Copyright (c) 2023 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in...
Version: 2023-03-01
module ietf-schc { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-schc"; prefix schc; organization "IETF IPv6 over Low Power Wide-Area Networks (lpwan) Working Group"; contact "WG Web: <https://datatracker.ietf.org/wg/lpwan/about/> WG List: <mailto:lp-wan@ietf.org> Editor: Laurent Toutain <mailto:laurent.toutain@imt-atlantique.fr> Editor: Ana Minaburo <mailto:ana@ackl.io>"; description "Copyright (c) 2023 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC 9363 (https://www.rfc-editor.org/info/rfc9363); see the RFC itself for full legal notices. 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 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here. *************************************************************** Generic data model for the Static Context Header Compression Rule for SCHC, based on RFCs 8724 and 8824. Including compression, no-compression, and fragmentation Rules. This module is a YANG data model for SCHC Rules (RFCs 8724 and 8824). RFC 8724 describes compression Rules in an abstract way through a table. |-----------------------------------------------------------------| | (FID) Rule 1 | |+-------+--+--+--+------------+-----------------+---------------+| ||Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| |+-------+--+--+--+------------+-----------------+---------------+| ||Field 2|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| |+-------+--+--+--+------------+-----------------+---------------+| ||... |..|..|..| ... | ... | ... || |+-------+--+--+--+------------+-----------------+---------------+| ||Field N|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| |+-------+--+--+--+------------+-----------------+---------------+| |-----------------------------------------------------------------| This module specifies a global data model that can be used for Rule exchanges or modification. It specifies both the data model format and the global identifiers used to describe some operations in fields. This data model applies to both compression and fragmentation."; revision "2023-03-01" { description "Initial version from RFC 9363."; reference "RFC 9363 A YANG Data Model for Static Context Header Compression (SCHC)"; } feature compression { description "SCHC compression capabilities are taken into account."; } feature fragmentation { description "SCHC fragmentation capabilities are taken into account."; } identity fid-base-type { description "Field ID base type for all fields."; } identity fid-ipv6-base-type { base fid-base-type; description "Field ID base type for IPv6 headers described in RFC 8200."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-version { base fid-ipv6-base-type; description "IPv6 version field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-trafficclass { base fid-ipv6-base-type; description "IPv6 Traffic Class field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-trafficclass-ds { base fid-ipv6-trafficclass; description "IPv6 Traffic Class field: Diffserv field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification, RFC 3168 The Addition of Explicit Congestion Notification (ECN) to IP"; } identity fid-ipv6-trafficclass-ecn { base fid-ipv6-trafficclass; description "IPv6 Traffic Class field: ECN field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification, RFC 3168 The Addition of Explicit Congestion Notification (ECN) to IP"; } identity fid-ipv6-flowlabel { base fid-ipv6-base-type; description "IPv6 Flow Label field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-payload-length { base fid-ipv6-base-type; description "IPv6 Payload Length field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-nextheader { base fid-ipv6-base-type; description "IPv6 Next Header field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-hoplimit { base fid-ipv6-base-type; description "IPv6 Next Header field."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-devprefix { base fid-ipv6-base-type; description "Corresponds to either the source address or the destination address prefix of RFC 8200 depending on whether it is an uplink or a downlink message."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-deviid { base fid-ipv6-base-type; description "Corresponds to either the source address or the destination address IID of RFC 8200 depending on whether it is an uplink or a downlink message."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-appprefix { base fid-ipv6-base-type; description "Corresponds to either the source address or the destination address prefix of RFC 8200 depending on whether it is an uplink or a downlink message."