draft-ietf-lpwan-schc-yang-data-model-01.txt   draft-ietf-lpwan-schc-yang-data-model-02.txt 
lpwan Working Group A. Minaburo lpwan Working Group A. Minaburo
Internet-Draft Acklio Internet-Draft Acklio
Intended status: Standards Track L. Toutain Intended status: Standards Track L. Toutain
Expires: July 26, 2020 Institut MINES TELECOM; IMT Atlantique Expires: August 31, 2020 Institut MINES TELECOM; IMT Atlantique
January 23, 2020 February 28, 2020
Data Model for Static Context Header Compression (SCHC) Data Model for Static Context Header Compression (SCHC)
draft-ietf-lpwan-schc-yang-data-model-01 draft-ietf-lpwan-schc-yang-data-model-02
Abstract Abstract
This document describes a YANG data model for the SCHC (Static This document describes a YANG data model for the SCHC (Static
Context Header Compression) compression and fragmentation rules. Context Header Compression) compression and fragmentation rules.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 26, 2020. This Internet-Draft will expire on August 31, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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2.4. Field position . . . . . . . . . . . . . . . . . . . . . 7 2.4. Field position . . . . . . . . . . . . . . . . . . . . . 7
2.5. Direction Indicator . . . . . . . . . . . . . . . . . . . 7 2.5. Direction Indicator . . . . . . . . . . . . . . . . . . . 7
2.6. Target Value . . . . . . . . . . . . . . . . . . . . . . 8 2.6. Target Value . . . . . . . . . . . . . . . . . . . . . . 8
2.7. Matching Operator . . . . . . . . . . . . . . . . . . . . 9 2.7. Matching Operator . . . . . . . . . . . . . . . . . . . . 9
2.7.1. Matching Operator arguments . . . . . . . . . . . . . 10 2.7.1. Matching Operator arguments . . . . . . . . . . . . . 10
2.8. Compression Decompresison Actions . . . . . . . . . . . . 10 2.8. Compression Decompresison Actions . . . . . . . . . . . . 10
2.8.1. Compression Decompression Action arguments . . . . . 12 2.8.1. Compression Decompression Action arguments . . . . . 12
3. Rule definition . . . . . . . . . . . . . . . . . . . . . . . 12 3. Rule definition . . . . . . . . . . . . . . . . . . . . . . . 12
3.1. Compression rule . . . . . . . . . . . . . . . . . . . . 14 3.1. Compression rule . . . . . . . . . . . . . . . . . . . . 14
3.1.1. Compression context representation. . . . . . . . . . 14 3.1.1. Compression context representation. . . . . . . . . . 14
3.1.2. Rule definition . . . . . . . . . . . . . . . . . . . 16 3.1.2. Rule definition . . . . . . . . . . . . . . . . . . . 15
3.2. Fragmentation rule . . . . . . . . . . . . . . . . . . . 16 3.2. Fragmentation rule . . . . . . . . . . . . . . . . . . . 16
3.3. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . 17 3.3. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . 17
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
5. Security considerations . . . . . . . . . . . . . . . . . . . 17 5. Security considerations . . . . . . . . . . . . . . . . . . . 19
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19
7. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 18 7. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 19
8. Normative References . . . . . . . . . . . . . . . . . . . . 18 8. Normative References . . . . . . . . . . . . . . . . . . . . 33
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 33
1. Introduction 1. Introduction
2. SCHC rules 2. SCHC rules
SCHC is a compression and fragmentation mechanism for constrained SCHC is a compression and fragmentation mechanism for constrained
networks defined in [I-D.ietf-lpwan-ipv6-static-context-hc] it is networks defined in [I-D.ietf-lpwan-ipv6-static-context-hc] it is
based on a static context shared by two entities at the boundary this based on a static context shared by two entities at the boundary this
contrained network. Draft [I-D.ietf-lpwan-ipv6-static-context-hc] contrained network. Draft [I-D.ietf-lpwan-ipv6-static-context-hc]
provides an abstract representation of the rules used either for provides an abstract representation of the rules used either for
skipping to change at page 6, line 9 skipping to change at page 6, line 9
Figure 2 gives an example of field ID identityref definitions. The Figure 2 gives an example of field ID identityref definitions. The
base identity is field-id-base-type, and field id are derived for it. base identity is field-id-base-type, and field id are derived for it.
