Mobile Ad hoc Networking (MANET) T. Clausen Internet-Draft LIX, Ecole Polytechnique, France Intended status: Standards Track C. Dearlove Expires: September 11, 2008 BAE Systems Advanced Technology Centre J. Dean Naval Research Laboratory The OLSRv2 Design Team MANET Working Group March 10, 2008 MANET Neighborhood Discovery Protocol (NHDP) draft-ietf-manet-nhdp-06 Status of This Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on September 11, 2008. Clausen, et al. Expires September 11, 2008 [Page 1] Internet-Draft MANET-NHDP March 2008 Abstract This document describes a 1-hop and symmetric 2-hop neighborhood discovery protocol (NHDP) for mobile ad hoc networks (MANETs). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 7 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 8 4.1. Nodes and Interfaces . . . . . . . . . . . . . . . . . . . 9 4.2. Information Base Overview . . . . . . . . . . . . . . . . 9 4.2.1. Local Information Base . . . . . . . . . . . . . . . . 9 4.2.2. Interface Information Bases . . . . . . . . . . . . . 10 4.2.3. Node Information Base . . . . . . . . . . . . . . . . 10 4.3. Signaling Overview . . . . . . . . . . . . . . . . . . . . 11 4.3.1. HELLO Message Generation . . . . . . . . . . . . . . . 11 4.3.2. HELLO Message Content . . . . . . . . . . . . . . . . 11 4.3.3. HELLO Message Processing . . . . . . . . . . . . . . . 12 4.4. Link Quality . . . . . . . . . . . . . . . . . . . . . . . 13 5. Protocol Parameters and Constants . . . . . . . . . . . . . . 14 5.1. Interface Parameters . . . . . . . . . . . . . . . . . . . 14 5.1.1. Message Intervals . . . . . . . . . . . . . . . . . . 14 5.1.2. Information Validity Times . . . . . . . . . . . . . . 15 5.1.3. Link Quality . . . . . . . . . . . . . . . . . . . . . 16 5.1.4. Jitter . . . . . . . . . . . . . . . . . . . . . . . . 17 5.2. Node Parameters . . . . . . . . . . . . . . . . . . . . . 17 5.2.1. Information Validity Time . . . . . . . . . . . . . . 17 5.3. Parameter Change Constraints . . . . . . . . . . . . . . . 17 5.4. Constants . . . . . . . . . . . . . . . . . . . . . . . . 19 6. Local Information Base . . . . . . . . . . . . . . . . . . . . 20 6.1. Local Interface Set . . . . . . . . . . . . . . . . . . . 20 6.2. Removed Interface Address Set . . . . . . . . . . . . . . 20 7. Interface Information Base . . . . . . . . . . . . . . . . . . 21 7.1. Link Set . . . . . . . . . . . . . . . . . . . . . . . . . 21 7.2. 2-Hop Set . . . . . . . . . . . . . . . . . . . . . . . . 22 8. Node Information Base . . . . . . . . . . . . . . . . . . . . 23 8.1. Neighbor Set . . . . . . . . . . . . . . . . . . . . . . . 23 8.2. Lost Neighbor Set . . . . . . . . . . . . . . . . . . . . 23 9. Local Information Base Changes . . . . . . . . . . . . . . . . 24 9.1. Adding an Interface . . . . . . . . . . . . . . . . . . . 24 9.2. Removing an Interface . . . . . . . . . . . . . . . . . . 24 9.3. Adding an Address to an Interface . . . . . . . . . . . . 25 9.4. Removing an Address from an Interface . . . . . . . . . . 26 10. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 27 10.1. HELLO Messages . . . . . . . . . . . . . . . . . . . . . . 27 10.1.1. Address Blocks . . . . . . . . . . . . . . . . . . . . 28 Clausen, et al. Expires September 11, 2008 [Page 2] Internet-Draft MANET-NHDP March 2008 11. HELLO Message Generation . . . . . . . . . . . . . . . . . . . 30 11.1. HELLO Message Specification . . . . . . . . . . . . . . . 30 11.2. HELLO Message Transmission . . . . . . . . . . . . . . . . 32 11.2.1. HELLO Message Jitter . . . . . . . . . . . . . . . . . 32 12. HELLO Message Processing . . . . . . . . . . . . . . . . . . . 33 12.1. Updating the Neighbor Set . . . . . . . . . . . . . . . . 34 12.2. Updating the Lost Neighbor Set . . . . . . . . . . . . . . 35 12.3. Updating the Link Set . . . . . . . . . . . . . . . . . . 35 12.4. Updating the 2-Hop Set . . . . . . . . . . . . . . . . . . 37 13. Other Information Base Changes . . . . . . . . . . . . . . . . 39 13.1. Link Tuple Not Symmetric . . . . . . . . . . . . . . . . . 39 13.2. Link Tuple Symmetric . . . . . . . . . . . . . . . . . . . 40 13.3. Link Tuple Heard Timeout . . . . . . . . . . . . . . . . . 41 14. Link Quality . . . . . . . . . . . . . . . . . . . . . . . . . 42 14.1. Deployment Without Link Quality . . . . . . . . . . . . . 42 14.2. Basic Principles of Link Quality . . . . . . . . . . . . . 42 14.3. When Link Quality Changes . . . . . . . . . . . . . . . . 43 14.4. Updating Link Quality . . . . . . . . . . . . . . . . . . 44 15. Proposed Values for Parameters and Constants . . . . . . . . . 45 15.1. Message Interval Interface Parameters . . . . . . . . . . 45 15.2. Information Validity Time Interface Parameters . . . . . . 45 15.3. Information Validity Time Node Parameters . . . . . . . . 45 15.4. Link Quality Interface Parameters . . . . . . . . . . . . 45 15.5. Jitter Interface Parameters . . . . . . . . . . . . . . . 45 15.6. Constants . . . . . . . . . . . . . . . . . . . . . . . . 46 16. Security Considerations . . . . . . . . . . . . . . . . . . . 47 16.1. Invalid HELLO messages . . . . . . . . . . . . . . . . . . 47 17. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 49 17.1. Message Types . . . . . . . . . . . . . . . . . . . . . . 49 17.2. TLV Types . . . . . . . . . . . . . . . . . . . . . . . . 49 17.3. LINK_STATUS and OTHER_NEIGHB Values . . . . . . . . . . . 50 18. References . . . . . . . . . . . . . . . . . . . . . . . . . . 51 18.1. Normative References . . . . . . . . . . . . . . . . . . . 51 18.2. Informative References . . . . . . . . . . . . . . . . . . 51 Appendix A. Address Block TLV Combinations . . . . . . . . . . . 52 Appendix B. HELLO Message Example . . . . . . . . . . . . . . . . 53 Appendix C. Constraints . . . . . . . . . . . . . . . . . . . . . 56 Appendix D. Flow and Congestion Control . . . . . . . . . . . . . 59 Appendix E. Contributors . . . . . . . . . . . . . . . . . . . . 60 Appendix F. Acknowledgements . . . . . . . . . . . . . . . . . . 61 Clausen, et al. Expires September 11, 2008 [Page 3] Internet-Draft MANET-NHDP March 2008 1. Introduction This document describes a neighborhood discovery protocol (NHDP) for a mobile ad hoc network (MANET) [RFC2501]. This protocol uses an exchange of HELLO messages in order that each node can determine the presence and status of its 1-hop and symmetric 2-hop neighbors. Messages are defined as instances of the specification [packetbb]. This neighborhood information is recorded in the form of Information Bases. These may be used by other protocols, such as MANET routing protocols, for determining local connectivity and node configuration. This protocol is designed to maintain this information in the presence of a dynamic network topology. This protocol makes no assumptions about the underlying link layer, other than support of link local broadcast or multicast. Link layer information may be used if available and applicable. This protocol is based on the neighborhood discovery process contained in the Optimized Link State Routing Protocol (OLSR) [RFC3626]. Clausen, et al. Expires September 11, 2008 [Page 4] Internet-Draft MANET-NHDP March 2008 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119 [RFC2119]. The terms "packet", "message", "address", "address block", "TLV", and "TLV block" in this document are to be interpreted as described in [packetbb]. Additionally, this document uses the following terminology: Node - A MANET router which implements this neighborhood discovery protocol. Interface - A network device, configured and assigned one or more IP addresses. Address - An address, as recorded in the Information Bases specified by this protocol, and included in HELLO messages generated by this protocol, may be either an address or an address prefix. These can be represented as a single address object in a HELLO message, as defined by [packetbb]. An address so represented is considered to have a prefix length equal to its length (in bits) when considered as an address object, and a similar convention is used in the Information Bases specified by this protocol. Two addresses (address objects) are considered equal only if their prefix lengths are also equal. MANET interface - An interface participating in a MANET and using this neighborhood discovery protocol. A node may have several MANET interfaces. Heard - A MANET interface of node X is considered heard on a MANET interface of a node Y if the latter can receive traffic from the former. Link - A pair of MANET interfaces from two different nodes, where at least one interface is heard by the other. Symmetric link - A link where both MANET interfaces are heard by the other. 1-hop neighbor - A node X is a 1-hop neighbor of a node Y if a MANET interface of node X is heard by a MANET interface of node Y. Clausen, et al. Expires September 11, 2008 [Page 5] Internet-Draft MANET-NHDP March 2008 Symmetric 1-hop neighbor - A node X is a symmetric 1-hop neighbor of a node Y if a symmetric link exists between a MANET interface on node X and a MANET interface on node Y. Symmetric 2-hop neighbor - A node X is a symmetric 2-hop neighbor of a node Y if node X is a symmetric 1-hop neighbor of a symmetric 1-hop neighbor of node Y, but is not node Y itself. 1-hop neighborhood - The 1-hop neighborhood of a node X is the set of the 1-hop neighbors of node X. Symmetric 1-hop neighborhood - The symmetric 1-hop neighborhood of a node X is the set of the symmetric 1-hop neighbors of node X. Symmetric 2-hop neighborhood - The symmetric 2-hop neighborhood of a node X is the set of the symmetric 2-hop neighbors of node X. (This may include nodes in the 1-hop neighborhood, or even in the symmetric 1-hop neighborhood, of node X.) Constant - A constant is a numerical value which MUST be the same for all MANET interfaces of all nodes in the MANET, at all times. Interface parameter - An interface parameter is a boolean or numerical value, specified separately for each MANET interface of each node. A node MAY change interface parameter values at any time, subject to some constraints. Node parameter - A node parameter is a boolean or numerical value, specified for each node. A node MAY change node parameter values at any time, subject to some constraints. Clausen, et al. Expires September 11, 2008 [Page 6] Internet-Draft MANET-NHDP March 2008 3. Applicability Statement This protocol: o Is applicable to networks, especially wireless networks, in which unknown neighbors (i.e. other nodes with which direct communication can be established) can be reached by local broadcast or multicast packets. o Is designed to work in networks with a dynamic topology, and in which messages may be lost, such as due to collisions in wireless networks. o Supports nodes that each have one or more participating MANET interfaces. The set of a node's interfaces may change over time. Each interface may have one or more interface addresses, and these may also be dynamically changing. o Can use the link local multicast address and either the "manet" UDP port or the "manet" IP protocol number specified in [manet-iana]. o Uses the packet and message formats specified in [packetbb]. Such packets may contain messages specified by this protocol as well as other protocols. o Specifies signaling using HELLO messages. The necessary contents of these messages are defined in this specification, and may be extended using the TLV mechanisms described in [packetbb]. o Can use relevant link layer information if it is available. o Provides each node with local topology information up to two hops away. This information is made available to other protocols, of which this protocol may be a part, in Information Bases defined in this specification. o Is designed to work in a completely distributed manner, and does not depend on any central entity. Clausen, et al. Expires September 11, 2008 [Page 7] Internet-Draft MANET-NHDP March 2008 4. Protocol Overview and Functioning The objective of this protocol is, for each node: o To identify other nodes with which bidirectional links can be established (symmetric 1-hop neighbors). o To agree on the status of such links with the corresponding symmetric 1-hop neighbor. o To find the node's symmetric 2-hop neighbors. o To record this information in Information Bases that can be used by other protocols, of which this neighborhood discovery protocol may be a part. These objectives are achieved using local (one hop) signaling that: o Advertises the presence of a node and its interfaces. o Discovers links with adjacent nodes. o Performs bidirectionality checks on the discovered links. o Advertises discovered links, and whether each is symmetric, to its 1-hop neighbors, and hence discovers symmetric 2-hop neighbors. This specification defines, in turn: o Parameters and constants used by the protocol. Parameters used by this protocol may be, where appropriate, specific to a MANET interface. This protocol allows all parameters to be changed dynamically. o The Information Bases describing local interfaces, discovered links and their status, current and former 1-hop neighbors, and symmetric 2-hop neighbors. o The format of the HELLO message that is used for local signaling. o The generation of HELLO messages from some of the information in the Information Bases. o The updating of the Information Bases according to received HELLO messages and other events. Clausen, et al. Expires September 11, 2008 [Page 8] Internet-Draft MANET-NHDP March 2008 4.1. Nodes and Interfaces In order for a node to participate in a MANET, it MUST have at least one, and possibly more, MANET interfaces. Each MANET interface: o Is characterized by a set of interface parameters, defining the behavior of this MANET interface. Each MANET interface MAY be individually parameterized. o Has an Interface Information Base, recording information regarding links to this MANET interface and symmetric 2-hop neighbors which can be reached through such links. o Generates and processes HELLO messages, according to the interface parameters for that MANET interface. In addition to a set of MANET interfaces as described above, each node has: o A Local Information Base, containing the addresses of the interfaces (MANET and non-MANET) of this node. The contents of this Information Base are not changed by signaling. o A Node Information Base, recording information regarding current and recently lost 1-hop neighbors of this node. A node may have both MANET interfaces and non-MANET interfaces. Interfaces of both of these types are recorded in a node's Local Information Base, which is used, but not updated, by the signaling of this protocol. 4.2. Information Base Overview Each node maintains the Information Bases described in the following sections. These are used for describing the protocol in this document. An implementation of this protocol MAY maintain this information in the indicated form, or in any other organization which offers access to this information. In particular note that it is not necessary to remove Tuples from Sets at the exact time indicated, only to behave as if the Tuples were removed at that time. 4.2.1. Local Information Base Each node maintains a Local Information Base, which contains: o The Local Interface Set, which consists of Local Interface Tuples, each of which records the addresses of an interface (MANET or non- MANET) of the node. Clausen, et al. Expires September 11, 2008 [Page 9] Internet-Draft MANET-NHDP March 2008 o The Removed Interface Address Set, which consists of Removed Interface Address Tuples, each of which records a recently used address of an interface (MANET or non-MANET) of the node. 4.2.2. Interface Information Bases Each node maintains, for each of its MANET interfaces, an Interface Information Base, which contains: o A Link Set, which records information about current and recently lost links between this interface and MANET interfaces of 1-hop neighbors. The Link Set consists of Link Tuples, each of which contains information about a single link. Recently lost links are recorded so that they can be advertised in HELLO messages, accelerating their removal from relevant 1-hop neighbors' Link Sets. Link quality information, if used and available, is recorded in Link Tuples and may indicate that links are treated as lost. o A 2-Hop Set, which records the existence of bidirectional links between symmetric 1-hop neighbors of this MANET interface and other nodes (symmetric 2-hop neighbors). The 2-Hop Set consists of 2-Hop Tuples, each of which records an interface address of a symmetric 2-hop neighbor, and all interface addresses of the corresponding symmetric 1-hop neighbor. The 2-Hop Set is updated by the signaling of this protocol, but is not itself reported in that signaling. 4.2.3. Node Information Base Each node maintains a Node Information Base, which contains: o The Neighbor Set, which records 1-hop neighbors, each of which must be currently heard, although this may be over a link with insufficient link quality. The Neighbor Set consists of Neighbor Tuples, each of which records all interface addresses (whether directly linked or not) of a single 1-hop neighbor. Neighbor Tuples are maintained as long as there are corresponding current Link Tuples. o The Lost Neighbor Set, which records recently lost symmetric 1-hop neighbors. The Lost Neighbor Set consists of Lost Neighbor Tuples, each of which records an interface address of such a neighbor. These are recorded so that they can be advertised in HELLO messages, accelerating their removal from other nodes' 2-Hop Sets. Clausen, et al. Expires September 11, 2008 [Page 10] Internet-Draft MANET-NHDP March 2008 4.3. Signaling Overview This protocol contains a signaling mechanism for maintaining the Interface Information Bases and the Node Information Base. If information from the link layer, or any other source, is available and appropriate, it may also be used to update these Information Bases. Such updates are subject to the constraints specified in Appendix C. Signaling consists of a single type of message, known as a HELLO message. Each node generates HELLO messages on each of its MANET interfaces. Each HELLO message identifies that MANET interface, and reports the other interfaces (MANET and non-MANET) of the node. Each HELLO message includes information from the Link Set of the Interface Information Base of the MANET interface, and from the Node Information Base. 4.3.1. HELLO Message Generation HELLO messages are generated by a node for each of its MANET interfaces, and MAY be sent: o Proactively, at a regular interval, known as HELLO_INTERVAL. HELLO_INTERVAL may be fixed, or may be dynamic. For example HELLO_INTERVAL may be backed off due to congestion or network stability. o As a response to a change in the node itself, or its 1-hop neighborhood, for example on first becoming active or in response to a new, broken, or changed status link. o In a combination of these proactive and responsive mechanisms. Jittering of HELLO message generation and transmission, as described in Section 11.2, SHOULD be used if appropriate. HELLO messages are generated independently on each MANET interface of a node. HELLO messages MAY be scheduled independently for each MANET interface, or, interface parameters permitting, using the same schedule for all MANET interfaces of a node. 4.3.2. HELLO Message Content Each HELLO message sent over a MANET interface need not contain all of the information appropriate to that MANET interface, however: o A HELLO message MUST contain all of the addresses in the Local Interface Set of the node to which the MANET interface belongs. Clausen, et al. Expires September 11, 2008 [Page 11] Internet-Draft MANET-NHDP March 2008 o Within every time interval of length REFRESH_INTERVAL, the HELLO messages sent on each MANET interface of a node MUST collectively include: * All of the relevant information in the Link Set of the Interface Information Base of that MANET interface. * All of the relevant information in the Node Information Base of that node. This applies to otherwise purely responsive nodes as well as to proactive nodes. In either case it means that all information appropriate to that MANET interface will have always been transmitted, in one or more HELLO messages, since the time REFRESH_INTERVAL ago. o A HELLO message MUST include a VALIDITY_TIME message TLV that indicates the length of time for which the message content is to be considered valid, and included in the receiving node's Interface Information Base. o A periodically generated HELLO message SHOULD include an INTERVAL_TIME message TLV that indicates the current value of HELLO_INTERVAL for that MANET interface, i.e. the period within which a further HELLO message is guaranteed to be sent on that MANET interface. o Additional information may be added by a protocol using this protocol using the TLV mechanisms described in [packetbb]. For example, if multipoint relays (MPRs) are to be calculated similarly to as in OLSR [RFC3626] and signaled to neighbors, then this information may be added to HELLO messages using an address block TLV. 4.3.3. HELLO Message Processing All HELLO messages received by a node are used to update: o The Interface Information Base for the MANET interface on which that HELLO message is received. o The Node Information Base. Specifically: o The node ensures that there is a single Neighbor Tuple corresponding to the originator of that HELLO message. Clausen, et al. Expires September 11, 2008 [Page 12] Internet-Draft MANET-NHDP March 2008 o If a Link Tuple corresponding to the link on which that HELLO message was received exists, then its duration is extended, otherwise such a Link Tuple is created. If the HELLO message indicates that the receiving MANET interface has been heard, then the link is considered symmetric, or its duration as symmetric is extended. If the HELLO message indicates that the receiving MANET interface is lost, then the link is no longer considered symmetric. In this case one or more Lost Neighbor Tuples may be created. o If the link on which the HELLO message is received is symmetric, then any symmetrically advertised neighbors in the HELLO message are added to the 2-Hop Set for the receiving interface, or if already present, the durations of the corresponding 2-Hop Tuples are extended. In all cases the processing takes account of unexpected and erroneous information in the HELLO message, maintaining the constraints specified in Appendix C. 4.4. Link Quality Some links in a MANET may be marginal, e.g. due to adverse wireless propagation. In order to avoid using such marginal links, a link quality is associated with each link in the Link Set, and links with insufficient link quality are considered lost. Modifying the link quality of a link is OPTIONAL. If link quality is not to be modified it MUST be set to indicate an always usable quality link. Link quality information is only used locally, it is not used in signaling, and nodes may interoperate whether they are using the same, different, or no, link quality information. Clausen, et al. Expires September 11, 2008 [Page 13] Internet-Draft MANET-NHDP March 2008 5. Protocol Parameters and Constants The parameters and constants used in this specification are described in this section. 