US 12,587,484 B2 · Packet ordering function for TSN/DetNet networks

Abstract

A PDU ordering function (POF) restores the proper order of PDUs in a stream, at the Layer-2 or 3 level of a TSN or DetNet. The sequence number of the last PDU forwarded is stored, and compared to the sequence number of a newly received PDU. If the new PDU is an earlier or the “next” PDU in the stream, it is forwarded and the value of the last PDU forwarded is updated. If the newly received PDU is two or more sequence numbers ahead of the last PDU forwarded, it is buffered. Other PDUs are received and processed, and the value of the last PDU forwarded is updated. When the buffered PDU is the next one to the last PDU forwarded, it is retrieved from the buffer and forwarded. To bound the total latency the POF can impose on aPDU stream, a predetermined maximum buffering time timer is started upon buffering the PDU. If the timer expires before the buffered PDU becomes “next” to the last PDU forwarded, it is nevertheless retrieved and forwarded.

Claims20

Dependent claims

A method of receiving Protocol Data Units (PDU) in a network stream of PDUs and forwarding the PDUs in a predetermined order, wherein each PDU includes a sequence number, comprising:

storing a sequence number of a last PDU forwarded;
receiving a first PDU;
comparing a sequence number of the first PDU to the sequence number of the last PDU forwarded;
in response to the sequence number of the first PDU being two or more greater than the sequence number of the last PDU forwarded, storing the first PDU until the earlier of a predetermined buffering time expires and the sequence number of the first PDU being equal to one greater than the sequence number of the last PDU forwarded;
in response to the sequence number of the first PDU being less than or equal to one greater than the sequence number of the last PDU forwarded, forwarding the first PDU;
updating the sequence number of the last PDU forwarded to be the sequence number of the first PDU;
and
initializing the sequence number of the last PDU forwarded to the sequence number of a received PDU, and forwarding the received PDU, when PDU ordering is reset;
and
initializing the sequence number of the last PDU forwarded to the sequence number of a received PDU, and forwarding the received PDU, in response to no PDU being received for a predetermined duration.

7 more elements

A network node implementing a Protocol Data Unit (PDU) Ordering Function (POF) operative to receive PDUs in a network stream of PDUs and forward the PDUs in a predetermined order, wherein each PDU includes a sequence number, the network node comprising:

communication circuitry configured to receive PDUs from, and transmit PDUs to, other network nodes;
and
processing circuitry operatively connected to the communication circuitry and configured to
store a sequence number of a last PDU forwarded;
receive a first PDU;
compare a sequence number of the first PDU to the sequence number of the last PDU forwarded;
in response to the sequence number of the first PDU being two or more greater than the sequence number of the last PDU forwarded, store the first PDU until the earlier of a predetermined maximum storage time expires and the sequence number of the first PDU being equal to one greater than the sequence number of the last PDU forwarded;
in response to the sequence number of the first PDU being less than or equal to one greater than the sequence number of the last PDU forwarded, forward the first PDU;
update the sequence number of the last PDU forwarded to be the sequence number of the first PDU;
and
initialize the sequence number of the last PDU forwarded to the sequence number of a received PDU, and forward the received PDU, when PDU ordering is reset;
and
initialize the sequence number of the last PDU forwarded to the sequence number of a received PDU, and forward the received PDU, in response to no PDU being received for a predetermined duration.

10 more elements

Dependencies are inferred from the claim text.

Packet ordering function for TSN/DetNet networks

Life of this patent

Packet ordering function for TSN/DetNet networks

Life of this patent

Abstract

Claims20