T Clausen

Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)

This document revises, extends, and replaces RFC 6622. It describes general and flexible TLVs for representing cryptographic Integrity Check Values (ICVs) and timestamps, using the generalized Mobile Ad Hoc Network (MANET) packet/message format defined in RFC 5444. It defines two Packet TLVs, two Message TLVs, and two Address Block TLVs for affixing ICVs and timestamps to a packet, a message, and one or more addresses, respectively.

Introduction

This document specifies a syntactical representation of securityrelated information for use with [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] addresses, messages, and packets. It also specifies IANA registrations of TLV types and type extension registries for these TLV types. This specification does not represent a stand-alone protocol, but it is intended for use by MANET routing protocols or security extensions thereof. Specifically, this document, which revises, extends, and replaces [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], specifies: o Two kinds of TLV: one for carrying Integrity Check Values (ICVs) and one for timestamps in packets, messages, and Address Blocks as defined by [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF].

o A generic framework for use of these TLVs, accounting for specific features of Packet, Message, and Address Block TLVs.

o IANA registrations for TLVs, and registries for TLV type extensions, replacing those from [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF].

This document specifies IANA registries for recording code points for ICV TLVs and TIMESTAMP TLVs, as well as timestamps, hash functions, and cryptographic functions.

Moreover, in Section 12, this document defines the following: o A method for generating ICVs using a combination of a cryptographic function and a hash function and for including such ICVs in the value field of a TLV. This document obsoletes [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], replacing that document as the specification of two TLV types, TIMESTAMP and ICV, for packets, messages and Address Blocks. For the ICV type, this document specifies a new type extension, 2 (see Section 12), in addition to including the original type extensions (0 and 1) from [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF].

The TLV value of an ICV TLV with type extension = 2 has the same internal structure as an ICV TLV with type extension = 1 but is calculated also over the source address of the IP datagram carrying the packet, message, or Address Block. The rationale for adding this type extension is that some MANET protocols, such as [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF], use the IP source address of the IP datagram carrying the packet, message, or Address Block, e.g., to identify links with neighbor routers. If this address is not otherwise contained in the packet, message, or Address Block payload (which is permitted, e.g., in [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF]), then the address is not protected against tampering.

This document also incorporates a number of editorial improvements over [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF]. In particular, it makes it clear that an ICV TLV may be used to carry a truncated ICV and that a single or multivalue TIMESTAMP or ICV Address Block TLV may cover more than one address. Moreover, to be consistent with the terminology in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF], the name of the TLVs specified in this document have changed from "Packet ICV TLV" to "ICV Packet TLV" and from "Packet TIMESTAMP TLV" to "TIMESTAMP Packet TLV" (and similar for Message and Address Block TLVs).

A normative requirement in Section 9.2 has changed from SHOULD to MUST in the following sentence:

If a message contains one or more TIMESTAMP TLVs and one or more ICV TLVs, then the TIMESTAMP TLVs (as well as any other Message TLVs) MUST be added to the message before the ICV TLVs....

Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. This document uses the terminology and notation defined in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF].

In particular, the following TLV fields and notation from [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] are used in this specification: <msg-hop-limit> is the hop limit of a message, as specified in Section 5.2 of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF].

<msg-hop-count> is the hop count of a message, as specified in Section 5.2 of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF].

<length> is the length of the value field in a TLV in octets, as specified in Section 5.4.1 of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF].

single-length is the length of a single value in the value field in a TLV in octets, as specified in Section 5.4.1 of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF]. (It is equal to <length> except in a multivalue Address Block TLV.)

In addition to using the regular expressions defined in Section 2.1.1 of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF], this document defines the following:

+ -One or more occurrences of the preceding element or group.

Applicability Statement

MANET routing protocols using the format defined in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] are accorded the ability to carry additional information in control messages and packets through the inclusion of TLVs. Information so included MAY be used by a MANET routing protocol, or by an extension of a MANET routing protocol, according to its specification.

This document specifies how to include an ICV for a packet, a message, and addresses in an Address Block within a message, using such TLVs. This document also specifies how to treat an empty Packet TLV Block, and "mutable" fields, specifically the <msg-hop-count> and <msg-hop-limit> fields, if present in the Message Header when calculating ICVs, such that the resulting ICV can be correctly verified by any recipient.

This document describes a generic framework for creating ICVs, and how to include these ICVs in TLVs. In Section 12, an example method for calculating such ICVs is given, using a cryptographic function and a hash function, for which two TLV type extensions are allocated.

This document does not specify a protocol. Protocol specifications that make use of the framework, specified in this document, will reference this document in a normative way, and they may require the implementation of some or all of the algorithms described in this document. As this document does not specify a protocol itself, key management and key exchange mechanisms are out of scope and may be specified in the protocol or protocol extension using this specification.

Security Architecture

MANET routing protocol specifications may have a clause allowing a control message to be rejected as "badly formed" or "insecure" prior to the message being processed or forwarded. In particular, MANET routing protocols such as the Neighborhood Discovery Protocol (NHDP) [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] and the Optimized Link State Routing Protocol version 2 [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF] recognize external reasons (such as failure to verify an ICV) for rejecting a message that would be considered "invalid for processing".

This architecture is a result of the observation that with respect to security in MANETs, "one size rarely fits all" and that MANET routing protocol deployment domains have varying security requirements ranging from "unbreakable" to "virtually none". The virtue of this approach is that MANET routing protocol specifications (and implementations) can remain "generic", with extensions providing proper security mechanisms specific to a deployment domain.

The MANET routing protocol "security architecture", in which this specification situates itself, can therefore be summarized as follows:

o MANET routing protocol specifications, each with a clause allowing an extension to reject a message (prior to processing/forwarding) as "badly formed" or "insecure".

o MANET routing protocol security extensions, each rejecting messages as "badly formed" or "insecure", as appropriate for a given security requirement specific to a deployment domain.

o Code points and an exchange format for information, necessary for specification of such MANET routing protocol security extensions.

This document addresses the last of the points above, by specifying a common exchange format for cryptographic ICVs and timestamps, making reservations from within the Packet TLV, Message TLV, and Address Block TLV registries of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF], to be used by (and shared among) MANET routing protocol security extensions.