5.1. Interface Parameters The interface parameters used by this specification may be classified into the following four categories: o Message intervals o Information validity times o Link quality o Jitter These are detailed in the following sections. Different MANET interfaces (on the same or on different nodes) MAY employ different interface parameter values, and may change their interface parameter values dynamically, subject to the constraints given in this section. A particular case is where all MANET interfaces on all MANET nodes within a given MANET employ the same set of interface parameter values. 5.1.1. Message Intervals The following interface parameters regulate HELLO message transmissions over a given MANET interface. HELLO messages serve two principal functions: o To advertise this node's own addresses to its 1-hop neighbors. The frequency of these advertisements is regulated by the interface parameters HELLO_INTERVAL and HELLO_MIN_INTERVAL. o To advertise this node's knowledge of each of its 1-hop neighbors. The frequency of the advertisement of each such neighbor is regulated by the interface parameter REFRESH_INTERVAL. Specifically, these parameters are as follows: HELLO_INTERVAL - is the maximum time between the transmission of two successive HELLO messages on this MANET interface. If using periodic transmission of HELLO messages, these SHOULD be at a separation of HELLO_INTERVAL, possibly modified by jitter as Clausen, et al. Expires September 11, 2008 [Page 14] Internet-Draft MANET-NHDP March 2008 specified in [RFC5148]. HELLO_MIN_INTERVAL - is the minimum interval between transmission of two successive HELLO messages, on this MANET interface. (This minimum interval MAY be modified by jitter, as defined in [RFC5148].) REFRESH_INTERVAL - is the maximum interval between advertisements in a HELLO message of each 1-hop neighbor address and its status. In all intervals of length REFRESH_INTERVAL, a node MUST include all 1-hop neighbor information which it is specified as sending in at least one HELLO message on this MANET interface. The following constraints apply to these interface parameters: o HELLO_INTERVAL > 0 o HELLO_MIN_INTERVAL >= 0 o HELLO_INTERVAL >= HELLO_MIN_INTERVAL o REFRESH_INTERVAL >= HELLO_INTERVAL o If INTERVAL_TIME message TLVs as defined in [timetlv] are included in HELLO messages, then HELLO_INTERVAL MUST be representable as described in [timetlv]. If REFRESH_INTERVAL > HELLO_INTERVAL, then a node may distribute its neighbor advertisements between HELLO messages in any manner, subject to the constraints above. For a node to employ this protocol in a purely responsive manner on a MANET interface, REFRESH_INTERVAL and HELLO_INTERVAL SHOULD both be set to a value such that a responsive HELLO message is always expected in a shorter period than this value. 5.1.2. Information Validity Times The following interface parameters manage the validity time of link information: L_HOLD_TIME - is the period of advertisement, on this MANET interface, of former 1-hop neighbor addresses as lost in HELLO messages, allowing recipients of these HELLO messages to accelerate removal of information from their Link Sets. L_HOLD_TIME can be set to zero if accelerated information removal is not required. Clausen, et al. Expires September 11, 2008 [Page 15] Internet-Draft MANET-NHDP March 2008 H_HOLD_TIME - is used as the value in the VALIDITY_TIME message TLV included in all HELLO messages on this MANET interface. The following constraints apply to these interface parameters: o L_HOLD_TIME >= 0 o H_HOLD_TIME >= REFRESH_INTERVAL o If HELLO messages can be lost then both SHOULD be significantly greater than REFRESH_INTERVAL. o H_HOLD_TIME MUST be representable as described in [timetlv]. 5.1.3. Link Quality The following interface parameters manage the usage of link quality (see Section 4.4): HYST_ACCEPT - is the link quality threshold at or above which a link becomes usable, if it was not already so. HYST_REJECT - is the link quality threshold below which a link becomes unusable, if it was not already so. INITIAL_QUALITY - is the initial quality of a newly identified link. INITIAL_PENDING - if true, then a newly identified link is considered pending, and is not usable until the link quality has reached or exceeded the HYST_ACCEPT threshold. The following constraints apply to these interface parameters: o 0 <= HYST_REJECT <= HYST_ACCEPT <= 1 o 0 <= INITIAL_QUALITY <= 1. o If link quality is not updated, then INITIAL_QUALITY >= HYST_ACCEPT. o If INITIAL_QUALITY >= HYST_ACCEPT, then INITIAL_PENDING == false. o If INITIAL_QUALITY < HYST_REJECT, then INITIAL_PENDING == true. Clausen, et al. Expires September 11, 2008 [Page 16] Internet-Draft MANET-NHDP March 2008 5.1.4. Jitter If jitter, as defined in [RFC5148], is used then these parameters are as follows: HP_MAXJITTER - represents the value of MAXJITTER used in [RFC5148] for periodically generated HELLO messages on this MANET interface. HT_MAXJITTER - represents the value of MAXJITTER used in [RFC5148] for externally triggered HELLO messages on this MANET interface. For constraints on these interface parameters see [RFC5148]. 5.2. Node Parameters The two node parameters defined by this specification are in the category of information validity time. 5.2.1. Information Validity Time The following node parameter manages the validity time of lost symmetric 1-hop neighbor information: N_HOLD_TIME - is used as the period during which former 1-hop neighbor addresses are advertised as lost in HELLO messages, allowing recipients of these HELLO messages to accelerate removal of information from their 2-Hop Sets. N_HOLD_TIME can be set to zero if accelerated information removal is not required. I_HOLD_TIME - is the period for which a recently used local interface address is recorded. The following constraints applies to these node parameters: o N_HOLD_TIME >= 0 o I_HOLD_TIME >= 0 5.3. Parameter Change Constraints This section presents guidelines, applicable if protocol parameters are changed dynamically. HELLO_INTERVAL * If the HELLO_INTERVAL for a MANET interface increases, then the next HELLO message on this MANET interface MUST be generated according to the previous, shorter, HELLO_INTERVAL. Additional Clausen, et al. Expires September 11, 2008 [Page 17] Internet-Draft MANET-NHDP March 2008 subsequent HELLO messages MAY be generated according to the previous, shorter, HELLO_INTERVAL (but MUST include times according to current parameters). * If the HELLO_INTERVAL for a MANET interface decreases, then the following HELLO messages on this MANET interface MUST be generated according to this current, shorter, HELLO_INTERVAL. REFRESH_INTERVAL * If the REFRESH_INTERVAL for a MANET interface increases, then the content of subsequent HELLO messages must be organized such that the specification of the old value of REFRESH_INTERVAL is satisfied for a further period equal to the old value of REFRESH_INTERVAL. * If the REFRESH_INTERVAL for a MANET interface decreases, then it MAY be necessary to reschedule HELLO message generation on that MANET interface, in order that the specification of REFRESH_INTERVAL is satisfied from the time of change. HYST_ACCEPT and HYST_REJECT * If HYST_ACCEPT or HYST_REJECT changes, then the appropriate actions for link quality change, as specified in Section 14.3 MUST be taken. L_HOLD_TIME * If L_HOLD_TIME changes, then L_time for all relevant Link Tuples MUST be changed. N_HOLD_TIME * If N_HOLD_TIME changes, then NL_time for all relevant Lost Neighbor Tuples MUST be changed. HP_MAXJITTER * If HP_MAXJITTER changes, then the periodic HELLO message schedule on this MANET interface MAY be changed. HT_MAXJITTER * If HT_MAXJITTER changes, then externally triggered HELLO messages on this MANET interface MAY be rescheduled. Clausen, et al. Expires September 11, 2008 [Page 18] Internet-Draft MANET-NHDP March 2008 5.4. Constants The constant C (time granularity) is used as specified in [timetlv]. Clausen, et al. Expires September 11, 2008 [Page 19] Internet-Draft MANET-NHDP March 2008 6. Local Information Base A node maintains a Local Information Base that records information about its interfaces (MANET and non-MANET). Each interface MUST have at least one address, and MAY have more than one address. The Local Information Base is not modified by signaling. If a node's interface configuration changes, then the Local Information Base MUST reflect these changes. This MAY also result in signaling to advertise these changes. 6.1. Local Interface Set A node's Local Interface Set records its local interfaces. It consists of Local Interface Tuples, one per interface: (I_local_iface_addr_list, I_manet) where: I_local_iface_addr_list is an unordered list of the addresses of this interface. I_manet is a boolean flag, describing if this interface is a MANET interface. 6.2. Removed Interface Address Set A node's Removed Interface Address Set records addresses which were recently local interface addresses. If a node's interface addresses are immutable then this set is always empty and MAY be omitted. It consists of Removed Interface Address Tuples, one per address: (IR_local_iface_addr, IR_time) where: IR_local_iface_addr is a recently used address of an interface of this node. IR_time specifies when this Tuple expires and MUST be removed. Clausen, et al. Expires September 11, 2008 [Page 20] Internet-Draft MANET-NHDP March 2008 7. Interface Information Base A node maintains an Interface Information Base for each of its MANET interfaces. This records information about links to that MANET interface and symmetric 2-hop neighbors which can be reached in two hops using those links as the first hop. The Interface Information Base includes the Link Set and the 2-Hop Set. A MANET interface address can be present as of both a 1-hop neighbor and a symmetric 2-hop neighbor. This allows the node with this MANET interface address to be immediately considered as a symmetric 2-hop neighbor if it fails to be a symmetric 1-hop neighbor. 