5.6 Application payload syntax
5.6.1 Introduction
Application payload message encoding using both XML (W3C XML) and EXI (W3C EXI) SHALL be supported by all servers. Application payload message encoding using either XML (W3C XML) or EXI (W3C EXI) SHALL be supported by all clients. Certain function sets may require additional encodings and, if so, are specified in their respective sections.
5.6.2 XML encoding
The XML declaration is optional as per W3C XML and SHOULD NOT be included in IEEE 2030.5 transactions, to reduce packet sizes. The XML version used SHALL be 1.0. For XML payloads, the encoding SHALL be UTF-8.
5.6.3 EXI encoding
The options for encoding EXI documents SHALL be as follows, and transactions will likely fail if different options are declared in the EXI option header. Options marked as (default) are EXI specification (W3C EXI) defaults and SHOULD NOT be specified explicitly.
Non-strict schema-informed grammar with the schema (IEEE Std 2030.5 supplemental material)
Alignment is bit-packed (default)
Compression is false (default)
Strict is false (default)
Fragment is false (default)
Preserve options are all false (default)
selfContained is false (default)
schemaId is “S1” (two bytes: 0x53, 0x31, without quotes). This schemaId corresponds to the normative schema of IEEE Std 2030.5-2018 (supplemental material).
datatypeRepresentationMap is not used (default)
valueMaxLength is unbounded (default)
valuePartitionCapacity is unbounded (default)
No user defined meta-data
The following XML document describes the EXI option header that SHALL be used to encode the messages:
<header xmlns="http://www.w3.org/2009/exi">
<common><schemaId>S1</schemaId></common>
</header>