Visible to Intel only — GUID: mnm1481130304126
Ixiasoft
Visible to Intel only — GUID: mnm1481130304126
Ixiasoft
17.6.5.2.3. End-to-End Transparent Clock
The end-to-end transparent clock supports the end-to-end delay measurement mechanism between slave clocks and the master clock. The end-to-end transparent clock forwards all messages like normal bridge, router, or repeater. The residence time of a PTP packet is the time taken by the PTP packet from the ingress port to the egress port.†
The residence time of a SYNC packet inside the end-to-end transparent clock is updated in the correction field of the associated Follow_Up PTP packet before it is transmitted. Similarly, the residence time of a Delay_Req packet inside the end-to-end transparent clock is updated in the correction field of the associated Delay_Resp PTP packet before it is transmitted. Therefore, the snapshot needs to be taken at both ingress and egress ports only for PTP messages SYNC or Delay_req. You can take the snapshot by setting the snapshot select bits (SNAPTYPSEL) to b'10 in the Timestamp Control (gmacgrp_timestamp_control) register.†
The snaptypsel bits, along with bits 15 and 14 in the Timestamp Control register, decide the set of PTP packet types for which a snapshot needs to be taken. The encoding is shown in the table below:†
snaptypsel (bits[17:16]) | tsmstrena (bit 15) | tsevntena (bit 14) | PTP Messages |
---|---|---|---|
0x0 | X | 0 | SYNC, Follow_Up, Delay_Req, Delay_Resp |
0x0 | 0 | 1 | SYNC |
0x0 | 1 | 1 | Delay_Req |
0x1 | X | 0 | SYNC, Follow_Up, Delay_Req, Delay_Resp, Pdelay_Req, Pdelay_Resp, Pdelay_Resp_Follow_Up |
0x1 | 0 | 1 | SYNC, Pdelay_Req, Pdelay_Resp |
0x1 | 1 | 1 | Delay_Req, Pdelay_Req, Pdelay_Resp |
0x2 | X | X | SYNC, Delay_Req |
0x3 | X | X | Pdelay_Req, Pdelay_Resp |