For the specific decomposition of an ICV using a cryptographic function and a hash function (specified in Section 12), this document specifies two IANA registries (see Section 13) for code points for hash functions and cryptographic functions. o A specific example of the Security Considerations section of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] (the authentication part).

Overview and Functioning

This document specifies a syntactical representation of securityrelated information for use with [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] addresses, messages, and packets, and also specifies IANA registrations (see Section 13) of TLV types and type extension registries for these TLV types.

Moreover, this document provides guidelines for how MANET routing protocols, and MANET routing protocol extensions using this specification, should treat ICV and Timestamp TLVs, and mutable fields in messages. This specification does not represent a standalone protocol. MANET routing protocols, and MANET routing protocol extensions using this specification, MUST provide instructions as to how to handle packets, messages, and addresses with security information, associated as specified in this document.

This document specifies TLV type assignments (see Section 13) from the registries defined for Packet, Message, and Address Block TLVs in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF]. When a TLV type is assigned from one of these registries, a registry for type extensions for that TLV type is created by IANA. This document specifies these type extension registries, in order to specify internal structure (and accompanying processing) of the <value> field of a TLV.

For example, and as specified in this document, an ICV TLV with type extension = 0 specifies that the <value> field has no predefined internal structure, but is simply a sequence of octets. An ICV TLV with type extension = 1 specifies that the <value> field has a predefined internal structure and defines its interpretation. An ICV TLV with type extension = 2 (added in this document) is the same as an ICV TLV with type extension = 1, except that the integrity protection also covers the source address of the IP datagram carrying the packet, message, or Address Block.

Specifically, with type extension = 1 or type extension = 2, the <value> field contains the result of combining a cryptographic function and a hash function, calculated over the contents of the packet, message, or Address Block. The <value> field contains subfields indicating which hash function and cryptographic function have been used, as specified in Section 12. Other documents can request assignments for other type extensions; if they do so, they MUST specify their internal structure (if any) and interpretation.

General ICV TLV Structure

The value of the ICV TLV is: <value> := <ICV-value>+ where:

<ICV-value> is a field, of length <length> octets (except in a multivalue Address Block TLV, where each <ICV-value> is of length single-length octets) that contains the information to be interpreted by the ICV verification process, as specified by the type extension.

Note that this does not specify how to calculate the <ICV-value> nor the internal structure thereof, if any; such information MUST be specified by the type extension for the ICV TLV type; see Section 13. This document specifies three such type extensions: one for ICVs without predefined structures and two for ICVs constructed combining a cryptographic function and a hash function.

General Timestamp TLV Structure

The value of the Timestamp TLV is: <value> := <time-value>+ where:

<time-value> is a field, of length <length> octets (except in a multivalue Address Block TLV, where each <time-value> is of length single-length octets) that contains the timestamp.

Note that this does not specify how to calculate the <time-value> nor the internal structure thereof, if any; such information MUST be specified by the type extension for the TIMESTAMP TLV type; see Section 13.

A timestamp is essentially "freshness information". As such, its setting and interpretation are to be determined by the MANET routing protocol, or MANET routing protocol extension, that uses the timestamp and can, for example, correspond to a POSIX timestamp, GPS timestamp, or a simple sequence number. Note that ensuring time synchronization in a MANET may be difficult because of the

Packet TLVs

Two Packet TLVs are defined: one for including the cryptographic ICV of a packet and one for including the timestamp indicating the time at which the cryptographic ICV was calculated.

ICV Packet TLV

An ICV Packet TLV is an example of an ICV TLV as described in Section 6. When determining the <ICV-value> for a packet, and adding an ICV Packet TLV to a packet, the following considerations MUST be applied:

o Because packets as defined in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] are never forwarded by routers, no special considerations are required regarding mutable fields (i.e., <msg-hop-count> and <msg-hop-limit>), if present within any messages in the packet, when calculating the ICV. A TIMESTAMP Packet TLV is an example of a Timestamp TLV as described in Section 7. If a packet contains one or more TIMESTAMP TLVs and one or more ICV TLVs, then the TIMESTAMP TLVs (as well as any other Packet TLVs) MUST be added to the packet before the ICV TLVs, in order to include the timestamps and other TLVs in the calculation of the ICVs.

Message TLVs

Two Message TLVs are defined: one for including the cryptographic ICV of a message and one for including the timestamp indicating the time at which the cryptographic ICV was calculated.

ICV Message TLV

An ICV Message TLV is an example of an ICV TLV as described in Section 6. When determining the <ICV-value> for a message, the following considerations MUST be applied:

o The fields <msg-hop-limit> and <msg-hop-count>, if present in the Message Header, MUST both be assumed to have the value 0 (zero) when calculating the ICV.

o Any ICV Message TLVs already present in the Message TLV Block MUST be removed before calculating the ICV, and the message size as well as the Message TLV Block size MUST be recalculated accordingly. Also, all relevant TLVs other than ICV TLVs MUST be added prior to ICV value calculation.

o Any removed ICV Message TLVs MUST be restored after having calculated the ICV, and the message size as well as the Message TLV Block size MUST be recalculated accordingly.

The rationale for removing any ICV Message TLVs already present prior to calculating the ICV is that several ICV TLVs may be added to the same message, e.g., using different ICV cryptographic and/or hash functions.

TIMESTAMP Message TLV

A TIMESTAMP Message TLV is an example of a Timestamp TLV as described in Section 7. If a message contains one or more TIMESTAMP TLVs and one or more ICV TLVs, then the TIMESTAMP TLVs (as well as any other Message TLVs) MUST be added to the message before the ICV TLVs, in order to include the timestamps and other Message TLVs in the calculation of the ICV. The rationale for not concatenating the addresses with any ICV TLV values already associated with the addresses when calculating the ICV is that several ICVs may be added to the same address or addresses, e.g., using different ICV cryptographic and/or hash functions, and the order of addition is not known to the recipient.

