Internet Engineering Task Force (IETF) C. Dearlove Request for Comments: 7631 BAE Systems ATC Updates: 5444 T. Clausen Category: Standards Track LIX, Ecole Polytechnique ISSN: 2070-1721 September 2015
TLV Naming in the Mobile Ad Hoc Network (MANET) Generalized Packet/Message Format
Abstract
This document reorganizes the naming of already-allocated TLV (type- length-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.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7631.
Dearlove & Clausen Standards Track [Page 1]
RFC 7631 TLV Naming September 2015
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
This document reorganizes and rationalizes the naming of TLVs (type- length-value structures) defined by [RFC5444] 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 [RFC7181]. 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 [RFC6130], 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 [RFC7188], 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]
RFC 7631 TLV Naming September 2015
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 [RFC5444], so as to establish a policy for consistent naming of future TLV type and type extension allocations.
For clarity, all currently allocated TLVs in [RFC5497], [RFC6130], [RFC6621], [RFC7181], and [RFC7182] 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 [RFC6621]). 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 [RFC6130] and [RFC7181], 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.
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 [RFC5444].
This document updates the Expert Review evaluation guidelines for allocations in [RFC5444] 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.
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 [RFC5444]:
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 [RFC6621].
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.
* When a new type extension is required, unless there are reasons to the contrary, the next consecutive type extension is allocated and given a name. (Reasons to the contrary MAY include maintaining a correspondence between corresponding Packet, Message, and Address Block TLVs, and reserving type extension zero if not yet allocated.)
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.
+---------+-------------------------------+-----------+ | Type | Description | Reference | +---------+-------------------------------+-----------+ | 0 | Defined by Type Extension | [RFC5497] | | 1 | Defined by Type Extension | [RFC5497] | | 2-4 | Unassigned | | | 5 | ICV | [RFC7182] | | 6 | TIMESTAMP | [RFC7182] | | 7 | Defined by Type Extension | [RFC7181] | | 8 | Defined by Type Extension | [RFC7181] | | 9-223 | Unassigned | | | 224-255 | Reserved for Experimental Use | [RFC5444] | +---------+-------------------------------+-----------+
Table 1: Message TLV Types
Dearlove & Clausen Standards Track [Page 6]
RFC 7631 TLV Naming September 2015
The IANA registry "INTERVAL_TIME Message Type Extensions" has been renamed "Type 0 Message TLV Type Extensions" and changed to match Table 2.
+-----------+---------------+---------------------------+-----------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+---------------+---------------------------+-----------+ | 0 | INTERVAL_TIME | The maximum time before | [RFC5497] | | | | another message of the | | | | | same type as this message | | | | | from the same originator | | | | | should be received | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for Experimental | [RFC5497] | | | | Use | | +-----------+---------------+---------------------------+-----------+
Table 2: Type 0 Message TLV Type Extensions
The IANA registry "VALIDITY_TIME Message Type Extensions" has been renamed "Type 1 Message TLV Type Extensions" and changed to match Table 3.
+-----------+---------------+---------------------------+-----------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+---------------+---------------------------+-----------+ | 0 | VALIDITY_TIME | The time from receipt of | [RFC5497] | | | | the message during which | | | | | the information contained | | | | | in the message is to be | | | | | considered valid | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for Experimental | [RFC5497] | | | | Use | | +-----------+---------------+---------------------------+-----------+
Table 3: Type 1 Message TLV Type Extensions
The 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]
RFC 7631 TLV Naming September 2015
The IANA registry "MPR_WILLING Message Type Extensions" has been renamed "Type 7 Message TLV Type Extensions" and changed to match Table 4.
+-----------+-------------+-----------------------------+-----------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+-------------+-----------------------------+-----------+ | 0 | MPR_WILLING | Bits 0-3 specify the | [RFC7181] | | | | originating router's | | | | | willingness to act as a | | | | | flooding MPR; bits 4-7 | | | | | specify the originating | | | | | router's willingness to act | | | | | as a routing MPR | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for Experimental | [RFC7181] | | | | Use | | +-----------+-------------+-----------------------------+-----------+
Table 4: Type 7 Message TLV Type Extensions
The IANA registry "CONT_SEQ_NUM Message Type Extensions" has been renamed "Type 8 Message TLV Type Extensions" and changed to match Table 5.
+-----------+--------------+----------------------------+-----------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+--------------+----------------------------+-----------+ | 0 | CONT_SEQ_NUM | Specifies a content | [RFC7181] | | | (COMPLETE) | sequence number for this | | | | | complete message | | | 1 | CONT_SEQ_NUM | Specifies a content | [RFC7181] | | | (INCOMPLETE) | sequence number for this | | | | | incomplete message | | | 2-223 | | Unassigned | | | 224-255 | | Reserved for Experimental | [RFC7181] | | | | Use | | +-----------+--------------+----------------------------+-----------+
Table 5: Type 8 Message TLV Type Extensions
The 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]
RFC 7631 TLV Naming 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.
+---------+-------------------------------+-----------+ | Type | Description | Reference | +---------+-------------------------------+-----------+ | 0 | Defined by Type Extension | [RFC5497] | | 1 | Defined by Type Extension | [RFC5497] | | 2 | Defined by Type Extension | [RFC6130] | | 3 | Defined by Type Extension | [RFC6130] | | 4 | Defined by Type Extension | [RFC6130] | | 5 | ICV | [RFC7182] | | 6 | TIMESTAMP | [RFC7182] | | 7 | LINK_METRIC | [RFC7181] | | 8 | Defined by Type Extension | [RFC7181] | | 9 | Defined by Type Extension | [RFC7181] | | 10 | Defined by Type Extension | [RFC7181] | | 11-223 | Unassigned | | | 224-255 | Reserved for Experimental Use | [RFC5444] | +---------+-------------------------------+-----------+
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.
