DLEP Radio Channel Utilization ExtensionFraunhofer FKIEFraunhofer Strasse 20Wachtberg53343DEhenning.rogge@fkie.fraunhofer.de
Routing
ManetDLEPPHYTLVThis document defines an extension to the Dynamic Link Exchange Protocol (DLEP) to provide the utilization of a radio channel.IntroductionThe Dynamic Link Exchange Protocol (DLEP) is defined in
.
It provides the exchange of link-related control information
between DLEP peers. DLEP peers are comprised of a modem and
a router. DLEP defines a base set of mechanisms as well as
support for possible extensions. This document defines one such
extension.
Radio channel utilization provides a packet/frame independent measurement
how a radio channel is used and how much resources are still available.
This allows a router to calculate a better routing metric or allows management
agents to detect a channel being unusable for communication because of
external jamming.Requirements LanguageIn many IETF documents, several words, when they are in all capitals
as shown below, are used to signify the requirements in the
specification. These capitalized words can bring significant clarity
and consistency to documents because their meanings are well defined.
This document defines how those words are interpreted in IETF
documents when the words are in all capitals.
These words can be used as defined here, but using them is not
required. Specifically, normative text does not require the use
of these key words. They are used for clarity and consistency
when that is what's wanted, but a lot of normative text does not
use them and is still normative.
The words have the meanings specified herein only when they are in
all capitals.
When these words are not capitalized, they have their normal
English meanings and are not affected by this document.
Authors who follow these guidelines should incorporate this phrase
near the beginning of their document:
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 BCP 14 when, and only when, they
appear in all capitals, as shown here.
Extension Usage and IdentificationThe use of the Channel Utilization Extension SHOULD be
configurable. To indicate that the Channel Utilization Extension
is to be used, an implementation MUST include the Radio Channel Utilization Extension ID in the Extensions Supported Data Item. The Extensions Supported Data Item is sent and processed according to
.All four Data Items are time measurements in nanoseconds since an arbitrary starting point, e.g. the radio bootup. They are never reseted and will just increase monotonic.The first Data Item (Radio Channel Active) announces the channels livetime of the radio channel while the other three provide the amount of time the channel has been used in different ways. Radio Channel Rx provides the time the radio is receiving data, Radio Channel Tx the time the radio is sending data and Radio Channel Busy the time the radio channel is blocked for any unknown reason.A radio that doesn't track the time for receiving and transmitting data explicitly can just add all times the radio channel is not free into the Radio Channel Busy Data Item.The time the radio channel has been free can be calculated by substracting the values of Busy, Rx and Tx from the value provided by the Radio Active Channel Data Item.Data ItemsAll four Data Items of this extension can be used both as Session specific and Destination specific metrics. If the radio is only tracking channel usage on interface level, the Data Items are used in SessionInitResponse and SessionUpdate messages. If the radio also is tracking channel usage for each Destination, they are also used in DestinationUp, DestinationUpdate and DestinationAnnounceResponse messages.Radio Channel Active Data ItemRadio Channel Active Item contains information how long the radio channel has been active. This provides the router with a reference to interpret the values provided by the other three Data Items. Because of this the value in this item must be larger than the values in the other three Data Items this extensions defines together.This Data Item is mandatory for SessionInitResponse and SessionUpdate messages.The format of the Radio Channel Active Data Item is:
Data Item Type:
TBD
Length:
8
Active Time:
Time in nanoseconds since the channel has been active.
Radio Channel Busy Data ItemRadio Channel Busy Item contains information how much time the radio channel has been busy, not including the time provided in the Channel Rx and Chanel Tx Data Item.This Data Item is mandatory for SessionInitResponse and SessionUpdate messages.The format of the Radio Channel Busy Data Item is:
Data Item Type:
TBD
Length:
8
Busy Time:
Time in nanoseconds the channel was busy during its active time.
Radio Channel Rx Data ItemRadio Channel Rx Item contains information how much time the local radio has been receiving data from other radios.The format of the Radio Channel Rx Data Item is:
Data Item Type:
TBD
Length:
8
Rx Time:
Time in nanoseconds the local radio was receiving data from other radios during its active time.
Radio Channel Tx Data ItemRadio Channel Tx Item contains information how much time the local radio has been transmitting data to other radios.The format of the Radio Channel Tx Data Item is:
Data Item Type:
TBD
Length:
8
Tx Time:
Time in nanoseconds the local radio was transmitting data to other radios during its active time.
Security ConsiderationsThe extension introduces a new Data Item for DLEP.
The extension does not inherently introduce any additional
vulnerabilities above those documented in
.
The approach taken to security in that document applies
equally when running the extension defined in this document.IANA ConsiderationsAs described below, IANA has assigned two values per this document.
Both assignments are to registries defined by
.Extension Type ValueIANA has assigned the following value in the "Extension Type Values"
registry within the "Dynamic Link Exchange Protocol (DLEP)
Parameters" registry. The new value is in the range with the
"Specification Required" policy:
New Extension Type Value
Code
Description
TBD
Radio Channel Utilization
Data Item ValueIANA has assigned the following value in the "Data Item Type
Values" registry within the "Dynamic Link Exchange Protocol
(DLEP) Parameters" registry. The new value is in the range
with the "Specification Required"
policy:
New Data Item Value
Type Code
Description
TBD
Radio Channel Active
TBD
Radio Channel Busy
TBD
Radio Channel Rx
TBD
Radio Channel Tx
Normative ReferencesKey words for use in RFCs to Indicate Requirement LevelsIn many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.Ambiguity of Uppercase vs Lowercase in RFC 2119 Key WordsRFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.Dynamic Link Exchange Protocol (DLEP)When routing devices rely on modems to effect communications over wireless links, they need timely and accurate knowledge of the characteristics of the link (speed, state, etc.) in order to make routing decisions. In mobile or other environments where these characteristics change frequently, manual configurations or the inference of state through routing or transport protocols does not allow the router to make the best decisions. This document introduces a new protocol called the Dynamic Link Exchange Protocol (DLEP), which provides a bidirectional, event-driven communication channel between the router and the modem to facilitate communication of changing link characteristics.Informative ReferencesGuidelines for Writing an IANA Considerations Section in RFCsMany protocols make use of points of extensibility that use constants to identify various protocol parameters. To ensure that the values in these fields do not have conflicting uses and to promote interoperability, their allocations are often coordinated by a central record keeper. For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA).To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications to existing values can be made, is needed. This document defines a framework for the documentation of these guidelines by specification authors, in order to assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in the operation of a registry.This is the third edition of this document; it obsoletes RFC 5226.