TIMESTAMP Address Block TLV

A TIMESTAMP Address Block TLV is an example of a Timestamp TLV as described in Section 7. If one or more TIMESTAMP TLVs and one or more ICV TLVs are associated with an address, the relevant TIMESTAMP TLV <time-value>(s) MUST be included before calculating the value of the ICV to be contained in the ICV TLV value (i.e., concatenated with the associated addresses and any other values as described in Section 10.1).

ICV: Basic

The basic ICV, represented by way of an ICV TLV with type extension = 0, has as TLV value a simple bit-field without specified structure (i.e, without explicitly included hash function, crypto function, key ID or other parameters). Moreover, it is not specified how to calculate the <ICV-value>. It is assumed that the mechanism specifying how ICVs are calculated and verified, as well as which parameters (if any) need to be exchanged prior to using the TLV with The <ICV-value>, when using type extension = 0, is:

<ICV-value> := <ICV-data> where:

<ICV-data> is a field, of length <length> octets (or single-length octets in a multivalue Address Block TLV) that contains the cryptographic ICV.

12. ICV: Hash Function and Cryptographic Function One common way of calculating an ICV is combining a cryptographic function and a hash function applied to the content. This decomposition is specified in this section, using either type extension = 1 or type extension = 2, in the ICV TLVs.

General ICV TLV Structure

The following data structure allows representation of a cryptographic ICV, including specification of the appropriate hash function and cryptographic function used for calculating the ICV:

<ICV-value> := <hash-function> <cryptographic-function> <key-id-length> <key-id>? <ICV-data> where:

<hash-function> is a one-octet unsigned integer field specifying the hash function.

<cryptographic-function> is a one-octet unsigned integer field specifying the cryptographic function.

<key-id-length> is a one-octet unsigned integer field specifying the length of the <key-id> field as a number of octets. The value zero (0x00) is reserved for using a single pre-installed, shared key.

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RFC 7182

ICV and Timestamp TLVs for MANETs April 2014 <key-id> is a field specifying the key identifier of the key that was used to calculate the ICV of the message, which allows unique identification of different keys with the same originator. It is the responsibility of each key originator to make sure that actively used keys that it issues have distinct key identifiers.

If <key-id-length> equals zero (0x00), the <key-id> field is not contained in the TLV, and a single pre-installed, shared key is used.

<ICV-data> is a field with length <length> -3 -<key-id-length> octets (except in a multivalue Address Block TLV, in which it is single-length -3 -<key-id-length> octets) and that contains the cryptographic ICV.

The version of this TLV, specified in this section, assumes that, unless otherwise specified, calculating the ICV can be decomposed into:

ICV-value = cryptographic-function(hash-function(content))

In some cases, a different combination of cryptographic function and hash function may be specified. This is the case for the Hashed Message Authentication Code (HMAC) function, which is specified as defined in Section 13.12, using the hash function twice. Using cryptographic-function "none" is provided for symmetry and possible future use, but it SHOULD NOT be used with any currently specified hash function.

The difference between the two type extensions is that in addition to the information covered by the ICV using type extension = 1 (which is detailed in the following sections), the ICV using type extension = 2 also MUST cover the source address of the IP datagram carrying the corresponding packet, message, or Address Block.

The <ICV-data> field MAY be truncated after being calculated, this is indicated by its length, calculated as described above. The truncation MUST be as specified for the relevant cryptographic function (and, if appropriate, hash function).

o When using truncation, the guidelines for minimal ICV length set out in [NIST-SP-800-107] MUST be followed. In particular the <ICV-data> field when using HMAC MUST NOT be truncated below 4 octets.

o The truncated ICV length MUST be so large that the probability of success of a dictionary attack is acceptably small. Such a success will arise if the ICV of a spoofed packet or message is verified. The probability of success is a function of (a) how many routers can be attacked, (b) how fast a router can receive packets or messages and attempt to verify their ICV, (c) the truncated ICV length, and (d) the lifetime of the network. If the truncated ICV length in bits is L, then 2^L packets or messages are required to attack with certainty of success. With a verification rate of R packets/messages per second, applied to N routers over an available time of T, the probability of success is given by NRT/2^L. If this is not to exceed a probability of P, then L > log2(NRT/P). For example, if N is 32, R is 1000, T is 86400 (I day) and P is 10^-6, then L must be at least 52 bits.

Some of the cryptographic and hash functions listed in Section 13 require the length of the content to be digitally signed to be a multiple of a certain number of octets. As a consequence, they specify padding mechanisms, e.g., AES-CMAC [RFC4493] specifies a padding mechanism for message lengths that are not equal to a multiple of 16 octets. Implementations of the framework in this document MUST support appropriate padding mechanisms, as specified in the cryptographic or hash function specifications.

The hash function and the cryptographic function correspond to the entries in two IANA registries, which are described in Section 13.

12.1.1. Rationale

The rationale for separating the hash function and the cryptographic function into two octets instead of having all combinations in a single octet --possibly as a TLV type extension --is that adding further hash functions or cryptographic functions in the future may lead to a non-contiguous number space as well as a smaller overall space.

The rationale for not including a field that lists parameters of the cryptographic ICV in the TLV is that, before being able to validate a cryptographic ICV, routers have to exchange or acquire keys. Any additional parameters can be provided together with the keys in that bootstrap process. Therefore, it is not necessary, and would even entail an extra overhead, to transmit the parameters within every message.

The rationale for the addition of type extension = 2 is that the source address is used in some cases, such as when processing HELLO messages in [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF]. This is applicable only to packets (which only ever travel one hop) and messages (and their Address Blocks) that only travel one hop. It is not applicable to messages that may be forwarded more than one hop, such as Topology Control (TC) messages in [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF]. o The same procedure as for type extension = 1 is used, except that the data used consists of a representation of the source address of the IP datagram carrying the packet, followed by the remaining data (as for type extension = 1). The representation of the source address consists of a single octet containing the address length, in octets, followed by that many octets containing the address in network byte order.

12.2.2. ICV Message TLV When determining the <ICV-data> for a message, with type extension = 1:

o The ICV is calculated over the fields <hash-function>, <cryptographic-function>, <key-id-length>, and --if present --<key-id> (in that order), followed by the entire message. The considerations in Section 9.1 MUST be applied.