+-----------+---------------+---------------------------+-----------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+---------------+---------------------------+-----------+ | 0 | INTERVAL_TIME | The maximum time before | [RFC5497] | | | | another message of the | | | | | same type as this message | | | | | from the same originator | | | | | and containing this | | | | | address should be | | | | | received | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for Experimental | [RFC5497] | | | | Use | | +-----------+---------------+---------------------------+-----------+
Table 7: Type 0 Address Block TLV Type Extensions
Dearlove & Clausen Standards Track [Page 9]
RFC 7631 TLV Naming September 2015
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.
+-----------+---------------+---------------------------+-----------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+---------------+---------------------------+-----------+ | 0 | VALIDITY_TIME | The time from receipt of | [RFC5497] | | | | the address during which | | | | | the information regarding | | | | | this address is to be | | | | | considered valid | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for Experimental | [RFC5497] | | | | Use | | +-----------+---------------+---------------------------+-----------+
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.
+-----------+----------+-----------------------+--------------------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+----------+-----------------------+--------------------+ | 0 | LOCAL_IF | This value is to be | [RFC7188][RFC6130] | | | | interpreted according | | | | | to the registry | | | | | "LOCAL_IF TLV Values" | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for | [RFC6130] | | | | Experimental Use | | +-----------+----------+-----------------------+--------------------+
Table 9: Type 2 Address Block TLV Type Extensions
Dearlove & Clausen Standards Track [Page 10]
RFC 7631 TLV Naming September 2015
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.
+-----------+-------------+--------------------+--------------------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+-------------+--------------------+--------------------+ | 0 | LINK_STATUS | This value is to | [RFC7188][RFC6130] | | | | be interpreted | | | | | according to the | | | | | registry | | | | | "LINK_STATUS TLV | | | | | Values" | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for | [RFC6130] | | | | Experimental Use | | +-----------+-------------+--------------------+--------------------+
Table 10: Type 3 Address Block TLV Type Extensions
The IANA registry "OTHER_NEIGHB Address Block TLV Type Extensions" has been renamed "Type 4 Address Block TLV Type Extensions" and changed to match Table 11.
+-----------+--------------+-------------------+--------------------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+--------------+-------------------+--------------------+ | 0 | OTHER_NEIGHB | This value is to | [RFC7188][RFC6130] | | | | be interpreted | | | | | according to the | | | | | registry | | | | | "OTHER_NEIGHB TLV | | | | | Values" | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for | [RFC6130] | | | | Experimental Use | | +-----------+--------------+-------------------+--------------------+
Table 11: Type 4 Address Block TLV Type Extensions
The IANA registry "ICV Address TLV Type Extensions" has been renamed "ICV Address Block TLV Type Extensions" but is otherwise unchanged.
The IANA registry "TIMESTAMP Address TLV Type Extensions" has been renamed "TIMESTAMP Address Block TLV Type Extensions" but is otherwise unchanged.
Dearlove & Clausen Standards Track [Page 11]
RFC 7631 TLV Naming September 2015
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.
+-----------+------+---------------------------+--------------------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+------+---------------------------+--------------------+ | 0 | MPR | This value is to be | [RFC7188][RFC7181] | | | | interpreted according to | | | | | the registry "MPR TLV Bit | | | | | Values" | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for Experimental | RFC 7631 (this | | | | Use | document) | +-----------+------+---------------------------+--------------------+
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.
+-----------+---------------+------------------+--------------------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+---------------+------------------+--------------------+ | 0 | NBR_ADDR_TYPE | This value is to | [RFC7188][RFC7181] | | | | be interpreted | | | | | according to the | | | | | registry | | | | | "NBR_ADDR_TYPE | | | | | Address Block | | | | | TLV Bit Values" | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for | RFC 7631 (this | | | | Experimental Use | document) | +-----------+---------------+------------------+--------------------+
Table 13: Type 9 Address Block TLV Type Extensions
Dearlove & Clausen Standards Track [Page 12]
RFC 7631 TLV Naming September 2015
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.
+-----------+---------+------------------------+--------------------+ | Type | Name | Description | Reference | | Extension | | | | +-----------+---------+------------------------+--------------------+ | 0 | GATEWAY | Specifies that a given | [RFC7188][RFC7181] | | | | network address is | | | | | reached via a gateway | | | | | on the originating | | | | | router, with value | | | | | equal to the number of | | | | | hops | | | 1-223 | | Unassigned | | | 224-255 | | Reserved for | RFC 7631 (this | | | | Experimental Use | document) | +-----------+---------+------------------------+--------------------+
Table 14: Type 10 Address Block TLV Type Extensions
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 [RFC5226], omitted in [RFC7181], to the last three tables.
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.
[RFC7188] Dearlove, C. and T. Clausen, "Optimized Link State Routing Protocol Version 2 (OLSRv2) and MANET Neighborhood Discovery Protocol (NHDP) Extension TLVs", RFC 7188, DOI 10.17487/RFC7188, April 2014, <http://www.rfc-editor.org/info/rfc7188>.
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.
Authors' Addresses
Christopher Dearlove BAE Systems Advanced Technology Centre West Hanningfield Road Great Baddow, Chelmsford United Kingdom