The naming convention is "fid" followed by the protocol name and the The naming convention is "fid" followed by the protocol name and the
field name. field name.
The yang model in annex gives the full definition of the field ID for The yang model in annex gives the full definition of the field ID for
[I-D.ietf-lpwan-ipv6-static-context-hc] and [I-D.ietf-lpwan-ipv6-static-context-hc] and
[I-D.ietf-lpwan-coap-static-context-hc]. [I-D.ietf-lpwan-coap-static-context-hc].
The type associated to this identity is field-id-type (cf. {{Fig-field-id-type}}) The type associated to this identity is field-id-type (cf. Figure 3)
typedef field-id-type { typedef field-id-type {
description "Field ID generic type."; description "Field ID generic type.";
type identityref { type identityref {
base field-id-base-type; base field-id-base-type;
} }
} }
Figure 3: Definition of indentityref for field IDs Figure 3: Definition of indentityref for field IDs
2.3. Field length 2.3. Field length
Field length is either an integer giving the size of a field in bits Field length is either an integer giving the size of a field in bits
or a function. [I-D.ietf-lpwan-ipv6-static-context-hc] defines the or a function. [I-D.ietf-lpwan-ipv6-static-context-hc] defines the
"var" function which allows variable length fields in byte and "var" function which allows variable length fields in byte and
[I-D.ietf-lpwan-coap-static-context-hc] defines the "tkl" function [I-D.ietf-lpwan-coap-static-context-hc] defines the "tkl" function
for managing the CoAP Token length field. for managing the CoAP Token length field.
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3.1.1. Compression context representation. 3.1.1. Compression context representation.
The compression rule described Figure 1 is associated to a rule ID. The compression rule described Figure 1 is associated to a rule ID.
The compression rule entry is defined in Figure 14. Each column in The compression rule entry is defined in Figure 14. Each column in
the table is either represented by a leaf or a list. Note that the table is either represented by a leaf or a list. Note that
Matching Operators and Compression Decompression actions can have Matching Operators and Compression Decompression actions can have
arguments. They are viewed a ordered list of strings and numbers as arguments. They are viewed a ordered list of strings and numbers as
in target values. in target values.
grouping compression-rule-entry { grouping compression-rule-entry {
leaf field-id { leaf field-id {
mandatory true; mandatory true;
type schc-id:field-id-type; type schc-id:field-id-type;
} }
leaf field-length { leaf field-length {
mandatory true; mandatory true;
type schc-id:field-length-type; type schc-id:field-length-type;
} }
leaf field-position { leaf field-position {
mandatory true; mandatory true;
type uint8; type uint8;
} }
leaf direction-indicator { leaf direction-indicator {
mandatory true; mandatory true;
type schc-id:direction-indicator-type; type schc-id:direction-indicator-type;
} }
list target-values { list target-values {
key position; key position;
uses target-values-struct;
uses target-values-struct; }
} leaf mo {
leaf mo { mandatory true;
mandatory true; type schc-id:matching-operator-type;
type schc-id:matching-operator-type; }
} list mo-value {
// /!\ Not always good, it allows to give several arguments to a MO, but key position;
// theses arguments are only int or strings, cannot be arrays. Is it necessary? uses target-values-struct;
list mo-value { }
key position; leaf cda {
uses target-values-struct; mandatory true;
} type schc-id:comp-decomp-action-type;
leaf cda { }
mandatory true; list cda-value {
type schc-id:cda-type; key position;
} uses target-values-struct;
list cda-value { }
key position; }
uses target-values-struct;
}
}
Figure 14: Definition of a compression entry Figure 14: Definition of a compression entry
3.1.2. Rule definition 3.1.2. Rule definition
A compression rule is a list of entries. A compression rule is a list of entries.