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-ipv6-appiid { base fid-ipv6-base-type; description "Corresponds to either the source address or the destination address IID of RFC 8200 depending on whether it is an uplink or a downlink message."; reference "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; } identity fid-udp-base-type { base fid-base-type; description "Field ID base type for UDP headers described in RFC 768."; reference "RFC 768 User Datagram Protocol"; } identity fid-udp-dev-port { base fid-udp-base-type; description "UDP source or destination port, if uplink or downlink communication, respectively."; reference "RFC 768 User Datagram Protocol"; } identity fid-udp-app-port { base fid-udp-base-type; description "UDP destination or source port, if uplink or downlink communication, respectively."; reference "RFC 768 User Datagram Protocol"; } identity fid-udp-length { base fid-udp-base-type; description "UDP length."; reference "RFC 768 User Datagram Protocol"; } identity fid-udp-checksum { base fid-udp-base-type; description "UDP length."; reference "RFC 768 User Datagram Protocol"; } identity fid-coap-base-type { base fid-base-type; description "Field ID base type for UDP headers described."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-version { base fid-coap-base-type; description "CoAP version."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-type { base fid-coap-base-type; description "CoAP type."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-tkl { base fid-coap-base-type; description "CoAP token length."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-code { base fid-coap-base-type; description "CoAP code."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-code-class { base fid-coap-code; description "CoAP code class."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-code-detail { base fid-coap-code; description "CoAP code detail."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-mid { base fid-coap-base-type; description "CoAP message ID."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-token { base fid-coap-base-type; description "CoAP token."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option { base fid-coap-base-type; description "Generic CoAP option."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-if-match { base fid-coap-option; description "CoAP option If-Match."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-uri-host { base fid-coap-option; description "CoAP option Uri-Host."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-etag { base fid-coap-option; description "CoAP option ETag."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-if-none-match { base fid-coap-option; description "CoAP option if-none-match."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-observe { base fid-coap-option; description "CoAP option Observe."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-uri-port { base fid-coap-option; description "CoAP option Uri-Port."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-location-path { base fid-coap-option; description "CoAP option Location-Path."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-uri-path { base fid-coap-option; description "CoAP option Uri-Path."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-content-format { base fid-coap-option; description "CoAP option Content Format."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-max-age { base fid-coap-option; description "CoAP option Max-Age."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-uri-query { base fid-coap-option; description "CoAP option Uri-Query."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-accept { base fid-coap-option; description "CoAP option Accept."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-location-query { base fid-coap-option; description "CoAP option Location-Query."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-block2 { base fid-coap-option; description "CoAP option Block2."; reference "RFC 7959 Block-Wise Transfers in the Constrained Application Protocol (CoAP)"; } identity fid-coap-option-block1 { base fid-coap-option; description "CoAP option Block1."; reference "RFC 7959 Block-Wise Transfers in the Constrained Application Protocol (CoAP)"; } identity fid-coap-option-size2 { base fid-coap-option; description "CoAP option Size2."; reference "RFC 7959 Block-Wise Transfers in the Constrained Application Protocol (CoAP)"; } identity fid-coap-option-proxy-uri { base fid-coap-option; description "CoAP option Proxy-Uri."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-proxy-scheme { base fid-coap-option; description "CoAP option Proxy-Scheme."