When determining the <ICV-data> for a message, with type extension = 2:

o The same procedure as for type extension = 1 is used, except that the data used consists of a representation of the source address of the IP datagram carrying the message, followed by the remaining data (as for type extension = 1). The representation of the source address consists of a single octet containing the address length, in octets, followed by that many octets containing the address in network byte order.

12.2.3. ICV Address Block TLV When determining the <ICV-data> for one or more addresses, with type extension = 1: o The ICV is calculated over the fields <hash-function>, <cryptographic-function>, <key-id-length>, and --if present --<key-id> (in that order), followed by the addresses, and followed by any other values o The same procedure as for type extension = 1 is used, except that the data used consists of a representation of the source address of the IP datagram carrying the Address Block, followed by the remaining data (as for type extension = 1). The representation of the source address consists of a single octet containing the address length, in octets, followed by that many octets containing the address in network byte order.

Example of a Message Including an ICV

The sample message depicted in Figure 1 is derived from Appendix E of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF]. The message contains an ICV Message TLV, with the value representing an ICV that is 16 octets long and a key identifier that is 4 octets long. The type extension of the Message TLV is 1, for the specific decomposition of an ICV using a cryptographic function and a hash function, as specified in Section 12. The IANA registrations for TLV Types and the TLV type extension registries given in this specification replace the identical registrations and registries from [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF]. This specification defines the following TLV Types, replacing the original specifications in [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF]: o Two Packet TLV Types, which have been allocated from the 0-223 range of the "Packet TLV Types" repository of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF], as specified in Table 1.

o Two Message TLV Types, which have been allocated from the 0-127 range of the "Message TLV Types" repository of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF], as specified in Table 2.

o Two Address Block TLV Types, which have been allocated from the 0-127 range of the "Address Block TLV Types" repository of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF], as specified in Table 3.

This specification updates the following registries that were created in [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF]:

o A type extension registry for each of these TLV types with values as listed in Tables 1, 2, and 3.

The following terms are used as defined in [START_REF] Narten | Guidelines for Writing an IANA Considerations Section in RFCs[END_REF]: "Namespace", "Registration", and "Designated Expert".

The following policy is used as defined in [START_REF] Narten | Guidelines for Writing an IANA Considerations Section in RFCs[END_REF]: "Expert Review".

Expert Review: Evaluation Guidelines

For TLV type extensions registries where an Expert Review is required, the Designated Expert SHOULD take the same general recommendations into consideration as those specified by [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF]. For both TIMESTAMP and ICV TLVs, functionally similar extensions for Packet, Message, and Address Block TLVs SHOULD be numbered identically.

Packet TLV Types

IANA has, in accordance with [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], made allocations from the "Packet TLV Types" namespace of [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] for the Packet TLVs specified in Table 1. IANA has modified this allocation as indicated.

+

o

  Any ICV Packet TLVs already present in the Packet TLV Block MUST be removed before calculating the ICV, and the Packet TLV Block size MUST be recalculated accordingly. o If the Packet TLV Block now contains no Packet TLVs, the Packet TLV Block MUST be removed, and the phastlv bit in the <pkt-flags> field in the Packet Header MUST be cleared ('0'). o Any removed ICV Packet TLVs MUST be restored after having calculated the ICV, and the Packet TLV Block size MUST be recalculated accordingly. o When any removed ICV Packet TLVs, and the newly calculated ICV Packet TLV, are added to the packet, if there is no Packet TLV Block, then one MUST be added, including setting ('1') the phastlv bit in the <pkt-flags> field in the Packet Header. The rationale for removing any ICV Packet TLVs already present prior to calculating the ICV is that several ICV TLVs may be added to the same packet, e.g., using different ICV cryptographic and/or hash functions. The rationale for removing an empty Packet TLV Block is because the receiver of the packet cannot tell the difference between what was an absent Packet TLV Block, and what was an empty Packet TLV Block when removing and verifying the ICV Packet TLV if no other Packet TLVs are present. Herberg, et al.

  ------+-------------+-----------+ | Type | Description | Reference | +------+-------------+-------------+-------------+-----------+Table1: Packet TLV Types 13.3. Message TLV Types IANA has, in accordance with[START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], made allocations from the "Message TLV Types" namespace of[START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] for the Message TLVs specified in Table2. IANA has modified this allocation as indicated.+------+-------------+-----------+ | Type | Description | Reference | +------+-------------+--------------+-------------+-----------+

Table 2 :

 2 Message TLV Types 13.4. Address Block TLV Types IANA has, in accordance with[START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], made allocations from the "Address Block TLV Types" namespace of[START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] for the Packet TLVs specified in Table3. IANA has modified this allocation as indicated.

	Herberg, et al.	Standards Track	[Page 20]

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 -----+-------------+-----------+Table 3: Address Block TLV Types 13.5. ICV Packet TLV Type Extensions IANA has, in accordance with [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], made allocations from the "ICV Packet TLV Type Extensions" namespace of [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF] for the Packet TLVs specified in Table 4. IANA has modified this allocation (including defining type extension = 2) as indicated. ----------+-------------------------------------------+----------- ----------+-------------------------------------------+----------- ----------+-------------------------------------------+-----------+ Table 4: ICV Packet TLV Type Extensions More than one ICV Packet TLV with the same type extension MAY be included in a packet if these represent different ICV calculations (e.g., with type extension 1 or 2 and different cryptographic function and/or hash function or with a different key identifier). ICV Packet TLVs that carry what is declared to be the same information MUST NOT be included in the same packet.

+-

TIMESTAMP Packet TLV Type Extensions

IANA has, in accordance with [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], made allocations from the "TIMESTAMP Packet TLV Type Extensions" namespace of [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF] for the Packet TLVs specified in Table 5. IANA has modified this allocation as indicated. ----------+-------------------------------------------+-----------+ Table 5: TIMESTAMP Packet TLV Type Extensions More than one TIMESTAMP Packet TLV with the same type extension MUST NOT be included in a packet.

