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AM263P4-Q1: Details on 802.1CB-like support in CPSW

Sung-IL
Mastermind 30860 points
Part Number: AM263P4-Q1

Tool/software:

Dear Champs,

In Ether-Ring example in MCU+SDK 10.1, I could not find any details how 802.1CB-like implemented in AM263Px.

Could you please let me know how 802.1CB-like is implemented in AM263Px in Ether-Ring example of MCU+SDK 10.1 and why 802.1CB-'like'? e.g. what is difference between 802.1CB and 802.1CB-'like'?

Thanks and Best Regards,

SI.

  • +1
    TI__Genius 16432 points

    Hi Sung-IL,

    The source code for the Ether-ring 802.1CB-like is present in the following path: mcu_plus_sdk\source\networking\enet\core\ether_ring\

    The "like" keyword here is used for two reasons:

    1. We don't implement the complete feature-set which 802.1CB talks about.

    2. We leverage both HW and SW for frame replication and elimination, but the actual implementation is not completely the way the IEEE standard defines it. We do it in a different way (for e.g. we don't perform the replication and elimination on all streams). 

    That is why the key-word "like" is used here and not the exact 802.1CB. 

    You can also refer the video here on Ether-ring demo: https://www.ti.com/video/6371560856112

    Regards,
    Shaunak

  • 0 in reply to Shaunak Deshpande
    TI__Mastermind 30860 points

    Hi Shaunak,

    Thanks for your response.

    I'm checking the sample output of Ether-Ring example in MCU+SDK 10.1 as below. What is the meaning of below RXTS values? where Current Ts Values?

    https://software-dl.ti.com/mcu-plus-sdk/esd/AM263PX/10_01_00_31/exports/docs/api_guide_am263px/EXAMPLES_ENET_CPSW_ETHERRING.html 

    ~~~~~~~

    Base time=20000000000ns,Cycle time=1000000ns
    Set admin control list succesfully
    INF:uconf:get_queue_map_params:netdev=tilld1, num_tc=8
    INF:cbase:TAS state is set to 2
    INF:cbase:TAS operational list status updated:
    INF:cbase:TAS state is set to 1
    INF:cbase:Successfully configure TAS
    WRN:gptp:000018-746101:md_pdelay_resp_sm_recv_req: port=2, expected SeqID=10723, but received=10724
    Starting the Stream Traffic
    RxTs and CurrentTs values stored
    [RXTS]: 29954385101
    [RXTS]: 29954510117
    [RXTS]: 29954635123
    [RXTS]: 29954760134
    [RXTS]: 29954885145
    [RXTS]: 29955010066
    [RXTS]: 29955135082
    [RXTS]: 29955260083
    [RXTS]: 29955385094
    [RXTS]: 29955510120
    [RXTS]: 29955635121
    [RXTS]: 29955760127
    [RXTS]: 29955885143
    [RXTS]: 29956010069
    [RXTS]: 29956135075
    [RXTS]: 29956260086
    [RXTS]: 29956385097
    [RXTS]: 29956510113
    [RXTS]: 29956635119
    [RXTS]: 29956760130
    [RXTS]: 29956885126
    [RXTS]: 29957010072
    [RXTS]: 29957135078
    ----------ETHERRING DEMONSTRATION COMPLETED----------

    Thanks and Best Regards,

    SI.

  • +1 in reply to Sung-IL
    TI__Prodigy 100 points

    Hi Sung-IL,

    In Ether-ring Application, Each node(LP-AM263Px) creates and sends ethernet packet to next node periodically. And Each node can be configured to send both Real-time traffic(125us periodicity) and Back-ground traffic(1ms) to the next node. While creating ethernet packet, the current timestamp value(Current Ts) is stored as part of payload. Once ethernet packet is received to the destination node, the Receive timestamp(RxTs) is stored per each packet and the CurrentTs which is embedded in payload is also retrieved from packet.

    RxTs and CurrentTs printed on destination node is used to calculated Latency and Jitter. Latency value gives the time taken by packet from Transmitter to Receiver. And Jitter shows the system's deterministic behaviour. Latency and Jitter has to calculated manually by using the RxTs and CurrentTs prints.

    Latency and Jitter Calculations:
    Latency[N] = RxTs[N] - CurrentTs[N]
    Jitter[N] = RxTs[N] - RxTs[N-1]

    In Ether-Ring application, CurrentTs values are not printed in 10.01 release. This will be fixed in the AM263px next release (10.02).

    Regards,
    Ranga Rakesh

  • 0 in reply to Ranga Rakesh Jonnalagadda
    TI__Mastermind 30860 points

    Hi Shaunak,

    I have question for TSN 802.1 CB like of AM263Px.

    Is there any compatibility in packet between TSN802.1 CB and TSN802.1 CB-like?

    e.g. Can TSN 802.1CB like of AM263Px work with TSN Switch supporting TSN 802.1 CB?

    Thanks and Best Regards,

    SI.

  • +1 in reply to Sung-IL
    TI__Prodigy 100 points

    Hi Sung-IL,

    Ether-Ring implementation is completely different compared to 802.1CB and it has nothing to do with 802.1CB. It is a TI custom protocol which is implemented by using CPSW hardware features and software assistance for adding "Custom Header" at the start of packet payload.
       Ether-Ring feature supports hardware "Packet Duplication", "Ring Termination" and software "Duplicate Packet Rejection". Ether-Ring is not compatible with TSN Switch supporting TSN 802.1 CB.

    Regards,
    Ranga Rakesh