Manet                                                         H.R. Rogge
Internet-Draft                                           Fraunhofer FKIE
Intended status: Standards Track                         5 November 2024
Expires: 9 May 2025


                      DLEP Radio Quality Extension
                 draft-ietf-manet-dlep-radio-quality-01

Abstract

   This document defines an extension to the Dynamic Link Exchange
   Protocol (DLEP) to provide the quality of incoming radio signals.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Extension Usage and Identification  . . . . . . . . . . . . .   2
   3.  Radio Quality Data Items  . . . . . . . . . . . . . . . . . .   2
     3.1.  Radio Biterror Rate Data Item . . . . . . . . . . . . . .   3
     3.2.  Radio SNR Data Item . . . . . . . . . . . . . . . . . . .   4
     3.3.  Radio Signal Strength Data Item (also called RSSI)  . . .   4
     3.4.  Radio Noise Data Item . . . . . . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Extension Type Value  . . . . . . . . . . . . . . . . . .   6
     5.2.  Data Item Value . . . . . . . . . . . . . . . . . . . . .   6
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   7.  Informative References  . . . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

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.

1.1.  Requirements Language

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

2.  Extension Usage and Identification

   The use of the Radio Quality Extension SHOULD be configurable.  To
   indicate that the Radio Quality Extension is to be used, an
   implementation MUST include the Radio Quality Extension Type Value in
   the Extensions Supported Data Item.  The Extensions Supported Data
   Item is sent and processed according to [RFC8175].

   The Radio Quality Extension Type Value is TBD; see Section 5.1.

3.  Radio Quality Data Items

   This section describes the quality related Data Items of this
   extension.





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   All Data Items available in this extension provide access to the
   radios physical layer measurements related to signal quality.
   Because of different designs of Radio PHY layers, this quality can be
   expressed in different ways, by referring to signal-to-noise ratio or
   by measuring the biterror rate (e.g. by using a forward error
   correction).  Both of these possible informations are very valuable
   for calculating MANET metrics for radio networks with moving nodes
   and low datarates, e.g.  VHF radio networks.  Estimating channel
   quality based on packet loss can be impractical, because the
   estimated value changes too fast (because of movement) compared to
   the number of received frames.  Biterror rate (and Signal Strength)
   can provice the additional information necessary to build a
   reasonable stable and agile metric.  Biterror rate (before error
   correction) is a more generic way to represent this value, because it
   is a radio independent measurement.

   The Biterror Rate data item is mandatory when using the Radio Quality
   extension.  All other TLVs presented in this document are optional.

3.1.  Radio Biterror Rate Data Item

   Radio Biterror Rate Data Item is a mandatory TLV that contains
   information about the radio receivers estimate how often a
   transmitted bit will be received wrong.  This value can often be
   either directly measured by the radio by comparing the result of a
   forward-error-correction to the original received data or calculated
   from the received signal-to-noise ratio and knowledge about the
   current modulation coding scheme.  This Data Item can be both
   interface and neighbor specific.

   The format of the Radio Biterror Rate 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                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Biterror   |
   +-+-+-+-+-+-+-+-+

                                  Figure 1

   Data Item Type:  TBD

   Length:  1

   Biterror:  Biterror rate measured as a negative exponent to base 10,




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      e.g. "4" for an error rate of 1 to 10^-4.  An error rate of 0 is
      encoded with a 255.

3.2.  Radio SNR Data Item

   Radio SNR Data Item contains information which signal to noise ratio
   the radio measured.  This Data Item can be both interface and
   neighbor specific.

   The format of the Radio SNR 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                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              SNR              |     Flags     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                  Figure 2

   Data Item Type:  TBD

   Length:  3

   SNR:  SNR measured in dB multiplied by 10 as a signed integer.

   Flags:  Flags field as defined below.

   The Flags field is defined as:

   0 1 2 3 4 5 6 7
   +-+-+-+-+-+-+-+-+
   |   Reserved  |I|
   +-+-+-+-+-+-+-+-+

                                  Figure 3

   I:  Interference Flag, indicating the the data includes interference
      into the noise value (SINR).

   Reserved:  MUST be zero.  Left for future assignment.

3.3.  Radio Signal Strength Data Item (also called RSSI)

   Radio Signal Strength Data Item contains information which absolute
   signal strength the radio measured.  This Data Item can be both
   interface and neighbor specific.



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   This Data Item could also be used together with the Request Link
   Characteristics message to reconfigure the outgoing signal strength,
   either to reduce the size of the collision domain or to increase the
   range of the radio.

   The format of the Radio Signal Strength 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                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Signal             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                  Figure 4

   Data Item Type:  TBD

   Length:  2

   Signal:  Signal Strength measured in dBm multiplied by 10 as a signed
      integer.

3.4.  Radio Noise Data Item

   Radio Noise Data Item contains information which absolute noise value
   the radio measured.  This Data Item SHOULD be interface specific.

   The format of the Radio Noise 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                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Noise             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                  Figure 5

   Data Item Type:  TBD

   Length:  2

   Noise:  Noise measured in dBm multiplied by 10 as a signed integer.





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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].

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   |
                          +------+---------------+
                          | TBD  | Radio Quality |
                          +------+---------------+

                           Table 1: 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:
















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                    +-----------+---------------------+
                    | Type Code | Description         |
                    +-----------+---------------------+
                    | TBD       | Radio Biterror Rate |
                    +-----------+---------------------+
                    | TBD       | Radio SNR           |
                    +-----------+---------------------+
                    | TBD       | Radio Signal        |
                    +-----------+---------------------+
                    | TBD       | Radio Noise         |
                    +-----------+---------------------+

                        Table 2: 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>.

   [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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