7.1. Link Set A node's Link Set records links from other nodes which are, or recently were, 1-hop neighbors. It consists of Link Tuples, each representing a single link: (L_neighbor_iface_addr_list, L_HEARD_time, L_SYM_time, L_quality, L_pending, L_lost, L_time) where: L_neighbor_iface_addr_list is an unordered list of the addresses of the MANET interface of the 1-hop neighbor; L_HEARD_time is the time until which the MANET interface of the 1-hop neighbor would be considered heard if not considering link quality; L_SYM_time is the time until which the link to the 1-hop neighbor would be considered symmetric if not considering link quality; L_quality is a dimensionless number between 0 (inclusive) and 1 (inclusive) describing the quality of a link; a greater value of L_quality indicating a higher quality link; L_pending is a boolean flag, describing if a link is considered pending (i.e. a candidate, but not yet established, link); L_lost is a boolean flag, describing if a link is considered lost due to link quality; L_time specifies when this Tuple expires and MUST be removed. The status of the link, as obtained through HELLO message exchange, and also taking link quality into account is denoted L_status. Clausen, et al. Expires September 11, 2008 [Page 21] Internet-Draft MANET-NHDP March 2008 L_status can take the values PENDING, HEARD, SYMMETRIC and LOST. The values LOST, SYMMETRIC and HEARD are defined in Section 17.3. The value PENDING is never used in a message, it is only used locally by a node, and any value distinct from LOST, SYMMETRIC and HEARD may be used. L_status is defined by: 1. If L_pending is true, then L_status = PENDING; 2. otherwise, if L_lost is true, then L_status = LOST; 3. otherwise, if L_SYM_time is not expired, then L_status = SYMMETRIC; 4. otherwise, if L_HEARD_time is not expired, then L_status = HEARD; 5. otherwise, L_status = LOST. 7.2. 2-Hop Set A node's 2-Hop Set records symmetric 2-hop neighbors, and the symmetric links to symmetric 1-hop neighbors through which the symmetric 2-hop neighbors can be reached. It consists of 2-Hop Tuples, each representing a single interface address of a symmetric 2-hop neighbor, and a single MANET interface of a symmetric 1-hop neighbor. (N2_neighbor_iface_addr_list, N2_2hop_iface_addr, N2_time) where: N2_neighbor_iface_addr_list is an unordered list of the addresses of the MANET interface of the symmetric 1-hop neighbor from which this information was received; N2_2hop_iface_addr is an address of an interface of a symmetric 2-hop neighbor which has a symmetric link (using any MANET interface) to the indicated symmetric 1-hop neighbor; N2_time specifies when this Tuple expires and MUST be removed. Clausen, et al. Expires September 11, 2008 [Page 22] Internet-Draft MANET-NHDP March 2008 8. Node Information Base Each node maintains a Node Information Base that records information about addresses of current and recently symmetric 1-hop neighbors. 8.1. Neighbor Set A node's Neighbor Set records all interface addresses of each 1-hop neighbor. It consists of Neighbor Tuples, each representing a single 1-hop neighbor: (N_neighbor_iface_addr_list, N_symmetric) where: N_neighbor_iface_addr_list is an unordered list of the interface addresses of a 1-hop neighbor; N_symmetric is a boolean flag, describing if this is a symmetric 1-hop neighbor. 8.2. Lost Neighbor Set A node's Lost Neighbor Set records addresses of all interfaces of nodes which recently were symmetric 1-hop neighbors, but are now advertised as lost. It consists of Lost Neighbor Tuples, each representing a single such address: (NL_neighbor_iface_addr, NL_time) where: NL_neighbor_iface_addr is an address of an interface of a node which recently was a symmetric 1-hop neighbor of this node; NL_time specifies when this Tuple expires and MUST be removed. Clausen, et al. Expires September 11, 2008 [Page 23] Internet-Draft MANET-NHDP March 2008 9. Local Information Base Changes The Local Information Base MUST change to respond to changes in the node's local interface configuration. The node MUST update its Interface and Node Information Bases in response to such changes. If any changes in the Interface and Node Information Bases satisfy any of the conditions described in Section 13, then those changes must be applied immediately, unless noted otherwise. A node MAY transmit HELLO messages in response to these changes. 9.1. Adding an Interface If an interface is added to the node then this is indicated by the addition of a Local Interface Tuple to the Local Interface Set. If the new interface is a MANET interface then an initially empty Interface Information Base MUST be created for this new MANET interface. The actions in Section 9.3 MUST be taken for each address of this added interface. A HELLO message MAY be sent on all MANET interfaces, it SHOULD be sent on the new interface if it is a MANET interface. If using scheduled messages, then a message schedule MUST be established on a new MANET interface. 9.2. Removing an Interface If an interface is removed from the node, then this MUST result in changes to the Local Information Base and the Node Information Base as follows: 1. Identify the Local Interface Tuple that corresponds to the interface to be removed. 2. For each address (henceforth removed address) in the I_local_iface_addr_list of that Local Interface Tuple, create a Removed Interface Address Tuple with: * IR_local_iface_addr = removed address; * IR_time = current time + I_HOLD_TIME. 3. Remove that Local Interface Tuple from the Local Interface Set. 4. If the interface to be removed is a MANET interface (i.e. with I_manet == true) then: 1. Remove the Interface Information Base for that MANET interface; Clausen, et al. Expires September 11, 2008 [Page 24] Internet-Draft MANET-NHDP March 2008 2. All Neighbor Tuples for which none of the addresses in its N_neighbor_iface_addr_list are found in any L_neighbor_iface_addr_list in any remaining Link Set, are removed. If a node removes the Local Interface Tuple that contains the interface address that is used to define the node's originator address, as defined in [packetbb], then the node MAY change originator address. If the removed interface is the last MANET interface of the node, then there will be no remaining Interface Information Bases, and the node will longer participate in this protocol. After removing the interface and making these changes, a HELLO message MAY be sent on all remaining MANET interfaces. 9.3. Adding an Address to an Interface If an address is added to an interface then this is indicated by the addition of an address to the appropriate I_local_iface_addr_list. The following changes MUST be made to the Information Bases: 1. The Neighbor Tuples, if any, whose N_neighbor_iface_addr_list contains the added address, are removed. 2. Any Link Tuples, in any Link Set, whose L_neighbor_iface_addr_list contains: * the added address; OR * any address in the N_neighbor_iface_addr_list of the removed Neighbor Tuples, if any are removed; apply Section 13.1, but not Section 13.3. 3. Any Lost Neighbor Tuples whose NL_neighbor_iface_addr is the added address, are removed. 4. Any 2-Hop Tuples whose N2_2hop_iface_addr is the added address, are removed. After adding the address and making these changes, a HELLO message MAY be sent on all MANET interfaces. Clausen, et al. Expires September 11, 2008 [Page 25] Internet-Draft MANET-NHDP March 2008 9.4. Removing an Address from an Interface If an address (henceforth removed address) is removed from an interface then: 1. Identify the Local Interface Tuple that corresponds to the interface to be removed. 2. If this is the only address of that interface (the only address in the corresponding I_local_iface_addr_list) then remove that interface as specified in Section 9.2. 3. Otherwise: 1. Remove the removed address from this I_local_iface_addr_list. 2. Create a Removed Interface Address Tuple with: + IR_local_iface_addr = removed address; + IR_time = current time + I_HOLD_TIME. If a node removes the interface address that is used to define the node's originator address, as defined in [packetbb], then the node MAY change originator address. After removing the address and making these changes, a HELLO message MAY be sent on all MANET interfaces. Clausen, et al. Expires September 11, 2008 [Page 26] Internet-Draft MANET-NHDP March 2008 10. Packets and Messages The packet and message format used by this protocol is defined in [packetbb], which is used with the following considerations: o This protocol specifies one message type, the HELLO message. o HELLO message header options MAY be used as specified by a protocol which uses this neighborhood discovery protocol. o HELLO messages MUST NOT be forwarded. o HELLO messages MAY be included in multi-message packets as specified in [packetbb]. o Packet header options MAY be used as specified by a protocol which uses this neighborhood discovery protocol. o Received HELLO messages MUST be parsed in accordance with [packetbb]. A HELLO message which is not in conformance with [packetbb] MUST be discarded. o This protocol specifies three address block TLVs. It also uses two message TLVs defined in [timetlv]. These five TLV types are all defined only with Type Extension == 0. TLVs of other types, and of these types but without Type Extension == 0, are ignored by this protocol. All references in this protocol to, for example, a TLV with Type == LINK_STATUS, are to be considered as referring to a TLV with Type == LINK_STATUS and Type Extension == 0. 