1. Maintenance Items
  2. 0315
  3. Request
Requested revision
Standard:IEEE 802.1CBClause:6.2
Clause title:Stream identification function
Rationale for revision
Clause 6.2, item a.2 states that frames that are not identified by a
stream identification function shall get the "null value" assigned for
the stream_handle. But "null value" is never defined.

Different implementations could defined "null value" differently thus
resulting in the impossibility to use this stream_handle for other
mechanisms like PSFP.
Proposed text
Define "null value" as the numerical value 0.

Append the following paragraph at the end of Sect. 6.2:
"The null-value, i.e., the stream_handle assigned to packets that belong
to no known stream, is 0."

Append the following note at the end of Sect. 9.1.1.1 tsnStreamIdHandle:
"NOTE - It is also possible to assign a packet that was identified as
belonging to a known stream (i.e., a specific tsnStreamIdEntry) a stream
handle equal 0, i.e., the null-value."
Impact on existing networks
Current implementations that define "null value" as something different than the numerical value 0 would be non-conformant.
Originator
Name:Marina GutierrezEmail:marina.gutierrez@tttech.com<mailto:marina.gutierrez@tttech.com>
Affiliation:TTTech Computertechnik AG
Submitted:2021-04-12