ICV Message TLV Type Extensions

IANA has, in accordance with [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], made allocations from the "ICV Message TLV Type Extensions" namespace of [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF] for the Message TLVs specified in Table 6. IANA has modified this allocation (including defining type extension = 2) as indicated. ----------+-------------------------------------------+----------- ----------+-------------------------------------------+----------- ----------+-------------------------------------------+----------- ----------+-------------------------------------------+----------- ----------+-------------------------------------------+----------- ----------+-------------------------------------------+----------- ----------+-------------------------------------------+----------- ----------+-------------------------------------------+-----------+ Table 9: TIMESTAMP Address Block TLV Type Extensions More than one TIMESTAMP Address Block TLV with the same type extension MUST NOT be associated with any address.

Hash Functions

IANA has, in accordance with [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], created a registry for hash functions that can be used when creating an ICV, as specified in Section 12 of this document. The initial assignments and allocation policies are specified in Table 10. IANA has modified this allocation as indicated. --------+-----------+---------------------------------+----------- --------+-----------+---------------------------------+-----------+ Table 10: Hash Function Registry 13.12. Cryptographic Functions IANA has, in accordance with [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF], created a registry for the cryptographic functions, as specified in Section 12 of this document. Initial assignments and allocation policies are specified in Table 11. IANA has modified this allocation as indicated. --------+-----------+---------------------------------+----------- In addition, a MANET routing protocol or MANET routing protocol extension that uses this specification MUST specify how to use the framework and the TLVs presented in this document. In addition, the protection that the MANET routing protocol or MANET routing protocol extensions attain by using this framework MUST be described.

As an example, a MANET routing protocol that uses this component to reject "badly formed" or "insecure" messages if a control message does not contain a valid ICV SHOULD indicate the security assumption that if the ICV is valid, the message is considered valid. It also SHOULD indicate the security issues that are counteracted by this measure (e.g., link or identity spoofing) as well as the issues that are not counteracted (e.g., compromised keys).

Acknowledgements

The authors would like to thank Bo Berry (Cisco), Alan Cullen (BAE Systems), Justin Dean (NRL), Paul Lambert (Marvell), Jerome Milan (Ecole Polytechnique), and Henning Rogge (FGAN) for their constructive comments on [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF].

The authors also appreciate the detailed reviews of [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF] from the Area Directors, in particular Stewart Bryant (Cisco), Stephen Farrell (Trinity College Dublin), and Robert Sparks (Tekelec), as well as Donald Eastlake (Huawei) from the Security Directorate.

The authors would like to thank Justin Dean (NRL) and Henning Rogge (FGAN) for their constructive comments on this specification.


C Dearlove

T Clausen

7466 BAE Systems ATC Updates: 6130, 7181

The link quality mechanism of the Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP) enables "ignoring" some 1-hop neighbors if the measured link quality from that 1-hop neighbor is below an acceptable threshold while still retaining the corresponding link information as acquired from the HELLO message exchange. This allows immediate reinstatement of the 1-hop neighbor if the link quality later improves sufficiently.

NHDP also collects information about symmetric 2-hop neighbors. However, it specifies that if a link from a symmetric 1-hop neighbor ceases being symmetric, including while "ignored" (as described above), then corresponding symmetric 2-hop neighbors are removed. This may lead to symmetric 2-hop neighborhood information being permanently removed (until further HELLO messages are received) if the link quality of a symmetric 1-hop neighbor drops below the acceptable threshold, even if only for a moment. This specification updates RFC 6130 "Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)" and RFC 7181 "The Optimized Link State Routing Protocol Version 2 (OLSRv2)" to permit, as an option, retaining, but ignoring, symmetric 2-hop information when the link quality from the corresponding 1-hop neighbor drops below the acceptable threshold. This allows immediate reinstatement of the symmetric 2-hop neighbor if the link quality later improves sufficiently, thus making the symmetric 2-hop neighborhood more "robust".

Section 14 of the MANET Neighborhood Discovery Protocol (NHDP) [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] contains a link admission mechanism known as "link quality" that allows a router using that protocol to "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." Specifically, [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] permits a router to disallow consideration of some of its 1-hop neighbors for as long as the quality of the link from that 1-hop neighbor is below an acceptable link quality threshold.

A feature of this mechanism is that while the link quality remains too low, the link information, established by the exchange of HELLO messages, is retained. Thus, if the link quality later goes above the required threshold (note that a hysteresis mechanism means that two thresholds are used), then the link is immediately established and will be immediately available for use.

[RFC6130] collects not only 1-hop neighbor information, but also information about symmetric 2-hop neighbors. However, [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] specifies that if a 1-hop neighbor was, but no longer is, considered symmetric, then the corresponding 2-Hop Tuples that may have been recorded for that 2-hop neighbor are to be removed without a retention mechanism for a (possibly temporary) loss due to link quality.

This means that if there is a short period in which link quality is too low, then when the link quality is re-established all 1-hop neighbor information is immediately available for use again. However, the corresponding symmetric 2-hop neighbor information has been removed and is not available for use until restored by receipt of the next corresponding HELLO message.

This specification describes how [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] can be modified to avoid this situation by retaining (but not using) 2-hop information, similar to what is done with 1-hop information. This modification is strictly optional, and routers that do and do not implement it can interwork entirely successfully (as they also can with different link quality specifications). In addition, by a suitable interpretation (that ignored 2-Hop Tuples are not externally advertised), this change can be invisible to any other protocols using [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF], in particular [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF]. However, the impact on [RFC7181] when 2-Hop Tuples are not so handled is also described (owing to the existence of implementations of that protocol that are not modularly separated from [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF]).

This specification therefore updates [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] and [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF].

Dearlove & Clausen Standards Track [Page 3]

This update to [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] does not change the definition of a symmetric 2-hop neighbor but adds new state information to each 2-Hop Tuple of [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF]. This is to retain some 2-hop neighbor information while recording it as currently not to be used. The new state information and retained 2-Hop Tuples are reflected in the corresponding tables of the updated NHDP-MIB module [NHDP-MIB].

Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

Additionally, this document uses the terminology of [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] and [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF].

Applicability Statement

This specification updates [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF]. The optimization presented in this specification is simply permissive, as it allows retaining information that otherwise would have been removed but does not use that information except when it could have been used by [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF].

