Document
conventions
Conformance
requirements
are
expressed
with
a
combination
of
descriptive
assertions
and
RFC
2119
terminology.
The
key
words
“MUST”,
“MUST
NOT”,
“REQUIRED”,
“SHALL”,
“SHALL
NOT”,
“SHOULD”,
“SHOULD
NOT”,
“RECOMMENDED”,
“MAY”,
and
“OPTIONAL”
in
the
normative
parts
of
this
document
are
to
be
interpreted
as
described
in
RFC
2119.
However,
for
readability,
these
words
do
not
appear
in
all
uppercase
letters
in
this
specification.
All
of
the
text
of
this
specification
is
normative
except
sections
explicitly
marked
as
non-normative,
examples,
and
notes.
[RFC2119]
Examples
in
this
specification
are
introduced
with
the
words
“for
example”
or
are
set
apart
from
the
normative
text
with
class="example"
,
like
this:
This
is
an
example
of
an
informative
example.
Informative
notes
begin
with
the
word
“Note”
and
are
set
apart
from
the
normative
text
with
class="note"
,
like
this:
Note,
this
is
an
informative
note.
Tests
Tests
relating
to
the
content
of
this
specification
may
be
documented
in
“Tests”
blocks
like
this
one.
Any
such
block
is
non-normative.