10.1. HELLO Messages A HELLO message MUST contain: o A VALIDITY_TIME message TLV as specified in [timetlv], representing H_HOLD_TIME for the transmitting MANET interface. The options included in [timetlv] for representing zero and infinite times MUST NOT be used. A HELLO message which is transmitted periodically SHOULD contain, and otherwise MAY contain: o An INTERVAL_TIME message TLV as specified in [timetlv], representing HELLO_INTERVAL for the transmitting MANET interface. The options included in [timetlv] for representing zero and infinite times MUST NOT be used. A HELLO message MAY contain: Clausen, et al. Expires September 11, 2008 [Page 27] Internet-Draft MANET-NHDP March 2008 o One or more address blocks, each with an associated TLV block. o Other message TLVs. 10.1.1. Address Blocks All addresses in a node's Local Interface Set (i.e. in any I_local_iface_addr_list) MUST be included in the address blocks in all generated HELLO messages with the following exception. If the MANET interface on which the HELLO message is to be sent has a single interface address with maximum prefix length then that address MAY be omitted. All addresses of the node's interfaces included in an address block MUST be associated with a TLV with Type == LOCAL_IF, as defined in Table 1. +----------+--------+-----------------------------------------------+ | Name | Value | Description | | | Length | | +----------+--------+-----------------------------------------------+ | LOCAL_IF | 1 | Specifies that the address is an address | | | octet | associated with the interface on which the | | | | message was sent (THIS_IF), another interface | | | | of the sending node (OTHER_IF), or an | | | | unspecified interface of the sending node | | | | (UNSPEC_IF). | +----------+--------+-----------------------------------------------+ Table 1 Note that the value UNSPEC_IF is not used by this protocol. It is provided for an expected alternative use of this TLV. Address blocks MAY contain current or recently lost 1-hop neighbors' interface addresses, each of which is associated with address block TLVs as described in Table 2. Clausen, et al. Expires September 11, 2008 [Page 28] Internet-Draft MANET-NHDP March 2008 +--------------+--------+-------------------------------------------+ | Name | Value | Description | | | Length | | +--------------+--------+-------------------------------------------+ | LINK_STATUS | 1 | Specifies the status of the link from the | | | octet | indicated address (LOST, SYMMETRIC or | | | | HEARD). | | | | | | OTHER_NEIGHB | 1 | Specifies that the address is (SYMMETRIC) | | | octet | or was (LOST) of an interface of a | | | | symmetric 1-hop neighbor of the node | | | | transmitting the HELLO message. | +--------------+--------+-------------------------------------------+ Table 2 A TLV with Type == LINK_STATUS and (Value == SYMMETRIC or Value == LOST) also performs the function of a TLV with Type == OTHER_NEIGHB and the same value. The latter SHOULD NOT also be included. If a TLV with Type == LINK_STATUS and Value == SYMMETRIC is combined with a TLV with Type == OTHER_NEIGHB and Value == LOST then the latter MUST be ignored, and SHOULD NOT be included. See Appendix A. Other addresses MAY be included in address blocks, but MUST NOT be associated with any of the TLVs specified in this section. Clausen, et al. Expires September 11, 2008 [Page 29] Internet-Draft MANET-NHDP March 2008 11. HELLO Message Generation Each MANET interface MUST generate HELLO messages according to the specification in this section. HELLO message generation and scheduling MUST be according to the interface parameters for that MANET interface and MAY be independent for each MANET interface or, interface parameters permitting, MANET interfaces MAY use the same schedule. If transmitting periodic HELLO messages then, following a HELLO message transmission on a MANET interface, another HELLO message MUST be transmitted on the same MANET interface after an interval not greater than HELLO_INTERVAL. Two successive HELLO message transmissions on the same MANET interface MUST be separated by at least HELLO_MIN_INTERVAL, except as noted in Section 11.2.1. 11.1. HELLO Message Specification HELLO messages are generated independently on each MANET interface. All addresses in any I_local_iface_addr_list MUST be included, except that: o If the interface on which the HELLO message is to be sent has a single interface address with maximum prefix length then that interface address MAY be omitted. All such included addresses MUST be associated with a TLV with Type == LOCAL_IF and value according to the following: o If the address is of the sending interface, then Value == THIS_IF. o Otherwise, Value == OTHER_IF. The following addresses of current or former 1-hop neighbors MAY be included in any HELLO message: o Addresses of MANET interfaces of 1-hop neighbors from the Link Set of the Interface Information Base for this MANET interface. o Other addresses of symmetric 1-hop neighbors from the Neighbor Set of this node's Node Information Base. o Addresses of MANET interfaces of previously symmetric or heard 1-hop neighbors connected on this MANET interface from the Link Set of the Interface Information Base for this MANET interface. (These are advertised for a period equal to this interface's L_HOLD_TIME after loss.) Clausen, et al. Expires September 11, 2008 [Page 30] Internet-Draft MANET-NHDP March 2008 o Other addresses of previously symmetric 1-hop neighbors from the Lost Neighbor Set of this node's Node Information Base. (These are advertised for a period equal to N_HOLD_TIME after loss.) Each such address MUST be associated with one or more appropriate TLVs, respecting the parameter REFRESH_INTERVAL for each association for each MANET interface. Specifically: 1. For each address (henceforth linked address) which appears in a Link Tuple in the Link Set for this MANET interface, for which L_status does not equal PENDING, include the linked address with an associated TLV with: * Type = LINK_STATUS; AND * Value = L_status. 2. For each address (henceforth neighbor address) which appears in an N_neighbor_iface_addr_list in a Neighbor Tuple with N_symmetric == true, and which has not already been included with an associated TLV with (Type == LINK_STATUS and Value == SYMMETRIC), include the neighbor address with an associated TLV with: * Type = OTHER_NEIGHB; AND * Value = SYMMETRIC. 3. For each Lost Neighbor Tuple whose NL_neighbor_iface_addr (henceforth lost address) has not already been included, include the lost address with an associated TLV with: * Type = OTHER_NEIGHB; AND * Value = LOST. If a 1-hop neighbor address is specified with more than one associated TLV, then these TLVs MAY be independently included or excluded from each HELLO message. Each such TLV MUST be included associated with that address in a HELLO message sent on that MANET interface in every interval of length equal to that MANET interface's parameter REFRESH_INTERVAL. TLVs associated with the same address included in the same HELLO message MAY be applied to the same or different copies of that address. Clausen, et al. Expires September 11, 2008 [Page 31] Internet-Draft MANET-NHDP March 2008 11.2. HELLO Message Transmission HELLO messages are transmitted in the packet/message format specified by [packetbb] using the "LL-MANET-Routers" multicast address specified by [manet-iana] as destination IP address, using either the "manet" UDP port, or the "manet" IP protocol number specified in [manet-iana]. 11.2.1. HELLO Message Jitter HELLO messages MAY be sent using periodic message generation or externally triggered message generation. If using data link and physical layers which are subject to packet loss due to collisions, HELLO messages SHOULD be jittered as described in [RFC5148]. Internally triggered message generation (such as due to a change in local interfaces) MAY be treated as if externally generated message generation, or MAY be not jittered. HELLO messages MUST NOT be forwarded, and thus message forwarding jitter does not apply to HELLO messages. Each form of jitter described in [RFC5148] requires a parameter MAXJITTER. These interface parameters may be dynamic, and are specified by: o For periodic message generation: HP_MAXJITTER. o For externally triggered message generation: HT_MAXJITTER. When HELLO message generation is delayed in order that a HELLO message is not sent within HELLO_MIN_INTERVAL of the previous HELLO message on the same MANET interface, then HELLO_MIN_INTERVAL SHOULD be reduced by jitter, with maximum reduction HP_MAXJITTER. In this case HP_MAXJITTER MUST NOT be greater than HELLO_MIN_INTERVAL. Clausen, et al. Expires September 11, 2008 [Page 32] Internet-Draft MANET-NHDP March 2008 12. HELLO Message Processing On receiving a HELLO message, a node MUST first check if any address associated with a TLV with Type == LOCAL_IF is one of the receiving node's current or recently used interface addresses (i.e. is in any I_local_iface_addr_list in the Local Interface Set or is equal to any IR_local_iface_addr in the Removed Interface Address Set). If so then the HELLO message MUST be discarded. Otherwise the receiving node MUST update its appropriate Interface Information Base and its Node Information Base according to this section. Section 12.1 to Section 12.4 MUST be performed in the order presented. If any changes satisfy any of the conditions described in Section 13 then the indicated consequences MUST be applied immediately, unless noted otherwise. For the purpose of this section, note the following definitions: o "validity time" is calculated from the VALIDITY_TIME message TLV of the HELLO message as specified in [timetlv]. All information in the HELLO message has the same validity time. o "Receiving Address List" is the I_local_iface_addr_list corresponding to the MANET interface on which the HELLO message was received o "Sending Address List" is the list of the addresses contained in the HELLO message with an associated TLV with Type == LOCAL_IF and Value == THIS_IF. If the Sending Address List is otherwise empty, then the Sending Address List contains a single address (with maximum prefix length) equal to the sending address of the IP datagram in which the HELLO message was included. o "Neighbor Address List" is the Sending Address List, plus the addresses contained in the HELLO message with an associated TLV with Type == LOCAL_IF and Value == OTHER_IF. o EXPIRED indicates that a timer is set to a value clearly preceding the current time (e.g. current time - 1). o "Removed Address List" is a list of addresses created by this HELLO message processing which were formerly reported as local by the node originating the HELLO message, but which are not included in the Neighbor Address List. This list is initialized as empty. o "Lost Address List" is a subset of the Removed Address List containing addresses which were formerly considered as symmetric. This list is initialized as empty. Clausen, et al. Expires September 11, 2008 [Page 33] Internet-Draft MANET-NHDP March 2008 12.1. Updating the Neighbor Set On receiving a HELLO message, the node MUST update its Neighbor Set and populate the Removed Address List and Lost Address List: 1. Find all Neighbor Tuples (hereafter matching Neighbor Tuples) where: * N_neighbor_iface_addr_list contains at least one address in the Neighbor Address List. 2. If there are no matching Neighbor Tuples, then: 1. Create a new Neighbor Tuple with: + N_neighbor_iface_addr_list = Neighbor Address List; + N_symmetric = false. 