This can, in some cases, ensure that the symmetric 2-hop neighborhood is more robust against temporary link quality changes and consequently yields a more stable network. The only other consequence of this optimization is that state for some otherwise expired 2-Hop Tuples may be maintained for longer.

This specification also updates [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF]. This could have been avoided had instead [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] been updated so as to make the changes to it invisible to any other protocol using it. However, as it is known that some implementations of [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF] are not independent of the implementation of [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] that they use, it is useful to indicate the direct impact on [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF].

A router that implements the optimization described in this specification will interoperate successfully with routers that implement [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] but do not implement this optimization.

Changes to NHDP

The following changes are made to [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] if using this specification. Note that while this specification is OPTIONAL, if any of these changes are made, then all of these changes MUST be made. In all other cases, including other cases with L_status = LOST, there will be no such 2-Hop Tuples.

Dearlove & Clausen

HELLO Message Processing

In Section 12.6 of [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF], make the following changes:

o In point 2, change "L_status = SYMMETRIC" to "L_SYM_time not expired".

o In point 2, point 1, point 1, under "then create a 2-Hop Tuple with:", add a second bullet point "N2_lost: = L_lost". (Note that "2-Hop Neighbor Tuple" has been corrected here to "2-Hop Tuple" per [START_REF]RFC Errata[END_REF].)

Information Base Changes

In Section 13, replace the second bullet point with:

o A Link Tuple's L_status changes from SYMMETRIC, L_SYM_time expires, or the Link Tuple is removed. In this case, the actions specified in Section 13.2 are performed.

Replace the paragraph after the bullet points with:

If a Link Tuple is removed, or if L_HEARD_time expires and either L_status changes from SYMMETRIC or L_SYM_time expires, then the actions specified in Section 13.2 MUST be performed before the actions specified in Section 13.3 are performed for that Link Tuple.

Changes to OLSRv2

If the implementation of [RFC6130] conceals from any protocol using it the existence of all 2-Hop Tuples with N2_lost = true, then no changes are required to any protocol using [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF]; in particular, no changes are required to [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF].

Dearlove o In Section 19.1 of [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], in the final main bullet point (marked as "(OPTIONAL)"), add "and N2_lost = false" after "N2_out_metric != UNKNOWN_METRIC".

o In Appendix C.7 of [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], in point 1, add "and N2_lost = false" after "N2_out_metric != UNKNOWN_METRIC".

Security Considerations

The update to [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] enables the retention and reuse of some information collected by that protocol, for only the duration that it could have been used in any case. As such, this protocol introduces no new security considerations to an implementation of [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] or of any other protocol that uses it, such as [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF].

  1. Introduction ....................................................3 2. Terminology .....................................................4 3. Applicability Statement .........................................4 4. Changes to NHDP .................................................4 4.1. Interface Information Bases ................................5 4.2. HELLO Message Processing ...................................5 4.3. Information Base Changes ...................................5 4.4. Constraints ................................................6 5. Changes to OLSRv2 ...............................................6 6. Security Considerations .........................................8 7. References ......................................................8 7.1. Normative References .......................................8 7.2. Informative References .....................................8 1. Introduction

  Hop Set is modified by adding this additional element to each 2-Hop Tuple: N2_lost is a boolean flag, which indicates the state of the corresponding Link Tuple. If L_status = SYMMETRIC (and thus L_lost = false), then N2_lost = false. If L_SYM_time has not expired, and L_lost = true (and hence L_status = LOST), then N2_lost = true.

  L_status then changes from SYMMETRIC to LOST because L_lost is set to true: 1. For each 2-Hop Tuple for the same MANET interface with: + N2_neighbor_iface_addr_list contains one or more network addresses in L_neighbor_iface_addr_list; set N2_lost := true. Also, in Section 13.2 of [RFC6130], remove point 1 and renumber point 2 as point 1. 4.4. Constraints In Appendix B of [RFC6130], under "In each 2-Hop Tuple:", change the first bullet point to: 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_SYM_time not expired; AND * L_lost = N2_lost.

* A 2 -

 2 Hop Tuple with N2_out_metric != UNKNOWN_METRIC and N2_lost = false is added or removed; OR * A 2-Hop Tuple with N2_out_metric != UNKNOWN_METRIC has N2_lost changed; OR * The N2_out_metric of any 2-Hop Tuple with N2_lost = false changes, and either the flooding MPR selection process uses metric values (see Section 18.4), or the change is to or from UNKNOWN_METRIC. o In Section 17.6 of [RFC7181], point 3, replace the final two bullet points with: * A 2-Hop Tuple with N2_in_metric != UNKNOWN_METRIC and N2_lost = false is added or removed; OR * A 2-Hop Tuple with N2_in_metric != UNKNOWN_METRIC has N2_lost changed; OR * The N2_in_metric of any 2-Hop Tuple with N2_lost = false changes.o In Section 17.7 of[START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], in the fifth bullet point, add "and N2_lost = false" after "N2_out_metric != UNKNOWN_METRIC".o In Section 18.4 of[START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], in the third bullet point, add ", N2_lost = false" after "N2_out_metric != UNKNOWN_METRIC".o In Section 18.5 of[START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], in the third bullet point, add ", N2_lost = false" after "N2_in_metric != UNKNOWN_METRIC".

Table of Contents

 of

Dearlove & ClausenStandards Track [Page 9]

Acknowledgements ...................................................9 Authors' Addresses .................................................9 Acknowledgements The authors would like to thank Liz Cullen (BAE Systems) for first illustrating the issue addressed in this specification. Authors' Addresses Christopher Dearlove BAE Systems Advanced Technology Centre West Hanningfield Road Great Baddow, Chelmsford United Kingdom Phone: +44 1245 242194 EMail: chris.dearlove@baesystems.com URI: http://www.baesystems.com/ Thomas Heide Clausen LIX, Ecole Polytechnique Phone: +33 6 6058 9349 EMail: T.Clausen@computer.org URI: http://www.ThomasClausen.org/

Steering Group (IESG). in Section 2 of RFC 5741


C Dearlove

T Clausen

7631 BAE Systems ATC Updates: 5444

This document reorganizes the naming of already-allocated TLV (typelength-value) types and type extensions in the "Mobile Ad hoc NETwork (MANET) Parameters" registries defined by RFC 5444 to use names appropriately. It has no consequences in terms of any protocol implementation.