grouping compression-content { grouping compression-content {
list entry { list entry {
key "field-id field-position direction-indicator"; // field-position direction-indicator"; key "field-id field-position direction-indicator";
uses compression-rule-entry; uses compression-rule-entry;
} }
} }
Figure 15: Definition of a compression rule Figure 15: Definition of a compression rule
To identify a specific entry Field ID, position and direction is To identify a specific entry Field ID, position and direction are
needed. needed.
3.2. Fragmentation rule 3.2. Fragmentation rule
TBD Parameters for fragmentation are defined in Annex D of
[I-D.ietf-lpwan-ipv6-static-context-hc]. Two new types are defined
for Ack on Error acknowlement behavior (ack-behavior-type) and the
RCS algorithm (RCS-algorithm-type).
grouping fragmentation-content { grouping fragmentation-content {
leaf dtagsize { leaf direction {
type uint8; type schc-id:direction-indicator-type;
} description "should be up or down";
leaf wsize { }
type uint8;
} leaf dtagsize {
leaf fcnsize { type uint8;
type uint8; description "size in bit of the DTag field";
} }
choice mode { leaf wsize {
case no-ack; type uint8;
case ack-always; description "size in bit of the window field";
case ack-on-error { }
leaf ack-method { leaf fcnsize {
type enumeration { type uint8;
enum afterAll0; description "size in bit of the FCN field";
enum afterAll1; }
enum always; leaf RCS-algorithm {
} type RCS-algorithm-type;
} default schc-id:RFC8724-RCS;
} description "Algoritm used for RCS";
} }
} leaf maximum-window-size {
type uint16;
description "by default 2^wsize - 1";
}
leaf retransmission-timer {
type uint64;
description "duration in seconds of the retransmission timer"; // Check the units
}
leaf inactivity-timer {
type uint64;
description "duration is seconds of the inactivity timer"; // check units
}
leaf max-ack-requests {
type uint8;
}
leaf maximum-packet-size {
type uint16;
mandatory true;
default 1280;
description "When decompression is done, packet size must not strictly exceed this limit in Bytes";
}
choice mode {
case no-ack;
case ack-always;
case ack-on-error {
leaf tile-size {
type uint8;
description "size in bit of tiles";
}
leaf tile-in-All1 {
type boolean;
description "When true, sender and receiver except a tile in All-1 frag";
}
leaf ack-behavior {
type schc-id:ack-behavior-type;
mandatory true;
}
}
}
}
Figure 16: Definition of a fragmentation rule Figure 16: Definition of a fragmentation rule
3.3. YANG Tree 3.3. YANG Tree
module: schc module: schc
+--rw schc +--rw schc
+--rw version? uint64 +--rw version? uint64
+--rw rule* [rule-id rule-length] +--rw rule* [rule-id rule-length]
+--rw rule-id uint32 +--rw rule-id uint32
+--rw rule-length uint8 +--rw rule-length uint8
+--rw (nature)? +--rw (nature)?