3. If there is one matching Neighbor Tuple, then: 1. If the N_neighbor_iface_addr_list of the matching Neighbor Tuple is not equal to the Neighbor Address List, then: 1. For each address (henceforth removed address) which is in the N_neighbor_iface_addr_list, but not in the Neighbor Address List: 1. Add the removed address to the Removed Address List. 2. If N_symmetric == true, then add the removed address to the Lost Address List. 2. Update the matching Neighbor Tuple by: - N_neighbor_iface_addr_list = Neighbor Address List. 4. If there are two or more matching Neighbor Tuples, then: 1. For each address (henceforth removed address) which is in the N_neighbor_iface_addr_list of any of the matching Neighbor Tuples: 1. Add the removed address to the Removed Address List. 2. If N_symmetric == true, then add the removed address to the Lost Address List. Clausen, et al. Expires September 11, 2008 [Page 34] Internet-Draft MANET-NHDP March 2008 2. Replace the matching Neighbor Tuples by a single Neighbor Tuple with: + N_neighbor_iface_addr_list = Neighbor Address List; + N_symmetric = false 12.2. Updating the Lost Neighbor Set On receiving a HELLO message, a node MUST update its Lost Neighbor Set: 1. For each address (henceforth lost address) in the Lost Address List, if no Lost Neighbor Tuple with NL_neighbor_iface_addr == lost address exists, then add a Lost Neighbor Tuple with: * NL_neighbor_iface_addr = lost address; * NL_time = current time + N_HOLD_TIME. 12.3. Updating the Link Set On receiving a HELLO message, a node MUST update its Link Set for the MANET interface on which the HELLO message is received: 1. Remove all addresses in the Removed Address List from the L_neighbor_iface_addr_list of all Link Tuples. 2. Remove all Link Tuples whose L_neighbor_iface_addr_list is now empty; apply Section 13.1, but not Section 13.3. 3. Find all Link Tuples (hereafter matching Link Tuples) where: * L_neighbor_iface_addr_list contains one or more addresses in the Sending Address List. 4. If there is more than one matching Link Tuple, then remove them all; apply Section 13.1, but not Section 13.3. 5. If no matching Link Tuples remain, then create a new matching Link Tuple with: * L_neighbor_iface_addr_list = empty; * L_HEARD_time = EXPIRED; * L_SYM_time = EXPIRED; Clausen, et al. Expires September 11, 2008 [Page 35] Internet-Draft MANET-NHDP March 2008 * L_quality = INITIAL_QUALITY; * L_pending = INITIAL_PENDING; * L_lost = false; * L_time = current time + validity time. 6. The matching Link Tuple, existing or new, is then modified as follows: 1. If the node finds any address (henceforth receiving address) in the Receiving Address List in an address block in the HELLO message, then the Link Tuple is modified as follows: 1. If any receiving address in the HELLO message is associated with a TLV with Type == LINK_STATUS and (Value == HEARD or Value == SYMMETRIC) then: - L_SYM_time = current time + validity time. 2. Otherwise if any receiving address in the HELLO message is associated with a TLV with Type == LINK_STATUS and Value == LOST then: 1. if L_SYM_time has not expired, then: 1. L_SYM_time = EXPIRED. 2. if L_status == HEARD or SYMMETRIC, then: * L_time = current time + L_HOLD_TIME. 2. L_neighbor_iface_addr_list = Sending Address List. 3. L_HEARD_time = max(current time + validity time, L_SYM_time). 4. If L_status == PENDING, then: + L_time = max(L_time, L_HEARD_time). 5. Otherwise if L_status == HEARD or SYMMETRIC, then: + L_time = max(L_time, L_HEARD_time + L_HOLD_TIME). Clausen, et al. Expires September 11, 2008 [Page 36] Internet-Draft MANET-NHDP March 2008 12.4. Updating the 2-Hop Set On receiving a HELLO message a node MUST update its 2-Hop Set for the MANET interface on which the HELLO message was received: 1. Remove all addresses in the Removed Address List from the N2_neighbor_iface_addr_list of all 2-Hop Tuples. 2. If the Link Tuple with L_neighbor_iface_addr_list == Sending Address List has L_status == SYMMETRIC then: 1. For each address (henceforth 2-hop address) in an address block of the HELLO message, which is not in the Neighbor Address List, in any I_local_iface_addr_list, or equal to any IR_local_iface_addr: 1. If the 2-hop address has an associated TLV with: - Type == LINK_STATUS and Value == SYMMETRIC; OR - Type == OTHER_NEIGHB and Value == SYMMETRIC, then, if there is no 2-Hop Tuple such that: - N2_neighbor_iface_addr_list contains one or more addresses in the Sending Address List; AND - N2_2hop_iface_addr == 2-hop address. then create a 2-Hop Neighbor Tuple with: - N2_2hop_iface_addr = 2-hop address. This 2-Hop Tuple (existing or new) is then modified as follows: - N2_neighbor_iface_addr_list = Sending Address List; - N2_time = current time + validity time. 2. Otherwise if the 2-hop address has a TLV with: - Type == LINK_STATUS and (Value == LOST or Value == HEARD); OR - Type == OTHER_NEIGHB and Value == LOST; then remove all 2-Hop Tuples with: Clausen, et al. Expires September 11, 2008 [Page 37] Internet-Draft MANET-NHDP March 2008 - N2_neighbor_iface_addr_list contains one or more addresses in the Sending Address List; AND - N2_2hop_iface_addr == 2-hop address. Clausen, et al. Expires September 11, 2008 [Page 38] Internet-Draft MANET-NHDP March 2008 13. Other Information Base Changes The Interface and Node Information Bases MUST be changed when some events occur. These events may result from HELLO message processing, or may be otherwise generated (e.g. expiry of timers or link quality changes). Events which cause changes in the Information Bases are: o A Link Tuple's state changes from symmetric, or the Link Tuple is removed. o A Link Tuple's state changes to symmetric. o A Link Tuple's L_HEARD_time expires, or the Link Tuple is removed. o Local interface address changes, as specified in Section 9. o Link quality changes, as specified in Section 14. A node MAY report updated information in response to any of these changes in HELLO message(s), subject to the constraints in Section 11. A node which transmits HELLO messages in response to such changes SHOULD transmit a HELLO message: o On all MANET interfaces, if the Neighbor Set changes such as to indicate the change in symmetry of any 1-hop neighbors (including addition or removal of symmetric 1-hop neighbors). o Otherwise, on all those MANET interfaces whose Link Set changes such as to indicate a change in status of any 1-hop neighbors (including the addition or removal of any 1-hop neighbors, other than those considered pending). 13.1. Link Tuple Not Symmetric If for any Link Tuple with L_status == SYMMETRIC: o L_status changes to any other value; OR o the Link Tuple is removed; then: 1. All 2-Hop Tuples for the same MANET interface with: Clausen, et al. Expires September 11, 2008 [Page 39] Internet-Draft MANET-NHDP March 2008 * N2_neighbor_iface_addr_list contains one or more addresses in L_neighbor_iface_addr_list; are removed. 2. For the Neighbor Tuple whose N_neighbor_iface_addr_list contains L_neighbor_iface_addr_list: 1. If there are no remaining Link Tuples for any MANET interface with: + L_neighbor_iface_addr_list contained in N_neighbor_iface_addr_list; AND + L_status == SYMMETRIC; then modify the Neighbor Tuple by: 1. N_symmetric = false. 2. For each address (henceforth neighbor address) in N_neighbor_iface_addr_list, add a Lost Neighbor Tuple with: - NL_neighbor_iface_addr = neighbor address; - NL_time = current time + N_HOLD_TIME. 13.2. Link Tuple Symmetric If, for any Link Tuple which does not have L_status == SYMMETRIC: o L_status changes to SYMMETRIC; (this includes a newly created Link Tuple which is immediately updated to have L_status == SYMMETRIC) then: 1. For the Neighbor Tuple whose N_neighbor_iface_addr_list includes L_neighbor_iface_addr_list, set: * N_symmetric = true. 2. Remove all Lost Neighbor Tuples whose NL_neighbor_iface_addr is included in that N_neighbor_iface_addr_list. Clausen, et al. Expires September 11, 2008 [Page 40] Internet-Draft MANET-NHDP March 2008 13.3. Link Tuple Heard Timeout If, for any Link Tuple: o L_HEARD_time expires; OR o the Link Tuple is removed; then: 1. For the Neighbor Tuple whose N_neighbor_iface_addr_list contains L_neighbor_iface_addr_list, if no Link Tuples for any MANET interface remain with: * L_neighbor_iface_addr_list contained in N_neighbor_iface_addr_list; AND * L_HEARD_time is not expired; then remove the Neighbor Tuple. Clausen, et al. Expires September 11, 2008 [Page 41] Internet-Draft MANET-NHDP March 2008 14. Link Quality Link quality is a mechanism whereby a node MAY take considerations other than message exchange into account for determining when a link is and is not a candidate for being considered as HEARD or SYMMETRIC. For deployments where no link quality is used, the considerations in Section 14.1 apply. For deployments were link quality is used, the general principles of link quality usage are described in Section 14.2. Section 14.3 and Section 14.4 detail link quality functioning. Link quality is used only locally by a node, and nodes may fully interoperate whether they are using the same, different or no link quality methods. 14.1. Deployment Without Link Quality In order for a node to not employ link quality, the node MUST define: o INITIAL_PENDING = false; o INITIAL_QUALITY >= HYST_REJECT (there is no reason not to define INITIAL_QUALITY = 1). 14.2. Basic Principles of Link Quality To enable link quality usage, the L_quality value of a Link Tuple is used in conjunction with two thresholds, HYST_ACCEPT and HYST_REJECT, to set the flags L_pending and L_lost of that Link Tuple. Based on these flags, the link status to advertise for that Link Tuple is determined as described in Section 7.1. The use of two thresholds implements link hysteresis, whereby a link which has HYST_REJECT <= L_quality < HYST_ACCEPT may be either accepted or rejected (depending on which threshold it has most recently crossed, or if neither the value of INITIAL_QUALITY). With appropriate values of these parameters, this prevents over-rapid changes of link status. The basic principles of link quality usage are as follows: o A node does not advertise a neighbor interface in any state until L_quality is acceptable: * If INITIAL_PENDING == true, then this is such that L_quality >= HYST_ACCEPT. Clausen, et al. Expires September 11, 2008 [Page 42] Internet-Draft MANET-NHDP March 2008 * Otherwise this is such that L_quality >= HYST_REJECT. To ensure this, a node MUST NOT define INITIAL_PENDING == false and INITIAL_QUALITY < HYST_REJECT. (A node also MUST NOT define INITIAL_PENDING == true and INITIAL_QUALITY >= HYST_ACCEPT.) * A link which is not yet advertised has L_pending == true. o Once L_quality >= HYST_ACCEPT, the L_pending flag is set false, indicating that the link can be advertised. o A link for which L_pending == false is advertised until its L_quality drops below HYST_REJECT. o If a link has L_pending == false and L_quality < HYST_REJECT, the link is LOST and is advertised as such. This link is not reconsidered as a candidate HEARD or SYMMETRIC link until L_quality >= HYST_ACCEPT. o A link which has an acceptable quality may be advertised as HEARD, SYMMETRIC or LOST according to the exchange of HELLO messages. 14.3. When Link Quality Changes If L_quality for a link changes, then the following actions MUST be taken: 1. If L_quality >= HYST_ACCEPT then the corresponding Link Tuple is modified by: 1. L_pending = false. 2. L_lost = false. 