Internet DRAFT - draft-toutain-lpwan-sid-allocation
draft-toutain-lpwan-sid-allocation
lpwan Working Group A. Minaburo
Internet-Draft Acklio
Intended status: Standards Track L. Toutain
Expires: 27 August 2023 Institut MINES TELECOM; IMT Atlantique
23 February 2023
SCHC Rule Access Control
draft-toutain-lpwan-sid-allocation-02
Abstract
blabla
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 27 August 2023.
Copyright Notice
Copyright (c) 2023 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 (https://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 Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Minaburo & Toutain Expires 27 August 2023 [Page 1]
Internet-Draft SCHC AC February 2023
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. SCHC YANG Data Model . . . . . . . . . . . . . . . . . . . . 2
2.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Recommendation for SID values . . . . . . . . . . . . . . . . 4
4. SID for data . . . . . . . . . . . . . . . . . . . . . . . . 4
5. SID allocation . . . . . . . . . . . . . . . . . . . . . . . 5
6. Normative References . . . . . . . . . . . . . . . . . . . . 9
Appendix A. Security Considerations . . . . . . . . . . . . . . 10
Appendix B. IANA Considerations . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
RFC9363 defines a YANG Data Model for SCHC rules.
[I-D.ietf-core-sid] specifies the process for SID allocation and
management. This document discuss of the SID allocation for RFC9363.
2. SCHC YANG Data Model
The version @2023-01-18 of the SCHC YANG Data Model published in the
RFC 9363 contains 136 SIDs (92 for identities, 2 for features and 42
for data). [I-D.ietf-core-sid] indicates that the SID range for the
YANG Data Model specified in RFC is between 1000 and 59 000 and that
the maximum request pool SHOULD NOT exceed 1000. The draft also
gives some pre allocated values.
Since SIDs will be used either to represent unique identity contained
in the data model and also leaves (data) forming this data model, it
could be wise to distinguish between identifiers and data.
Data structures are delta encoded and included as a CBOR element, the
size depends on the value. Deltas between -24 and +23 are encoded on
a single byte. Deltas between -256 and +255 use 2 bytes and larger
values corresponding to the RFC SID range will be encoded into 3
bytes. To optimize the CORECONF representation delta should be
smaller as possible for the more frequent leaves.
On the other hand identities are included in the CORECONF
representation and for the RFC SID range the size is constant and
equal to 3 bytes.
2.1. Example
Minaburo & Toutain Expires 27 August 2023 [Page 2]
Internet-Draft SCHC AC February 2023
CORECONF
{5095: {1: [{4:
[{1: 5015,
5: 5018,
6: 5068,
7: 4,
8: 1,
9: 5083,
13: [{1: 0, 2: h'06'}]},
{1: 5015,
5: 5018,
6: 2000003,
7: 8,
8: 1,
9: 5083,
13: [{1: 0, 2: h'00'}]}]
}]}
}
RESTCONF
{"ietf-schc:schc": {"rule": [{"entry":
[{"comp-decomp-action": "ietf-schc:cda-not-sent",
"direction-indicator": "ietf-schc:di-bidirectional",
"field-id": "ietf-schc:fid-ipv6-version",
"field-length": 4,
"field-position": 1,
"matching-operator": "ietf-schc:mo-equal",
"target-value": [{"index": 0, "value": "Bg=="}]},
{"comp-decomp-action": "ietf-schc:cda-not-sent",
"direction-indicator": "ietf-schc:di-bidirectional",
"field-id": "ietf-schc-oam:fid-icmpv6-type",
"field-length": 8,
"field-position": 1,
"matching-operator": "ietf-schc:mo-equal",
"target-value": [{"index": 0, "value": "gA=="}]} ]
}]}
}
Figure 1
The example in Figure 1 gives a CORECONF structure transposed the
CBOR diagnostic notation and its equivalent in RESTCONF with JSON.
For readability and compactness, this example is edited and do not
encode a full rule as defined in RFC9363.
Minaburo & Toutain Expires 27 August 2023 [Page 3]
Internet-Draft SCHC AC February 2023
The default SID numbering produced by pyang is used, starting from
5000 for SCHC Data Model defined in RFC9363 and 2000000 for an
experimental module for OAM.
