Requested revision
Standard: | IEEE 802.1CB | Clause: | 9.1 |
Clause title: | Stream identity table |
Rationale for revision
Clause 9.1 states that is possible that different entries in this table with 1) identical stream identification functions (e.g., Null stream identification with identical values for NullDownDestMac, NullDownTagged and NullDown Vlan), and 2) different values for tsnStreamIdHandle have the same port in their respective OutFacInput port list. According to clause 9.1.1.5, there is no restriction on the number of entries which can list the same port for the OutFacInput port list: "Any number of tsnStreamIdEntry objects can list the same port for the same tsnStreamIdHandle in its tsnStreamIdOutFacInputPortList." In order to cover this case, a rule for the order of precedence needs to be established.
Proposed text
Add a rule for the order of precedence inspired by PSFPs (IEEE 802.1Qci) Stream Filter Instance Table. Add the following paragraphs at the end of clause 9.1: "The table forms an ordered list of tsnStreamIdEntry objects, the order being determined by the tsnStreamIdInstance parameter. Rows in the table can be created or removed dynamically in implementations that support dynamic configuration of tsnStreamIdEntry objects. NOTE: In case more than one tsnStreamIdEntry with identical stream identifications exist, potentially with different tsnStreamIdHandles and mutually inclusive ports listed in the same port list, the tsnStreamIdHandle given by the tsnStreamIdEntry with the lower tsnStreamIdInstance shall take precedence over the others. Hence entries with a lower tsnStreamIdInstance may override settings with a higher tsnStreamIdInstance in that sense, that they effectively disable the assignment of the higher tsnStreamIdInstance entry's tsnStreamIdHandle on a certain port." Add the following subclause before clause 9.1.1.1 (renumber as appropriate): "9.1.1.1 tsnStreamIdInstance An integer value that uniquely identifies a tsnStreamIdEntry object in the Stream identity table, and acts as an index to the table. The ordering of the identifier values defines the ordering of the list of tsnStreamIdEntry objects; smaller identifier values appear earlier in the ordered list."
Impact on existing networks
None. Existing network networks could not have utilized this feature due
to undefined behavior of the implementation in stated cases.
Originator
Name: | Marina Gutierrez | Email: | marina.gutierrez@tttech.com<mailto:marina.gutierrez@tttech.com> |
Affiliation: | TTTech Computertechnik AG | ||
Submitted: | 2021-04-12 |