3. If L_status == HEARD or L_status == SYMMETRIC, then: + L_time = max(L_time, L_HEARD_time + L_HOLD_TIME) 2. If L_status is not equal to PENDING, and L_quality < HYST_REJECT then the corresponding Link Tuple is modified by: 1. If L_lost == false, then: + L_lost = true + L_time = min(L_time, current time + L_HOLD_TIME) Any appropriate action indicted in Section 13 MUST also be taken. Clausen, et al. Expires September 11, 2008 [Page 43] Internet-Draft MANET-NHDP March 2008 If L_quality for a link is updated based on HELLO message reception, or on reception of a packet including a HELLO message, then L_quality MUST be updated prior to the HELLO message processing described in Section 12. (If the receipt of the HELLO message, or the packet containing it, creates the Link Tuple then the Link Tuple MUST be created with the appropriately updated L_quality value, rather than with L_quality = INITIAL_QUALITY.) 14.4. Updating Link Quality A node MAY update link quality based on any information available to it. Particular cases that MAY be used include: o Information from the link layer, such as signal to noise ratio or acknowledgement reception and loss information. o Receipt or loss of packets. If packets include a packet sequence number as defined in [packetbb], then packets on a link SHOULD have sequential packet sequence numbers, whether or not they include HELLO messages. Link quality can be updated when a packet is received based on, for example, whether the last N out of M packets on the link were received, or a "leaky integrator" tracking packets. o Receipt or loss of HELLO messages. If the maximum interval between HELLO messages is known (such as by inclusion of a message TLV with Type == INTERVAL_TIME, as defined in [timetlv], in HELLO messages) then the loss of HELLO messages can be determined without the need to receive a HELLO message. Note that if this case is combined with the previous case then care must be taken to avoid "double counting" a lost HELLO message in a lost packet. Clausen, et al. Expires September 11, 2008 [Page 44] Internet-Draft MANET-NHDP March 2008 15. Proposed Values for Parameters and Constants This section lists the parameters and constants used in the specification of the protocol, and proposed values of each which may be used when a single value of each is used. 15.1. Message Interval Interface Parameters o HELLO_INTERVAL = 2 seconds o HELLO_MIN_INTERVAL = HELLO_INTERVAL/4 o REFRESH_INTERVAL = HELLO_INTERVAL 15.2. Information Validity Time Interface Parameters o H_HOLD_TIME = 3 x REFRESH_INTERVAL o L_HOLD_TIME = H_HOLD_TIME 15.3. Information Validity Time Node Parameters o N_HOLD_TIME = L_HOLD_TIME o I_HOLD_TIME = N_HOLD_TIME 15.4. Link Quality Interface Parameters If link quality is changed, then parameter values will depend on the link quality process. If link quality is not changed, then: o HYST_ACCEPT = 1 o HYST_REJECT = 0 o INITIAL_QUALITY = 1 o INITIAL_PENDING = false 15.5. Jitter Interface Parameters o HP_MAXJITTER = HELLO_INTERVAL/4 o HT_MAXJITTER = HP_MAXJITTER Clausen, et al. Expires September 11, 2008 [Page 45] Internet-Draft MANET-NHDP March 2008 15.6. Constants o C = 1/1024 second Clausen, et al. Expires September 11, 2008 [Page 46] Internet-Draft MANET-NHDP March 2008 16. Security Considerations The objective of this protocol is to allow each node in the network to acquire information describing its 1-hop and symmetric 2-hop neighborhoods. This is acquired through message exchange between neighboring nodes. The information is made available through the Interface Information Bases and Node Information Base, describing the node's 1-hop neighborhood and symmetric 2-hop neighborhood. Under normal circumstances, the information recorded in these Information Bases is correct - i.e. corresponds to the actual network topology, apart from any changes which have not (yet) been tracked by the HELLO message exchanges. If some node for some reason, malice or malfunction, injects invalid HELLO messages, incorrect information may be recorded in the Information Bases. The protocol specification does, however, prevent inconsistent information from being injected in the protocol sets through the constraints in Appendix C. The exact consequence of information inexactness depends on the use of these Information Bases, and should be reflected in the specification of protocols which use information provided by NHDP. This section, therefore, only outlines the ways in which correctly formed, but still invalid, HELLO messages may appear. 16.1. Invalid HELLO messages A correctly formed, but still invalid, HELLO message may take any of the following forms. Note that a present or absent address in an address block, does not in and by itself cause a problem. It is the presence, absence, or incorrectness of associated LOCAL_IF, LINK_STATUS and OTHER_NEIGHB TLVs that causes problems. A node may provide false information about its own identity: * The HELLO message may contain addresses with an associated LOCAL_IF TLV which do not correspond to addresses of interfaces of the node transmitting the HELLO message. * The HELLO message may omit addresses, or their associated LOCAL_IF TLV, of interfaces of the local node transmitting the HELLO message (other than the allowed omission of the only local interface address of the MANET interface over which the HELLO message is transmitted, if that is the case). * The HELLO message may incorrectly specify the LOCAL_IF TLV value associated with one or more local interface addresses, Clausen, et al. Expires September 11, 2008 [Page 47] Internet-Draft MANET-NHDP March 2008 indicating incorrectly whether they are associated with the MANET interface over which the HELLO message is transmitted. A node may provide false information about the identity of other nodes: * A present LINK_STATUS TLV may, incorrectly, identify an address as being of a MANET interface which is or was heard on the MANET interface over which the HELLO message is transmitted. * A consistently absent LINK_STATUS TLV may, incorrectly, fail to identify an address as being of a MANET interface which is or was heard on the MANET interface over which the HELLO message is transmitted. * A present OTHER_NEIGHB TLV may, incorrectly, identify an address as being of a node which is or was in the sending node's symmetric 1-hop neighborhood; * A consistently absent OTHER_NEIGHB TLV may, incorrectly, fail to identify an address as being of a node which is or was in the sending node's symmetric 1-hop neighborhood; * The value of a LINK_STATUS TLV may incorrectly indicate the status (LOST, SYMMETRIC or HEARD) of the link from a 1-hop neighbor. * The value of an OTHER_NEIGHB TLV may incorrectly indicate the status (LOST or SYMMETRIC) of a symmetric 1-hop neighbor. Clausen, et al. Expires September 11, 2008 [Page 48] Internet-Draft MANET-NHDP March 2008 17. IANA Considerations 17.1. Message Types This specification defines one message type, which must be allocated from the "Assigned Message Types" repository of [packetbb] with assignment as specified in Table 3. +-------+------+------------------+ | Name | Type | Description | +-------+------+------------------+ | HELLO | TBD1 | Local signaling. | +-------+------+------------------+ Table 3 17.2. TLV Types This specification defines three address block TLV types, which must be allocated from the "Assigned Address Block TLV Types" repository of [packetbb] with assignments as specified in Table 4. +--------------+------+-----------+---------------------------------+ | Name | Type | Type | Description | | | | extension | | +--------------+------+-----------+---------------------------------+ | LOCAL_IF | TBD2 | 0 | Specifies that the address is | | | | | associated with a local | | | | | interface of the sending node. | | | | | | | | | 1-255 | RESERVED | | | | | | | LINK_STATUS | TBD3 | 0 | Specifies the status of the | | | | | link from the indicated address | | | | | (LOST, SYMMETRIC or HEARD). | | | | | | | | | 1-255 | RESERVED | | | | | | | OTHER_NEIGHB | TBD4 | 0 | Specifies that the address is | | | | | (SYMMETRIC) or recently was | | | | | (LOST) of an interface of a | | | | | symmetric 1-hop neighbor of the | | | | | node transmitting the message. | | | | | | | | | 1-255 | RESERVED | +--------------+------+-----------+---------------------------------+ Table 4 Clausen, et al. Expires September 11, 2008 [Page 49] Internet-Draft MANET-NHDP March 2008 Type extensions indicated as RESERVED may be allocated by standards action, as specified in [RFC2434]. 17.3. LINK_STATUS and OTHER_NEIGHB Values The values which the LOCAL_IF TLV can use are the following: o UNSPEC_IF = 0 o THIS_IF = 1 o OTHER_IF = 2 The values which the LINK_STATUS TLV can use are the following: o LOST = 0 o SYMMETRIC = 1 o HEARD = 2 The values which the OTHER_NEIGHB TLV can use are the following: o LOST = 0 o SYMMETRIC = 1 Clausen, et al. Expires September 11, 2008 [Page 50] Internet-Draft MANET-NHDP March 2008 18. References 18.1. Normative References [packetbb] Clausen, T., Dearlove, C., Dean, J., and C. Adjih, "Generalized MANET Packet/Message Format", Work In Progress draft-ietf-manet-packetbb-12.txt, March 2008. [manet-iana] Chakeres, I., "IANA Allocations for MANET Protocols", Work In Progress draft-ietf-manet-iana-07.txt, November 2007. [timetlv] Clausen, T. and C. Dearlove, "Representing multi-value time in MANETs", Work In Progress draft-ietf-manet-timetlv-04.txt, November 2007. [RFC5148] Clausen, T., Dearlove, C., and B. Adamson, "Jitter considerations in MANETs", RFC 5148, February 2008. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, BCP 14, March 1997. [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 2434, BCP 26, October 1998. 