We can see the delta encoding. The first SID 5095 represents "ietf-
schc:schc". "/ietf-schc:schc/rule" which is coded with a +1 since SID
5096 has been assigned. "/ietf-schc:schc/rule/entry" is coded with a
delta of 4. Then a list of Field Description follows. +1 represents
the leaf "ietf-schc:schc/rule/entry/comp-decomp-action" and the value
assigned to that key contains the SID of "ietf-schc:cda-not-sent"
identity.
Note that the second element contains a "field-id" belonging to the
"ietf-schc-oam" module and the associate SID is 2000003.
3. Recommendation for SID values
The SCHC YANG Data Model defined in RFC 9363 will probably be
augmented, to include for instance access control data. To keep a
compact representation, delta values must be kept as small as
possible. The LPWAN working group should not use the automatic SID
numbering and provide a more optimal allocation scheme for
augmentation of the SCHC YANG Data Model.
A first recommendation is to avoid merging data and identity in order
to limit the delta encoding. The distance between these two sections
can be 255 SID to allow deltas on 2 bytes.
The second recommendation is to leave some unused SID around SCHC
rules to allow augmentation.
4. SID for data
We propose to use a range of 300 values for the YANG Data Model
defined in RFC9263, which introduce room for future augmentation of
the Data Model, such as [I-D.toutain-lpwan-access-control] or
[I-D.ietf-lpwan-schc-compound-ack]. This will break the automatic
allocation process done by pyang and based on the nature of the SID
and the alphabetical order.
It is also worth noting that in the current SID allocation based on
alphabetical order places rule-id-value and rule-id-length, rule-
nature from the 33 to 35 position. CBOR encoding will be on two
bytes for each of the values. Since these three values are present
in all the rules, a smaller value will optimize the CORECONF
representation.
The allocation algorithm is the following:
Minaburo & Toutain Expires 27 August 2023 [Page 4]
Internet-Draft SCHC AC February 2023
* leaves between containers and list a maximal distance of 23 SIDS.
Positive and negative deltas will be encoded on 1 byte.
* fill this gap with the more common values defined in the container
or the list
* keep unused values for future augmentations.
* a guard of 255 after the last list will be kept unused before
allocating identities. This range allow a delta encoded on 2
bytes.
The LPWAN group will receive an range of SID values (we suppose
starting at 5000). The SIDs will be allocated following the previous
algorithm.
Other RFCs modifying the SCHC YANG Data Model will include a YANG
module. The lpwan WG will decide of the SID allocation and produce a
SID file with the mapping.
5. SID allocation
We propose the following allocation scheme for RFC9363:
5000 - 5022 : RESERVED FOR /ietf-schc:schc
5023 module ietf-schc
5024 data /ietf-schc:schc
5025 - 5046 : RESERVED FOR /ietf-schc:schc AND /ietf-schc:schc/rule
5047 data /ietf-schc:schc/rule
5048 data /ietf-schc:schc/rule/rule-id-length
5049 data /ietf-schc:schc/rule/rule-id-value
5050 data /ietf-schc:schc/rule/rule-nature
5051 - 5069 : RESERVED FOR /ietf-schc:schc/rule AND /ietf-schc:schc/rule/entry
5070 data /ietf-schc:schc/rule/entry
5071 data /ietf-schc:schc/rule/entry/comp-decomp-action
5072 data /ietf-schc:schc/rule/entry/comp-decomp-action-value
5073 data /ietf-schc:schc/rule/entry/comp-decomp-action-value/index
5074 data /ietf-schc:schc/rule/entry/comp-decomp-action-value/value
5075 data /ietf-schc:schc/rule/entry/direction-indicator
5076 data /ietf-schc:schc/rule/entry/field-id
5077 data /ietf-schc:schc/rule/entry/field-length
5078 data /ietf-schc:schc/rule/entry/field-position
5079 data /ietf-schc:schc/rule/entry/matching-operator
Minaburo & Toutain Expires 27 August 2023 [Page 5]