+--:(fragmentation) +--:(fragmentation)
| +--rw dtagsize? uint8 | +--rw direction? schc-id:direction-indicator-type
| +--rw wsize? uint8 | +--rw dtagsize? uint8
| +--rw fcnsize? uint8 | +--rw wsize? uint8
| +--rw (mode)? | +--rw fcnsize? uint8
| +--rw RCS-algorithm? RCS-algorithm-type
| +--rw maximum-window-size? uint16
| +--rw retransmission-timer? uint64
| +--rw inactivity-timer? uint64
| +--rw max-ack-requests? uint8
| +--rw maximum-packet-size uint16
| +--rw (mode)
| +--:(no-ack) | +--:(no-ack)
| +--:(ack-always) | +--:(ack-always)
| +--:(ack-on-error) | +--:(ack-on-error)
| +--rw ack-method? enumeration | +--rw tile-size? uint8
| +--rw tile-in-All1? boolean
| +--rw ack-behavior schc-id:ack-behavior-type
+--:(compression) +--:(compression)
+--rw entry* [field-id field-position direction-indicator] +--rw entry* [field-id field-position direction-indicator]
+--rw field-id schc-id:field-id-type +--rw field-id schc-id:field-id-type
+--rw field-length schc-id:field-length-type +--rw field-length schc-id:field-length-type
+--rw field-position uint8 +--rw field-position uint8
+--rw direction-indicator schc-id:direction-indicator-type +--rw direction-indicator schc-id:direction-indicator-type
+--rw target-values* [position] +--rw target-values* [position]
| +--rw value? union | +--rw value? union
| +--rw position uint16 | +--rw position uint16
+--rw mo schc-id:matching-operator-type +--rw mo schc-id:matching-operator-type
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This document does not have any more Security consideration than the This document does not have any more Security consideration than the
ones already raised on [I-D.ietf-lpwan-ipv6-static-context-hc] ones already raised on [I-D.ietf-lpwan-ipv6-static-context-hc]
6. Acknowledgements 6. Acknowledgements
The authors would like to thank Dominique Barthel, Carsten Bormann, The authors would like to thank Dominique Barthel, Carsten Bormann,
Alexander Pelov. Alexander Pelov.
7. YANG Module 7. YANG Module
Currently the data model is split into two parts. The first one is
dedicated to SCHC identifiers and the second one contains the rules
definition. The goal is to allow some stabilities in the rule
identifiers if new SCHC identfiers are added. When the model will be
stable, these two files will be merged.
<code begins> file schc-id@2020-02-28.yang
module schc-id{
yang-version "1";
namespace "urn:ietf:lpwan:schc:schc-id";
prefix "schc-id";
description
"Identifiers used in SCHC data model.";
revision 2020-02-28 {
description "Add fragmentation identifiers";
}
revision 2020-02-11 {
description "Clean up";
}
revision 2020-01-07 {
description "First version of the SCHC identifiers";
}
// -------------------------
// Field ID type definition
//--------------------------
// generic value TV definition
identity field-id-base-type {
description "Field ID with SID";
}
identity fid-ipv6-version {
base field-id-base-type;
description "IPv6 version field from RFC8200";
}
identity fid-ipv6-trafficclass {
base field-id-base-type;
description "IPv6 Traffic Class field from RFC8200";
}
identity fid-ipv6-trafficclass-ds {
base field-id-base-type;
description "IPv6 Traffic Class field from RFC8200,
DiffServ field from RFC3168";
}
identity fid-ipv6-trafficclass-ecn {
base field-id-base-type;
description "IPv6 Traffic Class field from RFC8200,
ECN field from RFC3168";
}
identity fid-ipv6-flowlabel {
base field-id-base-type;
description "IPv6 Flow Label field from RFC8200";
}
identity fid-ipv6-payloadlength {
base field-id-base-type;
description "IPv6 Payload Length field from RFC8200";
}
identity fid-ipv6-nextheader {
base field-id-base-type;
description "IPv6 Next Header field from RFC8200";
}
identity fid-ipv6-hoplimit {
base field-id-base-type;
description "IPv6 Next Header field from RFC8200";
}
identity fid-ipv6-devprefix {
base field-id-base-type;
description "correspond either to the source address or the desdination