This document also updates the Expert Review guidelines in RFC 5444, so as to establish a policy for consistent naming of future TLV type and type extension allocations. It makes no other changes to RFC 5444.

This document reorganizes and rationalizes the naming of TLVs (typelength-value structures) defined by [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] and recorded by IANA in the following subregistries of the "Mobile Ad hoc NETwork (MANET) Parameters" registry: "Packet TLV Types", "Message TLV Types", and "Address Block TLV Types".

This document reorganizes the naming of already-allocated Packet, Message, and Address Block TLV types, and their corresponding type extensions. It also updates the corresponding IANA registries.

TLVs have a type (one octet) and a type extension (one octet) that together form a full type (of two octets). A TLV may omit the type extension when it is zero. However, that applies only to its representation; it still has a type extension of zero. A TLV type defines an IANA registry of type extensions for that type.

There have been two forms of TLV allocation.

The first, but less common, form of allocation has been that allocation of the TLV type has defined (but not necessarily allocated) all the type extensions for that TLV type. This applies, for example, to the Address Block TLV LINK_METRIC specified in [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF]. The LINK_METRIC type extensions are all available for allocation for different definitions of link metric. It is appropriate in this case to apply the name LINK_METRIC to the type, and also to all the full types corresponding to that type, as has been done. Type extensions can then be individually named or can be simply referred to by their number.

The second, more common, form of allocation has been that allocation of the TLV type has defined only type extension 0, and possibly type extension 1, for that TLV type. An example is the Address Block TLV LINK_STATUS defined in [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF], where only type extension 0 is allocated. It is not reasonable to assume that the remaining 255 type extensions will be allocated to forms of LINK_STATUS. (Other forms of link status are already catered to by the introduction, in [START_REF] Dearlove | Optimized Link State Routing Protocol Version 2 (OLSRv2) and MANET Neighborhood Discovery Protocol (NHDP) Extension TLVs[END_REF], of a registry for values of the LINK_STATUS TLV.) Thus, the name LINK_STATUS should be attached to the specific type extension for that type, i.e., to the full type and not to the TLV type when used with any other type extensions. This was, however, not done as part of the initial registration of this TLV type. Effectively, this leaves, for the LINK_STATUS TLV type, the type extensions 1-255 either unavailable for allocation (if applying strictly the interpretation that they must relate to a LINK_STATUS) or counterintuitively named for their intended function.

Dearlove & Clausen Standards Track [Page 3]

The purpose of this document is to change how names of the second form are applied and recorded in IANA registries, and to provide guidelines and instructions for future TLV type allocations. This is to facilitate the addition of new TLVs using type extensions other than 0, but without them having inappropriate names attached. So, for example, LINK_STATUS will become the name of the full type (composed of the TLV type 3 and the TLV type extension 0) and will cease being the name of the TLV type 3. This leaves the question of how to name the type. As it is not clear what other TLVs might be defined for other type extensions of the same type, the type is currently left unnamed and specified only by number.

This document also updates the Expert Review guidelines from [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF], so as to establish a policy for consistent naming of future TLV type and type extension allocations.

For clarity, all currently allocated TLVs in [START_REF] Clausen | Representing Multi-Value Time in Mobile Ad Hoc Networks (MANETs)[END_REF], [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF], [START_REF] Macker | Simplified Multicast Forwarding[END_REF], [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], and [START_REF] Herberg | Integrity Check Value and Timestamp TLV Definitions for Mobile Ad Hoc Networks (MANETs)[END_REF] are listed in the IANA Considerations section of this document, each specifying the updates or indicating no change when that is appropriate (such as the LINK_METRIC TLV and both TLVs defined in [START_REF] Macker | Simplified Multicast Forwarding[END_REF]). The only changes are of naming.

Note that nothing in this document changes the operation of any protocol. This naming is already used, in effect, in [START_REF] Clausen | Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)[END_REF] and [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], currently the main users of allocated TLVs. For example, the former indicates that all usage of LINK_STATUS refers to that TLV with type extension 0.

Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

All references to elements such as "packet", "message", and "TLV" in this document refer to those defined in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF].

IANA Considerations

This document updates the Expert Review evaluation guidelines for allocations in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF] in the "Packet TLV Types", "Message TLV Types", and "Address Block TLV Types" registries and updates the already-made allocations to conform with these guidelines.

Dearlove & Clausen Standards Track [Page 4]

Expert Review: Evaluation Guidelines

For registration in the "Packet TLV Types", "Message TLV Types", and "Address Block TLV Types" registries, the following guidelines apply, in addition to those given in Section 6.1 in [START_REF] Clausen | Generalized Mobile Ad Hoc Network (MANET) Packet/Message Format[END_REF]:

o If the requested TLV type immediately defines (but not necessarily allocates) all the corresponding type extensions for versions of that type, then a common name SHOULD be assigned for the TLV type.

This case is unchanged by this specification. This currently includes TLV types named ICV, TIMESTAMP, and LINK_METRIC; it also includes the HELLO Message-Type-specific TLVs defined in [START_REF] Macker | Simplified Multicast Forwarding[END_REF].

o Otherwise, if the requested TLV type does not immediately define all the corresponding type extensions for versions of that type, then a common name SHOULD NOT be assigned for that TLV type. Instead, it is RECOMMENDED that: * The "description" for the allocated TLV type be "Defined by Type Extension".

* For Packet TLV Types, the type extension registry, created for the TLV type, be named "Type XX Packet TLV Type Extensions", with XX replaced by the numerical value of the TLV type.

* For Message TLV Types, the type extension registry, created for the TLV type, be named "Type XX Message TLV Type Extensions", with XX replaced by the numerical value of the TLV type.

* For Address Block TLV Types, the type extension registry, created for the TLV type, be named "Type XX Address Block TLV Type Extensions", with XX replaced by the numerical value of the TLV type. The following changes (including correction of some existing minor errors) apply to the IANA registry "Mobile Ad hoc NETwork (MANET) Parameters". For clarity, registries that are unchanged, including those that define all type extensions of a TLV type, are listed as unchanged.

