]] [5, 13767778, ["EX3", 3, 5, ["NZD", 307]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG, 5, ["NZD", 307]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 5, ["NZD", 307]]]
h'83051a00d214628463455833010582634e5a44190133' h'83051a00d214628463455833030582634e5a44190133'
The responder asks for more time: The responder asks for more time:
[7, 13767778, 34965] [7, 13767778, 34965]
[M_WAIT, 13767778, 34965] [M_WAIT, 13767778, 34965]
h'83071a00d21462198895' h'83071a00d21462198895'
The responder continues to negotiate (increasing its offer): The responder continues to negotiate (increasing its offer):
[5, 13767778, ["EX3", 1, 4, ["NZD", 120]]] [5, 13767778, ["EX3", 3, 4, ["NZD", 120]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG, 4, ["NZD", 120]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 4, ["NZD", 120]]]
h'83051a00d214628463455833010482634e5a441878' h'83051a00d214628463455833030482634e5a441878'
The initiator continues to negotiate (reducing its request): The initiator continues to negotiate (reducing its request):
[5, 13767778, ["EX3", 1, 3, ["NZD", 246]]] [5, 13767778, ["EX3", 3, 3, ["NZD", 246]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG, 3, ["NZD", 246]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 3, ["NZD", 246]]]
h'83051a00d214628463455833010382634e5a4418f6' h'83051a00d214628463455833030382634e5a4418f6'
The responder refuses to negotiate further: The responder refuses to negotiate further:
[6, 13767778, [102, "Insufficient funds"]] [6, 13767778, [102, "Insufficient funds"]]
[M_END , 13767778, [O_DECLINE, "Insufficient funds"]] [M_END , 13767778, [O_DECLINE, "Insufficient funds"]]
h'83061a00d2146282186672496e73756666696369656e742066756e6473' h'83061a00d2146282186672496e73756666696369656e742066756e6473'
This negotiation has failed. If either side had sent [M_END, This negotiation has failed. If either side had sent [M_END,
13767778, [O_ACCEPT]] it would have succeeded, converging on the 13767778, [O_ACCEPT]] it would have succeeded, converging on the
objective value in the preceding M_NEGOTIATE. Note that apart from objective value in the preceding M_NEGOTIATE. Note that apart from
 End of changes. 111 change blocks. 
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