address prefix of RFC 8200. Depending if it is respectively
a uplink or an downklink message.";
}
identity fid-ipv6-deviid {
base field-id-base-type;
description "correspond either to the source address or the desdination
address prefix of RFC 8200. Depending if it is respectively
a uplink or an downklink message.";
}
identity fid-ipv6-appprefix {
base field-id-base-type;
description "correspond either to the source address or the desdination
address prefix of RFC 768. Depending if it is respectively
a downlink or an uplink message.";
}
identity fid-ipv6-appiid {
base field-id-base-type;
description "correspond either to the source address or the desdination
address prefix of RFC 768. Depending if it is respectively
a downlink or an uplink message.";
}
identity fid-udp-dev-port {
base field-id-base-type;
description "UDP length from RFC 768";
}
identity fid-udp-app-port {
base field-id-base-type;
description "UDP length from RFC 768";
}
identity fid-udp-length {
base field-id-base-type;
description "UDP length from RFC 768";
}
identity fid-udp-checksum {
base field-id-base-type;
description "UDP length from RFC 768";
}
identity fid-coap-version {
base field-id-base-type;
description "CoAP version from RFC 7252";
}
identity fid-coap-type {
base field-id-base-type;
description "CoAP type from RFC 7252";
}
identity fid-coap-tkl {
base field-id-base-type;
description "CoAP token length from RFC 7252";
}
identity fid-coap-code {
base field-id-base-type;
description "CoAP code from RFC 7252";
}
identity fid-coap-code-class {
base field-id-base-type;
description "CoAP code from RFC 7252";
}
identity fid-coap-code-detail {
base field-id-base-type;
description "CoAP code from RFC 7252";
}
identity fid-coap-mid {
base field-id-base-type;
description "CoAP message ID from RFC 7252";
}
identity fid-coap-token {
base field-id-base-type;
description "CoAP token from RFC 7252";
}
identity fid-coap-option-if-match {
base field-id-base-type;
description "CoAP option If-Match from RFC 7252";
}
identity fid-coap-option-uri-host {
base field-id-base-type;
description "CoAP option URI-Host from RFC 7252";
}
identity fid-coap-option-etag {
base field-id-base-type;
description "CoAP option Etag from RFC 7252";
}
identity fid-coap-option-if-none-match {
base field-id-base-type;
description "CoAP option if-none-match from RFC 7252";
}
identity fid-coap-option-observe {
base field-id-base-type;
description "CoAP option Observe from RFC 7641";
}
identity fid-coap-option-uri-port {
base field-id-base-type;
description "CoAP option Uri-Port from RFC 7252";
}
identity fid-coap-option-location-path {
base field-id-base-type;
description "CoAP option Location-Path from RFC 7252";
}
identity fid-coap-option-uri-path {
base field-id-base-type;
description "CoAP option Uri-Path from RFC 7252";
}
identity fid-coap-option-content-format {
base field-id-base-type;
description "CoAP option Content Format from RFC 7252";
}
identity fid-coap-option-max-age {
base field-id-base-type;
description "CoAP option Max-Age from RFC 7252";
}
identity fid-coap-option-uri-query {
base field-id-base-type;
description "CoAP option Uri-Query from RFC 7252";
}
identity fid-coap-option-accept {
base field-id-base-type;
description "CoAP option Max-Age from RFC 7252";
}
identity fid-coap-option-location-query {
base field-id-base-type;
description "CoAP option Location-Query from RFC 7252";
}
identity fid-coap-option-block2 {
base field-id-base-type;
description "CoAP option Block2 from RFC 7959";
}
identity fid-coap-option-block1 {
base field-id-base-type;
description "CoAP option Block1 from RFC 7959";
}
identity fid-coap-option-size2 {
base field-id-base-type;
description "CoAP option size2 from RFC 7959";
}
identity fid-coap-option-proxy-uri {
base field-id-base-type;
description "CoAP option Proxy-Uri from RFC 7252";
}
identity fid-coap-option-proxy-scheme {
base field-id-base-type;
description "CoAP option Proxy-scheme from RFC 7252";