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-size1 { base fid-coap-option; description "CoAP option Size1."; reference "RFC 7252 The Constrained Application Protocol (CoAP)"; } identity fid-coap-option-no-response { base fid-coap-option; description "CoAP option No response."; reference "RFC 7967 Constrained Application Protocol (CoAP) Option for No Server Response"; } identity fid-oscore-base-type { base fid-coap-option; description "OSCORE options (RFC8613) split in suboptions."; reference "RFC 8824 Static Context Header Compression (SCHC) for the Constrained Application Protocol (CoAP)"; } identity fid-coap-option-oscore-flags { base fid-coap-option; description "CoAP option OSCORE flags."; reference "RFC 8824 Static Context Header Compression (SCHC) for the Constrained Application Protocol (CoAP) (see Section 6.4)"; } identity fid-coap-option-oscore-piv { base fid-coap-option; description "CoAP option OSCORE flags."; reference "RFC 8824 Static Context Header Compression (SCHC) for the Constrained Application Protocol (CoAP) (see Section 6.4)"; } identity fid-coap-option-oscore-kid { base fid-coap-option; description "CoAP option OSCORE flags."; reference "RFC 8824 Static Context Header Compression (SCHC) for the Constrained Application Protocol (CoAP) (see Section 6.4)"; } identity fid-coap-option-oscore-kidctx { base fid-coap-option; description "CoAP option OSCORE flags."; reference "RFC 8824 Static Context Header Compression (SCHC) for the Constrained Application Protocol (CoAP)(see Section 6.4)"; } identity fl-base-type { description "Used to extend Field Length functions."; } identity fl-variable { base fl-base-type; description "Residue length in bytes is sent as defined for CoAP."; reference "RFC 8824 Static Context Header Compression (SCHC) for the Constrained Application Protocol (CoAP) (see Section 5.3)"; } identity fl-token-length { base fl-base-type; description "Residue length in bytes is sent as defined for CoAP."; reference "RFC 8824 Static Context Header Compression (SCHC) for the Constrained Application Protocol (CoAP) (see Section 4.5)"; } identity di-base-type { description "Used to extend Direction Indicators."; } identity di-bidirectional { base di-base-type; description "Direction Indicator of bidirectionality."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.1)"; } identity di-up { base di-base-type; description "Direction Indicator of uplink."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.1)"; } identity di-down { base di-base-type; description "Direction Indicator of downlink."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.1)"; } identity mo-base-type { description "Matching Operator: used in the Rule selection process to check if a Target Value matches the field's value."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.2)"; } identity mo-equal { base mo-base-type; description "equal MO."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.3)"; } identity mo-ignore { base mo-base-type; description "ignore MO."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.3)"; } identity mo-msb { base mo-base-type; description "MSB MO."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.3)"; } identity mo-match-mapping { base mo-base-type; description "match-mapping MO."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.3)"; } identity cda-base-type { description "Compression Decompression Actions. Specify the action to be applied to the field's value in a specific Rule."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.2)"; } identity cda-not-sent { base cda-base-type; description "not-sent CDA."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } identity cda-value-sent { base cda-base-type; description "value-sent CDA."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } identity cda-lsb { base cda-base-type; description "Least Significant Bit (LSB) CDA."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } identity cda-mapping-sent { base cda-base-type; description "mapping-sent CDA."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } identity cda-compute { base cda-base-type; description "compute-* CDA."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } identity cda-deviid { base cda-base-type; description "DevIID CDA."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } identity cda-appiid { base cda-base-type; description "Application Interface Identifier (AppIID) CDA."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } typedef fid-type { type identityref { base fid-base-type; } description "Field ID generic type."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } typedef fl-type { type identityref { base fl-base-type; } description "Function used to indicate Field Length."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } typedef di-type { type identityref { base di-base-type; } description "Direction in LPWAN network: up when emitted by the device, down when received by the device, or bi when emitted or received by the device."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } typedef mo-type { type identityref { base mo-base-type; } description "Matching Operator (MO) to compare field values with Target Values."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } typedef cda-type { type identityref { base cda-base-type; } description "Compression Decompression Action to compress or decompress a field."