1. Maintenance Items
  2. 0267
  3. Request
Requested revision
Standard:802.1Q-2018Clause:12.31.3 & 17.2.24 & 17.7.24
Clause title:The Stream Gate Instance Table
Rationale for revision
The parameter AdminCycleTime as well as the interval encapsulated in the
GateControlEntry cover a very large range. Especially according to the
MIB definition (clause 17.7.24), the ranges are (theoretically) as following:

AdminCycleTime: 1/2^32 s (approx. 0.2 ns) - 2^32/1 s (approx. 136 years)
Interval:       1 ns - approx. 4.2 sec

While the lower bound of the respective range is the next integer multiple of
parameter tickGranularity, the upper bound may be impractical for concrete
implementations. Certain domains may only require intervals and cycle times
in the milliseconds range.

However, by definition there is no restriction on the mentioned parameters,
so implementations may be forced to reject (according to the standard) legal
configurations without means to report the reason and or means to expose
their characteristics/limitations beforehand.

Therefore, the characteristics of an implementation shall be exposed similarly
as it is done for scheduled traffic in the Gate Parameters Table (clause 12.29.1,
managed objects added in P802.1Qcw as a result of maintenance item 0211).
Proposed text
The suggestion is to introduce two additional parameters declaring
characteristics of the implementation, i.e.,

Name                   Data Type        Operations    Conformance
                                        Supported
-----------------------------------------------------------------
SupportedCycleMax      RationalNumber       R             BE
SupportedIntervalMax   Integer              R             BE
-----------------------------------------------------------------


where both characteristics shall use the same semantics as the respectively
described parameter, i.e.,
-) SupportedCycleMax a rational number in seconds
-) SupportedIntervalMax a timeIntervalValue

Exposing these parameters support discovery of further characteristics and
enable the creation of lightweight implementations for certain application
domains.

Consequently also the Management Information Base definitions (clause 17.7.24), as
well as the upcoming YANG definitions (P802.1Qcw) shall reflect these
parameters.
Impact on existing networks
None. Existing networks might or might not be checking those max values anyway. This change just allows applications to see the limitations of the implementation and act accordingly.
Originator
Name:Marina GutierrezEmail:marina.gutierrez@tttech.com
Affiliation:TTTech Computertechnik AG
Submitted:2020-06-02