Internet-Draft SCHC AC February 2023
5080 data /ietf-schc:schc/rule/entry/matching-operator-value
5081 data /ietf-schc:schc/rule/entry/matching-operator-value/index
5082 data /ietf-schc:schc/rule/entry/matching-operator-value/value
5083 data /ietf-schc:schc/rule/entry/target-value
5084 data /ietf-schc:schc/rule/entry/target-value/index
5085 data /ietf-schc:schc/rule/entry/target-value/value
5086 - 5094 : RESERVED
5094 data /ietf-schc:schc/rule/ack-behavior
5095 data /ietf-schc:schc/rule/direction
5096 data /ietf-schc:schc/rule/dtag-size
5097 data /ietf-schc:schc/rule/fcn-size
5098 data /ietf-schc:schc/rule/fragmentation-mode
5099 data /ietf-schc:schc/rule/inactivity-timer
5100 data /ietf-schc:schc/rule/inactivity-timer/ticks-duration
5101 data /ietf-schc:schc/rule/inactivity-timer/ticks-numbers
5102 data /ietf-schc:schc/rule/l2-word-size
5103 data /ietf-schc:schc/rule/max-ack-requests
5104 data /ietf-schc:schc/rule/max-interleaved-frames
5105 data /ietf-schc:schc/rule/maximum-packet-size
5106 data /ietf-schc:schc/rule/rcs-algorithm
5107 data /ietf-schc:schc/rule/retransmission-timer
5108 data /ietf-schc:schc/rule/retransmission-timer/ticks-duration
5109 data /ietf-schc:schc/rule/retransmission-timer/ticks-numbers
5110 - 5115 : RESERVED FOR TIMER
5116 data /ietf-schc:schc/rule/tile-in-all-1
5117 data /ietf-schc:schc/rule/tile-size
5118 data /ietf-schc:schc/rule/w-size
5119 data /ietf-schc:schc/rule/window-size
5120 - 5299 : RESERVED FOR 2 BYTES DELTAS
5300 identity ack-behavior-after-all-0
5301 identity ack-behavior-after-all-1
5302 identity ack-behavior-base-type
5303 identity ack-behavior-by-layer2
5304 identity all-1-data-base-type
5305 identity all-1-data-no
5306 identity all-1-data-sender-choice
5307 identity all-1-data-yes
5308 identity cda-appiid
5309 identity cda-base-type
5310 identity cda-compute
5311 identity cda-deviid
5312 identity cda-lsb
Minaburo & Toutain Expires 27 August 2023 [Page 6]
Internet-Draft SCHC AC February 2023
5313 identity cda-mapping-sent
5314 identity cda-not-sent
5315 identity cda-value-sent
5316 identity di-base-type
5317 identity di-bidirectional
5318 identity di-down
5319 identity di-up
5320 identity fid-base-type
5321 identity fid-coap-base-type
5322 identity fid-coap-code
5323 identity fid-coap-code-class
5324 identity fid-coap-code-detail
5325 identity fid-coap-mid
5326 identity fid-coap-option
5327 identity fid-coap-option-accept
5328 identity fid-coap-option-block1
5329 identity fid-coap-option-block2
5330 identity fid-coap-option-content-format
5331 identity fid-coap-option-etag
5332 identity fid-coap-option-if-match
5333 identity fid-coap-option-if-none-match
5334 identity fid-coap-option-location-path
5335 identity fid-coap-option-location-query
5336 identity fid-coap-option-max-age
5337 identity fid-coap-option-no-response
5338 identity fid-coap-option-observe
5339 identity fid-coap-option-oscore-flags
5340 identity fid-coap-option-oscore-kid
5341 identity fid-coap-option-oscore-kidctx
5342 identity fid-coap-option-oscore-piv
5343 identity fid-coap-option-proxy-scheme
5344 identity fid-coap-option-proxy-uri
5345 identity fid-coap-option-size1
5346 identity fid-coap-option-size2
5347 identity fid-coap-option-uri-host
5348 identity fid-coap-option-uri-path
5349 identity fid-coap-option-uri-port
5350 identity fid-coap-option-uri-query
5351 identity fid-coap-tkl
5352 identity fid-coap-token
5353 identity fid-coap-type
5354 identity fid-coap-version
5355 identity fid-ipv6-appiid
5356 identity fid-ipv6-appprefix
5357 identity fid-ipv6-base-type
5358 identity fid-ipv6-deviid
5359 identity fid-ipv6-devprefix
5360 identity fid-ipv6-flowlabel
Minaburo & Toutain Expires 27 August 2023 [Page 7]
Internet-Draft SCHC AC February 2023
5361 identity fid-ipv6-hoplimit
5362 identity fid-ipv6-nextheader
5363 identity fid-ipv6-payload-length