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } identity fragmentation-mode-base-type { description "Define the fragmentation mode."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } identity fragmentation-mode-no-ack { base fragmentation-mode-base-type; description "No-ACK mode."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } identity fragmentation-mode-ack-always { base fragmentation-mode-base-type; description "ACK-Always mode."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } identity fragmentation-mode-ack-on-error { base fragmentation-mode-base-type; description "ACK-on-Error mode."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } typedef fragmentation-mode-type { type identityref { base fragmentation-mode-base-type; } description "Define the type used for fragmentation mode in Rules."; } identity ack-behavior-base-type { description "Define when to send an Acknowledgment."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } identity ack-behavior-after-all-0 { base ack-behavior-base-type; description "Fragmentation expects ACK after sending All-0 fragment."; } identity ack-behavior-after-all-1 { base ack-behavior-base-type; description "Fragmentation expects ACK after sending All-1 fragment."; } identity ack-behavior-by-layer2 { base ack-behavior-base-type; description "Layer 2 defines when to send an ACK."; } typedef ack-behavior-type { type identityref { base ack-behavior-base-type; } description "Define the type used for ACK behavior in Rules."; } identity all-1-data-base-type { description "Type to define when to send an Acknowledgment message."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } identity all-1-data-no { base all-1-data-base-type; description "All-1 contains no tiles."; } identity all-1-data-yes { base all-1-data-base-type; description "All-1 MUST contain a tile."; } identity all-1-data-sender-choice { base all-1-data-base-type; description "Fragmentation process chooses to send tiles or not in All-1."; } typedef all-1-data-type { type identityref { base all-1-data-base-type; } description "Define the type used for All-1 format in Rules."; } identity rcs-algorithm-base-type { description "Identify which algorithm is used to compute RCS. The algorithm also defines the size of the RCS field."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } identity rcs-crc32 { base rcs-algorithm-base-type; description "CRC32 defined as default RCS in RFC 8724. This RCS is 4 bytes long."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; } typedef rcs-algorithm-type { type identityref { base rcs-algorithm-base-type; } description "Define the type for RCS algorithm in Rules."; } grouping tv-struct { description "Defines the Target Value element. If the header field contains a text, the binary sequence uses the same encoding. field-id allows the conversion to the appropriate type."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; leaf index { type uint16; description "Index gives the position in the matching list. If only one element is present, index is 0. Otherwise, index is the order in the matching list, starting at 0."; } leaf value { type binary; description "Target Value content as an untyped binary value."; } } // grouping tv-struct grouping compression-rule-entry { description "These entries define a compression entry (i.e., a line), as defined in RFC 8724. +-------+--+--+--+------------+-----------------+---------------+ |Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act| +-------+--+--+--+------------+-----------------+---------------+ An entry in a compression Rule is composed of 7 elements: - Field ID: the header field to be compressed - Field Length : either a positive integer or a function - Field Position: a positive (and possibly equal to 0) integer - Direction Indicator: an indication in which direction the compression and decompression process is effective - Target Value: a value against which the header field is compared - Matching Operator: the comparison operation and optional associate parameters - Comp./Decomp. Action: the compression or decompression action and optional parameters "; leaf field-id { type fid-type; mandatory true; description "Field ID, identify a field in the header with a YANG identity reference."; } leaf field-length { type union { type uint8; type fl-type; } mandatory true; description "Field Length, expressed in number of bits if the length is known when the Rule is created or through a specific function if the length is variable."; } leaf field-position { type uint8; mandatory true; description "Field Position in the header is an integer. Position 1 matches the first occurrence of a field in the header, while incremented position values match subsequent occurrences. Position 0 means that this entry matches a field irrespective of its position of occurrence in the header. Be aware that the decompressed header may have position-0 fields ordered differently than they appeared