Manet H.R. Rogge
Internet-Draft Fraunhofer FKIE
Intended status: Standards Track 12 May 2025
Expires: 13 November 2025
DLEP Radio Channel Utilization Extension
draft-ietf-manet-dlep-channel-utilization-02
Abstract
This document defines an extension to the Dynamic Link Exchange
Protocol (DLEP) to provide the utilization of a radio channel.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Extension Usage and Identification . . . . . . . . . . . . . 3
3. Data Items . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Radio Channel Active Data Item . . . . . . . . . . . . . 4
3.2. Radio Channel Busy Data Item . . . . . . . . . . . . . . 5
3.3. Radio Channel Rx Data Item . . . . . . . . . . . . . . . 5
3.4. Radio Channel Tx Data Item . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5.1. Extension Type Value . . . . . . . . . . . . . . . . . . 7
5.2. Data Item Value . . . . . . . . . . . . . . . . . . . . . 7
6. Normative References . . . . . . . . . . . . . . . . . . . . 7
7. Informative References . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The Dynamic Link Exchange Protocol (DLEP) is defined in [RFC8175].
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.
While incoming and outgoing traffic can be easily measured on the
router, the amount of airtime used by management traffic of the radio
is invisible to the router, as is unicast traffic between two
adjecant radios (unless the radio supports promiscous mode). This
could present the a fully utilized radio channel to the router as
totally empty. Getting a direct radio level information how much
time on the radio channel has been used up by incoming or outgoing
data or control frames 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.
1.1. Requirements Language
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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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2. Extension Usage and Identification
The 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 [RFC8175].
The Channel Utilization TLVs can be used by the router to improve the
tracking of channel usage by different radios and give a more exact
estimate how much free capacity the channel has currently. This
information can be used for adjusting timing intervals between
automatically generated data, e.g. HELLO messages of the local
routing protocol.
All four Data Items are 64 bit unsigned integers time measurements in
nanoseconds since an arbitrary starting point, e.g. the radio bootup.
Each value monotonically increases for the entire duration of the
DLEP session; they are never reset.
Each of the four data items tracks the time the radio is in a certain
type of operation.
+--------+---------------------------------------+
| Type | Description |
+--------+---------------------------------------+
| Active | Time the radio has been operational |
| | and able to interact with the channel |
+--------+---------------------------------------+
| Busy | Time the radio channel was blocked |
| | for an arbitrary reason |
+--------+---------------------------------------+
| RX | Time the radio was receiving data |
+--------+---------------------------------------+
| TX | Time the radio was transmitting data |
+--------+---------------------------------------+
Table 1: Channel utilization data types
A radio that doesn't track the time for receiving (RX) and
transmitting (TX) data explicitly MUST add all time intervals 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. By tracking these values over
time the router can calculate the channel usage statistics for
routing metrics or report the received value to a management layer.
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A radio that is using independent channel resources for each neighbor
(e.g. by beam forming) can also track and report channel usage time
for each DLEP neighbor.
3. Data Items
All 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 the 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.
All four Data Items contain a single 64 bit unsigned integer time
interval measured in nanoseconds as the TLV value.
3.1. Radio Channel Active Data Item
Radio 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 messages.
The format of the Radio Channel Active Data Item is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Active Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Active Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
Data Item Type: TBD1
Length: 8
Active Time: Time in nanoseconds since the channel has been in use.
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3.2. Radio Channel Busy Data Item
Radio 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.
The format of the Radio Channel Busy Data Item is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Busy Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Busy Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
Data Item Type: TBD2
Length: 8
Busy Time: Time in nanoseconds the channel was busy during its
active time.
3.3. Radio Channel Rx Data Item
Radio 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:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rx Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rx Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3
Data Item Type: TBD3
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Length: 8
Rx Time: Time in nanoseconds the local radio has received data from
other radios during its active time.
3.4. Radio Channel Tx Data Item
Radio 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:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tx Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tx Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4
Data Item Type: TBD4
Length: 8
Tx Time: Time in nanoseconds the local radio has transmitted data to
other radios during its active time.
4. Security Considerations
The extension introduces a new Data Item for DLEP. The extension
does not inherently introduce any additional vulnerabilities above
those documented in [RFC8175]. The approach taken to security in
that document applies equally when running the extension defined in
this document.
5. IANA Considerations
As described below, IANA has assigned two values per this document.
Both assignments are to registries defined by [RFC8175].
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5.1. Extension Type Value
IANA 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" [RFC8126] policy:
+------+---------------------------+
| Code | Description |
+------+---------------------------+
| TBD5 | Radio Channel Utilization |
+------+---------------------------+
Table 2: New Extension Type Value
5.2. Data Item Value
IANA 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" [RFC8126] policy:
+-----------+----------------------+
| Type Code | Description |
+-----------+----------------------+
| TBD1 | Radio Channel Active |
+-----------+----------------------+
| TBD2 | Radio Channel Busy |
+-----------+----------------------+
| TBD3 | Radio Channel Rx |
+-----------+----------------------+
| TBD4 | Radio Channel Tx |
+-----------+----------------------+
Table 3: New Data Item Value
6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
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[RFC8175] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B.
Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175,
DOI 10.17487/RFC8175, June 2017,
<https://www.rfc-editor.org/info/rfc8175>.
7. Informative References
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
Author's Address
Henning Rogge
Fraunhofer FKIE
Fraunhofer Strasse 20
53343 Wachtberg
Germany
Email: henning.rogge@fkie.fraunhofer.de
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