The IANA registry "Packet TLV Types" is unchanged.

The IANA registry "ICV Packet TLV Type Extensions" is unchanged.

The IANA registry "TIMESTAMP Packet TLV Type Extensions" is unchanged.

The IANA registry "Message TLV Types" is changed to match Table 1. --------+-------------------------------+----------- --------+-------------------------------+----------- The IANA registry "INTERVAL_TIME Message Type Extensions" has been renamed "Type 0 Message TLV Type Extensions" and changed to match Table 2. ----------+---------------+---------------------------+----------- The IANA registry "VALIDITY_TIME Message Type Extensions" has been renamed "Type 1 Message TLV Type Extensions" and changed to match Table 3. The IANA registry "ICV Address TLV Type Extensions" has been renamed "ICV Address Block TLV Type Extensions" but is otherwise unchanged.

+---------+-------------------------------+-----------+ | Type | Description | Reference | +-
+-----------+---------------+---------------------------+-----------+ | Type | Name | Description | Reference | | Extension | | | | +-
+-----------+---------------+---------------------------+-----------+ | Type |
The IANA registry "TIMESTAMP Address TLV Type Extensions" has been renamed "TIMESTAMP Address Block TLV Type Extensions" but is otherwise unchanged.

  1. Introduction ....................................................3 2. Terminology .....................................................4 3. IANA Considerations .............................................4 3.1. Expert Review: Evaluation Guidelines .......................5 3.2. Updated IANA Registries ....................................6 4. Security Considerations ........................................13 5. References .....................................................13 5.1. Normative References ......................................13 5.2. Informative References ....................................14 Acknowledgments ...................................................15 Authors' Addresses ...............................................

  255 | Reserved for Experimental Use | [RFC5444] | +-

  Type 0 Message TLV Type Extensions

Table of Contents

 of

Table 1 :

 1 + Message TLV Types

	Dearlove & Clausen	Standards Track	[Page 6]

Table 3 :

 3 Type 1 Message TLV Type ExtensionsThe IANA registry "ICV Message TLV Type Extensions" is unchanged.

	The IANA registry "TIMESTAMP Message TLV Type Extensions" is
	unchanged.
	Dearlove & Clausen	Standards Track	[Page 7]

Table 5 :

 5 Type 8 Message TLV Type ExtensionsThe IANA registry "HELLO Message-Type-specific Message TLV Types" is unchanged.

	The IANA registry "SMF_TYPE Message TLV Type Extensions" is
	unchanged.
	Dearlove & Clausen	Standards Track	[Page 8]

Table 7 :

 7 Type 0 Address Block TLV Type Extensions

	Dearlove & Clausen	Standards Track	[Page 9]

Table 9 :

 9 Type 2 Address Block TLV Type Extensions

	Dearlove & Clausen	Standards Track	[Page 10]

Table 11 :

 11 Type 4 Address Block TLV Type Extensions

Table 13 :

 13 Type 9 Address Block TLV Type Extensions

	Dearlove & Clausen	Standards Track	[Page 12]

Dearlove & ClausenStandards Track [Page 15]

Acknowledgments

The authors would like to thank Adrian Farrel for pointing out the need to reorganize and rationalize the naming of the TLVs defined by [RFC5444] and Tom Taylor and the RFC Editor for pointing out some omissions and errors.

September 2015

The IANA registry "TC Message-Type-specific Message TLV Types" is unchanged.

The IANA registry "Address Block TLV Types" has been changed to match Table 6. --------+-------------------------------+----------- --------+-------------------------------+----------- --------+-------------------------------+-----------+ Table 6: Address Block TLV Types

+-

The IANA registry "INTERVAL_TIME Address Block TLV Type Extensions" has been renamed "Type 0 Address Block TLV Type Extensions" and changed to match Table 7. ----------+---------------+---------------------------+----------- ----------+---------------+---------------------------+----------- The IANA registry "VALIDITY_TIME Address Block TLV Type Extensions" has been renamed "Type 1 Address Block TLV Type Extensions" and changed to match Table 8. ----------+---------------+---------------------------+----------- ----------+---------------+---------------------------+-----------+ Table 8: Type 1 Address Block TLV Type Extensions

+-

The IANA registry "LOCAL_IF Address Block TLV Type Extensions" has been renamed "Type 2 Address Block TLV Type Extensions" and changed to match Table 9.

The IANA registry "LINK_STATUS Address Block TLV Type Extensions" has been renamed "Type 3 Address Block TLV Type Extensions" and changed to match Table 10. ----------+-------------+--------------------+--------------------

The IANA registry "LINK_METRIC Address Block TLV Type Extensions" is unchanged.

The IANA registry "MPR Address Block TLV Type Extensions" has been renamed "Type 8 Address Block TLV Type Extensions" and changed to match Table 12.

Table 12: Type 8 Address Block TLV Type Extensions

The IANA registry "NBR_ADDR_TYPE Address Block TLV Type Extensions" has been renamed "Type 9 Address Block TLV Type Extensions" and changed to match Table 13. ----------+---------------+------------------+--------------------

The IANA registry "GATEWAY Address Block TLV Type Extensions" has been renamed "Type 10 Address Block TLV Type Extensions" and changed to match Table 14. ----------+---------+------------------------+-------------------- ----------+---------+------------------------+-------------------- The IANA registry "HELLO Message-Type-specific Address Block TLV Types" is unchanged.

The IANA registry "SMF_NBR_TYPE Address Block TLV Type Extensions" is unchanged.

The IANA registry "TC Message-Type-specific Address Block TLV Types" is unchanged.

Note: This document adds reservations for Experimental Use [START_REF] Narten | Guidelines for Writing an IANA Considerations Section in RFCs[END_REF], omitted in [START_REF] Clausen | The Optimized Link State Routing Protocol Version 2[END_REF], to the last three tables.

Security Considerations

As this document is concerned only with how entities are named, those names being used only in documents such as this and IANA registries, this document has no security considerations.

Normative References