in the original packet."; } leaf direction-indicator { type di-type; mandatory true; description "Direction Indicator, indicate if this field must be considered for Rule selection or ignored based on the direction (bidirectional, only uplink, or only downlink)."; } list target-value { key "index"; description "A list of values to compare with the header field value. If Target Value is a singleton, position must be 0. For use as a matching list for the mo-match-mapping Matching Operator, index should take consecutive values starting from 0."; uses tv-struct; } // list target-value leaf matching-operator { type mo-type; must "../target-value or derived-from-or-self(., 'mo-ignore')" { error-message "mo-equal, mo-msb, and mo-match-mapping need target-value"; description "target-value is not required for mo-ignore."; } must "not (derived-from-or-self(., 'mo-msb')) or ../matching-operator-value" { error-message "mo-msb requires length value"; } mandatory true; description "MO: Matching Operator."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.3)"; } list matching-operator-value { key "index"; description "Matching Operator Arguments, based on TV structure to allow several arguments. In RFC 8724, only the MSB Matching Operator needs arguments (a single argument, which is the number of most significant bits to be matched)."; uses tv-struct; } // list matching-operator-value leaf comp-decomp-action { type cda-type; must "../target-value or derived-from-or-self(., 'cda-value-sent') or derived-from-or-self(., 'cda-compute') or derived-from-or-self(., 'cda-appiid') or derived-from-or-self(., 'cda-deviid')" { error-message "cda-not-sent, cda-lsb, and cda-mapping-sent need target-value"; description "target-value is not required for some CDA."; } mandatory true; description "CDA: Compression Decompression Action."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 7.4)"; } list comp-decomp-action-value { key "index"; description "CDA arguments, based on a TV structure, in order to allow for several arguments. The CDAs specified in RFC 8724 require no argument."; uses tv-struct; } // list comp-decomp-action-value } // grouping compression-rule-entry identity nature-base-type { description "A Rule, identified by its RuleID, is used for a single purpose. RFC 8724 defines 3 natures: compression, no-compression, and fragmentation."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 6)"; } identity nature-compression { base nature-base-type; description "Identify a compression Rule."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 6)"; } identity nature-no-compression { base nature-base-type; description "Identify a no-compression Rule."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 6)"; } identity nature-fragmentation { base nature-base-type; description "Identify a fragmentation Rule."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation (see Section 6)"; } typedef nature-type { type identityref { base nature-base-type; } description "Defines the type to indicate the nature of the Rule."; } grouping compression-content { description "Define a compression Rule composed of a list of entries."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; list entry { must "derived-from-or-self(../rule-nature, 'nature-compression')" { error-message "Rule nature must be compression"; } key "field-id field-position direction-indicator"; description "A compression Rule is a list of Rule entries, each describing a header field. An entry is identified through a field-id, its position in the packet, and its direction."; uses compression-rule-entry; } // list entry } // grouping compression-content grouping fragmentation-content { description "This grouping defines the fragmentation parameters for all the modes (No ACK, ACK Always, and ACK on Error) specified in RFC 8724."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; leaf fragmentation-mode { type fragmentation-mode-type; must "derived-from-or-self(../rule-nature, 'nature-fragmentation')" { error-message "Rule nature must be fragmentation"; } mandatory true; description "Which fragmentation mode is used (No ACK, ACK Always, or ACK on Error)."; } leaf l2-word-size { type uint8; default "8"; description "Size, in bits, of the Layer 2 Word."; } leaf direction { type di-type; must "derived-from-or-self(., 'di-up') or derived-from-or-self(., 'di-down')" { error-message "Direction for fragmentation Rules are up or down."; } mandatory true; description "MUST be up or down, bidirectional MUST NOT be used."; } leaf dtag-size { type uint8; default "0"; description "Size, in bits, of the DTag field (T variable from RFC 8724)."; } leaf w-size { when "derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-on-error') or derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-always') "; type uint8; description "Size, in bits, of the window field (M variable from RFC 8724)."; } leaf fcn-size { type uint8; mandatory