}
identity fid-coap-option-size1 {
base field-id-base-type;
description "CoAP option Size1 from RFC 7252";
}
identity fid-coap-option-no-response {
base field-id-base-type;
description "CoAP option No response from RFC 7967";
}
identity fid-coap-option-end-option {
base field-id-base-type;
description "CoAP End Option from RFC 7967";
}
//----------------------------------
// Field Length type definition
//----------------------------------
identity field-length-base-type {
description "used to extend field length functions";
}
identity fl-variable {
base field-length-base-type;
description "residue length in Byte is sent";
}
identity fl-token-length {
base field-length-base-type;
description "residue length in Byte is sent";
}
//---------------------------------
// Direction Indicator type
//---------------------------------
identity direction-indicator-base-type {
description "used to extend field length functions";
}
identity di-bidirectional {
base direction-indicator-base-type;
description "Direction Indication of bi directionality";
}
identity di-up {
base direction-indicator-base-type;
description "Direction Indication of upstream";
}
identity di-down {
base direction-indicator-base-type;
description "Direction Indication of downstream";
}
//----------------------------------
// Matching Operator type definition
//----------------------------------
identity matching-operator-base-type {
description "used to extend Matching Operators with SID values";
}
identity mo-equal {
base matching-operator-base-type;
description "SCHC draft";
}
identity mo-ignore {
base matching-operator-base-type;
description "SCHC draft";
}
identity mo-msb {
base matching-operator-base-type;
description "SCHC draft";
}
identity mo-matching {
base matching-operator-base-type;
description "SCHC draft";
}
//------------------------------
// CDA type definition
//------------------------------
identity compression-decompression-action-base-type;
identity cda-not-sent {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
identity cda-value-sent {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
identity cda-lsb {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
identity cda-mapping-sent {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
identity cda-compute-length {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
identity cda-compute-checksum {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
identity cda-deviid {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
identity cda-appiid {
base compression-decompression-action-base-type;
description "from SCHC draft";
}
// -- type definition
typedef field-id-type {
description "Field ID generic type.";
type identityref {
base field-id-base-type;
}
}
typedef field-length-type {
type union {
type int64; /* positive length */
type identityref { /* function */
base field-length-base-type;
}
}
}
typedef direction-indicator-type {
type identityref {
base direction-indicator-base-type;
}
}
typedef matching-operator-type {
type identityref {
base matching-operator-base-type;
}
}
typedef comp-decomp-action-type {
type identityref {
base compression-decompression-action-base-type;
}
}
// -- fragmentation types
identity ack-behavior-base-type {
description "type to define when to send an Acknowledgment message";
}
identity ack-behavior-after-All0 {
description "fragmentor expect Ack after sending All0 fragment.";
base ack-behavior-base-type;
}
identity ack-behavior-after-All1 {
description "fragmentor expect Ack after sending All1 fragment.";
base ack-behavior-base-type;
}
identity ack-behavior-after-Always {
description "fragmentor expect Ack after sending every fragment.";
base ack-behavior-base-type;
}
typedef ack-behavior-type {
type identityref {
base ack-behavior-base-type;
}
}
// -- fragmentation types
identity RCS-algorithm-base-type {
description "identify which algorithm is used to compute RSC.