18.2. Informative References [RFC3626] Clausen, T. and P. Jacquet, "The Optimized Link State Routing Protocol", RFC 3626, October 2003. [RFC2501] Macker, J. and S. Corson, "Mobile Ad hoc Networking (MANET): Routing Protocol Performance Issues and Evaluation Considerations", RFC 2501, January 1999. Clausen, et al. Expires September 11, 2008 [Page 51] Internet-Draft MANET-NHDP March 2008 Appendix A. Address Block TLV Combinations The algorithm for generating HELLO messages in Section 11 specifies which 1-hop addresses may be included in the address blocks, and with which associated TLVs. These TLVs may have Type == LINK_STATUS or Type == OTHER_NEIGHB, or both. TLVs with Type == LINK_STATUS may have three possible values (Value == HEARD, Value == SYMMETRIC or Value == LOST), and TLVs of TYPE == OTHER_NEIGHB may have two possible values (Value == SYMMETRIC or Value == LOST). When both TLVs are associated with the same address only certain combinations of these TLV values are necessary, and are the only combinations generated by the algorithm in Section 11. These combinations are indicated in Table 5. Cells labeled with "Yes" indicate the possible combinations which are generated by the algorithm in Section 11. Cells labeled with "No" indicate combinations not generated by the algorithm in Section 11, but which are correctly parsed and interpreted by the algorithm in Section 12. +----------------+----------------+----------------+----------------+ | | Type == | Type == | Type == | | | OTHER_NEIGHB | OTHER_NEIGHB, | OTHER_NEIGHB, | | | (absent) | Value == | Value == LOST | | | | SYMMETRIC | | +----------------+----------------+----------------+----------------+ | Type == | No | Yes | Yes | | LINK_STATUS | | | | | (absent) | | | | | | | | | | Type == | Yes | Yes | Yes | | LINK_STATUS, | | | | | Value == HEARD | | | | | | | | | | Type == | Yes | No | No | | LINK_STATUS, | | | | | Value == | | | | | SYMMETRIC | | | | | | | | | | Type == | Yes | Yes | No | | LINK_STATUS, | | | | | Value == LOST | | | | +----------------+----------------+----------------+----------------+ Table 5 Clausen, et al. Expires September 11, 2008 [Page 52] Internet-Draft MANET-NHDP March 2008 Appendix B. HELLO Message Example An example HELLO message, transmitted by an originator node with a single MANET interface, is as follows. The message uses IPv4 (four octet) addresses without specified prefix lengths. The message is transmitted with a full message header other than version number (message semantics octet is 30) with a hop limit of 1 and a hop count of 0. The overall message length is 49 octets. The message contains a message TLV block with content length 8 octets containing two message TLVs, of types VALIDITY_TIME and INTERVAL_TIME. Each uses a TLV with semantics value 8, indicating that each has a value. Each has a value length of 1 octet; the values included (0x64 and 0x58) are time codes representing the default values of parameters H_HOLD_TIME and HELLO_INTERVAL, respectively (6 seconds and 2 seconds) assuming the default value of constant C (1/1024 second). The message has a single address block containing 5 addresses. The semantics octet value 1 indicates an address head but no address tail. The head length of 3 octets indicates address mid sections of one octet each (Mid 0 to Mid 4). The following TLV block (content length 14 octets) includes two TLVs. The first is a LOCAL_IF TLV which (with semantics value 10) indicates that a single address, with index 0 (i.e. Head:Mid 0) is the single local interface address of this node (the 1 octet value LOCAL_IF indicates that this address is of this interface). The second is a LINK_STATUS TLV which (with semantics octet 44) specifies the link status values of all reported neighbors in a single multivalue TLV which covers the addresses with indexes 1 to 4. The TLV value length of 4 octets indicates one octet per value per address. The last four addresses are first and second HEARD, third SYMMETRIC, and fourth LOST. Clausen, et al. Expires September 11, 2008 [Page 53] Internet-Draft MANET-NHDP March 2008 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HELLO |0 0 0 1 1 1 1 0|0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Originator Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0| Message Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0| VALIDITY_TIME |0 0 0 0 1 0 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 1|0 1 1 0 0 1 0 0| INTERVAL_TIME |0 0 0 0 1 0 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 1|0 1 0 1 1 0 0 0|0 0 0 0 0 1 0 1|0 0 0 0 0 0 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 1 1| Head | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mid 0 | Mid 1 | Mid 2 | Mid 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mid 4 |0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0| LOCAL_IF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1 0 0 0 0|0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 1| THIS_IF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LINK_STATUS |0 0 1 0 1 1 0 0|0 0 0 0 0 0 0 1|0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 1 0 0| HEARD | HEARD | SYMMETRIC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LOST | +-+-+-+-+-+-+-+-+ Note that this example is for illustrative purposes. The essential information can be conveyed, more efficiently (assuming that the local interface address will be supplied by IP, and that the INTERVAL_TIME is not needed) by the 29 octets: Clausen, et al. Expires September 11, 2008 [Page 54] Internet-Draft MANET-NHDP March 2008 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HELLO |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| VALIDITY_TIME |0 0 0 0 1 0 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 1|0 1 1 0 0 1 0 0|0 0 0 0 0 1 0 0|0 0 0 0 0 0 1 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 1 1| Head | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mid 1 | Mid 2 | Mid 3 | Mid 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1| LINK_STATUS |0 0 1 0 1 0 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 1 0 0| HEARD | HEARD | SYMMETRIC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LOST | +-+-+-+-+-+-+-+-+ Clausen, et al. Expires September 11, 2008 [Page 55] Internet-Draft MANET-NHDP March 2008 Appendix C. Constraints Any process which updates the Local Information Base or the Node Information Base MUST ensure that all constraints specified in this appendix are maintained. In each Local Interface Tuple: o I_local_iface_addr_list MUST NOT be empty. o I_local_iface_addr_list MUST NOT contain any duplicated addresses. o I_local_iface_addr_list MUST NOT contain any address which is in the I_local_iface_addr_list of any other Local Interface Tuple. In each Removed Interface Address Tuple: o IR_local_iface_addr MUST NOT contain any address which is in the I_local_iface_addr_list of any Local Interface Tuple. o IR_local_iface_addr MUST NOT equal the IR_local_iface_addr of any other Removed Interface Address Tuple. In each Link Tuple: o L_neighbor_iface_addr_list MUST NOT be empty. o L_neighbor_iface_addr_list MUST NOT contain any address which is in the I_local_iface_addr_list of any Local Interface Tuple or the IR_local_iface_addr of any Removed Interface Address Tuple. o L_neighbor_iface_addr_list MUST NOT contain any duplicated addresses. o L_neighbor_iface_addr_list MUST NOT contain any address which is in the L_neighbor_iface_addr_list of any other Link Tuple in the same Link Set. o If L_HEARD_time has not expired then there MUST be a Neighbor Tuple whose N_neighbor_iface_addr_list contains L_neighbor_iface_addr_list. o L_HEARD_time MUST NOT be greater than L_time. o L_SYM_time MUST NOT be greater than L_HEARD_time (unless both are expired). Clausen, et al. Expires September 11, 2008 [Page 56] Internet-Draft MANET-NHDP March 2008 o L_quality MUST NOT be less than 0 or greater than 1. o If L_quality >= HYST_ACCEPT then L_pending MUST be false. o If L_quality < HYST_REJECT then L_status MUST be PENDING or LOST. o L_pending MUST NOT be set to true if it is currently false. In each Neighbor Tuple: o N_neighbor_iface_addr_list MUST NOT contain any address which is in the I_local_iface_addr_list of any Local Interface Tuple or the IR_local_iface_addr of any Removed Interface Address Tuple. o N_neighbor_iface_addr_list MUST NOT contain any duplicated addresses. o N_neighbor_iface_addr_list MUST NOT contain any address which is in the N_neighbor_iface_addr_list of any other Neighbor Tuple. o If N_symmetric == true, then there MUST be one or more Link Tuples with: * L_neighbor_iface_addr_list contained in N_neighbor_iface_addr_list; AND * L_status == SYMMETRIC. o If N_symmetric == false, then there MUST be one or more Link Tuples with: * L_neighbor_iface_addr_list contained in N_neighbor_iface_addr_list. All such Link Tuples MUST NOT have L_status == SYMMETRIC. At least one such Link Tuple MUST have L_HEARD_time not expired. In each Lost Neighbor Tuple: o NL_neighbor_iface_addr MUST NOT be in the I_local_iface_addr_list of any Local Interface Tuple or the IR_local_iface_addr of any Removed Interface Address Tuple. o NL_neighbor_iface_addr MUST NOT equal the NL_neighbor_iface_addr of any other Lost Neighbor Tuple. o NL_neighbor_iface_addr MUST NOT be in the N_neighbor_iface_addr_list of any Neighbor Tuple with N_symmetric Clausen, et al. Expires September 11, 2008 [Page 57] Internet-Draft MANET-NHDP March 2008 == true. In each 2-Hop Tuple: o There MUST be a Link Tuple associated with the same MANET interface with: * L_neighbor_iface_addr_list == N2_neighbor_iface_addr_list; AND * L_status == SYMMETRIC. o N2_2hop_iface_addr MUST NOT be in the I_local_iface_addr_list of any Local Interface Tuple or the IR_local_iface_addr of any Removed Interface Address Tuple. o N2_2hop_iface_addr MUST NOT be the N2_2hop_iface_addr of any other 2-Hop Tuple in the same 2-Hop Set and with the same N2_neighbor_iface_addr_list. o N2_2hop_iface_addr MUST NOT be in the N2_neighbor_iface_addr_list of the same 2-Hop Tuple. Clausen, et al. Expires September 11, 2008 [Page 58] Internet-Draft MANET-NHDP March 2008 Appendix D. Flow and Congestion Control This protocol specifies one message type, the HELLO message. The maximum size of a HELLO message is proportional to the size of the originating node's 1-hop neighborhood. HELLO messages MUST NOT be forwarded. A node MUST report its 1-hop neighborhood in HELLO messages on each of its MANET interfaces at least each REFRESH_INTERVAL. This puts a lower bound on the control traffic generated by each node in the network employing this protocol. A node MUST ensure that two successive HELLO messages sent on the same MANET interface are separated by at least HELLO_MIN_INTERVAL. (If using jitter then this may be reduced to a mean minimum value of HELLO_MIN_INTERVAL - HP_MAXJITTER/2.) Thus, this puts an upper bound on the control traffic generated by each node in the network employing this protocol. Clausen, et al. Expires September 11, 2008 [Page 59] Internet-Draft MANET-NHDP March 2008 Appendix E. Contributors This specification is the result of the joint efforts of the following contributors, listed alphabetically. o Brian Adamson, NRL, USA, o Cedric Adjih, INRIA, France, o Thomas Heide Clausen, LIX, France, o Justin Dean, NRL, USA, o Christopher Dearlove, BAE Systems, UK, o Philippe Jacquet, INRIA, France, Clausen, et al. Expires September 11, 2008 [Page 60] Internet-Draft MANET-NHDP March 2008 Appendix F. Acknowledgements The authors would like to acknowledge the team behind OLSRv1, specified in RFC3626 for their contributions. The authors would like to gratefully acknowledge the following people for intense technical discussions, early reviews and comments on the specification and its components: Joe Macker (NRL), Alan Cullen (BAE Systems), and the entire IETF MANET working group. Clausen, et al. Expires September 11, 2008 [Page 61] Internet-Draft MANET-NHDP March 2008 Authors' Addresses Thomas Heide Clausen LIX, Ecole Polytechnique, France Phone: +33 6 6058 9349 EMail: T.Clausen@computer.org URI: http://www.ThomasClausen.org/ Christopher Dearlove BAE Systems Advanced Technology Centre Phone: +44 1245 242194 EMail: chris.dearlove@baesystems.com URI: http://www.baesystems.com/ Justin W. Dean Naval Research Laboratory Phone: +1 202 767 3397 EMail: jdean@itd.nrl.navy.mil URI: http://pf.itd.nrl.navy.mil/ The OLSRv2 Design Team MANET Working Group Clausen, et al. Expires September 11, 2008 [Page 62] Internet-Draft MANET-NHDP March 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Clausen, et al. Expires September 11, 2008 [Page 63]