true; description "Size, in bits, of the FCN field (N variable from RFC 8724)."; } leaf rcs-algorithm { type rcs-algorithm-type; default "schc:rcs-crc32"; description "Algorithm used for RCS. The algorithm specifies the RCS size."; } leaf maximum-packet-size { type uint16; default "1280"; description "When decompression is done, packet size must not strictly exceed this limit, expressed in bytes."; } leaf window-size { type uint16; description "By default, if not specified, the FCN value is 2^w-size - 1. This value should not be exceeded. Possible FCN values are between 0 and window-size - 1."; } leaf max-interleaved-frames { type uint8; default "1"; description "Maximum of simultaneously fragmented frames. Maximum value is 2^dtag-size. All DTag values can be used, but more than max-interleaved-frames MUST NOT be active at any time."; } container inactivity-timer { description "Duration in seconds of the Inactivity Timer; 0 indicates that the timer is disabled. Allows a precision from microsecond to year by sending the tick-duration value. For instance: tick-duration: smallest value <-> highest value 20: 00y 000d 00h 00m 01s.048575<->00y 000d 19h 05m 18s.428159 21: 00y 000d 00h 00m 02s.097151<->00y 001d 14h 10m 36s.856319 22: 00y 000d 00h 00m 04s.194303<->00y 003d 04h 21m 13s.712639 23: 00y 000d 00h 00m 08s.388607<->00y 006d 08h 42m 27s.425279 24: 00y 000d 00h 00m 16s.777215<->00y 012d 17h 24m 54s.850559 25: 00y 000d 00h 00m 33s.554431<->00y 025d 10h 49m 49s.701119 Note that the smallest value is also the incrementation step."; leaf ticks-duration { type uint8; default "20"; description "Duration of one tick in microseconds: 2^ticks-duration/10^6 = 1.048s."; } leaf ticks-numbers { type uint16 { range "0..max"; } description "Timer duration = ticks-numbers*2^ticks-duration / 10^6."; } } // container inactivity-timer container retransmission-timer { when "derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-on-error') or derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-always') "; description "Duration in seconds of the Retransmission Timer. See the Inactivity Timer."; leaf ticks-duration { type uint8; default "20"; description "Duration of one tick in microseconds: 2^ticks-duration/10^6 = 1.048s."; } leaf ticks-numbers { type uint16 { range "1..max"; } description "Timer duration = ticks-numbers*2^ticks-duration / 10^6."; } } // container retransmission-timer leaf max-ack-requests { when "derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-on-error') or derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-always') "; type uint8 { range "1..max"; } description "The maximum number of retries for a specific SCHC ACK."; } choice mode { description "RFC 8724 defines 3 fragmentation modes."; case no-ack; case ack-always; case ack-on-error { leaf tile-size { when "derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-on-error')"; type uint8; description "Size, in bits, of tiles. If not specified or set to 0, tiles fill the fragment."; } leaf tile-in-all-1 { when "derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-on-error')"; type all-1-data-type; description "Defines whether the sender and receiver expect a tile in All-1 fragments or not, or if it is left to the sender's choice."; } leaf ack-behavior { when "derived-from-or-self(../fragmentation-mode, 'fragmentation-mode-ack-on-error')"; type ack-behavior-type; description "Sender behavior to acknowledge, after All-0 or All-1 or when the LPWAN allows it."; } } // case ack-on-error } // choice mode } // grouping fragmentation-content grouping rule-id-type { description "A RuleID is composed of a value and a length, expressed in bits."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; leaf rule-id-value { type uint32; description "RuleID value. This value must be unique, considering its length."; } leaf rule-id-length { type uint8 { range "0..32"; } description "RuleID length, in bits. The value 0 is for implicit Rules."; } } // grouping rule-id-type container schc { description "A SCHC set of Rules is composed of a list of Rules that are used for compression, no-compression, or fragmentation."; reference "RFC 8724 SCHC: Generic Framework for Static Context Header Compression and Fragmentation"; list rule { key "rule-id-value rule-id-length"; description "Set of compression, no-compression, or fragmentation Rules identified by their rule-id."; uses rule-id-type; leaf rule-nature { type nature-type; mandatory true; description "Specify the Rule's nature."; } choice nature { description "A Rule is for compression, for no-compression, or for fragmentation."; case fragmentation { if-feature fragmentation; uses fragmentation-content; } // case fragmentation case compression { if-feature compression; uses compression-content; } // case compression } // choice nature } // list rule } // container schc } // module ietf-schc
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