5364 identity fid-ipv6-trafficclass
5365 identity fid-ipv6-trafficclass-ds
5366 identity fid-ipv6-trafficclass-ecn
5367 identity fid-ipv6-version
5368 identity fid-oscore-base-type
5369 identity fid-udp-app-port
5370 identity fid-udp-base-type
5371 identity fid-udp-checksum
5372 identity fid-udp-dev-port
5373 identity fid-udp-length
5374 identity fl-base-type
5375 identity fl-token-length
5376 identity fl-variable
5377 identity fragmentation-mode-ack-always
5378 identity fragmentation-mode-ack-on-error
5379 identity fragmentation-mode-base-type
5380 identity fragmentation-mode-no-ack
5381 identity mo-base-type
5382 identity mo-equal
5383 identity mo-ignore
5384 identity mo-match-mapping
5385 identity mo-msb
5386 identity nature-base-type
5387 identity nature-compression
5388 identity nature-fragmentation
5389 identity nature-no-compression
5390 identity rcs-algorithm-base-type
5391 identity rcs-crc32
5392 feature compression
5393 feature fragmentation
5394 - 5500 : RESERVED FOR IDENTITY
For instance [I-D.toutain-lpwan-access-control] augments the model
with "ac-modify-set-of-rules" at the top level, "ac-modify-
compression-rule" for each compression rule, "ac-modify-field" in
each Field Description of a compression rule and finally "ac-modify-
timers" in fragmentation rules. Delta representation will be on 1
byte.
The following SIDs could be assigned:
* 5022: ac-modify-set-of-rules
* 5051: ac-modify-compression-rule
Minaburo & Toutain Expires 27 August 2023 [Page 8]
Internet-Draft SCHC AC February 2023
* 5069: ac-modify-field
* 5068: ac-modify-timers
[I-D.ietf-lpwan-schc-compound-ack] augments the model for
fragmentation, with 3 identity and two leaves. identities can get a
SID 5394 to 5396 and the two SIDs for the leaves can be 5120 and
5122. There delta representations will be coded on 2 bytes.
6. Normative References
[I-D.ietf-core-sid]
Veillette, M., Pelov, A., Petrov, I., Bormann, C., and M.
Richardson, "YANG Schema Item iDentifier (YANG SID)", Work
in Progress, Internet-Draft, draft-ietf-core-sid-19, 26
July 2022, <https://datatracker.ietf.org/doc/html/draft-
ietf-core-sid-19>.
[I-D.ietf-lpwan-schc-compound-ack]
Zúñiga, J. C., Gomez, C., Aguilar, S., Toutain, L.,
Cespedes, S., and D. S. W. L. Torre, "SCHC Compound ACK",
Work in Progress, Internet-Draft, draft-ietf-lpwan-schc-
compound-ack-12, 21 February 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-lpwan-
schc-compound-ack-12>.
[I-D.ietf-lpwan-schc-yang-data-model]
Minaburo, A. and L. Toutain, "Data Model for Static
Context Header Compression (SCHC)", Work in Progress,
Internet-Draft, draft-ietf-lpwan-schc-yang-data-model-21,
9 October 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-lpwan-schc-yang-data-model-21>.
[I-D.toutain-lpwan-access-control]
Minaburo, A., Toutain, L., and I. Martinez, "SCHC Rule
Access Control", Work in Progress, Internet-Draft, draft-
toutain-lpwan-access-control-01, 20 February 2023,
<https://datatracker.ietf.org/doc/html/draft-toutain-
lpwan-access-control-01>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/rfc/rfc8341>.
Minaburo & Toutain Expires 27 August 2023 [Page 9]
Internet-Draft SCHC AC February 2023
[RFC8824] Minaburo, A., Toutain, L., and R. Andreasen, "Static
Context Header Compression (SCHC) for the Constrained
Application Protocol (CoAP)", RFC 8824,
DOI 10.17487/RFC8824, June 2021,
<https://www.rfc-editor.org/rfc/rfc8824>.
Appendix A. Security Considerations
TBD
Appendix B. IANA Considerations
TBD
Authors' Addresses
Ana Minaburo
Acklio
1137A avenue des Champs Blancs
35510 Cesson-Sevigne Cedex
France
Email: ana@ackl.io
Laurent Toutain
Institut MINES TELECOM; IMT Atlantique
2 rue de la Chataigneraie
CS 17607
35576 Cesson-Sevigne Cedex
France
Email: Laurent.Toutain@imt-atlantique.fr
Minaburo & Toutain Expires 27 August 2023 [Page 10]