The algorithm defines also the size if the RSC field.";
}
identity RFC8724-RCS {
description "CRC 32 defined as default RCS in RFC8724.";
base RCS-algorithm-base-type;
}
typedef RCS-algorithm-type {
type identityref {
base RCS-algorithm-base-type;
}
}
}
<code ends>
Figure 18
<code begins> file schc@2020-02-28.yang
module schc{
yang-version "1";
namespace "urn:ietf:lpwan:schc:rules-description";
prefix "schc";
import schc-id {
prefix "schc-id";
}
description
"Generic Data model for Static Context Header Compression Rule for SCHC,
based on draft-ietf-lpwan-ipv6-static-context-hc-18. Include compression
rules and fragmentation rules.";
revision 2020-02-28 {
description "Add Fragmentation parameters";
}
revision 2020-01-23 {
description "Modified TV with binary and union";
}
revision 2020-01-07 {
description "First version of the YANG model";
}
// -------- RULE DEFINITION ------------
grouping target-values-struct {
leaf value {
type union {
type binary;
type string;
}
}
leaf position {
type uint16;
}
}
grouping compression-rule-entry {
leaf field-id {
mandatory true;
type schc-id:field-id-type;
}
leaf field-length {
mandatory true;
type schc-id:field-length-type;
}
leaf field-position {
mandatory true;
type uint8;
}
leaf direction-indicator {
mandatory true;
type schc-id:direction-indicator-type;
}
list target-values {
key position;
uses target-values-struct;
}
leaf mo {
mandatory true;
type schc-id:matching-operator-type;
}
list mo-value {
key position;
uses target-values-struct;
}
leaf cda {
mandatory true;
type schc-id:comp-decomp-action-type;
}
list cda-value {
key position;
uses target-values-struct;
}
}
grouping fragmentation-content {
leaf direction {
type schc-id:direction-indicator-type;
description "should be up or down";
}
leaf dtagsize {
type uint8;
description "size in bit of the DTag field";
}
leaf wsize {
type uint8;
description "size in bit of the window field";
}
leaf fcnsize {
type uint8;
description "size in bit of the FCN field";
}
leaf RCS-algorithm {
type RCS-algorithm-type;
default schc-id:RFC8724-RCS;
description "Algoritm used for RCS";
}
leaf maximum-window-size {
type uint16;
description "by default 2^wsize - 1";
}
leaf retransmission-timer {
type uint64;
description "duration in seconds of the retransmission timer"; // Check the units
}
leaf inactivity-timer {
type uint64;
description "duration is seconds of the inactivity timer"; // check units
}
leaf max-ack-requests {
type uint8;
}
leaf maximum-packet-size {
type uint16;
mandatory true;
default 1280;
description "When decompression is done, packet size must not strictly exceed this limit in Bytes";
}
choice mode {
mandatory true;
case no-ack;
case ack-always;
case ack-on-error {
leaf tile-size {
type uint8;
description "size in bit of tiles";
}
leaf tile-in-All1 {
type boolean;
description "When true, sender and receiver except a tile in All-1 frag";
}
leaf ack-behavior {
type schc-id:ack-behavior-type;
mandatory true;
}
}
}
}
grouping compression-content {
list entry {
key "field-id field-position direction-indicator";
uses compression-rule-entry;
}
}
// Define rule ID. Rule ID is composed of a RuleID value and a Rule ID Length
grouping rule-id-type {
leaf rule-id {
type uint32;
description "rule ID value, this value must be unique combined with the length";
}
leaf rule-length {
type uint8 {
range 0..32;
}
description "rule ID length in bits, value 0 is for implicit rules";
}
}
// SCHC table for a specific device.
container schc {
leaf version{
type uint64;
mandatory false;
description "used as an indication for versioning";
}
list rule {
key "rule-id rule-length";
uses rule-id-type;
choice nature {
case fragmentation {
uses fragmentation-content;
}
case compression {
uses compression-content;
}
}
}
}
}
<code ends>
Figure 19
8. Normative References 8. Normative References
[I-D.ietf-lpwan-coap-static-context-hc] [I-D.ietf-lpwan-coap-static-context-hc]
Minaburo, A., Toutain, L., and R. Andreasen, "LPWAN Static Minaburo, A., Toutain, L., and R. Andreasen, "LPWAN Static
Context Header Compression (SCHC) for CoAP", draft-ietf- Context Header Compression (SCHC) for CoAP", draft-ietf-
lpwan-coap-static-context-hc-12 (work in progress), lpwan-coap-static-context-hc-12 (work in progress),
December 2019. December 2019.
[I-D.ietf-lpwan-ipv6-static-context-hc] [I-D.ietf-lpwan-ipv6-static-context-hc]
Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and J. Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and J.
 End of changes. 17 change blocks. 
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